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Separation of presentation and business logic in PHP

- by Markus Ossi

I am programming my first real PHP website and am wondering how to make my code more readable to myself. The reference book I am using is PHP and MySQL Web Development 4th ed. The aforementioned book gives three approaches to separating logic and content: include files function or class API template system I haven't chosen any of these yet, as wrapping my brains around these concepts is taking some time. However, my code has become some hybrid of the first two as I am just copy-pasting away here and modifying as I go. On presentation side, all of my pages have these common elements: header, top navigation, sidebar navigation, content, right sidebar and footer. The function-based examples in the book suggest that I could have these display functions that handle all the presentation example. So, my page code will be like this: display_header(); display_navigation(); display_content(); display_footer(); However, I don't like this because the examples in the book have these print statements with HTML and PHP mixed up like this: echo "<tr bgcolor=\"".$color."\"><td><a href=\"".$url."\">" ... I would rather like to have HTML with some PHP in the middle, not the other way round. I am thinking of making my pages so that at the beginning of my page, I will fetch all the data from database and put it in arrays. I will also get the data for variables. If there are any errors in any of these processes, I will put them into error strings. Then, at the HTML code, I will loop through these arrays using foreach and display the content. In some cases, there will be some variables that will be shown. If there is an error variable that is set, I will display that at the proper position. (As a side note: The thing I do not understand is that in most example code, if some database query or whatnot gives an error, there is always: else echo 'Error'; This baffles me, because when the example code gives an error, it is sometimes echoed out even before the HTML has started...) For people who have used ASP.NET, I have gotten somewhat used to the code-behind files and lblError and I am trying to do something similar here. The thing I haven't figured out is how could I do this "do logic first, then presentation" thing so that I would not have to replicate for example the navigation logic and navigation presentation in all of the pages. Should I do some include files or could I use functions here but a little bit differently? Are there any good articles where these "styles" of separating presentation and logic are explained a little bit more thoroughly. The book I have only has one paragraph about this stuff. What I am thinking is that I am talking about some concepts or ways of doing PHP programming here, but I just don't know the terms for them yet. I know this isn't a straight forward question, I just need some help in organizing my thoughts.

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JavaScript date suffix formatting

- by TexasB

I have done my due diligence in investigating this and not had any success yet. Being rather green with JavaScript I am seeking some help. I am wanting to display the date NOV2012<br> 2<sup>nd</sup><br> 5:00 PM I have everything working (not my script) except being able to get the date suffix to change to st, nd, rd, or th as the case may be. This is what I have: <pre> <abbr title="Month"> <script type="text/javascript"> var d=new Date(); var month=new Array(12); month[0]="Jan"; month[1]="Feb"; month[2]="Mar"; month[3]="Apr"; month[4]="May"; month[5]="Jun"; month[6]="Jul"; month[7]="Aug"; month[8]="Sep"; month[9]="Oct"; month[10]="Nov"; month[11]="Dec"; document.write(month[d.getMonth()]); </script></abbr> <script type="text/javascript"> var d = new Date() document.write(d.getDate()) ordinal : function (number) { var d = number % 10; return (~~ (number % 100 / 10) === 1) ? 'th' : (d === 1) ? 'st' : (d === 2) ? 'nd' : (d === 3) ? 'rd' : 'th'; } }); </script> <sup>%</sup> <abbr><script type="text/javascript"> var d = new Date() document.write(d.getFullYear()) </script></abbr> <sub> <script type="text/javascript">  </script> </sub> </pre> I know the issue is with this part: <pre> <script type="text/javascript"> var d = new Date() document.write(d.getDate()) ordinal : function (number) { var d = number % 10; return (~~ (number % 100 / 10) === 1) ? 'th' : (d === 1) ? 'st' : (d === 2) ? 'nd' : (d === 3) ? 'rd' : 'th'; } }); </script> < sup > % < /sup > </pre> but I can't seem to work out the right fix. This is where it is sitting: http://www.bcreativeservices.com/ Thank you as always. B

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How can I keep my MVC Views, models, and model binders as clean as possible?

- by MBonig

I'm rather new to MVC and as I'm getting into the whole framework more and more I'm finding the modelbinders are becoming tough to maintain. Let me explain... I am writing a basic CRUD-over-database app. My domain models are going to be very rich. In an attempt to keep my controllers as thin as possible I've set it up so that on Create/Edit commands the parameter for the action is a richly populated instance of my domain model. To do this I've implemented a custom model binder. As a result, though, this custom model binder is very specific to the view and the model. I've decided to just override the DefaultModelBinder that ships with MVC 2. In the case where the field being bound to my model is just a textbox (or something as simple), I just delegate to the base method. However, when I'm working with a dropdown or something more complex (the UI dictates that date and time are separate data entry fields but for the model it is one Property), I have to perform some checks and some manual data munging. The end result of this is that I have some pretty tight ties between the View and Binder. I'm architecturally fine with this but from a code maintenance standpoint, it's a nightmare. For example, my model I'm binding here is of type Log (this is the object I will get as a parameter on my Action). The "ServiceStateTime" is a property on Log. The form values of "log.ServiceStartDate" and "log.ServiceStartTime" are totally arbitrary and come from two textboxes on the form (Html.TextBox("log.ServiceStartTime",...)) protected override object GetPropertyValue(ControllerContext controllerContext, ModelBindingContext bindingContext, PropertyDescriptor propertyDescriptor, IModelBinder propertyBinder) { if (propertyDescriptor.Name == "ServiceStartTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceStartDate").ConvertTo(typeof (string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceStartTime").ConvertTo(typeof (string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } if (propertyDescriptor.Name == "ServiceEndTime") { string date = bindingContext.ValueProvider.GetValue("log.ServiceEndDate").ConvertTo(typeof(string)) as string; string time = bindingContext.ValueProvider.GetValue("log.ServiceEndTime").ConvertTo(typeof(string)) as string; DateTime dateTime = DateTime.Parse(date + " " + time); return dateTime; } The Log.ServiceEndTime is a similar field. This doesn't feel very DRY to me. First, if I refactor the ServiceStartTime or ServiceEndTime into different field names, the text strings may get missed (although my refactoring tool of choice, R#, is pretty good at this sort of thing, it wouldn't cause a build-time failure and would only get caught by manual testing). Second, if I decided to arbitrarily change the descriptors "log.ServiceStartDate" and "log.ServiceStartTime", I would run into the same problem. To me, runtime silent errors are the worst kind of error out there. So, I see a couple of options to help here and would love to get some input from people who have come across some of these issues: Refactor any text strings in common between the view and model binders out into const strings attached to the ViewModel object I pass from controller to the aspx/ascx view. This pollutes the ViewModel object, though. Provide unit tests around all of the interactions. I'm a big proponent of unit tests and haven't started fleshing this option out but I've got a gut feeling that it won't save me from foot-shootings. If it matters, the Log and other entities in the system are persisted to the database using Fluent NHibernate. I really want to keep my controllers as thin as possible. So, any suggestions here are greatly welcomed! Thanks

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L2S DataContext out of synch: row not found or changed

- by awrigley

The Problem I am getting a number of errors that imply that the DataContext, or rather, the way I am using the DataContext is getting out of synch. The error occurs on db.SubmitChanges() where db is my DataContext instance. The error is: Row not found or changed. The problem only occurs intermitently, for example, adding a row then deleting it. If I stop the dev server and restart, the added row is there and I can delete it no problem. Ie, it seems that the problem is related to the DataContext losing track of the rows that have been added. IMPORTANT: Before anyone votes to close this thread, on the basis of it being a duplicate, I have checked the sql server profiler and there is no "Where 0 = 1" in the SQL. I have also recreated the dbml file, so am satisfied that the database schema is in synch with the schema represented by the dbml file. Ie, no cases of mismatched nullable/not nullable columns, etc. My Diagnosis (for what it is worth): It seems to be a problem related to how I am using the DataContext. I am new to MVC, Repositories and Services patterns, so suspect that I have wired things up wrong. The Setup Simple eLearning app in its early stages. Pupils need to be able to add and delete courses (Courses table) to their UserCourses. To do this, I have a service that gets a specific DataContext instance Dependency Injected into its constructor. Service Class Constructor: public class SqlPupilBlockService : IPupilBlockService { DataContext db; public SqlPupilBlockService(DataContext db) { this.db = db; CoursesRepository = new SqlRepository<Course>(db); UserCoursesRepository = new SqlRepository<UserCourse>(db); } // Etc, etc } The CoursesRepository and UserCoursesRepository are both private properties of the service class that are of Type IRepository (just a simple generic repository interface). Sql Respoitory Code: public class SqlRepository<T> : IRepository<T> where T : class { DataContext db; public SqlRepository(DataContext db) { this.db = db; } #region IRepository<T> Members public IQueryable<T> Query { get { return db.GetTable<T>(); } } public List<T> FetchAll() { return Query.ToList(); } public void Add(T entity) { db.GetTable<T>().InsertOnSubmit(entity); } public void Delete(T entity) { db.GetTable<T>().DeleteOnSubmit(entity); } public void Save() { db.SubmitChanges(); } #endregion } The two methods for adding and deleting UserCourses are: Service Methods for Adding and Deleting UserCourses: public void AddUserCourse(int courseId) { UserCourse uc = new UserCourse(); uc.IdCourse = courseId; uc.IdUser = UserId; uc.DateCreated = DateTime.Now; uc.DateAmended = DateTime.Now; uc.Role = "Pupil"; uc.CourseNotes = string.Empty; uc.ActiveStepIndex = 0; UserCoursesRepository.Add(uc); UserCoursesRepository.Save(); } public void DeleteUserCourse(int courseId) { var uc = (UserCoursesRepository.Query.Where(x => x.IdUser == UserId && x.IdCourse == courseId)).Single(); UserCoursesRepository.Delete(uc); UserCoursesRepository.Save(); } Ajax I am using Ajax via Ajax.BeginForm I don't think that is relevant. ASP.NET MVC 3 I am using mvc3, but don't think that is relevant: the errors are related to model code.

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(SQL) Selecting from a database based on multiple pairs of pairs

- by Owen Allen

The problem i've encountered is attempting to select rows from a database where 2 columns in that row align to specific pairs of data. IE selecting rows from data where id = 1 AND type = 'news'. Obviously, if it was 1 simple pair it would be easy, but the issue is we are selecting rows based on 100s of pair of data. I feel as if there must be some way to do this query without looping through the pairs and querying each individually. I'm hoping some SQL stackers can provide guidance. Here's a full code break down: Lets imagine that I have the following dataset where history_id is the primary key. I simplified the structure a bit regarding the dates for ease of reading. table: history history_id id type user_id date 1 1 news 1 5/1 2 1 news 1 5/1 3 1 photo 1 5/2 4 3 news 1 5/3 5 4 news 1 5/3 6 1 news 1 5/4 7 2 photo 1 5/4 8 2 photo 1 5/5 If the user wants to select rows from the database based on a date range we would take a subset of that data. SELECT history_id, id, type, user_id, date FROM history WHERE date BETWEEN '5/3' AND '5/5' Which returns the following dataset history_id id type user_id date 4 3 news 1 5/3 5 4 news 1 5/3 6 1 news 1 5/4 7 2 photo 1 5/4 8 2 photo 1 5/5 Now, using that subset of data I need to determine how many of those entries represent the first entry in the database for each type,id pairing. IE is row 4 the first time in the database that id: 3, type: news appears. So I use a with() min() query. In real code the two lists are programmatically generated from the result sets of our previous query, here I spelled them out for ease of reading. WITH previous AS ( SELECT history_id, id, type FROM history WHERE id IN (1,2,3,4) AND type IN ('news','photo') ) SELECT min(history_id) as history_id, id, type FROM previous GROUP BY id, type Which returns the following data set. history_id id type user_id date 1 1 news 1 5/1 2 1 news 1 5/1 3 1 photo 1 5/2 4 3 news 1 5/3 5 4 news 1 5/3 6 1 news 1 5/4 7 2 photo 1 5/4 8 2 photo 1 5/5 You'll notice it's the entire original dataset, because we are matching id and type individually in lists, rather than as a collective pairs. The result I desire is, but I can't figure out the SQL to get this result. history_id id type user_id date 1 1 news 1 5/1 4 3 news 1 5/3 5 4 news 1 5/3 7 2 photo 1 5/4 Obviously, I could go the route of looping through each pair and querying the database to determine it's first result, but that seems an inefficient solution. I figured one of the SQL gurus on this site might be able to spread some wisdom. In case I'm approaching this situation incorrectly, the gist of the whole routine is that the database stores all creations and edits in the same table. I need to track each users behavior and determine how many entries in the history table are edits or creations over a specific date range. Therefore I select all type:id pairs from the date range based on a user_id, and then for each pairing I determine if the user is responsible for the first that occurs in the database. If first, then creation else edit. Any assistance would be awesome.

