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  • ASP.Net MVC Exception Logging combined with Error Handling

    - by Saajid Ismail
    Hi. I am looking for a simple solution to do Exception Logging combined with Error Handling in my ASP.Net MVC 1.0 application. I've read lots of articles, including Questions posted here on StackOverflow, which all provide varying solutions for different situations. I am still unable to come up with a solution that suits my needs. Here are my requirements: To be able to use the [HandleError] attribute (or something equivalent) on my Controller, to handle all exceptions that could be thrown from any of the Actions or Views. This should handle all exceptions that were not handled specifically on any of the Actions (as described in point 2). I would like to be able to specify which View a user must be redirected to in error cases, for all actions in the Controller. I want to be able to specify the [HandleError] attribute (or something equivalent) at the top of specific Actions to catch specific exceptions and redirect users to a View appropriate to the exception. All other exceptions must still be handled by the [HandleError] attribute on the Controller. In both cases above, I want the exceptions to be logged using log4net (or any other logging library). How do I go about achieving the above? I've read about making all my Controllers inherit from a base controller which overrides the OnException method, and wherein I do my logging. However this will mess around with redirecting users to the appropriate Views, or make it messy. I've read about writing my own Filter Action which implements IExceptionFilter to handle this, but this will conflict with the [HandleError] attribute. So far, my thoughts are that the best solution is to write my own attribute that inherits from HandleErrorAttribute. That way I get all the functionality of [HandleError], and can add my own log4net logging. The solution is as follows: public class HandleErrorsAttribute: HandleErrorAttribute { private log4net.ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType); public override void OnException(ExceptionContext filterContext) { if (filterContext.Exception != null) { log.Error("Error in Controller", filterContext.Exception); } base.OnException(filterContext); } } Will the above code work for my requirements? If not, what solution does fulfill my requirements?

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  • SubSonic 2.x now supports TVP's - SqlDbType.Structure / DataTables for SQL Server 2008

    - by ElHaix
    For those interested, I have now modified the SubSonic 2.x code to recognize and support DataTable parameter types. You can read more about SQL Server 2008 features here: http://download.microsoft.com/download/4/9/0/4906f81b-eb1a-49c3-bb05-ff3bcbb5d5ae/SQL%20SERVER%202008-RDBMS/T-SQL%20Enhancements%20with%20SQL%20Server%202008%20-%20Praveen%20Srivatsav.pdf What this enhancement will now allow you to do is to create a partial StoredProcedures.cs class, with a method that overrides the stored procedure wrapper method. A bit about good form: My DAL has no direct table access, and my DB only has execute permissions for that user to my sprocs. As such, SubSonic only generates the AllStructs and StoredProcedures classes. The SPROC: ALTER PROCEDURE [dbo].[testInsertToTestTVP] @UserDetails TestTVP READONLY, @Result INT OUT AS BEGIN SET NOCOUNT ON; SET @Result = -1 --SET IDENTITY_INSERT [dbo].[tbl_TestTVP] ON INSERT INTO [dbo].[tbl_TestTVP] ( [GroupInsertID], [FirstName], [LastName] ) SELECT [GroupInsertID], [FirstName], [LastName] FROM @UserDetails IF @@ROWCOUNT > 0 BEGIN SET @Result = 1 SELECT @Result RETURN @Result END --SET IDENTITY_INSERT [dbo].[tbl_TestTVP] OFF END The TVP: CREATE TYPE [dbo].[TestTVP] AS TABLE( [GroupInsertID] [varchar](50) NOT NULL, [FirstName] [varchar](50) NOT NULL, [LastName] [varchar](50) NOT NULL ) GO The the auto gen tool runs, it creates the following erroneous method: /// <summary> /// Creates an object wrapper for the testInsertToTestTVP Procedure /// </summary> public static StoredProcedure TestInsertToTestTVP(string UserDetails, int? Result) { SubSonic.StoredProcedure sp = new SubSonic.StoredProcedure("testInsertToTestTVP", DataService.GetInstance("MyDAL"), "dbo"); sp.Command.AddParameter("@UserDetails", UserDetails, DbType.AnsiString, null, null); sp.Command.AddOutputParameter("@Result", DbType.Int32, 0, 10); return sp; } It sets UserDetails as type string. As it's good form to have two folders for a SubSonic DAL - Custom and Generated, I created a StoredProcedures.cs partial class in Custom that looks like this: /// <summary> /// Creates an object wrapper for the testInsertToTestTVP Procedure /// </summary> public static StoredProcedure TestInsertToTestTVP(DataTable dt, int? Result) { DataSet ds = new DataSet(); SubSonic.StoredProcedure sp = new SubSonic.StoredProcedure("testInsertToTestTVP", DataService.GetInstance("MyDAL"), "dbo"); // TODO: Modify the SubSonic code base in sp.Command.AddParameter to accept // a parameter type of System.Data.SqlDbType.Structured, as it currently only accepts // System.Data.DbType. //sp.Command.AddParameter("@UserDetails", dt, System.Data.SqlDbType.Structured null, null); sp.Command.AddParameter("@UserDetails", dt, SqlDbType.Structured); sp.Command.AddOutputParameter("@Result", DbType.Int32, 0, 10); return sp; } As you can see, the method signature now contains a DataTable, and with my modification to the SubSonic framework, this now works perfectly. I'm wondering if the SubSonic guys can modify the auto-gen to recognize a TVP in a sproc signature, as to avoid having to re-write the warpper? Does SubSonic 3.x support Structured data types? Also, I'm sure many will be interested in using this code, so where can I upload the new code? Thanks.

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  • How to avoid using duplicate savepoint names in nested transactions in nested stored procs?

    - by Gary McGill
    I have a pattern that I almost always follow, where if I need to wrap up an operation in a transaction, I do this: BEGIN TRANSACTION SAVE TRANSACTION TX -- Stuff IF @error <> 0 ROLLBACK TRANSACTION TX COMMIT TRANSACTION That's served me well enough in the past, but after years of using this pattern (and copy-pasting the above code), I've suddenly discovered a flaw which comes as a complete shock. Quite often, I'll have a stored procedure calling other stored procedures, all of which use this same pattern. What I've discovered (to my cost) is that because I'm using the same savepoint name everywhere, I can get into a situation where my outer transaction is partially committed - precisely the opposite of the atomicity that I'm trying to achieve. I've put together an example that exhibits the problem. This is a single batch (no nested stored procs), and so it looks a little odd in that you probably wouldn't use the same savepoint name twice in the same batch, but my real-world scenario would be too confusing to post. CREATE TABLE Test (test INTEGER NOT NULL) BEGIN TRAN SAVE TRAN TX BEGIN TRAN SAVE TRAN TX INSERT INTO Test(test) VALUES (1) COMMIT TRAN TX BEGIN TRAN SAVE TRAN TX INSERT INTO Test(test) VALUES (2) COMMIT TRAN TX DELETE FROM Test ROLLBACK TRAN TX COMMIT TRAN TX SELECT * FROM Test DROP TABLE Test When I execute this, it lists one record, with value "1". In other words, even though I rolled back my outer transaction, a record was added to the table. What's happening is that the ROLLBACK TRANSACTION TX at the outer level is rolling back as far as the last SAVE TRANSACTION TX at the inner level. Now that I write this all out, I can see the logic behind it: the server is looking back through the log file, treating it as a linear stream of transactions; it doesn't understand the nesting/hierarchy implied by either the nesting of the transactions (or, in my real-world scenario, by the calls to other stored procedures). So, clearly, I need to start using unique savepoint names instead of blindly using "TX" everywhere. But - and this is where I finally get to the point - is there a way to do this in a copy-pastable way so that I can still use the same code everywhere? Can I auto-generate the savepoint name on the fly somehow? Is there a convention or best-practice for doing this sort of thing? It's not exactly hard to come up with a unique name every time you start a transaction (could base it off the SP name, or somesuch), but I do worry that eventually there would be a conflict - and you wouldn't know about it because rather than causing an error it just silently destroys your data... :-(

