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  • How to edit item in a listbox shown from reading a .csv file?

    - by Shuvo
    I am working in a project where my application can open a .csv file and read data from it. The .csv file contains the latitude, longitude of places. The application reads data from the file shows it in a static map and display icon on the right places. The application can open multiple file at a time and it opens with a new tab every time. But I am having trouble in couple of cases When I am trying to add a new point to the .csv file opened. I am able to write new point on the same file instead adding a new point data to the existing its replacing others and writing the new point only. I cannot use selectedIndexChange event to perform edit option on the listbox and then save the file. Any direction would be great. using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.IO; namespace CourseworkExample { public partial class Form1 : Form { public GPSDataPoint gpsdp; List<GPSDataPoint> data; List<PictureBox> pictures; List<TabPage> tabs; public static int pn = 0; private TabPage currentComponent; private Bitmap bmp1; string[] symbols = { "hospital", "university" }; Image[] symbolImages; ListBox lb = new ListBox(); string name = ""; string path = ""; public Form1() { InitializeComponent(); data = new List<GPSDataPoint>(); pictures = new List<PictureBox>(); tabs = new List<TabPage>(); symbolImages = new Image[symbols.Length]; for (int i = 0; i < 2; i++) { string location = "data/" + symbols[i] + ".png"; symbolImages[i] = Image.FromFile(location); } } private void openToolStripMenuItem_Click(object sender, EventArgs e) { FileDialog ofd = new OpenFileDialog(); string filter = "CSV File (*.csv)|*.csv"; ofd.Filter = filter; DialogResult dr = ofd.ShowDialog(); if (dr.Equals(DialogResult.OK)) { int i = ofd.FileName.LastIndexOf("\\"); name = ofd.FileName; path = ofd.FileName; if (i > 0) { name = ofd.FileName.Substring(i + 1); path = ofd.FileName.Substring(0, i + 1); } TextReader input = new StreamReader(ofd.FileName); string mapName = input.ReadLine(); GPSDataPoint gpsD = new GPSDataPoint(); gpsD.setBounds(input.ReadLine()); string s; while ((s = input.ReadLine()) != null) { gpsD.addWaypoint(s); } input.Close(); TabPage tabPage = new TabPage(); tabPage.Location = new System.Drawing.Point(4, 22); tabPage.Name = "tabPage" + pn; lb.Width = 300; int selectedindex = lb.SelectedIndex; lb.Items.Add(mapName); lb.Items.Add("Bounds"); lb.Items.Add(gpsD.Bounds[0] + " " + gpsD.Bounds[1] + " " + gpsD.Bounds[2] + " " + gpsD.Bounds[3]); lb.Items.Add("Waypoint"); foreach (WayPoint wp in gpsD.DataList) { lb.Items.Add(wp.Name + " " + wp.Latitude + " " + wp.Longitude + " " + wp.Ele + " " + wp.Sym); } tabPage.Controls.Add(lb); pn++; tabPage.Padding = new System.Windows.Forms.Padding(3); tabPage.Size = new System.Drawing.Size(192, 74); tabPage.TabIndex = 0; tabPage.Text = name; tabPage.UseVisualStyleBackColor = true; tabs.Add(tabPage); tabControl1.Controls.Add(tabPage); tabPage = new TabPage(); tabPage.Location = new System.Drawing.Point(4, 22); tabPage.Name = "tabPage" + pn; pn++; tabPage.Padding = new System.Windows.Forms.Padding(3); tabPage.Size = new System.Drawing.Size(192, 74); tabPage.TabIndex = 0; tabPage.Text = mapName; string location = path + mapName; tabPage.UseVisualStyleBackColor = true; tabs.Add(tabPage); PictureBox pb = new PictureBox(); pb.Name = "pictureBox" + pn; pb.Image = Image.FromFile(location); tabControl2.Controls.Add(tabPage); pb.Width = pb.Image.Width; pb.Height = pb.Image.Height; tabPage.Controls.Add(pb); currentComponent = tabPage; tabPage.Width = pb.Width; tabPage.Height = pb.Height; pn++; tabControl2.Width = pb.Width; tabControl2.Height = pb.Height; bmp1 = (Bitmap)pb.Image; int lx, ly; float realWidth = gpsD.Bounds[1] - gpsD.Bounds[3]; float imageW = pb.Image.Width; float dx = imageW * (gpsD.Bounds[1] - gpsD.getWayPoint(0).Longitude) / realWidth; float realHeight = gpsD.Bounds[0] - gpsD.Bounds[2]; float imageH = pb.Image.Height; float dy = imageH * (gpsD.Bounds[0] - gpsD.getWayPoint(0).Latitude) / realHeight; lx = (int)dx; ly = (int)dy; using (Graphics g = Graphics.FromImage(bmp1)) { Rectangle rect = new Rectangle(lx, ly, 20, 20); if (gpsD.getWayPoint(0).Sym.Equals("")) { g.DrawRectangle(new Pen(Color.Red), rect); } else { if (gpsD.getWayPoint(0).Sym.Equals("hospital")) { g.DrawImage(symbolImages[0], rect); } else { if (gpsD.getWayPoint(0).Sym.Equals("university")) { g.DrawImage(symbolImages[1], rect); } } } } pb.Image = bmp1; pb.Invalidate(); } } private void openToolStripMenuItem_Click_1(object sender, EventArgs e) { FileDialog ofd = new OpenFileDialog(); string filter = "CSV File (*.csv)|*.csv"; ofd.Filter = filter; DialogResult dr = ofd.ShowDialog(); if (dr.Equals(DialogResult.OK)) { int i = ofd.FileName.LastIndexOf("\\"); name = ofd.FileName; path = ofd.FileName; if (i > 0) { name = ofd.FileName.Substring(i + 1); path = ofd.FileName.Substring(0, i + 1); } TextReader input = new StreamReader(ofd.FileName); string mapName = input.ReadLine(); GPSDataPoint gpsD = new GPSDataPoint(); gpsD.setBounds(input.ReadLine()); string s; while ((s = input.ReadLine()) != null) { gpsD.addWaypoint(s); } input.Close(); TabPage tabPage = new TabPage(); tabPage.Location = new System.Drawing.Point(4, 22); tabPage.Name = "tabPage" + pn; ListBox lb = new ListBox(); lb.Width = 300; lb.Items.Add(mapName); lb.Items.Add("Bounds"); lb.Items.Add(gpsD.Bounds[0] + " " + gpsD.Bounds[1] + " " + gpsD.Bounds[2] + " " + gpsD.Bounds[3]); lb.Items.Add("Waypoint"); foreach (WayPoint wp in gpsD.DataList) { lb.Items.Add(wp.Name + " " + wp.Latitude + " " + wp.Longitude + " " + wp.Ele + " " + wp.Sym); } tabPage.Controls.Add(lb); pn++; tabPage.Padding = new System.Windows.Forms.Padding(3); tabPage.Size = new System.Drawing.Size(192, 74); tabPage.TabIndex = 0; tabPage.Text = name; tabPage.UseVisualStyleBackColor = true; tabs.Add(tabPage); tabControl1.Controls.Add(tabPage); tabPage = new TabPage(); tabPage.Location = new System.Drawing.Point(4, 22); tabPage.Name = "tabPage" + pn; pn++; tabPage.Padding = new System.Windows.Forms.Padding(3); tabPage.Size = new System.Drawing.Size(192, 74); tabPage.TabIndex = 0; tabPage.Text = mapName; string location = path + mapName; tabPage.UseVisualStyleBackColor = true; tabs.Add(tabPage); PictureBox pb = new PictureBox(); pb.Name = "pictureBox" + pn; pb.Image = Image.FromFile(location); tabControl2.Controls.Add(tabPage); pb.Width = pb.Image.Width; pb.Height = pb.Image.Height; tabPage.Controls.Add(pb); currentComponent = tabPage; tabPage.Width = pb.Width; tabPage.Height = pb.Height; pn++; tabControl2.Width = pb.Width; tabControl2.Height = pb.Height; bmp1 = (Bitmap)pb.Image; int lx, ly; float realWidth = gpsD.Bounds[1] - gpsD.Bounds[3]; float imageW = pb.Image.Width; float dx = imageW * (gpsD.Bounds[1] - gpsD.getWayPoint(0).Longitude) / realWidth; float realHeight = gpsD.Bounds[0] - gpsD.Bounds[2]; float imageH = pb.Image.Height; float dy = imageH * (gpsD.Bounds[0] - gpsD.getWayPoint(0).Latitude) / realHeight; lx = (int)dx; ly = (int)dy; using (Graphics g = Graphics.FromImage(bmp1)) { Rectangle rect = new Rectangle(lx, ly, 20, 20); if (gpsD.getWayPoint(0).Sym.Equals("")) { g.DrawRectangle(new Pen(Color.Red), rect); } else { if (gpsD.getWayPoint(0).Sym.Equals("hospital")) { g.DrawImage(symbolImages[0], rect); } else { if (gpsD.getWayPoint(0).Sym.Equals("university")) { g.DrawImage(symbolImages[1], rect); } } } } pb.Image = bmp1; pb.Invalidate(); MessageBox.Show(data.ToString()); } } private void exitToolStripMenuItem_Click(object sender, EventArgs e) { this.Close(); } private void addBtn_Click(object sender, EventArgs e) { string wayName = nameTxtBox.Text; float wayLat = Convert.ToSingle(latTxtBox.Text); float wayLong = Convert.ToSingle(longTxtBox.Text); float wayEle = Convert.ToSingle(elevTxtBox.Text); WayPoint wp = new WayPoint(wayName, wayLat, wayLong, wayEle); GPSDataPoint gdp = new GPSDataPoint(); data = new List<GPSDataPoint>(); gdp.Add(wp); lb.Items.Add(wp.Name + " " + wp.Latitude + " " + wp.Longitude + " " + wp.Ele + " " + wp.Sym); lb.Refresh(); StreamWriter sr = new StreamWriter(name); sr.Write(lb); sr.Close(); DialogResult result = MessageBox.Show("Save in New File?","Save", MessageBoxButtons.YesNo); if (result == DialogResult.Yes) { SaveFileDialog saveDialog = new SaveFileDialog(); saveDialog.FileName = "default.csv"; DialogResult saveResult = saveDialog.ShowDialog(); if (saveResult == DialogResult.OK) { sr = new StreamWriter(saveDialog.FileName, true); sr.WriteLine(wayName + "," + wayLat + "," + wayLong + "," + wayEle); sr.Close(); } } else { // sr = new StreamWriter(name, true); // sr.WriteLine(wayName + "," + wayLat + "," + wayLong + "," + wayEle); sr.Close(); } MessageBox.Show(name + path); } } } GPSDataPoint.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; namespace CourseworkExample { public class GPSDataPoint { private float[] bounds; private List<WayPoint> dataList; public GPSDataPoint() { dataList = new List<WayPoint>(); } internal void setBounds(string p) { string[] b = p.Split(','); bounds = new float[b.Length]; for (int i = 0; i < b.Length; i++) { bounds[i] = Convert.ToSingle(b[i]); } } public float[] Bounds { get { return bounds; } } internal void addWaypoint(string s) { WayPoint wp = new WayPoint(s); dataList.Add(wp); } public WayPoint getWayPoint(int i) { if (i < dataList.Count) { return dataList[i]; } else return null; } public List<WayPoint> DataList { get { return dataList; } } internal void Add(WayPoint wp) { dataList.Add(wp); } } } WayPoint.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace CourseworkExample { public class WayPoint { private string name; private float ele; private float latitude; private float longitude; private string sym; public WayPoint(string name, float latitude, float longitude, float elevation) { this.name = name; this.latitude = latitude; this.longitude = longitude; this.ele = elevation; } public WayPoint() { name = "no name"; ele = 3.5F; latitude = 3.5F; longitude = 0.0F; sym = "no symbol"; } public WayPoint(string s) { string[] bits = s.Split(','); name = bits[0]; longitude = Convert.ToSingle(bits[2]); latitude = Convert.ToSingle(bits[1]); if (bits.Length > 4) sym = bits[4]; else sym = ""; try { ele = Convert.ToSingle(bits[3]); } catch (Exception e) { ele = 0.0f; } } public float Longitude { get { return longitude; } set { longitude = value; } } public float Latitude { get { return latitude; } set { latitude = value; } } public float Ele { get { return ele; } set { ele = value; } } public string Name { get { return name; } set { name = value; } } public string Sym { get { return sym; } set { sym = value; } } } } .csv file data birthplace.png 51.483788,-0.351906,51.460745,-0.302982 Born Here,51.473805,-0.32532,-,hospital Danced here,51,483805,-0.32532,-,hospital