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Exit code 3 (not my return value, looking for source)

- by Kathoz

Greetings, my program exits with the code 3. No error messages, no exceptions, and the exit is not initiated by my code. The problem occurs when I am trying to read extremely long integer values from a text file (the text file is present and correctly opened, with successful prior reading). I am using very large amounts of memory (in fact, I think that this might be the cause, as I am nearly sure I go over the 2GB per process memory limit). I am also using the GMP (or, rather, MPIR) library to multiply bignums. I am fairly sure that this is not a file I/O problem as I got the same error code on a previous program version that was fully in-memory. System: MS Visual Studio 2008 MS Windows Vista Home Premium x86 MPIR 2.1.0 rc2 4GB RAM Where might this error code originate from? EDIT: this is the procedure that exits with the code void condenseBinSplitFile(const char *sourceFilename, int partCount){ //condense results file into final P and Q std::string tempFilename; std::string inputFilename(sourceFilename); std::string outputFilename(BIN_SPLIT_FILENAME_DATA2); mpz_class *P = new mpz_class(0); mpz_class *Q = new mpz_class(0); mpz_class *PP = new mpz_class(0); mpz_class *QQ = new mpz_class(0); FILE *sourceFile; FILE *resultFile; fpos_t oldPos; int swapCount = 0; while (partCount > 1){ std::cout << partCount << std::endl; sourceFile = fopen(inputFilename.c_str(), "r"); resultFile = fopen(outputFilename.c_str(), "w"); for (int i=0; i<partCount/2; i++){ //Multiplication order: //Get Q, skip P //Get QQ, mul Q and QQ, print Q, delete Q //Jump back to P, get P //Mul P and QQ, delete QQ //Skip QQ, get PP //Mul P and PP, delete P and PP //Get Q, skip P mpz_inp_str(Q->get_mpz_t(), sourceFile, CALC_BASE); fgetpos(sourceFile, &oldPos); skipLine(sourceFile); skipLine(sourceFile); //Get QQ, mul Q and QQ, print Q, delete Q mpz_inp_str(QQ->get_mpz_t(), sourceFile, CALC_BASE); (*Q) *= (*QQ); mpz_out_str(resultFile, CALC_BASE, Q->get_mpz_t()); fputc('\n', resultFile); (*Q) = 0; //Jump back to P, get P fsetpos(sourceFile, &oldPos); mpz_inp_str(P->get_mpz_t(), sourceFile, CALC_BASE); //Mul P and QQ, delete QQ (*P) *= (*QQ); (*QQ) = 0; //Skip QQ, get PP skipLine(sourceFile); skipLine(sourceFile); mpz_inp_str(PP->get_mpz_t(), sourceFile, CALC_BASE); //Mul P and PP, delete PP, print P, delete P (*P) += (*PP); (*PP) = 0; mpz_out_str(resultFile, CALC_BASE, P->get_mpz_t()); fputc('\n', resultFile); (*P) = 0; } partCount /= 2; fclose(sourceFile); fclose(resultFile); //swap filenames tempFilename = inputFilename; inputFilename = outputFilename; outputFilename = tempFilename; swapCount++; } delete P; delete Q; delete PP; delete QQ; remove(BIN_SPLIT_FILENAME_RESULTS); if (swapCount%2 == 0) rename(sourceFilename, BIN_SPLIT_FILENAME_RESULTS); else rename(BIN_SPLIT_FILENAME_DATA2, BIN_SPLIT_FILENAME_RESULTS); }

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ValidationProperty not returning entered value for textbox

- by nat

hi I have a custom control, (relevant code at the bottom) it consists of some text/links and a hidden textbox (rather than a hidden input). when rendered, the user via another dialog and some JS sets the value of the textbox to an integer and clicks submit on the form. i am trying to assure that the user has entered a number (via the JS) and that the textbox is not still set to its default of "0" the requiredfieldvalidator works just fine, if i dont change the value it spots it on the client and fills the validation summary on the page with the appropriate message. unfortunately when i do fill the textbox, the validator also rejests the post as the controls textbox text value is still set to "0", even though on the form it has changed. clearly i am doing something wrong.. but cant work out what it is? could someone enlighten me please, this is driving me potty if i step through the code, when the get of the mediaidtext is hit,the findcontrol finds the textbox, but the value is still set to "0" many thanks code below nat [ValidationProperty("MediaIdText")] public class MediaLibraryFileControl: CompositeControl { private int mediaId = 0; public int MediaId { get { return mediaId; } set { mediaId = value; } } public string MediaIdText { get { string txt = "0"; Control ctrl = this.FindControl(this.UniqueID+ "_hidden"); try { txt = ((TextBox)ctrl).Text; MediaId = Convert.ToInt32(txt); } catch { MediaId = 0; } return txt; } } protected override void CreateChildControls() { this.Controls.Add(new LiteralControl("<span>")); this.Controls.Add(new LiteralControl("<span id=\"" + TextControlName + "\">" + getMediaDetails() + "</span>")); TextBox tb = new TextBox(); tb.Text = this.MediaId.ToString(); tb.ID = this.UniqueID + "_hidden"; tb.CssClass = "hidden"; this.Controls.Add(tb); if (Select == true) { this.Controls.Add(new LiteralControl(string.Format(" [<a href=\"javascript:{0}(this,'{1}','{2}')\" class=\"select\">{3}</a>]", dialog, this.UniqueID, this.categoryId, "select"))); this.Controls.Add(new LiteralControl(string.Format(" [<a href=\"javascript:{0}(this,'{1}')\" class=\"select\">{2}</a>]", clearDialog, this.ID, "clear"))); } this.Controls.Add(new LiteralControl("</span>")); } protected virtual string getMediaDetails() { //... return String.Empty; } } this is the code adding the validationcontrol the editcontrol is the instance of the control above public override Control RenderValidationControl(Control editControl) { Control ctrl = new PlaceHolder(); RequiredFieldValidator req = new RequiredFieldValidator(); req.ID = editControl.ClientID + "_validator"; req.ControlToValidate = editControl.ID; req.Display = ValidatorDisplay.None; req.InitialValue = "0"; req.EnableClientScript = false; req.ErrorMessage = "control cannot be blank"; ctrl.Controls.Add(req); return ctrl; }

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Setting a DataGrid background color based on the previous row

- by Zipper

I'm trying to setup a grid where I do column sorting, but I wanted to do zebra striping, only rather than every other row or every x rows, I want it to be based on the value of cells. i.e. All cells that contain 0 have a blue background, the next value would have a white background, the next value would be blue, etc.... The problem I have is that I can't seem to find where to actually do the setting of the background colors. I'm using a custom sorter and I tried setting it in there after I re-order the list and set the data source, but it appears that when the data source is set, that the rows don't exist yet. I tried using the DataContextChanged, but that event doesn't seem to be firing. Here is what I have now. namespace Foo.Bar { public partial class FooBar { List<Bla> ResultList { get; set; } SolidColorBrush stripeOneColor = new SolidColorBrush(Colors.Gold); SolidColorBrush stripeTwoColor = new SolidColorBrush(Colors.White); //********************************************************************************************* public Consistency() { InitializeComponent(); } //********************************************************************************************* override protected void PopulateTabWithData() { ResultList = GetBlas(); SortAndGroup("Source"); } //********************************************************************************************* private void SortAndGroup(string colName) { IOrderedEnumerable <Bla> ordered = null; switch (colName) { case "Source": case "ID": ordered = ResultList.OrderBy(r => r.Source).ThenBy(r => r.ID); break; case "Name": ordered = ResultList.OrderBy(r => r.Source).ThenBy(r => r.Name); break; case "Message": ordered = ResultList.OrderBy(r => r.Message); break; default: throw new Exception(colName); } ResultList = ordered.ThenBy(r => r.Source).ThenBy(r => r.ID).ToList(); // tie-breakers consistencyDataGrid.ItemsSource = null; consistencyDataGrid.ItemsSource = ResultList; ColorRows(); } //********************************************************************************************* private void consistencyDataGrid_Sorting(object sender, System.Windows.Controls.DataGridSortingEventArgs e) { SortAndGroup(e.Column.Header.ToString()); e.Handled = true; } private void ColorRows() { for (var i = 0; i < ResultList.Count; i++) { var currentItem = ResultList[i]; var row = myDataGrid.ItemContainerGenerator.ContainerFromItem(currentItem) as DataGridRow; if (row == null) { continue; } if (i > 0) { var previousItem = ResultList[i - 1]; var previousRow = myDataGrid.ItemContainerGenerator.ContainerFromItem(previousItem) as DataGridRow; if (currentItem.Source == previousItem.Source) { row.Background = previousRow.Background; } else { if (previousRow.Background == stripeOneColor) { row.Background = stripeTwoColor; } else { row.Background = stripeOneColor; } } } else { row.Background = stripeOneColor; } } } } } }

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What's the fastest lookup algorithm for a pair data structure (i.e, a map)?

- by truncheon

In the following example a std::map structure is filled with 26 values from A - Z (for key) and 0 – 26 for value. The time taken (on my system) to lookup the last entry (10000000 times) is roughly 250 ms for the vector, and 125 ms for the map. (I compiled using release mode, with O3 option turned on for g++ 4.4) But if for some odd reason I wanted better performance than the std::map, what data structures and functions would I need to consider using? I apologize if the answer seems obvious to you, but I haven't had much experience in the performance critical aspects of C++ programming. UPDATE: This example is rather trivial and hides the true complexity of what I'm trying to achieve. My real world project is a simple scripting language that uses a parser, data tree, and interpreter (instead of a VM stack system). I need to use some kind of data structure (perhaps map) to store the variables names created by script programmers. These are likely to be pretty randomly named, so I need a lookup method that can quickly find a particular key within a (probably) fairly large list of names. #include <ctime> #include <map> #include <vector> #include <iostream> struct mystruct { char key; int value; mystruct(char k = 0, int v = 0) : key(k), value(v) { } }; int find(const std::vector<mystruct>& ref, char key) { for (std::vector<mystruct>::const_iterator i = ref.begin(); i != ref.end(); ++i) if (i->key == key) return i->value; return -1; } int main() { std::map<char, int> mymap; std::vector<mystruct> myvec; for (int i = 'a'; i < 'a' + 26; ++i) { mymap[i] = i - 'a'; myvec.push_back(mystruct(i, i - 'a')); } int pre = clock(); for (int i = 0; i < 10000000; ++i) { find(myvec, 'z'); } std::cout << "linear scan: milli " << clock() - pre << "\n"; pre = clock(); for (int i = 0; i < 10000000; ++i) { mymap['z']; } std::cout << "map scan: milli " << clock() - pre << "\n"; return 0; }

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Why isn't the inline element inheriting height from its children?

- by jbarz

I'm trying to make a rather complicated grid of images and information (almost like Pinterest). Specifically, I'm trying to inline position one set of <ul>s right after another. I have it working but one aspect is causing issues so I'm trying to ask about this small piece to avoid the complication of the whole problem. In order to horizontally align the images and their information we are using inline <li>s with other inline-block level elements inside of them. Everything works correctly for the most part except that the <li>s have almost no height. HTML and CSS is in JSFiddle here if you want to mess with it in addition to below: HTML: <div> <ul class="Container"> <li> <span class="Item"> <a href="#"><img src="http://jsfiddle.net/img/logo.png"/></a> <span class="Info"> <a href="#">Title One</a> <span class="Details">One Point One</span> </span> </span> </li> <li> <span class="Item"> <a href="#"><img src="http://jsfiddle.net/img/logo.png"/></a> <span class="Info"> <a href="#">Title Two</a> <span class="Details">Two Point One</span> </span> </span> </li> </ul> CSS: .Container { list-style-type:none; } .Container li { background-color:grey; display:inline; text-align:center; } .Container li .Item { border:solid 2px #ccc; display:inline-block; min-height:50px; vertical-align:top; width:170px; } .Container li .Item .Info { display:inline-block; } .Container li .Item .Info a { display:inline-block; width:160px; } If you check out the result in the jsfiddle link you can see that the grey background only encompasses a small strip of the whole <li>. I know that changing the <li> to display:inline-block solves this problem but that isn't feasible for other reasons. So first of all, I'm just looking to see if anyone understands why the inline <li> element doesn't have any height. I can't find anything in the spec that explains this. I know I can't add height to an inline element but any explanation as to why this is happening that might enable me to fix would be great. Secondly, if you inspect the elements using IE's Developer Mode you will see that although the background color is in the correct location, the actual location of the <li>'s bounding box is at the bottom of the container according to hovering over the element. I could deal with this problem if it was at the top in every browser but it apparently varies. NOTE: I don't really care about older browsers in this case but I don't use HTML5 or JavaScript positioning. Thanks.

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Java saying XML Document Not Well Formed

- by Pyroclastic

Hey all. Java's XML parser seems to be thinking that my XML document is not well formed following the root element, but I've validated it with several tools and they all disagree. It's probably an error in my code rather than in the document itself, I'd really appreciate any help you all could offer me. Here is my Java method: private void loadFromXMLFile(File f) throws ParserConfigurationException, IOException, SAXException { File file = f; DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db; Document doc = null; db = dbf.newDocumentBuilder(); doc = db.parse(file); doc.getDocumentElement().normalize(); String desc = ""; String due = ""; String comment = ""; NodeList tasksList = doc.getElementsByTagName("task"); for (int i = 0; i < tasksList.getLength(); i++) { NodeList attributes = tasksList.item(i).getChildNodes(); for (int j = 0; i < attributes.getLength(); j++) { Node attribute = attributes.item(i); if (attribute.getNodeName() == "description") { desc = attribute.getTextContent(); } if (attribute.getNodeName() == "due") { due = attribute.getTextContent(); } if (attribute.getNodeName() == "comment") { comment = attribute.getTextContent(); } tasks.add(new Task(desc, due, comment)); } desc = ""; due = ""; comment = ""; } } And here is the XML file I'm trying to load: <?xml version="1.0"?> <tasklist> <task> <description>Task 1</description> <due>Due date 1</due> <comment>Comment 1</comment> <completed>false</completed> </task> <task> <description>Task 2</description> <due>Due date 2</due> <comment>Comment 2</comment> <completed>false</completed> </task> <task> <description>Task 3</description> <due>Due date 3</due> <comment>Comment 3</comment> <completed>true</completed> </task> </tasklist> And here is the error message java is throwing for me: run: [Fatal Error] tasks.xml:28:3: The markup in the document following the root element must be well-formed. May 17, 2010 6:07:02 PM todolist.TodoListGUI SEVERE: null org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed. at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:239) at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:283) at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:208) at todolist.TodoListGUI.loadFromXMLFile(TodoListGUI.java:199) at todolist.TodoListGUI.(TodoListGUI.java:42) at todolist.Main.main(Main.java:25) BUILD SUCCESSFUL (total time: 19 seconds) For reference TodoListGUI.java:199 is doc = db.parse(file); If context is helpful to anyone here, I'm trying to write a simple GUI application to manage a todo list that can read and write to and from XML files defining the tasks. Any advice is appreciated!

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How to reserve public API to internal usage in .NET?