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  • Linq to XML Read and output XML generated from lookup list

    - by Greg S
    I am trying to use XML created from a lookup list in SharePoint as a datasource for a treeview. It is in the form of : <NewDataSet> <test_data> <ID>1</ID> <Title>MenuItem_1</Title> <child_of /> </test_data> <test_data> <ID>2</ID> <Title>Subitem_1</Title> <Action>http://www.google.com</Action> <child_of>MenuItem_1</child_of> </test_data> <test_data> <ID>3</ID> <Title>Subitem_2</Title> <Action>http://www.google.com</Action> <child_of>MenuItem_1</child_of> </test_data> <test_data> <ID>4</ID> <Title>MenuItem_2</Title> <child_of /> </test_data> <test_data> <ID>5</ID> <Title>Subitem_2_1</Title> <Action>http://www.google.com</Action> <child_of>MenuItem_2</child_of> </test_data> <test_data> <ID>6</ID> <Title>Subitem_2_2</Title> <Action>http://www.google.com</Action> <child_of>MenuItem_2</child_of> </test_data> <test_data> <ID>7</ID> <Title>Subitem_2_2_1</Title> <Action>http://www.google.com</Action> <child_of>Subitem_2_2</child_of> </test_data> </NewDataSet> There may be N tiers, but the items relate to the parent via the <child_of> element. I can't seem to figure out how to write the LINQ in C# to nest the menu items properly. A friend recommended I post here. Any help is greatly appreciated.

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  • F# Add Constructor to a Record?

    - by akaphenom
    Basically I want to have a single construct to deal with serializing to both JSON and formatted xml. Records workd nicley for serializing to/from json. However XmlSerializer requires a parameterless construtor. I don't really want to have to go through the exercise of building class objects for these constructs (principal only). I was hoping there could be some shortcut for getting a parameterless constructor onto a record (perhaps with a wioth statement or something). I can't get it to behave - has anybody in the community had any luck? module JSONExample open System open System.IO open System.Net open System.Text open System.Web open System.Xml open System.Security.Authentication open System.Runtime.Serialization //add assemnbly reference System.Runtime.Serialization System.Xml open System.Xml.Serialization open System.Collections.Generic [<DataContract>] type ChemicalElementRecord = { [<XmlAttribute("name")>] [<field: DataMember(Name="name") >] Name:string [<XmlAttribute("name")>] [<field: DataMember(Name="boiling_point") >] BoilingPoint:string [<XmlAttribute("atomic-mass")>] [<field: DataMember(Name="atomic_mass") >] AtomicMass:string } [<XmlRoot("freebase")>] [<DataContract>] type FreebaseResultRecord = { [<XmlAttribute("code")>] [<field: DataMember(Name="code") >] Code:string [<XmlArrayAttribute("results")>] [<XmlArrayItem(typeof<ChemicalElementRecord>, ElementName = "chemical-element")>] [<field: DataMember(Name="result") >] Result: ChemicalElementRecord array [<XmlElement("message")>] [<field: DataMember(Name="message") >] Message:string } let getJsonFromWeb() = let query = "[{'type':'/chemistry/chemical_element','name':null,'boiling_point':null,'atomic_mass':null}]" let query = query.Replace("'","\"") let queryUrl = sprintf "http://api.freebase.com/api/service/mqlread?query=%s" "{\"query\":"+query+"}" let request : HttpWebRequest = downcast WebRequest.Create(queryUrl) request.Method <- "GET" request.ContentType <- "application/x-www-form-urlencoded" let response = request.GetResponse() let result = try use reader = new StreamReader(response.GetResponseStream()) reader.ReadToEnd(); finally response.Close() let data = Encoding.Unicode.GetBytes(result); let stream = new MemoryStream() stream.Write(data, 0, data.Length); stream.Position <- 0L stream let test = // get some JSON from the web let stream = getJsonFromWeb() // convert the stream of JSON into an F# Record let JsonSerializer = Json.DataContractJsonSerializer(typeof<FreebaseResultRecord>) let result: FreebaseResultRecord = downcast JsonSerializer.ReadObject(stream) // save the Records to disk as JSON use fs = new FileStream(@"C:\temp\freebase.json", FileMode.Create) JsonSerializer.WriteObject(fs,result) fs.Close() // save the Records to disk as System Controlled XML let xmlSerializer = DataContractSerializer(typeof<FreebaseResultRecord>); use fs = new FileStream(@"C:\temp\freebase.xml", FileMode.Create) xmlSerializer.WriteObject(fs,result) fs.Close() use fs = new FileStream(@"C:\temp\freebase-pretty.xml", FileMode.Create) let xmlSerializer = XmlSerializer(typeof<FreebaseResultRecord>) xmlSerializer.Serialize(fs,result) fs.Close() ignore(test)

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  • Getting XText to work

    - by Calmarius
    I know you don't like helping others in their homework but I have to make an XText grammar, write a sample code that matches this grammar and compile it to a html file. The lecturer showed us the steps and everything worked for him... He said "It's so simple it will be a 10 minute work for you". And I believed that. However at home almost nothing works as expected. And of course no more lectures to go only the exam avaits me where I have to show what I done to pass. Moreover the e-mail I sent him bounced back by the mailer-demon... I got Xtext along with Eclipse IDE from the xtext website and I unpacked it and I followed the steps in the official tuturial to get the default project template to work. The tutorial is found here: http://wiki.eclipse.org/Xtext/GettingStarted Now I'm at the step "Model". It says open the "MyModel.mydsl" I do that but the editor does not opened. It said: "Could not open the editor: The editor class could not be instantiated. This usually indicates a missing no-arg constructor or that the editor's class name was mistyped in plugin.xml." Since everything is generated, the error message does not helped me... There was an option to look at the stack trace (it was mile long) and on the top of it there was an exception: java.lang.IllegalStateException: The bundle has not yet been activated. Make sure the Manifest.MF contains 'Bundle-ActivationPolicy: lazy'. I opened Manifast.MF and Bundle-ActivationPolicy: lazy was set... I googled for the solution but no avail. It drove me nuts and I gave up. I have no experience with Eclipse and Java and XText, I just want to do my homework and forget everything until I will need it again... Anyone have experience with XText? Any help appreciated. ps: I will be on it too and I might resolve the problem in several hours. But now I am at a loss.