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  • Learn to use PHP and Python with Oracle Database

    - by christopher.jones
    The Oracle Learning Library has posted up the latest "Oracle By Example" labs giving an introduction to PHP & Python with the Oracle Database : Using PHP with Oracle Database 11g - a basic introduction Developing a PHP Web Application with Oracle Database 11g - a Zend Framework application using the NetBeans IDE Using Python With Oracle Database 11g - a basic introduction Using the Django Framework with Python and Oracle Database 11g - a basic web application

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  • Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 2

    - by rajbk
    In the previous post, you saw how to create an OData feed and pre-filter the data. In this post, we will see how to shape the data. A sample project is attached at the bottom of this post. Pre-filtering and shaping OData feeds using WCF Data Services and the Entity Framework - Part 1 Shaping the feed The Product feed we created earlier returns too much information about our products. Let’s change this so that only the following properties are returned – ProductID, ProductName, QuantityPerUnit, UnitPrice, UnitsInStock. We also want to return only Products that are not discontinued.  Splitting the Entity To shape our data according to the requirements above, we are going to split our Product Entity into two and expose one through the feed. The exposed entity will contain only the properties listed above. We will use the other Entity in our Query Interceptor to pre-filter the data so that discontinued products are not returned. Go to the design surface for the Entity Model and make a copy of the Product entity. A “Product1” Entity gets created.   Rename Product1 to ProductDetail. Right click on the Product entity and select “Add Association” Make a one to one association between Product and ProductDetails.   Keep only the properties we wish to expose on the Product entity and delete all other properties on it (see diagram below). You delete a property on an Entity by right clicking on the property and selecting “delete”. Keep the ProductID on the ProductDetail. Delete any other property on the ProductDetail entity that is already present in the Product entity. Your design surface should look like below:    Mapping Entity to Database Tables Right click on “ProductDetail” and go to “Table Mapping”   Add a mapping to the “Products” table in the Mapping Details.   After mapping ProductDetail, you should see the following.   Add a referential constraint. Lets add a referential constraint which is similar to a referential integrity constraint in SQL. Double click on the Association between the Entities and add the constraint with “Principal” set to “Product”. Let us review what we did so far. We made a copy of the Product entity and called it ProductDetail We created a one to one association between these entities Excluding the ProductID, we made sure properties were not duplicated between these entities  We added a ProductDetail entity to Products table mapping (Entity to Database). We added a referential constraint between the entities. Lets build our project. We get the following error: ”'NortwindODataFeed.Product' does not contain a definition for 'Discontinued' and no extension method 'Discontinued' accepting a first argument of type 'NortwindODataFeed.Product' could be found …" The reason for this error is because our Product Entity no longer has a “Discontinued” property. We “moved” it to the ProductDetail entity since we want our Product Entity to contain only properties that will be exposed by our feed. Since we have a one to one association between the entities, we can easily rewrite our Query Interceptor like so: [QueryInterceptor("Products")] public Expression<Func<Product, bool>> OnReadProducts() { return o => o.ProductDetail.Discontinued == false; } Similarly, all “hidden” properties of the Product table are available to us internally (through the ProductDetail Entity) for any additional logic we wish to implement. Compile the project and view the feed. We see that the feed returns only the properties that were part of the requirement.   To see the data in JSON format, you have to create a request with the following request header Accept: application/json, text/javascript, */* (easy to do in jQuery) The result should look like this: { "d" : { "results": [ { "__metadata": { "uri": "http://localhost.:2576/DataService.svc/Products(1)", "type": "NorthwindModel.Product" }, "ProductID": 1, "ProductName": "Chai", "QuantityPerUnit": "10 boxes x 20 bags", "UnitPrice": "18.0000", "UnitsInStock": 39 }, { "__metadata": { "uri": "http://localhost.:2576/DataService.svc/Products(2)", "type": "NorthwindModel.Product" }, "ProductID": 2, "ProductName": "Chang", "QuantityPerUnit": "24 - 12 oz bottles", "UnitPrice": "19.0000", "UnitsInStock": 17 }, { ... ... If anyone has the $format operation working, please post a comment. It was not working for me at the time of writing this.  We have successfully pre-filtered our data to expose only products that have not been discontinued and shaped our data so that only certain properties of the Entity are exposed. Note that there are several other ways you could implement this like creating a QueryView, Stored Procedure or DefiningQuery. You have seen how easy it is to create an OData feed, shape the data and pre-filter it by hardly writing any code of your own. For more details on OData, Google it with your favorite search engine :-) Also check out the one of the most passionate persons I have ever met, Pablo Castro – the Architect of Aristoria WCF Data Services. Watch his MIX 2010 presentation titled “OData: There's a Feed for That” here. Download Sample Project for VS 2010 RTM NortwindODataFeed.zip

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  • Are Ruby on Rails / Grails the fastest frameworks for getting sites up quickly?