- by mark

Dear ladies and sirs. Let me first present the case, which will explain my question. This is going to be a bit long, so I apologize in advance :-). I have objects and collections, which should support the Merge API (it is my custom API, the signature of which is immaterial for this question). This API must be internal, meaning only my framework should be allowed to invoke it. However, derived types should be able to override the basic implementation. The natural way to implement this pattern as I see it, is this: The Merge API is declared as part of some internal interface, let us say IMergeable. Because the interface is internal, derived types would not be able to implement it directly. Rather they must inherit it from a common base type. So, a common base type is introduced, which would implement the IMergeable interface explicitly, where the interface methods delegate to respective protected virtual methods, providing the default implementation. This way the API is only callable by my framework, but derived types may override the default implementation. The following code snippet demonstrates the concept: internal interface IMergeable { void Merge(object obj); } public class BaseFrameworkObject : IMergeable { protected virtual void Merge(object obj) { // The default implementation. } void IMergeable.Merge(object obj) { Merge(obj); } } public class SomeThirdPartyObject : BaseFrameworkObject { protected override void Merge(object obj) { // A derived type implementation. } } All is fine, provided a single common base type suffices, which is usually true for non collection types. The thing is that collections must be mergeable as well. Collections do not play nicely with the presented concept, because developers do not develop collections from the scratch. There are predefined implementations - observable, filtered, compound, read-only, remove-only, ordered, god-knows-what, ... They may be developed from scratch in-house, but once finished, they serve wide range of products and should never be tailored to some specific product. Which means, that either: they do not implement the IMergeable interface at all, because it is internal to some product the scope of the IMergeable interface is raised to public and the API becomes open and callable by all. Let us refer to these collections as standard collections. Anyway, the first option screws my framework, because now each possible standard collection type has to be paired with the respective framework version, augmenting the standard with the IMergeable interface implementation - this is so bad, I am not even considering it. The second option breaks the framework as well, because the IMergeable interface should be internal for a reason (whatever it is) and now this interface has to open to all. So what to do? My solution is this. make IMergeable public API, but add an extra parameter to the Merge method, I call it a security token. The interface implementation may check that the token references some internal object, which is never exposed to the outside. If this is the case, then the method was called from within the framework, otherwise - some outside API consumer attempted to invoke it and so the implementation can blow up with a SecurityException. Here is the modified code snippet demonstrating this concept: internal static class InternalApi { internal static readonly object Token = new object(); } public interface IMergeable { void Merge(object obj, object token); } public class BaseFrameworkObject : IMergeable { protected virtual void Merge(object obj) { // The default implementation. } public void Merge(object obj, object token) { if (!object.ReferenceEquals(token, InternalApi.Token)) { throw new SecurityException("bla bla bla"); } Merge(obj); } } public class SomeThirdPartyObject : BaseFrameworkObject { protected override void Merge(object obj) { // A derived type implementation. } } Of course, this is less explicit than having an internally scoped interface and the check is moved from the compile time to run time, yet this is the best I could come up with. Now, I have a gut feeling that there is a better way to solve the problem I have presented. I do not know, may be using some standard Code Access Security features? I have only vague understanding of it, but can LinkDemand attribute be somehow related to it? Anyway, I would like to hear other opinions. Thanks.

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How can I remove this query from within a loop?

- by Chris

I am currently designing a forum as a personal project. One of the recurring issues I've come across is database queries in loops. I've managed to avoid doing that so far by using table joins or caching of data in arrays for later use. Right now though I've come across a situation where I'm not sure how I can write the code in such a way that I can use either of those methods easily. However I'd still prefer to do at most 2 queries for this operation rather than 1 + 1 per group of forums, which so far has resulted in 5 per page. So while 5 isn't a huge number (though it will increase for each forum group I add) it's the principle that's important to me here, I do NOT want to write queries in loops What I'm doing is displaying forum index groupings (eg admin forums, user forums etc) and then each forum within that group on a single page index, it's the combination of both in one page that's causing me issue. If it had just been a single group per page, I'd use a table join and problem solved. But if I use a table join here, although I can potentially get all the data I need it'll be in one mass of results and it needs displaying properly. Here's the code (I've removed some of the html for clarity) <?php $sql= "select * from forum_groups"; //query 1 $result1 = $database->query($sql); while($group = mysql_fetch_assoc($result1)) //first loop {?> <table class="threads"> <tr> <td class="forumgroupheader"> <?php echo $group['group_name']; ?> </td> </tr> <tr> <td class="forumgroupheader2"> <?php echo $group['group_desc']; ?> </td> </tr> </table> <table> <tr> <th class="thforum"> Forum Name</th> <th class="thforum"> Forum Decsription</th> <th class="thforum"> Last Post </th> <tr> <?php $group_id = $group['id']; $sql = "SELECT forums.id, forums.forum_group_id, forums.forum_name, forums.forum_desc, forums.visible_rank, forums.locked, forums.lock_rank, forums.topics, forums.posts, forums.last_post, forums.last_post_id, users.username FROM forums LEFT JOIN users on forums.last_post_id=users.id WHERE forum_group_id='{$group_id}'"; //query 2 $result2 = $database->query($sql); while($forum = mysql_fetch_assoc($result2)) //second loop {?> So how can I either a) write the SQL in such a way as to remove the second query from inside the loop or b) combine the results in an array either way I need to be able to access the data as an when so I can format it properly for the page output, ie within the loops still.

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jQuery .find() doesn't return data in IE but does in Firefox and Chrome

- by Steve Hiner

I helped a friend out by doing a little web work for him. Part of what he needed was an easy way to change a couple pieces of text on his site. Rather than having him edit the HTML I decided to provide an XML file with the messages in it and I used jQuery to pull them out of the file and insert them into the page. It works great... In Firefox and Chrome, not so great in IE7. I was hoping one of you could tell me why. I did a fair but of googling but couldn't find what I'm looking for. Here's the XML: <?xml version="1.0" encoding="utf-8" ?> <messages> <message type="HeaderMessage"> This message is put up in the header area. </message> <message type="FooterMessage"> This message is put in the lower left cell. </message> </messages> And here's my jQuery call: <script type="text/javascript"> $(document).ready(function() { $.get('messages.xml', function(d) { //I have confirmed that it gets to here in IE //and it has the xml loaded. //alert(d); gives me a message box with the xml text in it //alert($(d).find('message')); gives me "[object Object]" //alert($(d).find('message')[0]); gives me "undefined" //alert($(d).find('message').Length); gives me "undefined" $(d).find('message').each(function() { //But it never gets to here in IE var $msg = $(this); var type = $msg.attr("type"); var message = $msg.text(); switch (type) { case "HeaderMessage": $("#HeaderMessageDiv").html(message); break; case "FooterMessage": $("#footermessagecell").html(message); break; default: } }); }); }); </script> Is there something I need to do differently in IE? Based on the message box with [object Object] I'm assumed that .find was working in IE but since I can't index into the array with [0] or check it's Length I'm guessing that means .find isn't returning any results. Any reason why that would work perfectly in Firefox and Chrome but fail in IE? I'm a total newbie with jQuery so I hope I haven't just done something stupid. That code above was scraped out of a forum and modified to suit my needs. Since jQuery is cross-platform I figured I wouldn't have to deal with this mess. Edit: I've found that if I load the page in Visual Studio 2008 and run it then it will work in IE. So it turns out it always works when run through the development web server. Now I'm thinking IE just doesn't like doing .find in XML loaded off of my local drive so maybe when this is on an actual web server it will work OK. I have confirmed that it works fine when browsed from a web server. Must be a peculiarity with IE. I'm guessing it's because the web server sets the mime type for the xml data file transfer and without that IE doesn't parse the xml correctly.

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Dynamic JSON Parsing in .NET with JsonValue

- by Rick Strahl

So System.Json has been around for a while in Silverlight, but it's relatively new for the desktop .NET framework and now moving into the lime-light with the pending release of ASP.NET Web API which is bringing a ton of attention to server side JSON usage. The JsonValue, JsonObject and JsonArray objects are going to be pretty useful for Web API applications as they allow you dynamically create and parse JSON values without explicit .NET types to serialize from or into. But even more so I think JsonValue et al. are going to be very useful when consuming JSON APIs from various services. Yes I know C# is strongly typed, why in the world would you want to use dynamic values? So many times I've needed to retrieve a small morsel of information from a large service JSON response and rather than having to map the entire type structure of what that service returns, JsonValue actually allows me to cherry pick and only work with the values I'm interested in, without having to explicitly create everything up front. With JavaScriptSerializer or DataContractJsonSerializer you always need to have a strong type to de-serialize JSON data into. Wouldn't it be nice if no explicit type was required and you could just parse the JSON directly using a very easy to use object syntax? That's exactly what JsonValue, JsonObject and JsonArray accomplish using a JSON parser and some sweet use of dynamic sauce to make it easy to access in code. Creating JSON on the fly with JsonValue Let's start with creating JSON on the fly. It's super easy to create a dynamic object structure. JsonValue uses the dynamic keyword extensively to make it intuitive to create object structures and turn them into JSON via dynamic object syntax. Here's an example of creating a music album structure with child songs using JsonValue:[TestMethod] public void JsonValueOutputTest() { // strong type instance var jsonObject = new JsonObject(); // dynamic expando instance you can add properties to dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; album.Artist = "AC/DC"; album.YearReleased = 1977; album.Songs = new JsonArray() as dynamic; dynamic song = new JsonObject(); song.SongName = "Dirty Deeds Done Dirt Cheap"; song.SongLength = "4:11"; album.Songs.Add(song); song = new JsonObject(); song.SongName = "Love at First Feel"; song.SongLength = "3:10"; album.Songs.Add(song); Console.WriteLine(album.ToString()); } This produces proper JSON just as you would expect: {"AlbumName":"Dirty Deeds Done Dirt Cheap","Artist":"AC\/DC","YearReleased":1977,"Songs":[{"SongName":"Dirty Deeds Done Dirt Cheap","SongLength":"4:11"},{"SongName":"Love at First Feel","SongLength":"3:10"}]} The important thing about this code is that there's no explicitly type that is used for holding the values to serialize to JSON. I am essentially creating this value structure on the fly by adding properties and then serialize it to JSON. This means this code can be entirely driven at runtime without compile time restraints of structure for the JSON output. Here I use JsonObject() to create a new object and immediately cast it to dynamic. JsonObject() is kind of similar in behavior to ExpandoObject in that it allows you to add properties by simply assigning to them. Internally, JsonValue/JsonObject these values are stored in pseudo collections of key value pairs that are exposed as properties through the DynamicObject functionality in .NET. The syntax gets a little tedious only if you need to create child objects or arrays that have to be explicitly defined first. Other than that the syntax looks like normal object access sytnax. Always remember though these values are dynamic - which means no Intellisense and no compiler type checking. It's up to you to ensure that the values you create are accessed consistently and without typos in your code. Note that you can also access the JsonValue instance directly and get access to the underlying type. This means you can assign properties by string, which can be useful for fully data driven JSON generation from other structures. Below you can see both styles of access next to each other:// strong type instance var jsonObject = new JsonObject(); // you can explicitly add values here jsonObject.Add("Entered", DateTime.Now); // expando style instance you can just 'use' properties dynamic album = jsonObject; album.AlbumName = "Dirty Deeds Done Dirt Cheap"; JsonValue internally stores properties keys and values in collections and you can iterate over them at runtime. You can also manipulate the collections if you need to to get the object structure to look exactly like you want. Again, if you've used ExpandoObject before JsonObject/Value are very similar in the behavior of the structure. Reading JSON strings into JsonValue The JsonValue structure supports importing JSON via the Parse() and Load() methods which can read JSON data from a string or various streams respectively. Essentially JsonValue includes the core JSON parsing to turn a JSON string into a collection of JsonValue objects that can be then referenced using familiar dynamic object syntax. Here's a simple example:[TestMethod] public void JsonValueParsingTest() { var jsonString = @"{""Name"":""Rick"",""Company"":""West Wind"",""Entered"":""2012-03-16T00:03:33.245-10:00""}"; dynamic json = JsonValue.Parse(jsonString); // values require casting string name = json.Name; string company = json.Company; DateTime entered = json.Entered; Assert.AreEqual(name, "Rick"); Assert.AreEqual(company, "West Wind"); } The JSON string represents an object with three properties which is parsed into a JsonValue object and cast to dynamic. Once cast to dynamic I can then go ahead and access the object using familiar object syntax. Note that the actual values - json.Name, json.Company, json.Entered - are actually of type JsonPrimitive and I have to assign them to their appropriate types first before I can do type comparisons. The dynamic properties will automatically cast to the right type expected as long as the compiler can resolve the type of the assignment or usage. The AreEqual() method oesn't as it expects two object instances and comparing json.Company to "West Wind" is comparing two different types (JsonPrimitive to String) which fails. So the intermediary assignment is required to make the test pass. The JSON structure can be much more complex than this simple example. Here's another example of an array of albums serialized to JSON and then parsed through with JsonValue():[TestMethod] public void JsonArrayParsingTest() { var jsonString = @"[ { ""Id"": ""b3ec4e5c"", ""AlbumName"": ""Dirty Deeds Done Dirt Cheap"", ""Artist"": ""AC/DC"", ""YearReleased"": 1977, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/61kTaH-uZBL._AA115_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/B00008BXJ4/ref=as_li_ss_tl?ie=UTF8&tag=westwindtechn-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B00008BXJ4"", ""Songs"": [ { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Dirty Deeds Done Dirt Cheap"", ""SongLength"": ""4:11"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Love at First Feel"", ""SongLength"": ""3:10"" }, { ""AlbumId"": ""b3ec4e5c"", ""SongName"": ""Big Balls"", ""SongLength"": ""2:38"" } ] }, { ""Id"": ""67280fb8"", ""AlbumName"": ""Echoes, Silence, Patience & Grace"", ""Artist"": ""Foo Fighters"", ""YearReleased"": 2007, ""Entered"": ""2012-03-16T00:13:12.2810521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/41mtlesQPVL._SL500_AA280_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/gp/product/B000UFAURI/ref=as_li_ss_tl?ie=UTF8&tag=westwindtechn-20&linkCode=as2&camp=1789&creative=390957&creativeASIN=B000UFAURI"", ""Songs"": [ { ""AlbumId"": ""67280fb8"", ""SongName"": ""The Pretender"", ""SongLength"": ""4:29"" }, { ""AlbumId"": ""67280fb8"", ""SongName"": ""Let it Die"", ""SongLength"": ""4:05"" }, { ""AlbumId"": ""67280fb8"", ""SongName"": ""Erase/Replay"", ""SongLength"": ""4:13"" } ] }, { ""Id"": ""7b919432"", ""AlbumName"": ""End of the Silence"", ""Artist"": ""Henry Rollins Band"", ""YearReleased"": 1992, ""Entered"": ""2012-03-16T00:13:12.2800521-10:00"", ""AlbumImageUrl"": ""http://ecx.images-amazon.com/images/I/51FO3rb1tuL._SL160_AA160_.jpg"", ""AmazonUrl"": ""http://www.amazon.com/End-Silence-Rollins-Band/dp/B0000040OX/ref=sr_1_5?ie=UTF8&qid=1302232195&sr=8-5"", ""Songs"": [ { ""AlbumId"": ""7b919432"", ""SongName"": ""Low Self Opinion"", ""SongLength"": ""5:24"" }, { ""AlbumId"": ""7b919432"", ""SongName"": ""Grip"", ""SongLength"": ""4:51"" } ] } ]"; dynamic albums = JsonValue.Parse(jsonString); foreach (dynamic album in albums) { Console.WriteLine(album.AlbumName + " (" + album.YearReleased.ToString() + ")"); foreach (dynamic song in album.Songs) { Console.WriteLine("\t" + song.SongName ); } } Console.WriteLine(albums[0].AlbumName); Console.WriteLine(albums[0].Songs[1].SongName);} It's pretty sweet how easy it becomes to parse even complex JSON and then just run through the object using object syntax, yet without an explicit type in the mix. In fact it looks and feels a lot like if you were using JavaScript to parse through this data, doesn't it? And that's the point…© Rick Strahl, West Wind Technologies, 2005-2012Posted in .NET Web Api JSON Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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SQL SERVER – Shrinking NDF and MDF Files – Readers’ Opinion