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  • Code Complete 2ed, composition and delegation.

    - by Arlukin
    Hi there. After a couple of weeks reading on this forum I thought it was time for me to do my first post. I'm currently rereading Code Complete. I think it's 15 years since the last time, and I find that I still can't write code ;-) Anyway on page 138 in Code Complete you find this coding horror example. (I have removed some of the code) class Emplyee { public: FullName GetName() const; Address GetAddress() const; PhoneNumber GetWorkPhone() const; ... bool IsZipCodeValid( Address address); ... private: ... } What Steve thinks is bad is that the functions are loosely related. Or has he writes "There's no logical connection between employees and routines that check ZIP codes, phone numbers or job classifications" Ok I totally agree with him. Maybe something like the below example is better. class ZipCode { public: bool IsValid() const; ... } class Address { public: ZipCode GetZipCode() const; ... } class Employee { public: Address GetAddress() const; ... } When checking if the zip is valid you would need to do something like this. employee.GetAddress().GetZipCode().IsValid(); And that is not good regarding to the Law of Demeter ([http://en.wikipedia.org/wiki/Law_of_Demeter][1]). So if you like to remove two of the three dots, you need to use delegation and a couple of wrapper functions like this. class ZipCode { public: bool IsValid(); } class Address { public: ZipCode GetZipCode() const; bool IsZipCodeValid() {return GetZipCode()->IsValid()); } class Employee { public: FullName GetName() const; Address GetAddress() const; bool IsZipCodeValid() {return GetAddress()->IsZipCodeValid()); PhoneNumber GetWorkPhone() const; } employee.IsZipCodeValid(); But then again you have routines that has no logical connection. I personally think that all three examples in this post are bad. Is it some other way that I haven't thougt about? //Daniel

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  • C# bluetooth file send.

    - by cheesebunz
    i'm new to bluetooth development and i found the 32netfeet . Right now i'm able to search for bluetooth devices nearby and connect to them but how do i send a file e.g SendTest.txt? I tried buttonclick event using the OBEX but i don't understand this is my example code: using InTheHand.Net; using InTheHand.Net.Sockets; using InTheHand.Net.Bluetooth; namespace BluetoothIntheHand { public partial class Form2 : Form { private Guid service = BluetoothService.DialupNetworking; private BluetoothClient bluetoothClient; public Form2() { InitializeComponent(); } private void btnSearch_Click(object sender, EventArgs e) { BluetoothRadio.PrimaryRadio.Mode = RadioMode.Discoverable; BluetoothRadio myRadio = BluetoothRadio.PrimaryRadio; lblSearch.Text = "" + myRadio.LocalAddress.ToString(); bluetoothClient = new BluetoothClient(); Cursor.Current = Cursors.WaitCursor; BluetoothDeviceInfo[] bluetoothDeviceInfo = { }; bluetoothDeviceInfo = bluetoothClient.DiscoverDevices(10); comboBox1.DataSource = bluetoothDeviceInfo; comboBox1.DisplayMember = "DeviceName"; comboBox1.ValueMember = "DeviceAddress"; comboBox1.Focus(); Cursor.Current = Cursors.Default; } private void btnConnect_Click(object sender, EventArgs e) { if (comboBox1.SelectedValue != null) { try { bluetoothClient.Connect(new BluetoothEndPoint((BluetoothAddress)comboBox1.SelectedValue, service)); MessageBox.Show("Connected"); } catch (Exception ex) { MessageBox.Show(ex.Message); } } } private void btnSend_Click(object sender, EventArgs e) { bluetoothClient.Connect(new BluetoothEndPoint((BluetoothAddress)comboBox1.SelectedValue, service)); String addr = "112233445566"; Uri uri = new Uri("obex://"+@"SendTest.txt"); ObexWebRequest req= new ObexWebRequest(uri); ObexWebResponse rsp; } I found the guide but don't really knw hw to convert to C# ' The host part of the URI is the device address, e.g. IrDAAddress.ToString(), ' and the file part is the OBEX object name. Dim addr As String = "112233445566" Dim uri As New Uri("obex://" & addr & "/HelloWorld2.txt") Dim req As New ObexWebRequest(uri) Using content As Stream = req.GetRequestStream() ' Using a StreamWriter to write text to the stream... Using wtr As New StreamWriter(content) wtr.WriteLine("Hello World GetRequestStream") wtr.WriteLine("Hello World GetRequestStream 2") wtr.Flush() ' Set the Length header value req.ContentLength = content.Length End Using ' In this case closing the StreamWriter also closed the Stream, but ... End Using Dim rsp As ObexWebResponse = CType(req.GetResponse(),ObexWebResponse) Console.WriteLine("Response Code: {0} (0x{0:X})", rsp.StatusCode)

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  • How to better create stacked bar graphs with multiple variables from ggplot2?

    - by deoksu
    I often have to make stacked barplots to compare variables, and because I do all my stats in R, I prefer to do all my graphics in R with ggplot2. I would like to learn how to do two things: First, I would like to be able to add proper percentage tick marks for each variable rather than tick marks by count. Counts would be confusing, which is why I take out the axis labels completely. Second, there must be a simpler way to reorganize my data to make this happen. It seems like the sort of thing I should be able to do natively in ggplot2 with plyR, but the documentation for plyR is not very clear (and I have read both the ggplot2 book and the online plyR documentation. My best graph looks like this, the code to create it follows: the R code I use to get it is the following: library(epicalc) ### recode the variables to factors ### recode(c(int_newcoun, int_newneigh, int_neweur, int_newusa, int_neweco, int_newit, int_newen, int_newsp, int_newhr, int_newlit, int_newent, int_newrel, int_newhth, int_bapo, int_wopo, int_eupo, int_educ), c(1,2,3,4,5,6,7,8,9, NA), c('Very Interested','Somewhat Interested','Not Very Interested','Not At All interested',NA,NA,NA,NA,NA,NA)) ### Combine recoded variables to a common vector Interest1<-c(int_newcoun, int_newneigh, int_neweur, int_newusa, int_neweco, int_newit, int_newen, int_newsp, int_newhr, int_newlit, int_newent, int_newrel, int_newhth, int_bapo, int_wopo, int_eupo, int_educ) ### Create a second vector to label the first vector by original variable ### a1<-rep("News about Bangladesh", length(int_newcoun)) a2<-rep("Neighboring Countries", length(int_newneigh)) [...] a17<-rep("Education", length(int_educ)) Interest2<-c(a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12, a13, a14, a15, a16, a17) ### Create a Weighting vector of the proper length ### Interest.weight<-rep(weight, 17) ### Make and save a new data frame from the three vectors ### Interest.df<-cbind(Interest1, Interest2, Interest.weight) Interest.df<-as.data.frame(Interest.df) write.csv(Interest.df, 'C:\\Documents and Settings\\[name]\\Desktop\\Sweave\\InterestBangladesh.csv') ### Sort the factor levels to display properly ### Interest.df$Interest1<-relevel(Interest$Interest1, ref='Not Very Interested') Interest.df$Interest1<-relevel(Interest$Interest1, ref='Somewhat Interested') Interest.df$Interest1<-relevel(Interest$Interest1, ref='Very Interested') Interest.df$Interest2<-relevel(Interest$Interest2, ref='News about Bangladesh') Interest.df$Interest2<-relevel(Interest$Interest2, ref='Education') [...] Interest.df$Interest2<-relevel(Interest$Interest2, ref='European Politics') detach(Interest) attach(Interest) ### Finally create the graph in ggplot2 ### library(ggplot2) p<-ggplot(Interest, aes(Interest2, ..count..)) p<-p+geom_bar((aes(weight=Interest.weight, fill=Interest1))) p<-p+coord_flip() p<-p+scale_y_continuous("", breaks=NA) p<-p+scale_fill_manual(value = rev(brewer.pal(5, "Purples"))) p update_labels(p, list(fill='', x='', y='')) I'd very much appreciate any tips, tricks or hints. Thanks.