    - by Jon
    I'm considering using Grails for a new website, but am open to other/new programming languages and frameworks. I have done development using J2EE/JSF2, ASP.NET, and PHP. Is Grails or Ruby on Rails pretty much the best way to get functionality up and running quickly? Some initial thoughts: DJango looks similar to RoR/Grails and I'd consider it GWT is an interesting concept but it doesn't seem like turnaround time is quite as fast Thanks, -Jon

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  • Aggregating cache data from OCEP in CQL

    - by Manju James
    There are several use cases where OCEP applications need to join stream data with external data, such as data available in a Coherence cache. OCEP’s streaming language, CQL, supports simple cache-key based joins of stream data with data in Coherence (more complex queries will be supported in a future release). However, there are instances where you may need to aggregate the data in Coherence based on input data from a stream. This blog describes a sample that does just that. For our sample, we will use a simplified credit card fraud detection use case. The input to this sample application is a stream of credit card transaction data. The input stream contains information like the credit card ID, transaction time and transaction amount. The purpose of this application is to detect suspicious transactions and send out a warning event. For the sake of simplicity, we will assume that all transactions with amounts greater than $1000 are suspicious. The transaction history is available in a Coherence distributed cache. For every suspicious transaction detected, a warning event must be sent with maximum amount, total amount and total number of transactions over the past 30 days, as shown in the diagram below. Application Input Stream input to the EPN contains events of type CCTransactionEvent. This input has to be joined with the cache with all credit card transactions. The cache is configured in the EPN as shown below: <wlevs:caching-system id="CohCacheSystem" provider="coherence"/> <wlevs:cache id="CCTransactionsCache" value-type="CCTransactionEvent" key-properties="cardID, transactionTime" caching-system="CohCacheSystem"> </wlevs:cache> Application Output The output that must be produced by the application is a fraud warning event. This event is configured in the spring file as shown below. Source for cardHistory property can be seen here. <wlevs:event-type type-name="FraudWarningEvent"> <wlevs:properties type="tuple"> <wlevs:property name="cardID" type="CHAR"/> <wlevs:property name="transactionTime" type="BIGINT"/> <wlevs:property name="transactionAmount" type="DOUBLE"/> <wlevs:property name="cardHistory" type="OBJECT"/> </wlevs:properties </wlevs:event-type> Cache Data Aggregation using Java Cartridge In the output warning event, cardHistory property contains data from the cache aggregated over the past 30 days. To get this information, we use a java cartridge method. This method uses Coherence’s query API on credit card transactions cache to get the required information. Therefore, the java cartridge method requires a reference to the cache. This may be set up by configuring it in the spring context file as shown below: <bean class="com.oracle.cep.ccfraud.CCTransactionsAggregator"> <property name="cache" ref="CCTransactionsCache"/> </bean> This is used by the java class to set a static property: public void setCache(Map cache) { s_cache = (NamedCache) cache; } The code snippet below shows how the total of all the transaction amounts in the past 30 days is computed. Rest of the information required by CardHistory object is calculated in a similar manner. Complete source of this class can be found here. To find out more information about using Coherence's API to query a cache, please refer Coherence Developer’s Guide. public static CreditHistoryData(String cardID) { … Filter filter = QueryHelper.createFilter("cardID = :cardID and transactionTime :transactionTime", map); CardHistoryData history = new CardHistoryData(); Double sum = (Double) s_cache.aggregate(filter, new DoubleSum("getTransactionAmount")); history.setTotalAmount(sum); … return history; } The java cartridge method is used from CQL as seen below: select cardID, transactionTime, transactionAmount, CCTransactionsAggregator.execute(cardID) as cardHistory from inputChannel where transactionAmount1000 This produces a warning event, with history data, for every credit card transaction over $1000. That is all there is to it. The complete source for the sample application, along with the configuration files, is available here. In the sample, I use a simple java bean to load the cache with initial transaction history data. An input adapter is used to create and send transaction events for the input stream.

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  • Zend Framwork scaffolding capabilities

    - by rockstarz
    Are there any open source projects any of you would recommend to follow or contribute toward, including those already documented among the zf contributors, to add zend framework scaffolding of crud functionality for rapid development as found in many competitors frameworks (Yii, Symfony, Rails, Django, etc.)? As a user of zf on a daily basis on enterprise implementations, I know this is a topic of interest and I feel professional developers like you would find here would have something to contribute toward my question and finding a library that is underway that can be contributed to.

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  • Getting started with Oracle Database In-Memory Part III - Querying The IM Column Store

    - by Maria Colgan
    In my previous blog posts, I described how to install, enable, and populate the In-Memory column store (IM column store). This weeks post focuses on how data is accessed within the IM column store. Let’s take a simple query “What is the most expensive air-mail order we have received to date?” SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE  lo_shipmode = 5; The LINEORDER table has been populated into the IM column store and since we have no alternative access paths (indexes or views) the execution plan for this query is a full table scan of the LINEORDER table. You will notice that the execution plan has a new set of keywords “IN MEMORY" in the access method description in the Operation column. These keywords indicate that the LINEORDER table has been marked for INMEMORY and we may use the IM column store in this query. What do I mean by “may use”? There are a small number of cases were we won’t use the IM column store even though the object has been marked INMEMORY. This is similar to how the keyword STORAGE is used on Exadata environments. You can confirm that the IM column store was actually used by examining the session level statistics, but more on that later. For now let's focus on how the data is accessed in the IM column store and why it’s faster to access the data in the new column format, for analytical queries, rather than the buffer cache. There are four main reasons why accessing the data in the IM column store is more efficient. 1. Access only the column data needed The IM column store only has to scan two columns – lo_shipmode and lo_ordtotalprice – to execute this query while the traditional row store or buffer cache has to scan all of the columns in each row of the LINEORDER table until it reaches both the lo_shipmode and the lo_ordtotalprice column. 2. Scan and filter data in it's compressed format When data is populated into the IM column it is automatically compressed using a new set of compression algorithms that allow WHERE clause predicates to be applied against the compressed formats. This means the volume of data scanned in the IM column store for our query will be far less than the same query in the buffer cache where it will scan the data in its uncompressed form, which could be 20X larger. 3. Prune out any unnecessary data within each column The fastest read you can execute is the read you don’t do. In the IM column store a further reduction in the amount of data accessed is possible due to the In-Memory Storage Indexes(IM storage indexes) that are automatically created and maintained on each of the columns in the IM column store. IM storage indexes allow data pruning to occur based on the filter predicates supplied in a SQL statement. An IM storage index keeps track of minimum and maximum values for each column in each of the In-Memory Compression Unit (IMCU). In our query the WHERE clause predicate is on the lo_shipmode column. The IM storage index on the lo_shipdate column is examined to determine if our specified column value 5 exist in any IMCU by comparing the value 5 to the minimum and maximum values maintained in the Storage Index. If the value 5 is outside the minimum and maximum range for an IMCU, the scan of that IMCU is avoided. For the IMCUs where the value 5 does fall within the min, max range, an additional level of data pruning is possible via the metadata dictionary created when dictionary-based compression is used on IMCU. The dictionary contains a list of the unique column values within the IMCU. Since we have an equality predicate we can easily determine if 5 is one of the distinct column values or not. The combination of the IM storage index and dictionary based pruning, enables us to only scan the necessary IMCUs. 4. Use SIMD to apply filter predicates For the IMCU that need to be scanned Oracle takes advantage of SIMD vector processing (Single Instruction processing Multiple Data values). Instead of evaluating each entry in the column one at a time, SIMD vector processing allows a set of column values to be evaluated together in a single CPU instruction. The column format used in the IM column store has been specifically designed to maximize the number of column entries that can be loaded into the vector registers on the CPU and evaluated in a single CPU instruction. SIMD vector processing enables the Oracle Database In-Memory to scan billion of rows per second per core versus the millions of rows per second per core scan rate that can be achieved in the buffer cache. I mentioned earlier in this post that in order to confirm the IM column store was used; we need to examine the session level statistics. You can monitor the session level statistics by querying the performance views v$mystat and v$statname. All of the statistics related to the In-Memory Column Store begin with IM. You can see the full list of these statistics by typing: display_name format a30 SELECT display_name FROM v$statname WHERE  display_name LIKE 'IM%'; If we check the session statistics after we execute our query the results would be as follow; SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE lo_shipmode = 5; SELECT display_name FROM v$statname WHERE  display_name IN ('IM scan CUs columns accessed',                        'IM scan segments minmax eligible',                        'IM scan CUs pruned'); As you can see, only 2 IMCUs were accessed during the scan as the majority of the IMCUs (44) in the LINEORDER table were pruned out thanks to the storage index on the lo_shipmode column. In next weeks post I will describe how you can control which queries use the IM column store and which don't. +Maria Colgan

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  • Best Programming Language for Web Development

    - by Harish Kurup
    I am a Web Developer in PHP, and also know Javascript and some bit of CSS which is needed for web development. I use Symfony framework to build Websites and Web Application. As now i want to learn new Programming Language, which is best for Web Development(like Ruby, Python), as i have heard about Frameworks like Rails and Django. Which language will be best for Web Development apart from PHP or like PHP?