- by pinaldave

Previously, I had written a blog post about SQL SERVER – Shrinking NDF and MDF Files – A Safe Operation. After that, I have written the following blog post that talks about the advantage and disadvantage of Shrinking and why one should not be Shrinking a file SQL SERVER – SHRINKFILE and TRUNCATE Log File in SQL Server 2008. On this subject, SQL Server Expert Imran Mohammed left an excellent comment. I just feel that his comment is worth a big article itself. For everybody to read his wonderful explanation, I am posting this blog post here. Thanks Imran! Shrinking Database always creates performance degradation and increases fragmentation in the database. I suggest that you keep that in mind before you start reading the following comment. If you are going to say Shrinking Database is bad and evil, here I am saying it first and loud. Now, the comment of Imran is written while keeping in mind only the process showing how the Shrinking Database Operation works. Imran has already explained his understanding and requests further explanation. I have removed the Best Practices section from Imran’s comments, as there are a few corrections. Comments from Imran - Before I explain to you the concept of Shrink Database, let us understand the concept of Database Files. When we create a new database inside the SQL Server, it is typical that SQl Server creates two physical files in the Operating System: one with .MDF Extension, and another with .LDF Extension. .MDF is called as Primary Data File. .LDF is called as Transactional Log file. If you add one or more data files to a database, the physical file that will be created in the Operating System will have an extension of .NDF, which is called as Secondary Data File; whereas, when you add one or more log files to a database, the physical file that will be created in the Operating System will have the same extension as .LDF. The questions now are, “Why does a new data file have a different extension (.NDF)?”, “Why is it called as a secondary data file?” and, “Why is .MDF file called as a primary data file?” Answers: Note: The following explanation is based on my limited knowledge of SQL Server, so experts please do comment. A data file with a .MDF extension is called a Primary Data File, and the reason behind it is that it contains Database Catalogs. Catalogs mean Meta Data. Meta Data is “Data about Data”. An example for Meta Data includes system objects that store information about other objects, except the data stored by the users. sysobjects stores information about all objects in that database. sysindexes stores information about all indexes and rows of every table in that database. syscolumns stores information about all columns that each table has in that database. sysusers stores how many users that database has. Although Meta Data stores information about other objects, it is not the transactional data that a user enters; rather, it’s a system data about the data. Because Primary Data File (.MDF) contains important information about the database, it is treated as a special file. It is given the name Primary Data file because it contains the Database Catalogs. This file is present in the Primary File Group. You can always create additional objects (Tables, indexes etc.) in the Primary data file (This file is present in the Primary File group), by mentioning that you want to create this object under the Primary File Group. Any additional data file that you add to the database will have only transactional data but no Meta Data, so that’s why it is called as the Secondary Data File. It is given the extension name .NDF so that the user can easily identify whether a specific data file is a Primary Data File or a Secondary Data File(s). There are many advantages of storing data in different files that are under different file groups. You can put your read only in the tables in one file (file group) and read-write tables in another file (file group) and take a backup of only the file group that has read the write data, so that you can avoid taking the backup of a read-only data that cannot be altered. Creating additional files in different physical hard disks also improves I/O performance. A real-time scenario where we use Files could be this one: Let’s say you have created a database called MYDB in the D-Drive which has a 50 GB space. You also have 1 Database File (.MDF) and 1 Log File on D-Drive and suppose that all of that 50 GB space has been used up and you do not have any free space left but you still want to add an additional space to the database. One easy option would be to add one more physical hard disk to the server, add new data file to MYDB database and create this new data file in a new hard disk then move some of the objects from one file to another, and put the file group under which you added new file as default File group, so that any new object that is created gets into the new files, unless specified. Now that we got a basic idea of what data files are, what type of data they store and why they are named the way they are, let’s move on to the next topic, Shrinking. First of all, I disagree with the Microsoft terminology for naming this feature as “Shrinking”. Shrinking, in regular terms, means to reduce the size of a file by means of compressing it. BUT in SQL Server, Shrinking DOES NOT mean compressing. Shrinking in SQL Server means to remove an empty space from database files and release the empty space either to the Operating System or to SQL Server. Let’s examine this through an example. Let’s say you have a database “MYDB” with a size of 50 GB that has a free space of about 20 GB, which means 30GB in the database is filled with data and the 20 GB of space is free in the database because it is not currently utilized by the SQL Server (Database); it is reserved and not yet in use. If you choose to shrink the database and to release an empty space to Operating System, and MIND YOU, you can only shrink the database size to 30 GB (in our example). You cannot shrink the database to a size less than what is filled with data. So, if you have a database that is full and has no empty space in the data file and log file (you don’t have an extra disk space to set Auto growth option ON), YOU CANNOT issue the SHRINK Database/File command, because of two reasons: There is no empty space to be released because the Shrink command does not compress the database; it only removes the empty space from the database files and there is no empty space. Remember, the Shrink command is a logged operation. When we perform the Shrink operation, this information is logged in the log file. If there is no empty space in the log file, SQL Server cannot write to the log file and you cannot shrink a database. Now answering your questions: (1) Q: What are the USEDPAGES & ESTIMATEDPAGES that appear on the Results Pane after using the DBCC SHRINKDATABASE (NorthWind, 10) ? A: According to Books Online (For SQL Server 2000): UsedPages: the number of 8-KB pages currently used by the file. EstimatedPages: the number of 8-KB pages that SQL Server estimates the file could be shrunk down to. Important Note: Before asking any question, make sure you go through Books Online or search on the Google once. The reasons for doing so have many advantages: 1. If someone else already has had this question before, chances that it is already answered are more than 50 %. 2. This reduces your waiting time for the answer. (2) Q: What is the difference between Shrinking the Database using DBCC command like the one above & shrinking it from the Enterprise Manager Console by Right-Clicking the database, going to TASKS & then selecting SHRINK Option, on a SQL Server 2000 environment? A: As far as my knowledge goes, there is no difference, both will work the same way, one advantage of using this command from query analyzer is, your console won’t be freezed. You can do perform your regular activities using Enterprise Manager. (3) Q: What is this .NDF file that is discussed above? I have never heard of it. What is it used for? Is it used by end-users, DBAs or the SERVER/SYSTEM itself? A: .NDF File is a secondary data file. You never heard of it because when database is created, SQL Server creates database by default with only 1 data file (.MDF) and 1 log file (.LDF) or however your model database has been setup, because a model database is a template used every time you create a new database using the CREATE DATABASE Command. Unless you have added an extra data file, you will not see it. This file is used by the SQL Server to store data which are saved by the users. Hope this information helps. I would like to as the experts to please comment if what I understand is not what the Microsoft guys meant. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Readers Contribution, Readers Question, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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Using LINQ Distinct: With an Example on ASP.NET MVC SelectListItem

- by Joe Mayo

One of the things that might be surprising in the LINQ Distinct standard query operator is that it doesn’t automatically work properly on custom classes. There are reasons for this, which I’ll explain shortly. The example I’ll use in this post focuses on pulling a unique list of names to load into a drop-down list. I’ll explain the sample application, show you typical first shot at Distinct, explain why it won’t work as you expect, and then demonstrate a solution to make Distinct work with any custom class. The technologies I’m using are LINQ to Twitter, LINQ to Objects, Telerik Extensions for ASP.NET MVC, ASP.NET MVC 2, and Visual Studio 2010. The function of the example program is to show a list of people that I follow. In Twitter API vernacular, these people are called “Friends”; though I’ve never met most of them in real life. This is part of the ubiquitous language of social networking, and Twitter in particular, so you’ll see my objects named accordingly. Where Distinct comes into play is because I want to have a drop-down list with the names of the friends appearing in the list. Some friends are quite verbose, which means I can’t just extract names from each tweet and populate the drop-down; otherwise, I would end up with many duplicate names. Therefore, Distinct is the appropriate operator to eliminate the extra entries from my friends who tend to be enthusiastic tweeters. The sample doesn’t do anything with the drop-down list and I leave that up to imagination for what it’s practical purpose could be; perhaps a filter for the list if I only want to see a certain person’s tweets or maybe a quick list that I plan to combine with a TextBox and Button to reply to a friend. When the program runs, you’ll need to authenticate with Twitter, because I’m using OAuth (DotNetOpenAuth), for authentication, and then you’ll see the drop-down list of names above the grid with the most recent tweets from friends. Here’s what the application looks like when it runs: As you can see, there is a drop-down list above the grid. The drop-down list is where most of the focus of this article will be. There is some description of the code before we talk about the Distinct operator, but we’ll get there soon. This is an ASP.NET MVC2 application, written with VS 2010. Here’s the View that produces this screen: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<TwitterFriendsViewModel>" %> <%@ Import Namespace="DistinctSelectList.Models" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <fieldset> <legend>Twitter Friends</legend> <div> <%= Html.DropDownListFor( twendVM => twendVM.FriendNames, Model.FriendNames, "<All Friends>") %> </div> <div> <% Html.Telerik().Grid<TweetViewModel>(Model.Tweets) .Name("TwitterFriendsGrid") .Columns(cols => { cols.Template(col => { %> <img src="<%= col.ImageUrl %>" alt="<%= col.ScreenName %>" /> <% }); cols.Bound(col => col.ScreenName); cols.Bound(col => col.Tweet); }) .Render(); %> </div> </fieldset> </asp:Content> As shown above, the Grid is from Telerik’s Extensions for ASP.NET MVC. The first column is a template that renders the user’s Avatar from a URL provided by the Twitter query. Both the Grid and DropDownListFor display properties that are collections from a TwitterFriendsViewModel class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { /// /// For finding friend info on screen /// public class TwitterFriendsViewModel { /// /// Display names of friends in drop-down list /// public List FriendNames { get; set; } /// /// Display tweets in grid /// public List Tweets { get; set; } } } I created the TwitterFreindsViewModel. The two Lists are what the View consumes to populate the DropDownListFor and Grid. Notice that FriendNames is a List of SelectListItem, which is an MVC class. Another custom class I created is the TweetViewModel (the type of the Tweets List), shown below: namespace DistinctSelectList.Models { /// /// Info on friend tweets /// public class TweetViewModel { /// /// User's avatar /// public string ImageUrl { get; set; } /// /// User's Twitter name /// public string ScreenName { get; set; } /// /// Text containing user's tweet /// public string Tweet { get; set; } } } The initial Twitter query returns much more information than we need for our purposes and this a special class for displaying info in the View. Now you know about the View and how it’s constructed. Let’s look at the controller next. The controller for this demo performs authentication, data retrieval, data manipulation, and view selection. I’ll skip the description of the authentication because it’s a normal part of using OAuth with LINQ to Twitter. Instead, we’ll drill down and focus on the Distinct operator. However, I’ll show you the entire controller, below, so that you can see how it all fits together: using System.Linq; using System.Web.Mvc; using DistinctSelectList.Models; using LinqToTwitter; namespace DistinctSelectList.Controllers { [HandleError] public class HomeController : Controller { private MvcOAuthAuthorization auth; private TwitterContext twitterCtx; /// /// Display a list of friends current tweets /// /// public ActionResult Index() { auth = new MvcOAuthAuthorization(InMemoryTokenManager.Instance, InMemoryTokenManager.AccessToken); string accessToken = auth.CompleteAuthorize(); if (accessToken != null) { InMemoryTokenManager.AccessToken = accessToken; } if (auth.CachedCredentialsAvailable) { auth.SignOn(); } else { return auth.BeginAuthorize(); } twitterCtx = new TwitterContext(auth); var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); var twendsVM = new TwitterFriendsViewModel { Tweets = friendTweets, FriendNames = friendNames }; return View(twendsVM); } public ActionResult About() { return View(); } } } The important part of the listing above are the LINQ to Twitter queries for friendTweets and friendNames. Both of these results are used in the subsequent population of the twendsVM instance that is passed to the view. Let’s dissect these two statements for clarification and focus on what is happening with Distinct. The query for friendTweets gets a list of the 20 most recent tweets (as specified by the Twitter API for friend queries) and performs a projection into the custom TweetViewModel class, repeated below for your convenience: var friendTweets = (from tweet in twitterCtx.Status where tweet.Type == StatusType.Friends select new TweetViewModel { ImageUrl = tweet.User.ProfileImageUrl, ScreenName = tweet.User.Identifier.ScreenName, Tweet = tweet.Text }) .ToList(); The LINQ to Twitter query above simplifies what we need to work with in the View and the reduces the amount of information we have to look at in subsequent queries. Given the friendTweets above, the next query performs another projection into an MVC SelectListItem, which is required for binding to the DropDownList. This brings us to the focus of this blog post, writing a correct query that uses the Distinct operator. The query below uses LINQ to Objects, querying the friendTweets collection to get friendNames: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct() .ToList(); The above implementation of Distinct seems normal, but it is deceptively incorrect. After running the query above, by executing the application, you’ll notice that the drop-down list contains many duplicates. This will send you back to the code scratching your head, but there’s a reason why this happens. To understand the problem, we must examine how Distinct works in LINQ to Objects. Distinct has two overloads: one without parameters, as shown above, and another that takes a parameter of type IEqualityComparer<T>. In the case above, no parameters, Distinct will call EqualityComparer<T>.Default behind the scenes to make comparisons as it iterates through the list. You don’t have problems with the built-in types, such as string, int, DateTime, etc, because they all implement IEquatable<T>. However, many .NET Framework classes, such as SelectListItem, don’t implement IEquatable<T>. So, what happens is that EqualityComparer<T>.Default results in a call to Object.Equals, which performs reference equality on reference type objects. You don’t have this problem with value types because the default implementation of Object.Equals is bitwise equality. However, most of your projections that use Distinct are on classes, just like the SelectListItem used in this demo application. So, the reason why Distinct didn’t produce the results we wanted was because we used a type that doesn’t define its own equality and Distinct used the default reference equality. This resulted in all objects being included in the results because they are all separate instances in memory with unique references. As you might have guessed, the solution to the problem is to use the second overload of Distinct that accepts an IEqualityComparer<T> instance. If you were projecting into your own custom type, you could make that type implement IEqualityComparer<T>, but SelectListItem belongs to the .NET Framework Class Library. Therefore, the solution is to create a custom type to implement IEqualityComparer<T>, as in the SelectListItemComparer class, shown below: using System.Collections.Generic; using System.Web.Mvc; namespace DistinctSelectList.Models { public class SelectListItemComparer : EqualityComparer { public override bool Equals(SelectListItem x, SelectListItem y) { return x.Value.Equals(y.Value); } public override int GetHashCode(SelectListItem obj) { return obj.Value.GetHashCode(); } } } The SelectListItemComparer class above doesn’t implement IEqualityComparer<SelectListItem>, but rather derives from EqualityComparer<SelectListItem>. Microsoft recommends this approach for consistency with the behavior of generic collection classes. However, if your custom type already derives from a base class, go ahead and implement IEqualityComparer<T>, which will still work. EqualityComparer is an abstract class, that implements IEqualityComparer<T> with Equals and GetHashCode abstract methods. For the purposes of this application, the SelectListItem.Value property is sufficient to determine if two items are equal. Since SelectListItem.Value is type string, the code delegates equality to the string class. The code also delegates the GetHashCode operation to the string class.You might have other criteria in your own object and would need to define what it means for your object to be equal. Now that we have an IEqualityComparer<SelectListItem>, let’s fix the problem. The code below modifies the query where we want distinct values: var friendNames = (from tweet in friendTweets select new SelectListItem { Text = tweet.ScreenName, Value = tweet.ScreenName }) .Distinct(new SelectListItemComparer()) .ToList(); Notice how the code above passes a new instance of SelectListItemComparer as the parameter to the Distinct operator. Now, when you run the application, the drop-down list will behave as you expect, showing only a unique set of names. In addition to Distinct, other LINQ Standard Query Operators have overloads that accept IEqualityComparer<T>’s, You can use the same techniques as shown here, with SelectListItemComparer, with those other operators as well. Now you know how to resolve problems with getting Distinct to work properly and also have a way to fix problems with other operators that require equality comparisons. @JoeMayo