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  • Trying to read FormsAuthentication tickets to read in other areas of site

    - by Pasha Aryana
    Hi, NOTE: I have included 3 links in here to my localhost areas but could not submit the post so I seperetaed them with a space character so it would post on stackoverflow. I currently have 2 ASP.NET MVC apps in my solution. First I run the first one by setting it to be startup project. It goes to the login page, from there once the data has been entered I execute the following code: var authTicket = new FormsAuthenticationTicket(1, login.LoginDataContract.MSISDN, DateTime.Now, DateTime.Now.AddMinutes(Convert.ToDouble("30")), true, ""); string cookieContents = FormsAuthentication.Encrypt(authTicket); var cookie = new HttpCookie(FormsAuthentication.FormsCookieName, cookieContents) { Expires = authTicket.Expiration, //Path = FormsAuthentication.FormsCookiePath //Path = "http://localhost" Domain = "" }; if (System.Web.HttpContext.Current != null) { System.Web.HttpContext.Current.Response.Cookies.Add(cookie); } As you can see I have set the Domain = "", so theoretically speaking it should work on any thing under my http: //localhost. Then I have set the persist security of the cookie to true so I can access it from any where under localhost. The cookie writes fine and I get logged in and all godd for now. BTW the url for this login page is: http //localhost/MyAccount/Login Now then I stop the solution and set the other MVC apps to be the startup. Then I run it. The URL for the second site is: http: //localhost/WebActivations/ Here is the code in the other apps start controller: public class HomeController : Controller { public ActionResult Index() { ViewData["Message"] = "Welcome to ASP.NET MVC!"; // PASHA: Added code to read the authorization cookie set at // login in MyAccount *.sln for (int i = 0; i < System.Web.HttpContext.Current.Request.Cookies.Count;i++) { Response.Write(System.Web.HttpContext.Current.Request.Cookies[i].Name + " " + System.Web.HttpContext.Current.Request.Cookies[i].Value); } HttpCookie authorizationCookie = System.Web.HttpContext.Current.Request.Cookies[FormsAuthentication.FormsCookieName.ToString()]; // decrypt. FormsAuthenticationTicket authorizationForm = FormsAuthentication.Decrypt(authorizationCookie.Value); ViewData["Message"] = authorizationForm.UserData[0].ToString(); return View(); } public ActionResult About() { return View(); } The problem is in this Home controller when I run the solution it cannot read the authentication cookie, you see the loop there it does not find the .ASPXAUTH cookie. But once it crashes in Firefox I have a look in the Page Info and then security and Cookies and its there and its the same cookie. What am I doing wrong?

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  • C# Design Questions

    - by guazz
    How to approach unit testing of private methods? I have a class that loads Employee data into a database. Here is a sample: public class EmployeeFacade { public Employees EmployeeRepository = new Employees(); public TaxDatas TaxRepository = new TaxDatas(); public Accounts AccountRepository = new Accounts(); //and so on for about 20 more repositories etc. public bool LoadAllEmployeeData(Employee employee) { if (employee == null) throw new Exception("..."); EmployeeRepository emps = new EmployeeRepository(); bool exists = emps.FetchExisting(emps.Id); if (!exists) { emps.AddNew(); } try { emps.Id = employee.Id; emps.Name = employee.EmployeeDetails.PersonalDetails.Active.Names.FirstName; emps.SomeOtherAttribute; } catch() {} try { emps.Save(); } catch(){} try { LoadorUpdateTaxData(employee.TaxData); } catch() {} try { LoadorUpdateAccountData(employee.AccountData); } catch() {} ... etc. for about 20 more other employee objects } private bool LoadorUpdateTaxData(employeeId, TaxData taxData) { if (taxData == null) throw new Exception("..."); ...same format as above but using AccountRepository } private bool LoadorUpdateAccountData(employee.TaxData) { ...same format as above but using TaxRepository } } I am writing an application to take serialised objects(e.g. Employee above) and load the data to the database. I have a few design question that I would like opinions on: A - I am calling this class "EmployeeFacade" because I am (attempting?) to use the facade pattern. Is it good practace to name the pattern on the class name? B - Is it good to call the concrete entities of my DAL layer classes "Repositories" e.g. "EmployeeRepository" ? C - Is using the repositories in this way sensible or should I create a method on the repository itself to take, say, the Employee and then load the data from there e.g. EmployeeRepository.LoadAllEmployeeData(Employee employee)? I am aim for cohesive class and but this will requrie the repository to have knowledge of the Employee object which may not be good? D - Is there any nice way around of not having to check if an object is null at the begining of each method? E - I have a EmployeeRepository, TaxRepository, AccountRepository declared as public for unit testing purpose. These are really private enities but I need to be able to substitute these with stubs so that the won't write to my database(I overload the save() method to do nothing). Is there anyway around this or do I have to expose them? F - How can I test the private methods - or is this done (something tells me it's not)? G- "emps.Name = employee.EmployeeDetails.PersonalDetails.Active.Names.FirstName;" this breaks the Law of Demeter but how do I adjust my objects to abide by the law?