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  • Can't remove the libpcap0.8 package

    - by Yogesh
    I am getting error when running apt-get remove root@System:~/Downloads# sudo apt-get remove The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. and when I ran apt-get remove -f this is what happens: root@System:~/Downloads# sudo apt-get remove -f The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# clear root@System:~/Downloads# sudo apt-get remove -f Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads# root@System:~/Downloads# sudo apt-get check Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: libpcap0.8 : Breaks: libpcap0.8:i386 (!= 1.4.0-2) but 1.5.3-2 is installed libpcap0.8:i386 : Breaks: libpcap0.8 (!= 1.5.3-2) but 1.4.0-2 is installed libpcap0.8-dev : Depends: libpcap0.8 (= 1.5.3-2) but 1.4.0-2 is installed E: Unmet dependencies. Try using -f. root@System:~/Downloads# apt-cache policy libpcap0.8:amd64 libpcap0.8 libpcap0.8-dev libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8: Installed: 1.4.0-2 Candidate: 1.5.3-2 Version table: 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages *** 1.4.0-2 0 100 /var/lib/dpkg/status libpcap0.8-dev: Installed: 1.5.3-2 Candidate: 1.5.3-2 Version table: *** 1.5.3-2 0 500 http://in.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages 100 /var/lib/dpkg/status root@System:~/Downloads# root@System:~/Downloads# sudo apt-get -f remove libpcap0.8 libpcap0.8-dev libpcap0.8-dev:i386 libpcap0.8:i386 Reading package lists... Done Building dependency tree Reading state information... Done Package 'libpcap0.8-dev:i386' is not installed, so not removed. Did you mean 'libpcap0.8-dev'? You might want to run 'apt-get -f install' to correct these: The following packages have unmet dependencies: libpcap-dev : Depends: libpcap0.8-dev but it is not going to be installed E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution). root@System:~/Downloads# sudo apt-get -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following extra packages will be installed: libpcap0.8 The following packages will be upgraded: libpcap0.8 1 upgraded, 0 newly installed, 0 to remove and 365 not upgraded. 2 not fully installed or removed. Need to get 0 B/110 kB of archives. After this operation, 13.3 kB of additional disk space will be used. Do you want to continue? [Y/n] y (Reading database ... 163539 files and directories currently installed.) Preparing to unpack .../libpcap0.8_1.5.3-2_amd64.deb ... Unpacking libpcap0.8:amd64 (1.5.3-2) over (1.4.0-2) ... dpkg: error processing archive /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb (--unpack): trying to overwrite shared '/usr/share/man/man7/pcap-filter.7.gz', which is different from other instances of package libpcap0.8:amd64 dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Processing triggers for man-db (2.6.7.1-1) ... Errors were encountered while processing: /var/cache/apt/archives/libpcap0.8_1.5.3-2_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) root@System:~/Downloads#

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  • YouTube API Office Hours June 6, 2012

    YouTube API Office Hours June 6, 2012 This is a recording of the YouTube API Hangout on Air from Wednesday 6/6 at 10am PDT (UTC-7). JJ Behrens interviewed Neal Norwitz, a senior engineer at YouTube and well-known Python developer, about Google's engineering culture. We also had a surprise guest, Adrian Holovaty, co-benevolent dictator for life of the open-source Django web framework, who asked several questions about fine-grained timing control in the player APIs. From: GoogleDevelopers Views: 650 14 ratings Time: 39:07 More in Science & Technology

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  • How should I land my next consulting gig? [closed]

    - by MrOodles
    For the last couple of years, I've been working on speculative projects, expanding my skillset with side work, and paying the bills while having a blast consulting for startups. However, for a number of personal reasons, I need to spend the next 6-9 months maximizing my cash income. I want to put this into effect starting in early August. So that means I have one month to put the necessary client list/portfolio/resume together to start making this happen. As a programmer, I am very proficient in building Django web apps. I can write the necessary SQL, python, javascript, and css to build every part of a Django app, and then do the system administration necessary to deploy on AWS using EC2. I can also rig up a CDN to work seemlessly with the app using S3 and Cloudfront. I have built GIS applications using GeoDjango and PostGIS, and I have constructed social video apps by implementing Encoding.com as a service to prepare raw video files for consumption on the web. I am also moderately proficient in programming PHP, Java, and C#. I have built web apps in PHP, and desktop apps in Java and C#. I have dabbled with Android applications and iPhone apps, but nothing I would show off. I have experience doing SEO, social media marketing, and content marketing. Many of my clients have needed their apps promoted after they were built, and I was always happy to oblige when I could. I have also worked with biometrics technology including fingerprints for government contractors. This was as much a business analyst role as it was a programming gig, as I had to help answer RFPs, make checklists, and work around reems and reems of regulations to build applications that met very large bureaucratic requirements. I only have two real requirements for my next gig(s): 1) Work remotely. I live in North East Ohio, and I don't plan on leaving, but I wouldn't mind traveling one or two weeks out of every month to service clients who need on-site help. 2) $60.00hr-$∞ USD contracting rate. So what should I do for the next 30 days to achieve this? Should I target some large company and learn the requisite buzzwords to impress them? Should I learn some new language or technology? Polish some skill that I already have? Should I build something using my current skillset, or with some new technology? Should I put a website for my consultancy together to market myself? Should I do that using latest technology x, y, and z? Or should I just slap something up on Tumblr? I'm willing to do anything (moral) over the next 4 weeks to put myself into a position to maximize my income, and I'm open to all and every idea Programmers users may have. Let me hear them.

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  • Why aren't web frameworks simple, elegant and fun like programming languages? [on hold]

    - by Ryan
    When I think of pretty much any programming language - like C, C++, PHP, SQL, JavaScript, Python, ActionScript, Haskell, Lua, Lisp, Java, etc - I'm like awesome I would love to develop a computer application using any of those languages. But when I think of web frameworks(I do mostly PHP) - like Cake, CI, Symfony, Laravel, Zend, Drupal, Joomla, Wordpress, Rails, Django, etc - I'm like god no. Why aren't there web frameworks that provide me with simple, fun and powerful constructs like a programming language?

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  • Correct permissions for /var/www and wordpress

    - by dpbklyn
    Hello and thank you in advance! I am relatively new to ubuntu, so please excuse the newbie-ness of this question... I have set up a LAMP server (ubuntu server 11.10) and I have access via SSH and to the "it works" page from a web browser from inside my network (via ip address) and from outside using dyndns. I have a couple of projects in development with some outside developers and I want to use this server as a development server for testing and for client approvals. We have some Wordpress projects that sit in subdirectories in /var/www/wordpress1 /var/www/wordpress2, etc. I cannot access these sub directories from a browser in order to set up WP--or (I assume) to see the content on a browser. I get a 403 Forbidden error on my browser. I assume that this is a permissions problem. Can you please tell me the proper settings for the permissions to: 1) Allow the developers and me to read/write. 2) to allow WP set up and do its thing 3) Allow visitors to access the site(s) via the web. I should also mention that the subfolder are actually simlinks to folder on another internal hdd--I don't think this will make a difference, but I thought I should disclose. Since I am a newbie to ubuntu, step-by-step directions are greatly appreciated! Thank you for taking the time! dp total 12 drwxr-xr-x 2 root root 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 root root 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 root root 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 root root 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 root root 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress Here is the result of using chown -R www-data:www-data /var/www total 12 drwxr-xr-x 2 www-data www-data 4096 2012-07-12 10:55 . drwxr-xr-x 13 root root 4096 2012-07-11 20:02 .. lrwxrwxrwx 1 www-data www-data 43 2012-07-11 20:45 admin_media -> /root/django_src/django/contrib/admin/media -rw-r--r-- 1 www-data www-data 177 2012-07-11 17:50 index.html lrwxrwxrwx 1 www-data www-data 14 2012-07-11 20:42 media -> /hdd/web/media lrwxrwxrwx 1 www-data www-data 18 2012-07-12 10:55 wordpress -> /hdd/web/wordpress I am still unable to access via browser...