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Azure - Part 4 - Table Storage Service in Windows Azure

- by Shaun

In Windows Azure platform there are 3 storage we can use to save our data on the cloud. They are the Table, Blob and Queue. Before the Chinese New Year Microsoft announced that Azure SDK 1.1 had been released and it supports a new type of storage – Drive, which allows us to operate NTFS files on the cloud. I will cover it in the coming few posts but now I would like to talk a bit about the Table Storage. Concept of Table Storage Service The most common development scenario is to retrieve, create, update and remove data from the data storage. In the normal way we communicate with database. When we attempt to move our application over to the cloud the most common requirement should be have a storage service. Windows Azure provides a in-build service that allow us to storage the structured data, which is called Windows Azure Table Storage Service. The data stored in the table service are like the collection of entities. And the entities are similar to rows or records in the tradtional database. An entity should had a partition key, a row key, a timestamp and set of properties. You can treat the partition key as a group name, the row key as a primary key and the timestamp as the identifer for solving the concurrency problem. Different with a table in a database, the table service does not enforce the schema for tables, which means you can have 2 entities in the same table with different property sets. The partition key is being used for the load balance of the Azure OS and the group entity transaction. As you know in the cloud you will never know which machine is hosting your application and your data. It could be moving based on the transaction weight and the number of the requests. If the Azure OS found that there are many requests connect to your Book entities with the partition key equals “Novel” it will move them to another idle machine to increase the performance. So when choosing the partition key for your entities you need to make sure they indecate the category or gourp information so that the Azure OS can perform the load balance as you wish. Consuming the Table Although the table service looks like a database, you cannot access it through the way you are using now, neither ADO.NET nor ODBC. The table service exposed itself by ADO.NET Data Service protocol, which allows you can consume it through the RESTful style by Http requests. The Azure SDK provides a sets of classes for us to connect it. There are 2 classes we might need: TableServiceContext and TableServiceEntity. The TableServiceContext inherited from the DataServiceContext, which represents the runtime context of the ADO.NET data service. It provides 4 methods mainly used by us: CreateQuery: It will create a IQueryable instance from a given type of entity. AddObject: Add the specified entity into Table Service. UpdateObject: Update an existing entity in the Table Service. DeleteObject: Delete an entity from the Table Service. Beofre you operate the table service you need to provide the valid account information. It’s something like the connect string of the database but with your account name and the account key when you created the storage service on the Windows Azure Development Portal. After getting the CloudStorageAccount you can create the CloudTableClient instance which provides a set of methods for using the table service. A very useful method would be CreateTableIfNotExist. It will create the table container for you if it’s not exsited. And then you can operate the eneities to that table through the methods I mentioned above. Let me explain a bit more through an exmaple. We always like code rather than sentence. Straightforward Accessing to the Table Here I would like to build a WCF service on the Windows Azure platform, and for now just one requirement: it would allow the client to create an account entity on the table service. The WCF service would have a method named Register and accept an instance of the account which the client wants to create. After perform some validation it will add the entity into the table service. So the first thing I should do is to create a Cloud Application on my VIstial Studio 2010 RC. (The Azure SDK 1.1 only supports VS2008 and VS2010 RC.) The solution should be like this below. Then I added a configuration items for the storage account through the Settings section under the cloud project. (Double click the Services file under Roles folder and navigate to the Setting section.) This setting will be used when to retrieve my storage account information. Since for now I just in the development phase I will select “UseDevelopmentStorage=true”. And then I navigated to the WebRole.cs file under my WCF project. If you have read my previous posts you would know that this file defines the process when the application start, and terminate on the cloud. What I need to do is to when the application start, set the configuration publisher to load my config file with the config name I specified. So the code would be like below. I removed the original service and contract created by the VS template and add my IAccountService contract and its implementation class - AccountService. And I add the service method Register with the parameters: email, password and it will return a boolean value to indicates the result which is very simple. At this moment if I press F5 the application will be established on my local development fabric and I can see my service runs well through the browser. Let’s implement the service method Rigister, add a new entity to the table service. As I said before the entities you want to store in the table service must have 3 properties: partition key, row key and timespan. You can create a class with these 3 properties. The Azure SDK provides us a base class for that named TableServiceEntity in Microsoft.WindowsAzure.StorageClient namespace. So what we need to do is more simply, create a class named Account and let it derived from the TableServiceEntity. And I need to add my own properties: Email, Password, DateCreated and DateDeleted. The DateDeleted is a nullable date time value to indecate whether this entity had been deleted and when. Do you notice that I missed something here? Yes it’s the partition key and row key I didn’t assigned. The TableServiceEntity base class defined 2 constructors one was a parameter-less constructor which will be used to fill values into the properties from the table service when retrieving data. The other was one with 2 parameters: partition key and row key. As I said below the partition key may affect the load balance and the row key must be unique so here I would like to use the email as the parition key and the email plus a Guid as the row key. OK now we finished the entity class we need to store onto the table service. The next step is to create a data access class for us to add it. Azure SDK gives us a base class for it named TableServiceContext as I mentioned below. So let’s create a class for operate the Account entities. The TableServiceContext need the storage account information for its constructor. It’s the combination of the storage service URI that we will create on Windows Azure platform, and the relevant account name and key. The TableServiceContext will use this information to find the related address and verify the account to operate the storage entities. Hence in my AccountDataContext class I need to override this constructor and pass the storage account into it. All entities will be saved in the table storage with one or many tables which we call them “table containers”. Before we operate an entity we need to make sure that the table container had been created on the storage. There’s a method we can use for that: CloudTableClient.CreateTableIfNotExist. So in the constructor I will perform it firstly to make sure all method will be invoked after the table had been created. Notice that I passed the storage account enpoint URI and the credentials to specify where my storage is located and who am I. Another advise is that, make your entity class name as the same as the table name when create the table. It will increase the performance when you operate it over the cloud especially querying. Since the Register WCF method will add a new account into the table service, here I will create a relevant method to add the account entity. Before implement, I should add a reference - System.Data.Services.Client to the project. This reference provides some common method within the ADO.NET Data Service which can be used in the Windows Azure Table Service. I will use its AddObject method to create my account entity. Since the table service are not fully implemented the ADO.NET Data Service, there are some methods in the System.Data.Services.Client that TableServiceContext doesn’t support, such as AddLinks, etc. Then I implemented the serivce method to add the account entity through the AccountDataContext. You can see in the service implmentation I load the storage account information through my configuration file and created the account table entity from the parameters. Then I created the AccountDataContext. If it’s my first time to invoke this method the constructor of the AccountDataContext will create a table container for me. Then I use Add method to add the account entity into the table. Next, let’s create a farely simple client application to test this service. I created a windows console application and added a service reference to my WCF service. The metadata information of the WCF service cannot be retrieved if it’s deployed on the Windows Azure even though the <serviceMetadata httpGetEnabled="true"/> had been set. If we need to get its metadata we can deploy it on the local development service and then changed the endpoint to the address which is on the cloud. In the client side app.config file I specified the endpoint to the local development fabric address. And the just implement the client to let me input an email and a password then invoke the WCF service to add my acocunt. Let’s run my application and see the result. Of course it should return TRUE to me. And in the local SQL Express I can see the data had been saved in the table. Summary In this post I explained more about the Windows Azure Table Storage Service. I also created a small application for demostration of how to connect and consume it through the ADO.NET Data Service Managed Library provided within the Azure SDK. I only show how to create an eneity in the storage service. In the next post I would like to explain about how to query the entities with conditions thruogh LINQ. I also would like to refactor my AccountDataContext class to make it dyamic for any kinds of entities. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Parallelism in .NET – Part 3, Imperative Data Parallelism: Early Termination

- by Reed

Although simple data parallelism allows us to easily parallelize many of our iteration statements, there are cases that it does not handle well. In my previous discussion, I focused on data parallelism with no shared state, and where every element is being processed exactly the same. Unfortunately, there are many common cases where this does not happen. If we are dealing with a loop that requires early termination, extra care is required when parallelizing. Often, while processing in a loop, once a certain condition is met, it is no longer necessary to continue processing. This may be a matter of finding a specific element within the collection, or reaching some error case. The important distinction here is that, it is often impossible to know until runtime, what set of elements needs to be processed. In my initial discussion of data parallelism, I mentioned that this technique is a candidate when you can decompose the problem based on the data involved, and you wish to apply a single operation concurrently on all of the elements of a collection. This covers many of the potential cases, but sometimes, after processing some of the elements, we need to stop processing. As an example, lets go back to our previous Parallel.ForEach example with contacting a customer. However, this time, we’ll change the requirements slightly. In this case, we’ll add an extra condition – if the store is unable to email the customer, we will exit gracefully. The thinking here, of course, is that if the store is currently unable to email, the next time this operation runs, it will handle the same situation, so we can just skip our processing entirely. The original, serial case, with this extra condition, might look something like the following: foreach(var customer in customers) { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) break; customer.LastEmailContact = DateTime.Now; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Here, we’re processing our loop, but at any point, if we fail to send our email successfully, we just abandon this process, and assume that it will get handled correctly the next time our routine is run. If we try to parallelize this using Parallel.ForEach, as we did previously, we’ll run into an error almost immediately: the break statement we’re using is only valid when enclosed within an iteration statement, such as foreach. When we switch to Parallel.ForEach, we’re no longer within an iteration statement – we’re a delegate running in a method. This needs to be handled slightly differently when parallelized. Instead of using the break statement, we need to utilize a new class in the Task Parallel Library: ParallelLoopState. The ParallelLoopState class is intended to allow concurrently running loop bodies a way to interact with each other, and provides us with a way to break out of a loop. In order to use this, we will use a different overload of Parallel.ForEach which takes an IEnumerable<T> and an Action<T, ParallelLoopState> instead of an Action<T>. Using this, we can parallelize the above operation by doing: Parallel.ForEach(customers, (customer, parallelLoopState) => { // Run some process that takes some time... DateTime lastContact = theStore.GetLastContact(customer); TimeSpan timeSinceContact = DateTime.Now - lastContact; // If it's been more than two weeks, send an email, and update... if (timeSinceContact.Days > 14) { // Exit gracefully if we fail to email, since this // entire process can be repeated later without issue. if (theStore.EmailCustomer(customer) == false) parallelLoopState.Break(); else customer.LastEmailContact = DateTime.Now; } }); There are a couple of important points here. First, we didn’t actually instantiate the ParallelLoopState instance. It was provided directly to us via the Parallel class. All we needed to do was change our lambda expression to reflect that we want to use the loop state, and the Parallel class creates an instance for our use. We also needed to change our logic slightly when we call Break(). Since Break() doesn’t stop the program flow within our block, we needed to add an else case to only set the property in customer when we succeeded. This same technique can be used to break out of a Parallel.For loop. That being said, there is a huge difference between using ParallelLoopState to cause early termination and to use break in a standard iteration statement. When dealing with a loop serially, break will immediately terminate the processing within the closest enclosing loop statement. Calling ParallelLoopState.Break(), however, has a very different behavior. The issue is that, now, we’re no longer processing one element at a time. If we break in one of our threads, there are other threads that will likely still be executing. This leads to an important observation about termination of parallel code: Early termination in parallel routines is not immediate. Code will continue to run after you request a termination. This may seem problematic at first, but it is something you just need to keep in mind while designing your routine. ParallelLoopState.Break() should be thought of as a request. We are telling the runtime that no elements that were in the collection past the element we’re currently processing need to be processed, and leaving it up to the runtime to decide how to handle this as gracefully as possible. Although this may seem problematic at first, it is a good thing. If the runtime tried to immediately stop processing, many of our elements would be partially processed. It would be like putting a return statement in a random location throughout our loop body – which could have horrific consequences to our code’s maintainability. In order to understand and effectively write parallel routines, we, as developers, need a subtle, but profound shift in our thinking. We can no longer think in terms of sequential processes, but rather need to think in terms of requests to the system that may be handled differently than we’d first expect. This is more natural to developers who have dealt with asynchronous models previously, but is an important distinction when moving to concurrent programming models. As an example, I’ll discuss the Break() method. ParallelLoopState.Break() functions in a way that may be unexpected at first. When you call Break() from a loop body, the runtime will continue to process all elements of the collection that were found prior to the element that was being processed when the Break() method was called. This is done to keep the behavior of the Break() method as close to the behavior of the break statement as possible. We can see the behavior in this simple code: var collection = Enumerable.Range(0, 20); var pResult = Parallel.ForEach(collection, (element, state) => { if (element > 10) { Console.WriteLine("Breaking on {0}", element); state.Break(); } Console.WriteLine(element); }); If we run this, we get a result that may seem unexpected at first: 0 2 1 5 6 3 4 10 Breaking on 11 11 Breaking on 12 12 9 Breaking on 13 13 7 8 Breaking on 15 15 What is occurring here is that we loop until we find the first element where the element is greater than 10. In this case, this was found, the first time, when one of our threads reached element 11. It requested that the loop stop by calling Break() at this point. However, the loop continued processing until all of the elements less than 11 were completed, then terminated. This means that it will guarantee that elements 9, 7, and 8 are completed before it stops processing. You can see our other threads that were running each tried to break as well, but since Break() was called on the element with a value of 11, it decides which elements (0-10) must be processed. If this behavior is not desirable, there is another option. Instead of calling ParallelLoopState.Break(), you can call ParallelLoopState.Stop(). The Stop() method requests that the runtime terminate as soon as possible , without guaranteeing that any other elements are processed. Stop() will not stop the processing within an element, so elements already being processed will continue to be processed. It will prevent new elements, even ones found earlier in the collection, from being processed. Also, when Stop() is called, the ParallelLoopState’s IsStopped property will return true. This lets longer running processes poll for this value, and return after performing any necessary cleanup. The basic rule of thumb for choosing between Break() and Stop() is the following. Use ParallelLoopState.Stop() when possible, since it terminates more quickly. This is particularly useful in situations where you are searching for an element or a condition in the collection. Once you’ve found it, you do not need to do any other processing, so Stop() is more appropriate. Use ParallelLoopState.Break() if you need to more closely match the behavior of the C# break statement. Both methods behave differently than our C# break statement. Unfortunately, when parallelizing a routine, more thought and care needs to be put into every aspect of your routine than you may otherwise expect. This is due to my second observation: Parallelizing a routine will almost always change its behavior. This sounds crazy at first, but it’s a concept that’s so simple its easy to forget. We’re purposely telling the system to process more than one thing at the same time, which means that the sequence in which things get processed is no longer deterministic. It is easy to change the behavior of your routine in very subtle ways by introducing parallelism. Often, the changes are not avoidable, even if they don’t have any adverse side effects. This leads to my final observation for this post: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