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  • Some questions about writing on ASP.NET response stream

    - by vtortola
    Hi, I'm making tests with ASP.NET HttpHandler for download a file writting directly on the response stream, and I'm not pretty sure about the way I'm doing it. This is a example method, in the future the file could be stored in a BLOB in the database: public void GetFile(HttpResponse response) { String fileName = "example.iso"; response.ClearHeaders(); response.ClearContent(); response.ContentType = "application/octet-stream"; response.AppendHeader("Content-Disposition", "attachment; filename=" + fileName); using (FileStream fs = new FileStream(Path.Combine(HttpContext.Current.Server.MapPath("~/App_Data"), fileName), FileMode.Open)) { Byte[] buffer = new Byte[4096]; Int32 readed = 0; while ((readed = fs.Read(buffer, 0, buffer.Length)) > 0) { response.OutputStream.Write(buffer, 0, readed); response.Flush(); } } } But, I'm not sure if this is correct or there is a better way to do it. My questions are: When I open the url with the browser, appears the "Save File" dialog... but it seems like the server has started already to push data into the stream before I click "Save", is that normal? If I remove the line"response.Flush()", when I open the url with the browser, ... I see how the web server is pushing data but the "Save File" dialog doesn't come up, (or at least not in a reasonable time fashion) why? When I open the url with a WebRequest object, I see that the HttpResponse.ContentLength is "-1", although I can read the stream and get the file. What is the meaning of -1? When is HttpResponse.ContentLength going to show the length of the response? For example, I have a method that retrieves a big xml compresed with deflate as a binary stream, but in that case... when I access it with a WebRequest, in the HttpResponse I can actually see the ContentLength with the length of the stream, why? What is the optimal length for the Byte[] array that I use as buffer for optimal performance in a web server? I've read that is between 4K and 8K... but which factors should I consider to make the correct decision. Does this method bloat the IIS or client memory usage? or is it actually buffering the transference correctly? Sorry for so many questions, I'm pretty new in web development :P Cheers.

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  • kill -9 doesn't work

    - by Daniel
    I have a server with 3 oracle instances on it, and the file system is nfs with netapp. After shutdown the databases, one process for each database doesn't quit for a long time. Each kill -i doesn't work. I tried to truss, pfile it, the command through error. And iostat shows there are lots of IO to the netapp server. So someone said the process was busy writing data to remote netapp server, and before the write complete, it won't quit. So what need to be done was just wait until all the IO was done. After wait for longer time (about 1.5 hours), the processes exit. So my question is: how can a process ignore the kill signal? As far as I know, if we kill -9, it will stop immediately. Do you encounter such situation kill -i doesn't kill the process right away? TEST7-stdby-phxdbnfs11$ ps -ef|grep dbw0 oracle 1469 25053 0 22:36:53 pts/1 0:00 grep dbw0 oracle 26795 1 0 21:55:23 ? 0:00 ora_dbw0_TEST7 oracle 1051 1 0 Apr 08 ? 3958:51 ora_dbw0_TEST2 oracle 471 1 0 Apr 08 ? 6391:43 ora_dbw0_TEST1 TEST7-stdby-phxdbnfs11$ kill -9 1051 TEST7-stdby-phxdbnfs11$ ps -ef|grep dbw0 oracle 1493 25053 0 22:37:07 pts/1 0:00 grep dbw0 oracle 26795 1 0 21:55:23 ? 0:00 ora_dbw0_TEST7 oracle 1051 1 0 Apr 08 ? 3958:51 ora_dbw0_TEST2 oracle 471 1 0 Apr 08 ? 6391:43 ora_dbw0_TEST1 TEST7-stdby-phxdbnfs11$ kill -9 471 TEST7-stdby-phxdbnfs11$ ps -ef|grep dbw0 oracle 26795 1 0 21:55:23 ? 0:00 ora_dbw0_TEST7 oracle 1051 1 0 Apr 08 ? 3958:51 ora_dbw0_TEST2 oracle 471 1 0 Apr 08 ? 6391:43 ora_dbw0_TEST1 oracle 1495 25053 0 22:37:22 pts/1 0:00 grep dbw0 TEST7-stdby-phxdbnfs11$ ps -ef|grep smon oracle 1524 25053 0 22:38:02 pts/1 0:00 grep smon TEST7-stdby-phxdbnfs11$ ps -ef|grep dbw0 oracle 1526 25053 0 22:38:06 pts/1 0:00 grep dbw0 oracle 26795 1 0 21:55:23 ? 0:00 ora_dbw0_TEST7 oracle 1051 1 0 Apr 08 ? 3958:51 ora_dbw0_TEST2 oracle 471 1 0 Apr 08 ? 6391:43 ora_dbw0_TEST1 TEST7-stdby-phxdbnfs11$ kill -9 1051 471 26795 TEST7-stdby-phxdbnfs11$ ps -ef|grep dbw0 oracle 1528 25053 0 22:38:19 pts/1 0:00 grep dbw0 oracle 26795 1 0 21:55:23 ? 0:00 ora_dbw0_TEST7 oracle 1051 1 0 Apr 08 ? 3958:51 ora_dbw0_TEST2 oracle 471 1 0 Apr 08 ? 6391:43 ora_dbw0_TEST1 TEST7-stdby-phxdbnfs11$ truss -p 26795 truss: unanticipated system error: 26795 TEST7-stdby-phxdbnfs11$ pfiles 26795 pfiles: unanticipated system error: 26795

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  • Client-side templating frameworks to streamline using jQuery with REST/JSON

    - by Tauren
    I'm starting to migrate some html generation tasks from a server-side framework to the client. I'm using jQuery on the client. My goal is to get JSON data via a REST api and use this data to populate HTML into the page. Right now, when a user on my site clicks a link to My Projects, the server generates HTML like this: <dl> <dt>Clean Toilet</dt> <dd>Get off your butt and clean this filth!</dd> <dt>Clean Car</dt> <dd>I think there's something growing in there...</dd> <dt>Replace Puked on Baby Sheets</dt> </dl> I'm changing this so that clicking My Projects will now do a GET request that returns something like this: [ { "name":"Clean Car", "description":"I think there's something growing in there..." }, { "name":"Clean Toilets", "description":"Get off your butt and clean this filth!" }, { "name":"Replace Puked on Baby Sheets" } ] I can certainly write custom jQuery code to take that JSON and generate the HTML from it. This is not my question, and I don't need advice on how to do that. What I'd like to do is completely separate the presentation and layout from the logic (jquery code). I don't want to be creating DL, DT, and DD elements via jQuery code. I'd rather use some sort of HTML templates that I can fill the data in to. These templates could simply be HTML snippets that are hidden in the page that the application was loaded from. Or they could be dynamically loaded from the server (to support user specific layouts, i18n, etc.). They could be displayed a single time, as well as allow looping and repeating. Perhaps it should support sub-templates, if/then/else, and so forth. I have LOTS of lists and content on my site that are presented in many different ways. I'm looking to create a simple and consistent way to generate and display content without creating custom jQuery code for every different feature on my site. To me, this means I need to find or build a small framework on top of jQuery (probably as a plugin) that meets these requirements. The only sort of framework that I've found that is anything like this is jTemplates. I don't know how good it is, as I haven't used it yet. At first glance, I'm not thrilled by it's template syntax. Anyone know of other frameworks or plugins that I should look into? Any blog posts or other resources out there that discuss doing this sort of thing? I just want to make sure that I've surveyed everything out there before building it myself. Thanks!