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  • What do you do when working with multiple languages with different capitalization schemes?

    - by dvcolgan
    I'm making a webapp using Django. The Python convention for naming variables is lowercase_with_underscores, but the Javascript convention is camelCase. In addition, I've seen many people use lowercase-with-hyphens for CSS identifiers. Would you suggest using all three naming conventions where appropriate, or picking one and using it, even if the other two recommend something else? Switching back and forth isn't a huge problem, but it can still be mental overhead.

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  • What is the best language to learn for WEB Development? [closed]

    - by Spoon Yukina
    I'm an IT student in my second year, and I want to learn a web development language, but I'm confused to choose between these languages: Django-J2EE-PHP-ASP.NET-Ruby & Rails, So what is the best language to learn of these, And which management database can be work perfectly with it? note that I learned these languages: C# - C - Assembly language - Python, for web development : HTML-CSS-JavaScript and for management database : SQL SERVER - ACCESS and for the moment I'm learning Java and C++

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  • Getting client denied when accessing a wsgi graphite script

    - by Dr BDO Adams
    I'm trying to set up graphite on my Mac OS X 10.7 lion, i've set up apache to call the python graphite script via WSGI, but when i try to access it, i get a forbiden from apache and in the error log. "client denied by server configuration: /opt/graphite/webapp/graphite.wsgi" I've checked that the scripts location is allowed in httpd.conf, and the permissions of the file, but they seem correct. What do i have to do to get access. Below is the httpd.conf, which is nearly the graphite example. <IfModule !wsgi_module.c> LoadModule wsgi_module modules/mod_wsgi.so </IfModule> WSGISocketPrefix /usr/local/apache/run/wigs <VirtualHost _default_:*> ServerName graphite DocumentRoot "/opt/graphite/webapp" ErrorLog /opt/graphite/storage/log/webapp/error.log CustomLog /opt/graphite/storage/log/webapp/access.log common WSGIDaemonProcess graphite processes=5 threads=5 display-name='%{GROUP}' inactivity-timeout=120 WSGIProcessGroup graphite WSGIApplicationGroup %{GLOBAL} WSGIImportScript /opt/graphite/conf/graphite.wsgi process-group=graphite application-group=%{GLOBAL} # XXX You will need to create this file! There is a graphite.wsgi.example # file in this directory that you can safely use, just copy it to graphite.wgsi WSGIScriptAlias / /opt/graphite/webapp/graphite.wsgi Alias /content/ /opt/graphite/webapp/content/ <Location "/content/"> SetHandler None </Location> # XXX In order for the django admin site media to work you Alias /media/ "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site- packages/django/contrib/admin/media/" <Location "/media/"> SetHandler None </Location> # The graphite.wsgi file has to be accessible by apache. <Directory "/opt/graphite/webapp/"> Options +ExecCGI Order deny,allow Allow from all </Directory> </VirtualHost> Can you help?

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  • Apache error: could not make child process 25105 exit, attempting to continue anyway

    - by Temnovit
    Hello! I have a web server based on Ubuntu Server 9.10 with this software: apache 2 PHP 5.3 MySQL 5 Python 2.5 Few of my websites are PHP based, few use python/django through mod_wsgi. For month or so, every day my apache server stops responding until I manually restart it. Error logs show: [Fri Mar 05 17:06:47 2010] [error] could not make child process 25059 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25061 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 24930 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25084 exit, attempting to continue anyway [Fri Mar 05 17:06:47 2010] [error] could not make child process 25105 exit, attempting to continue anyway and so on. I tried to google this problem but it seems, that I can't find a solution there. How can I determine the cause of this error and how do I fix it? Thank you for your help. UPDATE Updating mod-wsgi to version 3.1 didn't solve the problem Updating PHP to 5.3 also didn't solve it Here is a list of all installed modules: core mod_log_config mod_logio prefork http_core mod_so mod_alias mod_auth_basic mod_authn_file mod_authz_default mod_authz_groupfile mod_authz_host mod_authz_user mod_autoindex mod_cgi mod_deflate mod_dir mod_env mod_mime mod_negotiation mod_php5 mod_rewrite mod_setenvif mod_status mod_wsgi Here's how my virtual host with wsgi looks: <VirtualHost *:80> ServerName example.net DocumentRoot /var/www/example.net #wcgi script that serves all the thing WSGIScriptAlias / /var/www/example.net/index.wsgi WSGIDaemonProcess example user=wsgideamonuser group=root processes=1 threads=10 WSGIProcessGroup example Alias /static /var/www/example.net/static #serving admin files Alias /media/ /usr/local/lib/python2.6/dist-packages/django/contrib/admin/media/ <Location "/static"> SetHandler None </Location> <Location "/media"> SetHandler None </Location> ErrorLog /var/www/example.net/error.log </VirtualHost> Error log now contains two types of errors fallowed one by another: [error] child process 9486 still did not exit, sending a SIGKILL [error] could not make child process 9106 exit, attempting to continue anyway

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  • mod_wsgi, .htaccess and rewriterule

    - by hadaraz
    I'm using several django projects running on the same apache instance through mod_wsgi, configured with virtualhost for each site, see the httpd.conf here. For one of the sites I want to use static-cache (staticgenerator), so I set up a directory with .htaccess file which contains: RequestHeader unset X-Forwarded-Host RewriteEngine on RewriteBase / RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME}/index.html !-f RewriteRule ^(.*) http://127.0.0.1:3456/$1 [P] where 3456 is the django port on the server. Using this rewrite rule, the request is always forwarded to the mod_wsgi handler, even if the file or directory exists, and if the file index.html exists the request shows as request-path/index.html. I tried another setup: RequestHeader unset X-Forwarded-Host RewriteEngine on RewriteBase / RewriteCond $1 !-d RewriteCond $1index.html !-f RewriteRule ^(.*) http://127.0.0.1:3456/$1 [P] but got almost the same results. All requests are transferred to the mod_wsgi handler, but the request path is now the original one. To sum it up: What is the correct RewriteCond to use here? How do you transfer a request to the mod_wsgi handler? Is it the right way? If that's not the way to do it, then how do you serve static files from a directory when they exist, and when they don't you serve from apache/mode_wsgi? Thanks for your help.

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  • sharing a folder between linux and windows over the internet

    - by valya
    Hello Currently my job is to make websites with Django. I use many things like virtualenv, PIL, etc. The problem is, I can't stand Linux on my desktop. I like it on servers, It's greate to use it over the SSH. But for desktop? No way. But for the development Linux is quite essential. Of course almost everything is ported to Windows, but it's not as simple to use as in Linux. For example, Windows shell is awful in comparison with Linux. So I've tried Cygwin, but it's too damn slow. Every time django dev server reloads, it tooks almost 20-30 seconds. In comparison, then using "native" python on Windows or Linux, it reloads instantly. Even worse, Cygwin makes all my system very slow. I've been thinking about it and have thought up a way to go. I can share a folder with my application with some Linux box. The devserver and everything will run on that box, while I'll be happy editing files and running the browser on my Windows 7. SSH shell is much quickier and handy than Cygwin. Currently there are no Linux boxes in my home network (except for my android phone :) but I have several VDS boxes with Debian. So, how do I share a Windows folder with VDS box? I can't rely on my desktop IP but I can rely on the VDS's one. I need sharing to be as quick as possible (well, 2-3 seconds ping is OK) and "native" for both systems, so I could use a folder like a normal folder in both Windows and Linux.

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  • How to get nginx to pass HTTP_AUTHORIZATION header to Apache

    - by codeinthehole
    Am using Nginx as a reverse proxy to an Apache server that uses HTTP Auth. For some reason, I can't get the HTTP_AUTHORIZATION header through to Apache, it seems to get filtered out by Nginx. Hence, no requests can authenticate. Note that the Basic auth is dynamic so I don't want to hard-code it in my nginx config. My nginx config is: server { listen 80; server_name example.co.uk ; access_log /var/log/nginx/access.cdk-dev.tangentlabs.co.uk.log; gzip on; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; proxy_read_timeout 120; location / { proxy_pass http://localhost:81/; } location ~* \.(jpg|png|gif|jpeg|js|css|mp3|wav|swf|mov|doc|xls|ppt|docx|pptx|xlsx|swf)$ { if (!-f $request_filename) { break; proxy_pass http://localhost:81; } root /var/www/example; } } Anyone know why this is happening? Update - turns out the problem was something I had overlooked in my original question: mod_wsgi. The site in question here is a Django site, and it turns out that Apache does get the auth variables passed through, however mod_wsgi filters them out. The resolution is to use: WSGIPassAuthorization On See http://www.arnebrodowski.de/blog/508-Django,-mod_wsgi-and-HTTP-Authentication.html for more details

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  • In solaris, how monitor & auto-respond to critical events

    - by mamcx
    I have a website that randomly fail. Is running in open solaris on joyent. I have a monitoring service that alert me when the site is down, but, I want a way to put a "insider" tool that tell me why that happened. Is because the cpu is too high? Not memory? Which process fail? Is possible to have a backtrace of that? Everything is running on the Solaris Service Management Facility. The webserver is cherokee, the database is mysql and the language is python/django. I want the most simple setup to monitor that & auto-respond , ie: restart the webserver or the django process in case of failure. I prefer a low-overhead tool. I don't need the fancy monitoring that some tools have, no ned graphs or sms alert. Only know what fail, restart it if possible (maybe up to n times), and have a log somewhere when I will check it.