- by Reed

In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations. Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects. By introducing Parallelism to our declarative model, we add some extra complexity. This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable. The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>. Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface. This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Other LINQ variants work in a similar fashion. For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable. When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel(). This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ. There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>. Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type. This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>. The difference only arises at the beginning of our parallelization. When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel(). There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>. This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning. This can be useful if you have an operation which will not parallelize well or is not thread safe. For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects. If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation. PLINQ, by default, does not preserve the order of of source collection. This is by design. In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time. Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary. Therefore, by default, the system is allowed to completely change the order of your sequence during processing. If you are doing a standard query operation, this is usually not an issue. However, there are times when keeping a specific ordering in place is important. If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method. This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements. In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved. To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially. This will cause our query to run slower, since there is overhead involved in maintaining the ordering. However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful. It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously. There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything. When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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Dual Boot issues with Windows 7 and Ubuntu

- by Michael

I'm finding myself in a rather unique situation. I've read through just about every resource I can find about this and while things have helped me understand some background, I haven't yet been able to find a solution. So I'm asking here. I originally had just a Windows 7 64-bit OS installation on my desktop. Learning that I couldn't do anything with Apache, PHP and MySql from within a 64-bit system, I did some research and found out that I could use Ubuntu. I've installed the latest version: 11.04. I created a CD to install Ubuntu from and the install went just fine. I installed it side-by-side with Windows 7. I can boot into Ubuntu just fine through the dual-boot option. When I reboot to load Windows though, the Grub2 list shows Windows 7 (loader) and when I select this option the Windows System Recovery loads instead of the actual OS. I haven't made it past there because I didn't know what to do. I just shut the computer down and rebooted into Ubuntu. I've been working for the last hour and a half to try to figure out how to boot into the Windows 7 OS and I haven't got a clue. While I'm somewhat proficient with Windows 7, I'm totally new to Ubuntu, so if you do know what needs to happen, please keep it simple enough that I'll be able to understand. Thanks for all your help in advance. Here's the results after using the Boot Info Script: Boot Info Script 0.55 dated February 15th, 2010 ============================= Boot Info Summary: ============================== => Grub 2 is installed in the MBR of /dev/sda and looks on the same drive in partition #5 for cbh. => Windows is installed in the MBR of /dev/sdb => Grub 2 is installed in the MBR of /dev/mapper/pdc_bdadcfbdif and looks on the same drive in partition #5 for cbh. sda1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sda2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sda3: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy sdb1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /Boot/BCD sdb2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: sdb3: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /boot/BCD sdb4: _________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: _________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 11.04 Boot files/dirs: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb6: _________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: pdc_bdadcfbdif1: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files/dirs: /bootmgr /Boot/BCD pdc_bdadcfbdif2: _________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files/dirs: /bootmgr /Boot/BCD /Windows/System32/winload.exe pdc_bdadcfbdif3: _________________________________________________________________________ File system: Boot sector type: Unknown Boot sector info: Mounting failed: fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy fuse: mount failed: Device or resource busy mount: unknown filesystem type '' =========================== Drive/Partition Info: ============================= Drive: sda ___________________ _____________________________________________________ Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/sda1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/sda2 206,911 1,440,372,735 1,440,165,825 7 HPFS/NTFS /dev/sda3 1,440,372,736 1,464,856,575 24,483,840 7 HPFS/NTFS Drive: sdb ___________________ _____________________________________________________ Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/sdb1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/sdb2 206,911 1,342,554,688 1,342,347,778 7 HPFS/NTFS /dev/sdb3 1,930,344,448 1,953,521,663 23,177,216 7 HPFS/NTFS /dev/sdb4 1,342,556,158 1,930,344,447 587,788,290 5 Extended /dev/sdb5 1,342,556,160 1,896,806,399 554,250,240 83 Linux /dev/sdb6 1,896,808,448 1,930,344,447 33,536,000 82 Linux swap / Solaris Drive: pdc_bdadcfbdif ___________________ _____________________________________________________ Disk /dev/mapper/pdc_bdadcfbdif: 750.0 GB, 749999947776 bytes 255 heads, 63 sectors/track, 91182 cylinders, total 1464843648 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start End Size Id System /dev/mapper/pdc_bdadcfbdif1 * 2,048 206,847 204,800 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif2 206,911 1,440,372,735 1,440,165,825 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif3 1,440,372,736 1,464,856,575 24,483,840 7 HPFS/NTFS /dev/mapper/pdc_bdadcfbdif3 ends after the last sector of /dev/mapper/pdc_bdadcfbdif blkid -c /dev/null: ____________________________________________________________ Device UUID TYPE LABEL /dev/mapper/pdc_bdadcfbdif1 888E54CC8E54B482 ntfs SYSTEM /dev/mapper/pdc_bdadcfbdif2 C2766BF6766BEA1D ntfs OS /dev/mapper/pdc_bdadcfbdif: PTTYPE="dos" /dev/sda1 888E54CC8E54B482 ntfs SYSTEM /dev/sda2 C2766BF6766BEA1D ntfs OS /dev/sda3 BE6CA31D6CA2CF87 ntfs HP_RECOVERY /dev/sda promise_fasttrack_raid_member /dev/sdb1 20B65685B6565B7C ntfs SYSTEM /dev/sdb2 B4467A314679F508 ntfs HP /dev/sdb3 6E10B7A410B77227 ntfs FACTORY_IMAGE /dev/sdb4: PTTYPE="dos" /dev/sdb5 266f9801-cf4f-4acc-affa-2092be035f0c ext4 /dev/sdb6 1df35749-a887-45ff-a3de-edd52239847d swap /dev/sdb: PTTYPE="dos" error: /dev/mapper/pdc_bdadcfbdif3: No such file or directory error: /dev/sdc: No medium found error: /dev/sdd: No medium found error: /dev/sde: No medium found error: /dev/sdf: No medium found error: /dev/sdg: No medium found ============================ "mount | grep ^/dev output: =========================== Device Mount_Point Type Options /dev/sdb5 / ext4 (rw,errors=remount-ro,commit=0) =========================== sdb5/boot/grub/grub.cfg: =========================== # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm fi terminal_output gfxterm insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 2.6.38-8-generic-pae' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux /boot/vmlinuz-2.6.38-8-generic-pae root=UUID=266f9801-cf4f-4acc- affa-2092be035f0c ro quiet splash vt.handoff=7 initrd /boot/initrd.img-2.6.38-8-generic-pae } menuentry 'Ubuntu, with Linux 2.6.38-8-generic-pae (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c echo 'Loading Linux 2.6.38-8-generic-pae ...' linux /boot/vmlinuz-2.6.38-8-generic-pae root=UUID=266f9801-cf4f-4acc-affa-2092be035f0c ro single echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-2.6.38-8-generic-pae } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(/dev/sdb,msdos5)' search --no-floppy --fs-uuid --set=root 266f9801-cf4f-4acc-affa-2092be035f0c linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sdb1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(/dev/sdb,msdos1)' search --no-floppy --fs-uuid --set=root 20B65685B6565B7C chainloader +1 } menuentry "Windows Recovery Environment (loader) (on /dev/sdb3)" --class windows --class os { insmod part_msdos insmod ntfs set root='(/dev/sdb,msdos3)' search --no-floppy --fs-uuid --set=root 6E10B7A410B77227 drivemap -s (hd0) ${root} chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### =============================== sdb5/etc/fstab: =============================== # /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' to print the universally unique identifier # for a device; this may be used with UUID= as a more robust way to name # devices that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sdb5 during installation UUID=266f9801-cf4f-4acc-affa-2092be035f0c / ext4 errors=remount-ro 0 1 # swap was on /dev/sdb6 during installation UUID=1df35749-a887-45ff-a3de-edd52239847d none swap sw 0 0 =================== sdb5: Location of files loaded by Grub: =================== 900.1GB: boot/grub/core.img 825.0GB: boot/grub/grub.cfg 688.7GB: boot/initrd.img-2.6.38-8-generic-pae 688.0GB: boot/vmlinuz-2.6.38-8-generic-pae 688.7GB: initrd.img 688.0GB: vmlinuz =========================== Unknown MBRs/Boot Sectors/etc ======================= Unknown BootLoader on pdc_bdadcfbdif3 =======Devices which don't seem to have a corresponding hard drive============== sdc sdd sde sdf sdg =============================== StdErr Messages: =============================== ERROR: dos: partition address past end of RAID device hexdump: /dev/mapper/pdc_bdadcfbdif3: No such file or directory hexdump: /dev/mapper/pdc_bdadcfbdif3: No such file or directory ERROR: dos: partition address past end of RAID device

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When should I use Areas in TFS instead of Team Projects