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  • .NET SerialPort DataReceived event thread interference with main thread

    - by Kiran
    I am writing a serial communication program using the SerialPort class in C# to interact with a strip machine connected via a RS232 cable. When i send the command to the machine it responds with some bytes depending on the command. Like when i send a "\D" command, i am expecting to download the machine program data of 180 bytes as a continous string. As per the machine's manual, it suggests as a best practice to send an unreognized characters like comma (,) character to make sure the machine is initialized before sending the first command in the cycle. My serial communication code is as follows: public class SerialHelper { SerialPort commPort = null; string currentReceived = string.Empty; string receivedStr = string.Empty; private bool CommInitialized() { try { commPort = new SerialPort(); commPort.PortName = "COM1"; if (!commPort.IsOpen) commPort.Open(); commPort.BaudRate = 9600; commPort.Parity = System.IO.Ports.Parity.None; commPort.StopBits = StopBits.One; commPort.DataBits = 8; commPort.RtsEnable = true; commPort.DtrEnable = true; commPort.DataReceived += new SerialDataReceivedEventHandler(commPort_DataReceived); return true; } catch (Exception ex) { return false; } } void commPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { SerialPort currentPort = (SerialPort)sender; currentReceived = currentPort.ReadExisting(); receivedStr += currentReceived; } internal int CommIO(string outString, int outLen, ref string inBuffer, int inLen) { receivedStr = string.Empty; inBuffer = string.Empty; if (CommInitialized()) { commPort.Write(outString); } System.Threading.Thread.Sleep(1500); int i = 0; while ((receivedStr.Length < inLen) && i < 10) { System.Threading.Thread.Sleep(500); i += 1; } if (!string.IsNullOrEmpty(receivedStr)) { inBuffer = receivedStr; } commPort.Close(); return inBuffer.Length; } } I am calling this code from a windows form as follows: len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) len = SerialHelperObj.CommIO(",",1,ref inBuffer, 4) If(inBuffer == "!?*O") { len = SerialHelperObj.CommIO("\D",2,ref inBuffer, 180) } A valid return value from the serial port looks like this: \D00000010000000000010 550 3250 0000256000 and so on ... I am getting some thing like this: \D00000010D,, 000 550 D,, and so on... I feel that my comm calls are getting interferred with the one when i send commands. But i am trying to make sure the result of the comma command then initiating the actual command. but the received thread is inserting the bytes from the previous communication cycle. Can any one please shed some light into this...? I lost quite some hair just trying to get this work. I am not sure where i am doing wrong

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  • AccessViolationException thrown

    - by user255371
    Hi, I’m working on a project that’s written in C# and uses a C++ dll to communicate with a robot. Originally the software was written in C# VS 2003 and was converted to VS 2008 (no change to the code) using .Net 2.0. Now, I started seeing the “Attempted to read or write protected memory…” on some computers. The Access violation error is always thrown when the code calls a particular method from the dll, however, that very same method is called over and over throughout the task and executes fine, just sometimes it throws the error. Also, the robot seems to execute the command fine which tells me that the values passed into the dll exist and thus are accessible. The software with the .Net 1.1 has been used for years and worked fine without ever throwing any memory errors. Now that it has been using .Net 2.0 it throws errors on some computers only. I’m not sure what’s causing the issue. I ruled out inappropriate calling (incorrect marshalling …) of the dll methods as it has been working fine with .Net 1.1 for years and thus should work fine in .Net 2.0 as well. I’ve seen some posts suggesting that it could be the GC, but then again why would it only happen on this one computer and only sometimes. Also, the values passed in are all global variables in the C# code and thus they should exist until the application is shut down and GC has no business moving any of those around or deleting them. Another observation, as I mentioned above, the robot executes the command normally which means that it gets all its necessary values. Not sure what the C++ dll’s method would do at the end where the GC could mess up stuff. It shouldn’t try to delete the global variables passed in and the method is not modifying those variables either (I’m not expecting any return values through the passed in values, the only return value is the method return which again shouldn’t have anything to do with GC.) One important piece of information I should add is that I have no access to the C++ code and thus cannot make any changes there. The fix has to come through the C# code or some settings on the computer or something else that I am in control of. Any help greatly appreciated. Thanks. Code snippet: Original method call in VS 2003 [DllImport("TOOLB32.dll",EntryPoint="TbxMoveWash")] public static extern int TbxMoveWash(int tArmId, string lpszCarrierRackId, int eZSelect, int[] lpTipSet, int tVol, bool bFastW); which I modified after seeing the error to the following (but the error still occurs): [DllImport("TOOLB32.dll",EntryPoint="TbxMoveWash")] public static extern int TbxMoveWash(int tArmId, string lpszCarrierRackId, int eZSelect, [MarshalAs(UnmanagedType.LPArray, SizeConst = 8)] int[] lpTipSet, int tVol, bool bFastW);

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  • Classic ASP vs. ASP.NET encryption options

    - by harrije
    I'm working on a web site where the new pages are ASP.NET and the legacy pages are Classic ASP. Being new to development in the Windows env, I've been studying the latest technology, i.e. .NET and I become like a deer in headlights when ever legacy issues come up regarding COM objects. Security on the website is an abomination, but I've easily encrypted the connectionStrings in the web.config file per http://www.4guysfromrolla.com/articles/021506-1.aspx based on DPAPI machine mode. I understand this approach is not the most secure, but it's better than nothing which is what it was for the ASP.NET pages. Now, I question how to do similar encryption for the connection strings used by the Classic ASP pages. A complicating factor is that the web sited is hosted where I do not have admin permissions or even command line access, just FTP. Moreover I want to avoid managing the key. My research has found: DPAPI with COM interop. Seems like this should already be available, but the only thing I could find discussing this is CyptoUtility (see http://msdn.microsoft.com/en-us/magazine/cc163884.aspx) which is not installed on the hosting server. There are plenty of other third party COM objects, e.g. Crypto from Dalun Software http://www.dalun.com, but these aren't on the hosted server either, and they look to me to require you to do some kind of key management. There is CAPICOM on the hosted server, but M$ has deprecated it and many report it is not the easiest to use. It is not clear to me whether I can avoid key management with CAPICOM similar to using DPAPI for ASP.NET. If anyone happens to know, please clue me in. I could write an web service in ASP.NET and have the classic ASP pages use it to get the decrypted connection strings and then store those in an application variable. I would not need to use SSL since I could use localhost and nothing would be sent over the internet. In the simpliest form I could implement what someone termed a poor man's version based on a simple XML stream, however, I really was looking to avoid any development since I find it hard to believe there is not a simple solution for Classic ASP like there is for ASP.NET. Maybe I'm missing some options... Recommendations are requested...