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  • System Slow After Uprading Ubuntu

    - by Aragon N
    I have an Ubuntu network machine which has release of 10.04.1 LTS Lucid. On this system I have Apache, PostgreSQL and django. For some app. development I have to install PGP and php-curl. Due to being on network, I have exported a VMware machine to the Internet and firstly I have upgraded the system and then installed php5 packages on it. I don't know is it all about django or apache configuration. Maybe some Apache settings had changed. In this case in apache where I have to look at ? After all replacing it with its old place, I see that the new system query is slow according to another. Old system query time : 140 ms New system query time : 9.11 s I have checked /etc/network interface and it seems there is no problem. I have checked /etc/resolv.conf and it seems OK I have checked /etc/nsswitch.conf and only host section is different from old one which old system has hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 and then I have checked time host -t A services.myapp.com and I got real 0m0.355s user 0m0.010s sys 0m0.020s and I have checked apache2 HostnameLookups : find /etc/apache2/ -type f | xargs grep -i HostnameLookups It returned : /etc/apache2/apache2.conf:# HostnameLookups: Log the names of clients or just their IP addresses /etc/apache2/apache2.conf:HostnameLookups Off and now what can I have to check for boosting my system as before?

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  • nginx reverse proxy to apache mod_wsgi doesn't work

    - by user11243
    I'm trying to run a django site with apache mod-wsgi with nginx as the front-end to reverse proxy into apache. In my Apache ports.conf file: NameVirtualHost 192.168.0.1:7000 Listen 192.168.0.1:7000 <VirtualHost 192.168.0.1:7000> DocumentRoot /var/apps/example/ ServerName example.com WSGIDaemonProcess example WSGIProcessGroup example Alias /m/ /var/apps/example/forum/skins/ Alias /upfiles/ /var/apps/example/forum/upfiles/ <Directory /var/apps/example/forum/skins> Order deny,allow Allow from all </Directory> WSGIScriptAlias / /var/apps/example/django.wsgi </VirtualHost> In my nginx config: server { listen 80; server_name example.com; location / { include /usr/local/nginx/conf/proxy.conf; proxy_pass http://192.168.0.1:7000; proxy_redirect default; root /var/apps/example/forum/skins/; } #error_page 404 /404.html; # redirect server error pages to the static page /50x.html error_page 500 502 503 504 /50x.html; location = /50x.html { root html; } } After restarting both apache and nginx, nothing works, example.com simply hangs or serves index.html in my /var/www/ folder. I'd appreciate any advice to point me in the right direction. I've tried several tutorials online to no avail.

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  • An Introduction to jQuery Templates