- by Martin Hinshelwood

Well, it depends…. If you are a small company that creates a finite number of internal projects then you will find it easier to create a single project for each of your products and have TFS do the heavy lifting with reporting, SharePoint sites and Version Control. But what if you are not… Update 9th March 2010 Michael Fourie gave me some feedback which I have integrated. Ed Blankenship via @edblankenship offered encouragement and a nice quote. Ewald Hofman gave me a couple of Cons, and maybe a few more soon. Ewald’s company, Avanade, currently uses Areas, but it looks like the manual management is getting too much and the project is getting cluttered. What if you are likely to have hundreds of projects, possibly with a multitude of internal and external projects? You might have 1 project for a customer or 10. This is the situation that most consultancies find themselves in and thus they need a more sustainable and maintainable option. What I am advocating is that we should have 1 “Team Project” per customer, and use areas to create “sub projects” within that single “Team Project”. "What you describe is what we generally do internally and what we recommend. We make very heavy use of area path to categorize the work within a larger project." - Brian Harry, Microsoft Technical Fellow & Product Unit Manager for Team Foundation Server "We tend to use areas to segregate multiple projects in the same team project and it works well." - Tiago Pascoal, Visual Studio ALM MVP "In general, I believe this approach provides consistency [to multi-product engagements] and lowers the administration and maintenance costs. All good." - Michael Fourie, Visual Studio ALM MVP “@MrHinsh BTW, I'm very much a fan of very large, if not huge, team projects in TFS. Just FYI :) Use Areas & Iterations.” Ed Blankenship, Visual Studio ALM MVP This would mean that SSW would have a single Team Project called “SSW” that contains all of our internal projects and consequently all of the Areas and Iteration move down one hierarchy to accommodate this. Where we would have had “\SSW\Sprint 1” we now have “\SSW\SqlDeploy\Sprint1” with “SqlDeploy” being our internal project. At the moment SSW has over 70 internal projects and more than 170 total projects in TFS. This method has long term benefits that help to simplify the support model for companies that often have limited internal support time and many projects. But, there are implications as TFS does not provide this model “out-of-the-box”. These implications stretch across Areas, Iterations, Queries, Project Portal and Version Control. Michael made a good comment, he said: I agree with your approach, assuming that in a multi-product engagement with a client, they are happy to adopt the same process template across all products. If they are not, then it’ll either be easy to convince them or there is a valid reason for having a different template - Michael Fourie, Visual Studio ALM MVP At SSW we have a standard template that we use and this is applied across the board, to all of our projects. We even apply any changes to the core process template to all of our existing projects as well. If you have multiple projects for the same clients on multiple templates and you want to keep it that way, then this approach will not work for you. However, if you want to standardise as we have at SSW then this approach may benefit you as well. Implications around Areas Areas should be used for topological classification/isolation of work items. You can think of this as architecture areas, organisational areas or even the main features of your application. In our scenario there is an additional top level item that represents the Project / Product that we want to chop our Team Project into. Figure: Creating a sub area to represent a product/project is easy. <teamproject> <teamproject>\<Functional Area/module whatever> Becomes: <teamproject> <teamproject>\<ProjectName>\ <teamproject>\<ProjectName>\<Functional Area/module whatever> Implications around Iterations Iterations should be used for chronological classification/isolation of work items. This could include isolated time boxes, milestones or release timelines and really depends on the logical flow of your project or projects. Due to the new level in Area we need to add the same level to Iteration. This is primarily because it is unlikely that the sprints in each of your projects/products will start and end at the same time. This is just a reality of managing multiple projects. Figure: Adding the same Area value to Iteration as the top level item adds flexibility to Iteration. <teamproject>\Sprint 1 Or <teamproject>\Release 1\Sprint 1 Becomes: <teamproject>\<ProjectName>\Sprint 1 Or <teamproject>\<ProjectName>\Release 1\Sprint 1 Implications around Queries Queries are used to filter your work items based on a specified level of granularity. There are a number of queries that are built into a project created using the MSF Agile 5.0 template, but we now have multiple projects and it would be a pain to have to edit all of the work items every time we changed project, and that would only allow one team to work on one project at a time. Figure: The Queries that are created in a normal MSF Agile 5.0 project do not quite suit our new needs. In order for project contributors to be able to query based on their project we need a couple of things. The first thing I did was to create an “_Area Template” folder that has a copy of the project layout with all the queries setup to filter based on the “_Area Template” Area and the “_Sprint template” you can see in the Area and Iteration views. Figure: The template is currently easily drag and drop, but you then need to edit the queries to point at the right Area and Iteration. This needs a tool. I then created an “Areas” folder to hold all of the area specific queries. So, when you go to create a new TFS Sub-Project you just drag “_Area Template” while holding “Ctrl” and drop it onto “Areas”. There is a little setup here. That said I managed it in around 10 minutes which is not so bad, and I can imagine it being quite easy to build a tool to create these queries Figure: These new queries can be configured in around 10 minutes, which includes setting up the Area and Iteration as well. Version Control What about your source code? Well, that is the easiest of the lot. Just create a sub folder for each of your projects/products. Figure: Creating sub folders in source control is easy as “Right click | Create new folder”. <teamproject>\DEV\Main\ Becomes: <teamproject>\<ProjectName>\DEV\Main\ Conclusion I think it is up to each company to make a call on how you want to configure your Team Projects and it depends completely on how many projects/products you are going to have for each customer including yourself. If we decide to utilise this route it will require some configuration to get our 170+ projects into this format, and I will probably be writing some tools to help. Pros You only have one project to upgrade when a process template changes – After going through an upgrade of over 170 project prior to the changes in the RC I can tell you that that many projects is no fun. Standardises your Process Template – You will always have the same Process implementation across projects/products without exception You get tighter control over the permissions – Yes, you can do this on a standard Team Project, but it gets a lot easier with practice. You can “move” work items from one “product” to another – Have we not always wanted to do that. You can rename your projects – Wahoo: everyone wants to do this, now you can. One set of Reporting Services reports to manage – You set an area and iteration to run reports anyway, so you may as well set both. Simplified Check-In Policies– There is only one set of check-in policies per client. This simplifies administration of policies. Simplified Alerts – As alerts are applied across multiple projects this simplifies your alert rules as per client. Cons All of these cons could be mitigated by a custom tool that helps automate creation of “Sub-projects” within Team Projects. This custom tool could create areas, Iteration, permissions, SharePoint and queries. It just does not exist yet :) You need to configure the Areas and Iterations You need to configure the permissions You may need to configure sub sites for SharePoint (depends on your requirement) – If you have two projects/products in the same Team Project then you will not see the burn down for each one out-of-the-box, but rather a cumulative for the Team Project. This is not really that much of a problem as you would have to configure your burndown graphs for your current iteration anyway. note: When you create a sub site to a TFS linked portal it will inherit the settings of its parent site :) This is fantastic as it means that you can easily create sub sites and then set the Area and Iteration path in each of the reports to be the correct one. Every team wants their own customization (via Ewald Hofman) - small teams of 2 persons against teams of 30 – or even outsourcing – need their own process, you cannot allow that because everybody gets the same work item types. note: Luckily at SSW this is not a problem as our template is standardised across all projects and customers. Large list of builds (via Ewald Hofman) – As the build list in Team Explorer is just a flat list it can get very cluttered. note: I would mitigate this by removing any build that has not been run in over 30 days. The build template and workflow will still be available in version control, but it will clean the list. Feedback Now that I have explained this method, what do you think? What other pros and cons can you see? What do you think of this approach? Will you be using it? What tools would you like to support you? Technorati Tags: Visual Studio ALM,TFS Administration,TFS,Team Foundation Server,Project Planning,TFS Customisation

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ASP.NET GZip Encoding Caveats

- by Rick Strahl

GZip encoding in ASP.NET is pretty easy to accomplish using the built-in GZipStream and DeflateStream classes and applying them to the Response.Filter property. While applying GZip and Deflate behavior is pretty easy there are a few caveats that you have watch out for as I found out today for myself with an application that was throwing up some garbage data. But before looking at caveats let’s review GZip implementation for ASP.NET. ASP.NET GZip/Deflate Basics Response filters basically are applied to the Response.OutputStream and transform it as data is written to it through the ASP.NET Response object. So a Response.Write eventually gets written into the output stream which if a filter is also written through the filter stream’s interface. To perform the actual GZip (and Deflate) encoding typically used by Web pages .NET includes the GZipStream and DeflateStream stream classes which can be readily assigned to the Repsonse.OutputStream. With these two stream classes in place it’s almost trivially easy to create a couple of reusable methods that allow you to compress your HTTP output. In my standard WebUtils utility class (from the West Wind West Wind Web Toolkit) created two static utility methods – IsGZipSupported and GZipEncodePage – that check whether the client supports GZip encoding and then actually encodes the current output (note that although the method includes ‘Page’ in its name this code will work with any ASP.NET output). /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("deflate")) { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } else { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } } } As you can see the actual assignment of the Filter is as simple as: Response.Filter = new DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); which applies the filter to the OutputStream. You also need to ensure that your response reflects the new GZip or Deflate encoding and ensure that any pages that are cached in Proxy servers can differentiate between pages that were encoded with the various different encodings (or no encoding). To use this utility function now is trivially easy: In any ASP.NET code that wants to compress its Response output you simply use: protected void Page_Load(object sender, EventArgs e) { WebUtils.GZipEncodePage(); Entry = WebLogFactory.GetEntry(); var entries = Entry.GetLastEntries(App.Configuration.ShowEntryCount, "pk,Title,SafeTitle,Body,Entered,Feedback,Location,ShowTopAd", "TEntries"); if (entries == null) throw new ApplicationException("Couldn't load WebLog Entries: " + Entry.ErrorMessage); this.repEntries.DataSource = entries; this.repEntries.DataBind(); } Here I use an ASP.NET page, but the above WebUtils.GZipEncode() method call will work in any ASP.NET application type including HTTP Handlers. The only requirement is that the filter needs to be applied before any other output is sent to the OutputStream. For example, in my CallbackHandler service implementation by default output over a certain size is GZip encoded. The output that is generated is JSON or XML and if the output is over 5k in size I apply WebUtils.GZipEncode(): if (sbOutput.Length > GZIP_ENCODE_TRESHOLD) WebUtils.GZipEncodePage(); Response.ContentType = ControlResources.STR_JsonContentType; HttpContext.Current.Response.Write(sbOutput.ToString()); Ok, so you probably get the idea: Encoding GZip/Deflate content is pretty easy. Hold on there Hoss –Watch your Caching Or is it? There are a few caveats that you need to watch out for when dealing with GZip content. The fist issue is that you need to deal with the fact that some clients don’t support GZip or Deflate content. Most modern browsers support it, but if you have a programmatic Http client accessing your content GZip/Deflate support is by no means guaranteed. For example, WinInet Http clients don’t support GZip out of the box – it has to be explicitly implemented. Other low level HTTP clients on other platforms too don’t support GZip out of the box. The problem is that your application, your Web Server and Proxy Servers on the Internet might be caching your generated content. If you return content with GZip once and then again without, either caching is not applied or worse the wrong type of content is returned back to the client from a cache or proxy. The result is an unreadable response for *some clients* which is also very hard to debug and fix once in production. You already saw the issue of Proxy servers addressed in the GZipEncodePage() function: // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); This ensures that any Proxy servers also check for the Content-Encoding HTTP Header to cache their content – not just the URL. The same thing applies if you do OutputCaching in your own ASP.NET code. If you generate output for GZip on an OutputCached page the GZipped content will be cached (either by ASP.NET’s cache or in some cases by the IIS Kernel Cache). But what if the next client doesn’t support GZip? She’ll get served a cached GZip page that won’t decode and she’ll get a page full of garbage. Wholly undesirable. To fix this you need to add some custom OutputCache rules by way of the GetVaryByCustom() HttpApplication method in your global_ASAX file: public override string GetVaryByCustomString(HttpContext context, string custom) { // Override Caching for compression if (custom == "GZIP") { string acceptEncoding = HttpContext.Current.Response.Headers["Content-Encoding"]; if (string.IsNullOrEmpty(acceptEncoding)) return ""; else if (acceptEncoding.Contains("gzip")) return "GZIP"; else if (acceptEncoding.Contains("deflate")) return "DEFLATE"; return ""; } return base.GetVaryByCustomString(context, custom); } In a page that use Output caching you then specify: <%@ OutputCache Duration="180" VaryByParam="none" VaryByCustom="GZIP" %> To use that custom rule. It’s all Fun and Games until ASP.NET throws an Error Ok, so you’re up and running with GZip, you have your caching squared away and your pages that you are applying it to are jamming along. Then BOOM, something strange happens and you get a lovely garbled page that look like this: Lovely isn’t it? What’s happened here is that I have WebUtils.GZipEncode() applied to my page, but there’s an error in the page. The error falls back to the ASP.NET error handler and the error handler removes all existing output (good) and removes all the custom HTTP headers I’ve set manually (usually good, but very bad here). Since I applied the Response.Filter (via GZipEncode) the output is now GZip encoded, but ASP.NET has removed my Content-Encoding header, so the browser receives the GZip encoded content without a notification that it is encoded as GZip. The result is binary output. Here’s what Fiddler says about the raw HTTP header output when an error occurs when GZip encoding was applied: HTTP/1.1 500 Internal Server Error Cache-Control: private Content-Type: text/html; charset=utf-8 Date: Sat, 30 Apr 2011 22:21:08 GMT Content-Length: 2138 Connection: close ?`I?%&/m?{J?J??t??` … binary output striped here Notice: no Content-Encoding header and that’s why we’re seeing this garbage. ASP.NET has stripped the Content-Encoding header but left our filter intact. So how do we fix this? In my applications I typically have a global Application_Error handler set up and in this case I’ve been using that. One thing that you can do in the Application_Error handler is explicitly clear out the Response.Filter and set it to null at the top: protected void Application_Error(object sender, EventArgs e) { // Remove any special filtering especially GZip filtering Response.Filter = null; … } And voila I get my Yellow Screen of Death or my custom generated error output back via uncompressed content. BTW, the same is true for Page level errors handled in Page_Error or ASP.NET MVC Error handling methods in a controller. Another and possibly even better solution is to check whether a filter is attached just before the headers are sent to the client as pointed out by Adam Schroeder in the comments: protected void Application_PreSendRequestHeaders() { // ensure that if GZip/Deflate Encoding is applied that headers are set // also works when error occurs if filters are still active HttpResponse response = HttpContext.Current.Response; if (response.Filter is GZipStream && response.Headers["Content-encoding"] != "gzip") response.AppendHeader("Content-encoding", "gzip"); else if (response.Filter is DeflateStream && response.Headers["Content-encoding"] != "deflate") response.AppendHeader("Content-encoding", "deflate"); } This uses the Application_PreSendRequestHeaders() pipeline event to check for compression encoding in a filter and adjusts the content accordingly. This is actually a better solution since this is generic – it’ll work regardless of how the content is cleaned up. For example, an error Response.Redirect() or short error display might get changed and the filter not cleared and this code actually handles that. Sweet, thanks Adam. It’s unfortunate that ASP.NET doesn’t natively clear out Response.Filters when an error occurs just as it clears the Response and Headers. I can’t see where leaving a Filter in place in an error situation would make any sense, but hey - this is what it is and it’s easy enough to fix as long as you know where to look. Riiiight! IIS and GZip I should also mention that IIS 7 includes good support for compression natively. If you can defer encoding to let IIS perform it for you rather than doing it in your code by all means you should do it! Especially any static or semi-dynamic content that can be made static should be using IIS built-in compression. Dynamic caching is also supported but is a bit more tricky to judge in terms of performance and footprint. John Forsyth has a great article on the benefits and drawbacks of IIS 7 compression which gives some detailed performance comparisons and impact reviews. I’ll post another entry next with some more info on IIS compression since information on it seems to be a bit hard to come by. Related Content Built-in GZip/Deflate Compression in IIS 7.x HttpWebRequest and GZip Responses © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET IIS7

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How about a new platform for your next API… a CMS?