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  • C# Nested Property Accessing overloading OR Sequential Operator Overloading

    - by Tim
    Hey, I've been searching around for a solution to a tricky problem we're having with our code base. To start, our code resembles the following: class User { int id; int accountId; Account account { get { return Account.Get(accountId); } } } class Account { int accountId; OnlinePresence Presence { get { return OnlinePresence.Get(accountId); } } public static Account Get(int accountId) { // hits a database and gets back our object. } } class OnlinePresence { int accountId; bool isOnline; public static OnlinePresence Get(int accountId) { // hits a database and gets back our object. } } What we're often doing in our code is trying to access the account Presence of a user by doing var presence = user.Account.Presence; The problem with this is that this is actually making two requests to the database. One to get the Account object, and then one to get the Presence object. We could easily knock this down to one request if we did the following : var presence = UserPresence.Get(user.id); This works, but sort of requires developers to have an understanding of the UserPresence class/methods that would be nice to eliminate. I've thought of a couple of cool ways to be able to handle this problem, and was wondering if anyone knows if these are possible, if there are other ways of handling this, or if we just need to think more as we're coding and do the UserPresence.Get instead of using properties. Overload nested accessors. It would be cool if inside the User class I could write some sort of "extension" that would say "any time a User object's Account property's Presence object is being accessed, do this instead". Overload the . operator with knowledge of what comes after. If I could somehow overload the . operator only in situations where the object on the right is also being "dotted" it would be great. Both of these seem like things that could be handled at compile time, but perhaps I'm missing something (would reflection make this difficult?). Am I looking at things completely incorrectly? Is there a way of enforcing this that removes the burden from the user of the business logic? Thanks! Tim

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  • Code Golf - Banner Generation

    - by Claudiu
    When thanking someone, you don't want to just send them an e-mail saying "Thanks!", you want to have something FLASHY: Input: THANKS!! Output: TTT H H AAA N N K K SSS !!! !!! T H H A A NNN K K S !!! !!! T HHH AAA NNN KK SSS !!! !!! T H H A A N N K K S T H H A A N N K K SSS !!! !!! Write a program to generate a banner. You only have to generate upper-case A-Z along with spaces and exclamation points (what is a banner without an exclamation point?). All characters are made up of a 3x5 grid of the same character (so the S is a 3x5 grid made of S). All output should be on one row (so no newlines). Here are all the letters you need: Input: ABCDEFGHIJKL Output: AAA BBB CCC DD EEE FFF GGG H H III JJJ K K L A A B B C D D E F G H H I J K K L AAA BBB C D D EE FF G G HHH I J KK L A A B B C D D E F G G H H I J J K K L A A BBB CCC DD EEE F GGG H H III JJJ K K LLL Input: MNOPQRSTUVWX Output: M M N N OOO PPP QQQ RR SSS TTT U U V V W W X X MMM NNN O O P P Q Q R R S T U U V V W W X M M NNN O O PPP Q Q RR SSS T U U V V WWW X M M N N O O P QQQ R R S T U U V V WWW X M M N N OOO P QQQ R R SSS T UUU V WWW X X Input: YZ! Output: Y Y ZZZ !!! Y Y Z !!! YYY Z !!! Y Z YYY ZZZ !!! The winner is the shortest source code. Source code should read input from stdin, output to stdout. You can assume input will only contain [A-Z! ]. If you insult the user on incorrect input, you get a 10 character discount =P. I was going to require these exact 27 characters, but to make it more interesting, you can choose how you want them to look - whatever makes your code shorter! To prove that your letters do look like normal letters, show the output of the last three runs.

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  • XML to be validated against multiple xsd schemas

    - by Michael Rusch
    I'm writing the xsd and the code to validate, so I have great control here. I would like to have an upload facility that adds stuff to my application based on an xml file. One part of the xml file should be validated against different schemas based on one of the values in the other part of it. Here's an example to illustrate: <foo> <name>Harold</name> <bar>Alpha</bar> <baz>Mercury</baz> <!-- ... more general info that applies to all foos ... --> <bar-config> <!-- the content here is specific to the bar named "Alpha" --> </bar-config> <baz-config> <!-- the content here is specific to the baz named "Mercury" --> </baz> </foo> In this case, there is some controlled vocabulary for the content of <bar>, and I can handle that part just fine. Then, based on the bar value, the appropriate xml schema should be used to validate the content of bar-config. Similarly for baz and baz-config. The code doing the parsing/validation is written in Java. Not sure how language-dependent the solution will be. Ideally, the solution would permit the xml author to declare the appropriate schema locations and what-not so that s/he could get the xml validated on the fly in a sufficiently smart editor. Also, the possible values for <bar> and <baz> are orthogonal, so I don't want to do this by extension for every possible bar/baz combo. What I mean is, if there are 24 possible bar values/schemas and 8 possible baz values/schemas, I want to be able to write 1 + 24 + 8 = 33 total schemas, instead of 1 * 24 * 8 = 192 total schemas. Also, I'd prefer to NOT break out the bar-config and baz-config into separate xml files if possible. I realize that might make all the problems much easier, as each xml file would have a single schema, but I'm trying to see if there is a good single-xml-file solution.

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  • Good Email Notification Sending Service

    - by Philibert Perusse
    I need to send a few but important email notifications to individual users. For instance, when they register their software I send them a confirmation email. Right now, I am using 'sendmail' from my Perl CGI script to do the job. Most of my automated email are lost or marked as junk. Unfortunately, I am using shared hosting services and not a very good control over the SPF and SenderID DNS records. Even more bad, some other user of that shared server has been infected with some kind of SPAM-BOT and the IP is now blacklisted until further notice! Anyway I just don't want to deal with this kind of headache. I am looking for an online service that I will be able to subscribe to and pay something like 0.10$ per email I send with no monthly fees. I just need and API to be able to send the email from PHP or Perl code I will have to write. I have been looking around at all those "Email Sending Services" and they are all wrapped around creating campains and managing lists for bulk email marketing distribution and newsletters. But remember, I want to send an email notification to a "single" recipient. So far, I have look at MailChimp, SocketLabs, iContact, ConstantContact, StreamSend and so many others to no avail. I have seen one comment at Hackers News saying that MailChimp have an API for transactional e-mails (i.e. ad-hoc ones to welcome a user for example). So you're not just restricted to using them for bulk emails But I cannot find this in the API documentation supplied, maybe this was removed. Any suggestions out there. Here is a summary of my requirements: Allows ad hoc sending of email to a single recipient. Throughput may well be throttle I don't care, i am sending like 2-5 emails a day. API available in PHP or Perl to connect to that web service. Ideally I can send HTML formatted emails, otherwise I will live with text only. Solution not too expensive, between 0.01$ and 0.25$ per email would be acceptable. No recurring monthly fees.

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  • Extracting the source code of a facebook page with JavaScript

    - by Hafizi Vilie
    If I write code in the JavaScript console of Chrome, I can retrieve the whole HTML source code by entering: var a = document.body.InnerHTML; alert(a); For fb_dtsg on Facebook, I can easily extract it by writing: var fb_dtsg = document.getElementsByName('fb_dtsg')[0].value; Now, I am trying to extract the code "h=AfJSxEzzdTSrz-pS" from the Facebook Page. The h value is especially useful for Facebook reporting. How can I get the h value for reporting? I don't know what the h value is; the h value is totally different when you communicate with different users. Without that h correct value, you can not report. Actually, the h value is AfXXXXXXXXXXX (11 character values after 'Af'), that is what I know. Do you have any ideas for getting the value or any function to generate on Facebook page. The Facebook Source snippet is below, you can view source on facebook profile, and search h=Af, you will get the value: <code class="hidden_elem" id="ukftg4w44"> <!-- <div class="mtm mlm"> ... .... <span class="itemLabel fsm">Unfriend...</span></a></li> <li class="uiMenuItem" data-label="Report/Block..."> <a class="itemAnchor" role="menuitem" tabindex="-1" href="/ajax/report/social.php?content_type=0&amp;cid=1352686914&amp;rid=1352686914&amp;ref=http%3A%2F%2Fwww.facebook.com%2 F%3Fq&amp;h=AfjSxEzzdTSrz-pS&amp;from_gear=timeline" rel="dialog"> <span class="itemLabel fsm">Report/Block...</span></a></li></ul></div> ... .... </div> --> </code> Please guide me. How can extract the value exactly? I tried with following code, but the comment block prevent me to extract the code. How can extract the value which is inside comment block? var a = document.getElementsByClassName('hidden_elem')[3].innerHTML;alert(a);