    - by Stephen Walther
    The goal of this blog entry is to provide you with enough information to start working with jQuery Templates. jQuery Templates enable you to display and manipulate data in the browser. For example, you can use jQuery Templates to format and display a set of database records that you have retrieved with an Ajax call. jQuery Templates supports a number of powerful features such as template tags, template composition, and wrapped templates. I’ll concentrate on the features that I think that you will find most useful. In order to focus on the jQuery Templates feature itself, this blog entry is server technology agnostic. All the samples use HTML pages instead of ASP.NET pages. In a future blog entry, I’ll focus on using jQuery Templates with ASP.NET Web Forms and ASP.NET MVC (You can do some pretty powerful things when jQuery Templates are used on the client and ASP.NET is used on the server). Introduction to jQuery Templates The jQuery Templates plugin was developed by the Microsoft ASP.NET team in collaboration with the open-source jQuery team. While working at Microsoft, I wrote the original proposal for jQuery Templates, Dave Reed wrote the original code, and Boris Moore wrote the final code. The jQuery team – especially John Resig – was very involved in each step of the process. Both the jQuery community and ASP.NET communities were very active in providing feedback. jQuery Templates will be included in the jQuery core library (the jQuery.js library) when jQuery 1.5 is released. Until jQuery 1.5 is released, you can download the jQuery Templates plugin from the jQuery Source Code Repository or you can use jQuery Templates directly from the ASP.NET CDN. The documentation for jQuery Templates is already included with the official jQuery documentation at http://api.jQuery.com. The main entry for jQuery templates is located under the topic plugins/templates. A Basic Sample of jQuery Templates Let’s start with a really simple sample of using jQuery Templates. We’ll use the plugin to display a list of books stored in a JavaScript array. Here’s the complete code: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html > <head> <title>Intro</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html> When you open this page in a browser, a list of books is displayed: There are several things going on in this page which require explanation. First, notice that the page uses both the jQuery 1.4.4 and jQuery Templates libraries. Both libraries are retrieved from the ASP.NET CDN: <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> You can use the ASP.NET CDN for free (even for production websites). You can learn more about the files included on the ASP.NET CDN by visiting the ASP.NET CDN documentation page. Second, you should notice that the actual template is included in a script tag with a special MIME type: <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> This template is displayed for each of the books rendered by the template. The template displays a book picture, title, and price. Notice that the SCRIPT tag which wraps the template has a MIME type of text/x-jQuery-tmpl. Why is the template wrapped in a SCRIPT tag and why the strange MIME type? When a browser encounters a SCRIPT tag with an unknown MIME type, it ignores the content of the tag. This is the behavior that you want with a template. You don’t want a browser to attempt to parse the contents of a template because this might cause side effects. For example, the template above includes an <img> tag with a src attribute that points at “BookPictures/${picture}”. You don’t want the browser to attempt to load an image at the URL “BookPictures/${picture}”. Instead, you want to prevent the browser from processing the IMG tag until the ${picture} expression is replaced by with the actual name of an image by the jQuery Templates plugin. If you are not worried about browser side-effects then you can wrap a template inside any HTML tag that you please. For example, the following DIV tag would also work with the jQuery Templates plugin: <div id="bookTemplate" style="display:none"> <div> <h2>${title}</h2> price: ${formatPrice(price)} </div> </div> Notice that the DIV tag includes a style=”display:none” attribute to prevent the template from being displayed until the template is parsed by the jQuery Templates plugin. Third, notice that the expression ${…} is used to display the value of a JavaScript expression within a template. For example, the expression ${title} is used to display the value of the book title property. You can use any JavaScript function that you please within the ${…} expression. For example, in the template above, the book price is formatted with the help of the custom JavaScript formatPrice() function which is defined lower in the page. Fourth, and finally, the template is rendered with the help of the tmpl() method. The following statement selects the bookTemplate and renders an array of books using the bookTemplate. The results are appended to a DIV element named bookContainer by using the standard jQuery appendTo() method. $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); Using Template Tags Within a template, you can use any of the following template tags. {{tmpl}} – Used for template composition. See the section below. {{wrap}} – Used for wrapped templates. See the section below. {{each}} – Used to iterate through a collection. {{if}} – Used to conditionally display template content. {{else}} – Used with {{if}} to conditionally display template content. {{html}} – Used to display the value of an HTML expression without encoding the value. Using ${…} or {{= }} performs HTML encoding automatically. {{= }}-- Used in exactly the same way as ${…}. {{! }} – Used for displaying comments. The contents of a {{!...}} tag are ignored. For example, imagine that you want to display a list of blog entries. Each blog entry could, possibly, have an associated list of categories. The following page illustrates how you can use the { if}} and {{each}} template tags to conditionally display categories for each blog entry:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>each</title> <link href="1_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="blogPostContainer"></div> <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var blogPosts = [ { postTitle: "How to fix a sink plunger in 5 minutes", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Sinks", "Plumbing"] }, { postTitle: "How to remove a broken lightbulb", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna.", categories: ["HowTo", "Lightbulbs", "Electricity"] }, { postTitle: "New associate website", postEntry: "Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna." } ]; // Render the blog posts $("#blogPostTemplate").tmpl(blogPosts).appendTo("#blogPostContainer"); </script> </body> </html> When this page is opened in a web browser, the following list of blog posts and categories is displayed: Notice that the first and second blog entries have associated categories but the third blog entry does not. The third blog entry is “Uncategorized”. The template used to render the blog entries and categories looks like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script> Notice the special expression $value used within the {{each}} template tag. You can use $value to display the value of the current template item. In this case, $value is used to display the value of each category in the collection of categories. Template Composition When building a fancy page, you might want to build a template out of multiple templates. In other words, you might want to take advantage of template composition. For example, imagine that you want to display a list of products. Some of the products are being sold at their normal price and some of the products are on sale. In that case, you might want to use two different templates for displaying a product: a productTemplate and a productOnSaleTemplate. The following page illustrates how you can use the {{tmpl}} tag to build a template from multiple templates:   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Composition</title> <link href="2_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContainer"> <h1>Products</h1> <div id="productListContainer"></div> <!-- Show list of products using composition --> <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script> <!-- Show product --> <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script> <!-- Show product on sale --> <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> var products = [ { name: "Laptop", onSale: false }, { name: "Apples", onSale: true }, { name: "Comb", onSale: false } ]; $("#productListTemplate").tmpl(products).appendTo("#productListContainer"); </script> </div> </body> </html>   In the page above, the main template used to display the list of products looks like this: <script id="productListTemplate" type="text/x-jQuery-tmpl"> <div> {{if onSale}} {{tmpl "#productOnSaleTemplate"}} {{else}} {{tmpl "#productTemplate"}} {{/if}} </div> </script>   If a product is on sale then the product is displayed with the productOnSaleTemplate (which includes an on sale image): <script id="productOnSaleTemplate" type="text/x-jQuery-tmpl"> <b>${name}</b> <img src="images/on_sale.png" alt="On Sale" /> </script>   Otherwise, the product is displayed with the normal productTemplate (which does not include the on sale image): <script id="productTemplate" type="text/x-jQuery-tmpl"> ${name} </script>   You can pass a parameter to the {{tmpl}} tag. The parameter becomes the data passed to the template rendered by the {{tmpl}} tag. For example, in the previous section, we used the {{each}} template tag to display a list of categories for each blog entry like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{each categories}} <i>${$value}</i> {{/each}} {{else}} Uncategorized {{/if}} </script>   Another way to create this template is to use template composition like this: <script id="blogPostTemplate" type="text/x-jQuery-tmpl"> <h1>${postTitle}</h1> <p> ${postEntry} </p> {{if categories}} Categories: {{tmpl(categories) "#categoryTemplate"}} {{else}} Uncategorized {{/if}} </script> <script id="categoryTemplate" type="text/x-jQuery-tmpl"> <i>${$data}</i> &nbsp; </script>   Using the {{each}} tag or {{tmpl}} tag is largely a matter of personal preference. Wrapped Templates The {{wrap}} template tag enables you to take a chunk of HTML and transform the HTML into another chunk of HTML (think easy XSLT). When you use the {{wrap}} tag, you work with two templates. The first template contains the HTML being transformed and the second template includes the filter expressions for transforming the HTML. For example, you can use the {{wrap}} template tag to transform a chunk of HTML into an interactive tab strip: When you click any of the tabs, you see the corresponding content. This tab strip was created with the following page: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Wrapped Templates</title> <style type="text/css"> body { font-family: Arial; background-color:black; } .tabs div { display:inline-block; border-bottom: 1px solid black; padding:4px; background-color:gray; cursor:pointer; } .tabs div.tabState_true { background-color:white; border-bottom:1px solid white; } .tabBody { border-top:1px solid white; padding:10px; background-color:white; min-height:400px; width:400px; } </style> </head> <body> <div id="tabsView"></div> <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script> <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Global for tracking selected tab var selectedTabIndex = 0; // Render the tab strip $("#tabsContent").tmpl().appendTo("#tabsView"); // When a tab is clicked, update the tab strip $("#tabsView") .delegate(".tabState_false", "click", function () { var templateItem = $.tmplItem(this); selectedTabIndex = $(this).index(); templateItem.update(); }); </script> </body> </html>   The “source” for the tab strip is contained in the following template: <script id="tabsContent" type="text/x-jquery-tmpl"> {{wrap "#tabsWrap"}} <h3>Tab 1</h3> <div> Content of tab 1. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 2</h3> <div> Content of tab 2. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> <h3>Tab 3</h3> <div> Content of tab 3. Lorem ipsum dolor <b>sit</b> amet, consectetuer adipiscing elit. Maecenas porttitor congue massa. Fusce posuere, magna sed pulvinar ultricies, purus lectus malesuada libero, sit amet commodo magna eros quis urna. </div> {{/wrap}} </script>   The tab strip is created with a list of H3 elements (which represent each tab) and DIV elements (which represent the body of each tab). Notice that the HTML content is wrapped in the {{wrap}} template tag. This template tag points at the following tabsWrap template: <script id="tabsWrap" type="text/x-jquery-tmpl"> <div class="tabs"> {{each $item.html("h3", true)}} <div class="tabState_${$index === selectedTabIndex}"> ${$value} </div> {{/each}} </div> <div class="tabBody"> {{html $item.html("div")[selectedTabIndex]}} </div> </script> The tabs DIV contains all of the tabs. The {{each}} template tag is used to loop through each of the H3 elements from the source template and render a DIV tag that represents a particular tab. The template item html() method is used to filter content from the “source” HTML template. The html() method accepts a jQuery selector for its first parameter. The tabs are retrieved from the source template by using an h3 filter. The second parameter passed to the html() method – the textOnly parameter -- causes the filter to return the inner text of each h3 element. You can learn more about the html() method at the jQuery website (see the section on $item.html()). The tabBody DIV renders the body of the selected tab. Notice that the {{html}} template tag is used to display the tab body so that HTML content in the body won’t be HTML encoded. The html() method is used, once again, to grab all of the DIV elements from the source HTML template. The selectedTabIndex global variable is used to display the contents of the selected tab. Remote Templates A common feature request for jQuery templates is support for remote templates. Developers want to be able to separate templates into different files. Adding support for remote templates requires only a few lines of extra code (Dave Ward has a nice blog entry on this). For example, the following page uses a remote template from a file named BookTemplate.htm: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Remote Templates</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg" }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg" }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg" }, ]; // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The remote template is retrieved (and rendered) with the following code: // Get the remote template $.get("BookTemplate.htm", null, function (bookTemplate) { // Render the books using the remote template $.tmpl(bookTemplate, books).appendTo("#bookContainer"); });   This code uses the standard jQuery $.get() method to get the BookTemplate.htm file from the server with an Ajax request. After the BookTemplate.htm file is successfully retrieved, the $.tmpl() method is used to render an array of books with the template. Here’s what the BookTemplate.htm file looks like: <div> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> Notice that the template in the BooksTemplate.htm file is not wrapped by a SCRIPT element. There is no need to wrap the template in this case because there is no possibility that the template will get interpreted before you want it to be interpreted. If you plan to use the bookTemplate multiple times – for example, you are paging or sorting the books -- then you should compile the template into a function and cache the compiled template function. For example, the following page can be used to page through a list of 100 products (using iPhone style More paging). <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Caching</title> <link href="6_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <h1>Products</h1> <div id="productContainer"></div> <button id="more">More</button> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Globals var pageIndex = 0; // Create an array of products var products = []; for (var i = 0; i < 100; i++) { products.push({ name: "Product " + (i + 1) }); } // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); }); $("#more").click(function () { pageIndex++; renderProducts(); }); function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   The ProductTemplate is retrieved from an external file named ProductTemplate.htm. This template is retrieved only once. Furthermore, it is compiled and cached with the help of the $.template() method: // Get the remote template $.get("ProductTemplate.htm", null, function (productTemplate) { // Compile and cache the template $.template("productTemplate", productTemplate); // Render the products renderProducts(0); });   The $.template() method compiles the HTML representation of the template into a JavaScript function and caches the template function with the name productTemplate. The cached template can be used by calling the $.tmp() method. The productTemplate is used in the renderProducts() method: function renderProducts() { // Get page of products var pageOfProducts = products.slice(pageIndex * 5, pageIndex * 5 + 5); // Used cached productTemplate to render products $.tmpl("productTemplate", pageOfProducts).appendTo("#productContainer"); } In the code above, the first parameter passed to the $.tmpl() method is the name of a cached template. Working with Template Items In this final section, I want to devote some space to discussing Template Items. A new Template Item is created for each rendered instance of a template. For example, if you are displaying a list of 100 products with a template, then 100 Template Items are created. A Template Item has the following properties and methods: data – The data associated with the Template Instance. For example, a product. tmpl – The template associated with the Template Instance. parent – The parent template item if the template is nested. nodes – The HTML content of the template. calls – Used by {{wrap}} template tag. nest – Used by {{tmpl}} template tag. wrap – Used to imperatively enable wrapped templates. html – Used to filter content from a wrapped template. See the above section on wrapped templates. update – Used to re-render a template item. The last method – the update() method -- is especially interesting because it enables you to re-render a template item with new data or even a new template. For example, the following page displays a list of books. When you hover your mouse over any of the books, additional book details are displayed. In the following screenshot, details for ASP.NET Kick Start are displayed. <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Template Item</title> <link href="0_Site.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="pageContent"> <h1>ASP.NET Bookstore</h1> <div id="bookContainer"></div> </div> <script id="bookTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} </div> </script> <script id="bookDetailsTemplate" type="text/x-jQuery-tmpl"> <div class="bookItem"> <img src="BookPictures/${picture}" alt="" /> <h2>${title}</h2> price: ${formatPrice(price)} <p> ${description} </p> </div> </script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.4.4.js"></script> <script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.templates/beta1/jquery.tmpl.js"></script> <script type="text/javascript"> // Create an array of books var books = [ { title: "ASP.NET 4 Unleashed", price: 37.79, picture: "AspNet4Unleashed.jpg", description: "The most comprehensive book on Microsoft’s new ASP.NET 4.. " }, { title: "ASP.NET MVC Unleashed", price: 44.99, picture: "AspNetMvcUnleashed.jpg", description: "Writing for professional programmers, Walther explains the crucial concepts that make the Model-View-Controller (MVC) development paradigm work…" }, { title: "ASP.NET Kick Start", price: 4.00, picture: "AspNetKickStart.jpg", description: "Visual Studio .NET is the premier development environment for creating .NET applications…." }, { title: "ASP.NET MVC Unleashed iPhone", price: 44.99, picture: "AspNetMvcUnleashedIPhone.jpg", description: "ASP.NET MVC Unleashed for the iPhone…" }, ]; // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer"); // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); }); function formatPrice(price) { return "$" + price.toFixed(2); } </script> </body> </html>   There are two templates used to display a book: bookTemplate and bookDetailsTemplate. When you hover your mouse over a template item, the standard bookTemplate is swapped out for the bookDetailsTemplate. The bookDetailsTemplate displays a book description. The books are rendered with the bookTemplate with the following line of code: // Render the books using the template $("#bookTemplate").tmpl(books).appendTo("#bookContainer");   The following code is used to swap the bookTemplate and the bookDetailsTemplate to show details for a book: // Get compiled details template var bookDetailsTemplate = $("#bookDetailsTemplate").template(); // Add hover handler $(".bookItem").mouseenter(function () { // Get template item associated with DIV var templateItem = $(this).tmplItem(); // Change template to compiled template templateItem.tmpl = bookDetailsTemplate; // Re-render template templateItem.update(); });   When you hover your mouse over a DIV element rendered by the bookTemplate, the mouseenter handler executes. First, this handler retrieves the Template Item associated with the DIV element by calling the tmplItem() method. The tmplItem() method returns a Template Item. Next, a new template is assigned to the Template Item. Notice that a compiled version of the bookDetailsTemplate is assigned to the Template Item’s tmpl property. The template is compiled earlier in the code by calling the template() method. Finally, the Template Item update() method is called to re-render the Template Item with the bookDetailsTemplate instead of the original bookTemplate. Summary This is a long blog entry and I still have not managed to cover all of the features of jQuery Templates J However, I’ve tried to cover the most important features of jQuery Templates such as template composition, template wrapping, and template items. To learn more about jQuery Templates, I recommend that you look at the documentation for jQuery Templates at the official jQuery website. Another great way to learn more about jQuery Templates is to look at the (unminified) source code.