- by Elton Stoneman

Originally posted on: http://geekswithblogs.net/EltonStoneman/archive/2014/05/22/how-about-a-new-platform-for-your-next-apihellip-a.aspxSay what? I’m seeing a type of API emerge which serves static or long-lived resources, which are mostly read-only and have a controlled process to update the data that gets served. Think of something like an app configuration API, where you want a central location for changeable settings. You could use this server side to store database connection strings and keep all your instances in sync, or it could be used client side to push changes out to all users (and potentially driving A/B or MVT testing). That’s a good candidate for a RESTful API which makes proper use of HTTP expiration and validation caching to minimise traffic, but really you want a front end UI where you can edit the current config that the API returns and publish your changes. Sound like a Content Mangement System would be a good fit? I’ve been looking at that and it’s a great fit for this scenario. You get a lot of what you need out of the box, the amount of custom code you need to write is minimal, and you get a whole lot of extra stuff from using CMS which is very useful, but probably not something you’d build if you had to put together a quick UI over your API content (like a publish workflow, fine-grained security and an audit trail). You typically use a CMS for HTML resources, but it’s simple to expose JSON instead – or to do content negotiation to support both, so you can open a resource in a browser and see a nice visual representation, or request it with: Accept=application/json and get the same content rendered as JSON for the app to use. Enter Umbraco Umbraco is an open source .NET CMS that’s been around for a while. It has very good adoption, a lively community and a good release cycle. It’s easy to use, has all the functionality you need for a CMS-driven API, and it’s scalable (although you won’t necessarily put much scale on the CMS layer). In the rest of this post, I’ll build out a simple app config API using Umbraco. We’ll define the structure of the configuration resource by creating a new Document Type and setting custom properties; then we’ll build a very simple Razor template to return configuration documents as JSON; then create a resource and see how it looks. And we’ll look at how you could build this into a wider solution. If you want to try this for yourself, it’s ultra easy – there’s an Umbraco image in the Azure Website gallery, so all you need to to is create a new Website, select Umbraco from the image and complete the installation. It will create a SQL Azure website to store all the content, as well as a Website instance for editing and accessing content. They’re standard Azure resources, so you can scale them as you need. The default install creates a starter site for some HTML content, which you can use to learn your way around (or just delete). 1. Create Configuration Document Type In Umbraco you manage content by creating and modifying documents, and every document has a known type, defining what properties it holds. We’ll create a new Document Type to describe some basic config settings. In the Settings section from the left navigation (spanner icon), expand Document Types and Master, hit the ellipsis and select to create a new Document Type: This will base your new type off the Master type, which gives you some existing properties that we’ll use – like the Page Title which will be the resource URL. In the Generic Properties tab for the new Document Type, you set the properties you’ll be able to edit and return for the resource: Here I’ve added a text string where I’ll set a default cache lifespan, an image which I can use for a banner display, and a date which could show the user when the next release is due. This is the sort of thing that sits nicely in an app config API. It’s likely to change during the life of the product, but not very often, so it’s good to have a centralised place where you can make and publish changes easily and safely. It also enables A/B and MVT testing, as you can change the response each client gets based on your set logic, and their apps will behave differently without needing a release. 2. Define the response template Now we’ve defined the structure of the resource (as a document), in Umbraco we can define a C# Razor template to say how that resource gets rendered to the client. If you only want to provide JSON, it’s easy to render the content of the document by building each property in the response (Umbraco uses dynamic objects so you can specify document properties as object properties), or you can support content negotiation with very little effort. Here’s a template to render the document as HTML or JSON depending on the Accept header, using JSON.NET for the API rendering: @inherits Umbraco.Web.Mvc.UmbracoTemplatePage @using Newtonsoft.Json @{ Layout = null; } @if(UmbracoContext.HttpContext.Request.Headers["accept"] != null && UmbracoContext.HttpContext.Request.Headers["accept"] == "application/json") { Response.ContentType = "application/json"; @Html.Raw(JsonConvert.SerializeObject(new { cacheLifespan = CurrentPage.cacheLifespan, bannerImageUrl = CurrentPage.bannerImage, nextReleaseDate = CurrentPage.nextReleaseDate })) } else { <h1>App configuration</h1> <p>Cache lifespan: <b>@CurrentPage.cacheLifespan</b></p> <p>Banner Image: </p> <img src="@CurrentPage.bannerImage"> <p>Next Release Date: <b>@CurrentPage.nextReleaseDate</b></p> } That’s a rough-and ready example of what you can do. You could make it completely generic and just render all the document’s properties as JSON, but having a specific template for each resource gives you control over what gets sent out. And the templates are evaluated at run-time, so if you need to change the output – or extend it, say to add caching response headers – you just edit the template and save, and the next client request gets rendered from the new template. No code to build and ship. 3. Create the content With your document type created, in the Content pane you can create a new instance of that document, where Umbraco gives you a nice UI to input values for the properties we set up on the Document Type: Here I’ve set the cache lifespan to an xs:duration value, uploaded an image for the banner and specified a release date. Each property gets the appropriate input control – text box, file upload and date picker. At the top of the page is the name of the resource – myapp in this example. That specifies the URL for the resource, so if I had a DNS entry pointing to my Umbraco instance, I could access the config with a URL like http://static.x.y.z.com/config/myapp. The setup is all done now, so when we publish this resource it’ll be available to access. 4. Access the resource Now if you open that URL in the browser, you’ll see the HTML version rendered: - complete with the image and formatted date. Umbraco lets you save changes and preview them before publishing, so the HTML view could be a good way of showing editors their changes in a usable view, before they confirm them. If you browse the same URL from a REST client, specifying the Accept=application/json request header, you get this response: That’s the exact same resource, with a managed UI to publish it, being accessed as HTML or JSON with a tiny amount of effort. 5. The wider landscape If you have fairy stable content to expose as an API, I think this approach is really worth considering. Umbraco scales very nicely, but in a typical solution you probably wouldn’t need it to. When you have additional requirements, like logging API access requests - but doing it out-of-band so clients aren’t impacted, you can put a very thin API layer on top of Umbraco, and cache the CMS responses in your API layer: Here the API does a passthrough to CMS, so the CMS still controls the content, but it caches the response. If the response is cached for 1 minute, then Umbraco only needs to handle 1 request per minute (multiplied by the number of API instances), so if you need to support 1000s of request per second, you’re scaling a thin, simple API layer rather than having to scale the more complex CMS infrastructure (including the database). This diagram also shows an approach to logging, by asynchronously publishing a message to a queue (Redis in this case), which can be picked up later and persisted by a different process. Does it work? Beautifully. Using Azure, I spiked the solution above (including the Redis logging framework which I’ll blog about later) in half a day. That included setting up different roles in Umbraco to demonstrate a managed workflow for publishing changes, and a couple of document types representing different resources. Is it maintainable? We have three moving parts, which are all managed resources in Azure – an Azure Website for Umbraco which may need a couple of instances for HA (or may not, depending on how long the content can be cached), a message queue (Redis is in preview in Azure, but you can easily use Service Bus Queues if performance is less of a concern), and the Web Role for the API. Two of the components are off-the-shelf, from open source projects, and the only custom code is the API which is very simple. Does it scale? Pretty nicely. With a single Umbraco instance running as an Azure Website, and with 4x instances for my API layer (Standard sized Web Roles), I got just under 4,000 requests per second served reliably, with a Worker Role in the background saving the access logs. So we had a nice UI to publish app config changes, with a friendly Web preview and a publishing workflow, capable of supporting 14 million requests in an hour, with less than a day’s effort. Worth considering if you’re publishing long-lived resources through your API.

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CodePlex Daily Summary for Tuesday, March 09, 2010

CodePlex Daily Summary for Tuesday, March 09, 2010New Projects.NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: .NET Excel Wrapper encapsulates the complexity of working with multiple Excel objects giving you one central point to do all your processing. It h...Advancement Voyage: Advancement Voyage is a high quality RPG experience that provides all the advancement and voyaging that a player could hope for.ASP.Net Routing configuration: ASP.NET routing configuration enables you to configure the routes in the web.config bbinjest: bbinjestBuildUp: BuildUp is a build number increment tool for C# .net projects. It is run as a post build step in Visual Studio.Controlled Vocabulary: This project is devoted to creating tools to assist with Controlling Vocabulary in communication. The initial delivery is an Outlook 2010 Add-in w...CycleList: A replacement for the WPF ListBox Control. Displays only a single item and allows the user to change the selected item by clicking on it once. Very...Forensic Suite: A suite of security softwareFREE DNN Chat Module for 123 Flash Chat -- Embed FREE Chat Room!: 123 Flash Chat is a live chat solution and its DotNetNuke Chat Module helps to embed a live chat room into website with DotNetNuke(DNN) integrated ...HouseFly experimental controls: Experimental controls for use in HouseFly.ICatalogAll: junkMidiStylus: MidiStylus allows you to control MIDI-enabled hardware or software using your pressure-sensitive pen tablet. The program maps the X position, Y po...myTunes: Search for your favorite artistsNColony - Pluggable Socialism?: NColony will maximize the use of MEF to create flexible application architectures through a suite of plug-in solutions. If MEF is an outlet for plu...Network Monitor Decryption Expert: NmDecrypt is a Network Monitor Expert which when given a trace with encrypted frames, a security certificate, and a passkey will create a new trace...occulo: occulo is a free steganography program, meant to embed files within images with optional encrytion. Open Ant: A implementation of a Open Source Ant which is created to show what is possible in the serious game AntMe! The First implementation of that ProjectProgramming Patterns by example: Design patterns provide solutions to common software design problems. This project will contain samples, written in c# and ruby, of each design pat...project4k: Developing bulk mail system storing email informationQuail - Selenium Remote Control Made Easy: Quail makes it easy for Quality Assurance departments write automated tests against web applications. Both HTML and Silverlight applications can b...RedBulb for XNA Framework: RedBulb is a collection of utility functions and classes that make writing games with XNA a lot easier. Key features: Console,GUI (Labels, Buttons,...RegExpress: RegExpress is a WPF application that combines interactive demos of regular expressions with slide content. This was designed for a user group prese...RemoveFolder: Small utility program to remove empty foldersScrumTFS: ScrumTFSSharePoint - Open internal link in new window list definition: A simple SharePoint list definition to render SharePoint internal links with the option to open them in a new window.SqlSiteMap4MVC: SqlSiteMapProvider for ASP.Net MVC.T Sina .NET Client: t.sina.com.cn api 新浪微博APITest-Lint-Extensions: Test Lint is a free Typemock VS 2010 Extension that finds common problems in your unit tests as you type them. this project will host extensions ...ThinkGearNET: ThinkGearNET is a library for easy usage of the Neurosky Mindset headset from .NET .Wiki to Maml: This project enables you to write wiki syntax and have it converted into MAML syntax for Sandcastle documentation projects.WPF Undo/Redo Framework: This project attempts to solve the age-old programmer problem of supporting unlimited undo/redo in an application, in an easily reusable manner. Th...WPFValidators: WPF Validators Validações de campos para WPFWSP Listener: The WSP listener is a windows service application which waits for new WSC and WSP files in a specific folder. If a new WSC and WSP file are added, ...New Releases.NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: First Release: This is the first release which includes the main library release..NET Excel Wrapper - Read, Write, Edit & Automate Excel Files in .NET with ease: Updated Version: New Features:SetRangeValue using multidimensional array Print current worksheet Print all worksheets Format ranges background, color, alig...ArkSwitch: ArkSwitch v1.1.2: This release removes all memory reporting information, and is focused on stability.BattLineSvc: V2.1: - Fixed a bug where on system start-up, it would pop up a notification box to let you know the service started. Annoying! And fixed! - Fixed the ...BuildUp: BuildUp 1.0 Alpha 1: Use at your own risk!Not yet feature complete. Basic build incrementing and attribute overriding works. Still working on cascading build incremen...Controlled Vocabulary: 1.0.0.1: Initial Alpha Release. System Requirements Outlook 2010 .Net Framework 3.5 Installation 1. Close Outlook (Use Task Manager to ensure no running i...CycleList: CycleList: The binaries contain the .NET 3.5 DLL ONLY. Please download source for usage examples.FluentNHibernate.Search: 0.3 Beta: 0.3 Beta take the following changes : Mappings : - Field Mapping without specifying "Name" - Id Mapping without specifiying "Field" - Builtin Anal...FREE DNN Chat Module for 123 Flash Chat -- Embed FREE Chat Room!: 123 Flash Chat DNN Chat Module: With FREE DotNetNuke Chat Module of 123 Flash Chat, webmaster will be assist to add a chat room into DotNetNuke instantly and help to attract more ...GameStore League Manager: League Manager 1.0 release 3: This release includes a full installer so that you can get your league running faster and generate interest quicker.iExporter - iTunes playlist exporting: iExporter gui v2.3.1.0 - console v1.2.1.0: Paypal donate! Solved a big bug for iExporter ( Gui & Console ) When a track isn't located under the main iTunes library, iExporter would crash! ...jQuery.cssLess: jQuery.cssLess 0.3: New - Removed the dependency from XRegExp - Added comment support (both CSS style and C style) - Optimised it for speed - Added speed test TOD...jQuery.cssLess: jQuery.cssLess 0.4: NEW - @import directive - preserving of comments in the resulting CSS - code refactoring - more class oriented approach TODO - implement operation...MapWindow GIS: MapWindow 6.0 msi (March 8): Rewrote the shapefile saving code in the indexed case so that it uses the shape indices rather than trying to create features. This should allow s...MidiStylus: MidiStylus 0.5.1: MidiStylus Beta 0.5.1 This release contains basic functionality for transmitting MIDI data based on X position, Y position, and pressure value rea...MiniTwitter: 1.09.1: MiniTwitter 1.09.1 更新内容修正 URL に & が含まれている時に短縮 URL がおかしくなるバグを修正Mosaictor: first executable: .exe file of the app in its current state. Mind you that this will likely be highly unstable due to heaps of uncaught errors.MvcContrib a Codeplex Foundation project: T4MVC: T4MVC is a T4 template that generates strongly typed helpers for ASP.NET MVC. You can download it below, and check out the documention here.N2 CMS: 2.0 beta: Major Changes ASP.NET MVC 2 templates Refreshed management UI LINQ support Performance improvements Auto image resize Upgrade Make a comp...NotesForGallery: ASP.NET AJAX Photo Gallery Control: NotesForGallery 2.0: PresentationNotesForGallery is an open source control on top of the Microsoft ASP.NET AJAX framework for easy displaying image galleries in the as...occulo: occulo 0.1 binaries: Windows binaries. Tested on Windows XP SP2.occulo: occulo 0.1 source: Initial source release.Open NFe: DANFE 1.9.5: Ajuste de layout e correção dos campos de ISS.patterns & practices Web Client Developer Guidance: Web Application Guidance -- March 8th Drop: This iteration we focused on documentation and bug fixes.PoshConsole: PoshConsole 2.0 Beta: With this release, I am refocusing PoshConsole... 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