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  • Diophantine Equation [closed]

    - by ANIL
    In mathematics, a Diophantine equation (named for Diophantus of Alexandria, a third century Greek mathematician) is a polynomial equation where the variables can only take on integer values. Although you may not realize it, you have seen Diophantine equations before: one of the most famous Diophantine equations is: X^n+Y^n=Z^n We are not certain that McDonald's knows about Diophantine equations (actually we doubt that they do), but they use them! McDonald's sells Chicken McNuggets in packages of 6, 9 or 20 McNuggets. Thus, it is possible, for example, to buy exactly 15 McNuggets (with one package of 6 and a second package of 9), but it is not possible to buy exactly 16 nuggets, since no non- negative integer combination of 6's, 9's and 20's adds up to 16. To determine if it is possible to buy exactly n McNuggets, one has to solve a Diophantine equation: find non-negative integer values of a, b, and c, such that 6a + 9b + 20c = n. Problem 1 Show that it is possible to buy exactly 50, 51, 52, 53, 54, and 55 McNuggets, by finding solutions to the Diophantine equation. You can solve this in your head, using paper and pencil, or writing a program. However you chose to solve this problem, list the combinations of 6, 9 and 20 packs of McNuggets you need to buy in order to get each of the exact amounts. Given that it is possible to buy sets of 50, 51, 52, 53, 54 or 55 McNuggets by combinations of 6, 9 and 20 packs, show that it is possible to buy 56, 57,..., 65 McNuggets. In other words, show how, given solutions for 50-55, one can derive solutions for 56-65. Problem 2 Write an iterative program that finds the largest number of McNuggets that cannot be bought in exact quantity. Your program should print the answer in the following format (where the correct number is provided in place of n): "Largest number of McNuggets that cannot be bought in exact quantity: n" Hints: Hypothesize possible instances of numbers of McNuggets that cannot be purchased exactly, starting with 1 For each possible instance, called n, a. Test if there exists non-negative integers a, b, and c, such that 6a+9b+20c = n. (This can be done by looking at all feasible combinations of a, b, and c) b. If not, n cannot be bought in exact quantity, save n When you have found six consecutive values of n that in fact pass the test of having an exact solution, the last answer that was saved (not the last value of n that had a solution) is the correct answer, since you know by the theorem that any amount larger can also be bought in exact quantity

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  • progressIndicator does not update till about 10 seconds after awakeFromNib occures

    - by theprojectabot
    I have been trying to get this one section of my UI to immediatly up date when the document loads into view. The awakeFromNib fires the pasted code and then starts a timer to repeat every 10 seconds... I load a default storage location: ~/Movies... which shows up immediately.. yet the network location that is saved in the document that gets pulled from the XML only seems to show up after the second firing of the - (void)updateDiskSpaceDisplay timer. I have set breakpoints and know that the ivars that contain the values that are being put into the *fileSystemAttributes is the network location right when the awakeFromNib occurs... Im confused why it magically appears after the second time firing instead of immediately displaying the write values. - (void)updateDiskSpaceDisplay { // Obtain information about the file system used on the selected storage path. NSError *error = NULL; NSDictionary *fileSystemAttributes = [[NSFileManager defaultManager] attributesOfFileSystemForPath:[[[self settings] containerSettings] storagePath] error:&error]; if( !fileSystemAttributes ) return; // Get the byte capacity of the drive. long long byteCapacity = [[fileSystemAttributes objectForKey:NSFileSystemSize] unsignedLongLongValue]; // Get the number of free bytes. long long freeBytes = [[fileSystemAttributes objectForKey:NSFileSystemFreeSize] unsignedLongLongValue]; // Update the level indicator, and the text fields to show the current information. [totalDiskSpaceField setStringValue:[self formattedStringFromByteCount:byteCapacity]]; [totalDiskSpaceField setNeedsDisplay:YES]; [usedDiskSpaceField setStringValue:[self formattedStringFromByteCount:(byteCapacity - freeBytes)]]; [usedDiskSpaceField setNeedsDisplay:YES]; [diskSpaceIndicator setMaxValue:100]; [diskSpaceIndicator setIntValue:(((float) (byteCapacity - freeBytes) / (float) byteCapacity) * 100.0)]; [diskSpaceIndicator display:YES]; } thoughts? my awakeFromNib: - (void)awakeFromNib { [documentWindow setAcceptsMouseMovedEvents:YES]; [documentWindow setDelegate:self]; [self updateSettingsDisplay]; [self updateDiskSpaceDisplay]; [self setDiskSpaceUpdateTimer:[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(updateDiskSpaceDisplay) userInfo:NULL repeats:YES]]; [self setUpClipInfoTabButtons]; [self performSelector:@selector(setupEngineController) withObject:NULL afterDelay:0.1]; }

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  • Most efficient algorithm for merging sorted IEnumerable<T>

    - by franck
    Hello, I have several huge sorted enumerable sequences that I want to merge. Theses lists are manipulated as IEnumerable but are already sorted. Since input lists are sorted, it should be possible to merge them in one trip, without re-sorting anything. I would like to keep the defered execution behavior. I tried to write a naive algorithm which do that (see below). However, it looks pretty ugly and I'm sure it can be optimized. It may exist a more academical algorithm... IEnumerable<T> MergeOrderedLists<T, TOrder>(IEnumerable<IEnumerable<T>> orderedlists, Func<T, TOrder> orderBy) { var enumerators = orderedlists.ToDictionary(l => l.GetEnumerator(), l => default(T)); IEnumerator<T> tag = null; var firstRun = true; while (true) { var toRemove = new List<IEnumerator<T>>(); var toAdd = new List<KeyValuePair<IEnumerator<T>, T>>(); foreach (var pair in enumerators.Where(pair => firstRun || tag == pair.Key)) { if (pair.Key.MoveNext()) toAdd.Add(pair); else toRemove.Add(pair.Key); } foreach (var enumerator in toRemove) enumerators.Remove(enumerator); foreach (var pair in toAdd) enumerators[pair.Key] = pair.Key.Current; if (enumerators.Count == 0) yield break; var min = enumerators.OrderBy(t => orderBy(t.Value)).FirstOrDefault(); tag = min.Key; yield return min.Value; firstRun = false; } } The method can be used like that: // Person lists are already sorted by age MergeOrderedLists(orderedList, p => p.Age); assuming the following Person class exists somewhere: public class Person { public int Age { get; set; } } Duplicates should be conserved, we don't care about their order in the new sequence. Do you see any obvious optimization I could use?

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