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  • ASP.NET and HTML5 Local Storage

    - by Stephen Walther
    My favorite feature of HTML5, hands-down, is HTML5 local storage (aka DOM storage). By taking advantage of HTML5 local storage, you can dramatically improve the performance of your data-driven ASP.NET applications by caching data in the browser persistently. Think of HTML5 local storage like browser cookies, but much better. Like cookies, local storage is persistent. When you add something to browser local storage, it remains there when the user returns to the website (possibly days or months later). Importantly, unlike the cookie storage limitation of 4KB, you can store up to 10 megabytes in HTML5 local storage. Because HTML5 local storage works with the latest versions of all modern browsers (IE, Firefox, Chrome, Safari), you can start taking advantage of this HTML5 feature in your applications right now. Why use HTML5 Local Storage? I use HTML5 Local Storage in the JavaScript Reference application: http://Superexpert.com/JavaScriptReference The JavaScript Reference application is an HTML5 app that provides an interactive reference for all of the syntax elements of JavaScript (You can read more about the application and download the source code for the application here). When you open the application for the first time, all of the entries are transferred from the server to the browser (all 300+ entries). All of the entries are stored in local storage. When you open the application in the future, only changes are transferred from the server to the browser. The benefit of this approach is that the application performs extremely fast. When you click the details link to view details on a particular entry, the entry details appear instantly because all of the entries are stored on the client machine. When you perform key-up searches, by typing in the filter textbox, matching entries are displayed very quickly because the entries are being filtered on the local machine. This approach can have a dramatic effect on the performance of any interactive data-driven web application. Interacting with data on the client is almost always faster than interacting with the same data on the server. Retrieving Data from the Server In the JavaScript Reference application, I use Microsoft WCF Data Services to expose data to the browser. WCF Data Services generates a REST interface for your data automatically. Here are the steps: Create your database tables in Microsoft SQL Server. For example, I created a database named ReferenceDB and a database table named Entities. Use the Entity Framework to generate your data model. For example, I used the Entity Framework to generate a class named ReferenceDBEntities and a class named Entities. Expose your data through WCF Data Services. I added a WCF Data Service to my project and modified the data service class to look like this:   using System.Data.Services; using System.Data.Services.Common; using System.Web; using JavaScriptReference.Models; namespace JavaScriptReference.Services { [System.ServiceModel.ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class EntryService : DataService<ReferenceDBEntities> { // This method is called only once to initialize service-wide policies. public static void InitializeService(DataServiceConfiguration config) { config.UseVerboseErrors = true; config.SetEntitySetAccessRule("*", EntitySetRights.All); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; } // Define a change interceptor for the Products entity set. [ChangeInterceptor("Entries")] public void OnChangeEntries(Entry entry, UpdateOperations operations) { if (!HttpContext.Current.Request.IsAuthenticated) { throw new DataServiceException("Cannot update reference unless authenticated."); } } } }     The WCF data service is named EntryService. Notice that it derives from DataService<ReferenceEntitites>. Because it derives from DataService<ReferenceEntities>, the data service exposes the contents of the ReferenceEntitiesDB database. In the code above, I defined a ChangeInterceptor to prevent un-authenticated users from making changes to the database. Anyone can retrieve data through the service, but only authenticated users are allowed to make changes. After you expose data through a WCF Data Service, you can use jQuery to retrieve the data by performing an Ajax call. For example, I am using an Ajax call that looks something like this to retrieve the JavaScript entries from the EntryService.svc data service: $.ajax({ dataType: "json", url: “/Services/EntryService.svc/Entries”, success: function (result) { var data = callback(result["d"]); } });     Notice that you must unwrap the data using result[“d”]. After you unwrap the data, you have a JavaScript array of the entries. I’m transferring all 300+ entries from the server to the client when the application is opened for the first time. In other words, I transfer the entire database from the server to the client, once and only once, when the application is opened for the first time. The data is transferred using JSON. Here is a fragment: { "d" : [ { "__metadata": { "uri": "http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries(1)", "type": "ReferenceDBModel.Entry" }, "Id": 1, "Name": "Global", "Browsers": "ff3_6,ie8,ie9,c8,sf5,es3,es5", "Syntax": "object", "ShortDescription": "Contains global variables and functions", "FullDescription": "<p>\nThe Global object is determined by the host environment. In web browsers, the Global object is the same as the windows object.\n</p>\n<p>\nYou can use the keyword <code>this</code> to refer to the Global object when in the global context (outside of any function).\n</p>\n<p>\nThe Global object holds all global variables and functions. For example, the following code demonstrates that the global <code>movieTitle</code> variable refers to the same thing as <code>window.movieTitle</code> and <code>this.movieTitle</code>.\n</p>\n<pre>\nvar movieTitle = \"Star Wars\";\nconsole.log(movieTitle === this.movieTitle); // true\nconsole.log(movieTitle === window.movieTitle); // true\n</pre>\n", "LastUpdated": "634298578273756641", "IsDeleted": false, "OwnerId": null }, { "__metadata": { "uri": "http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries(2)", "type": "ReferenceDBModel.Entry" }, "Id": 2, "Name": "eval(string)", "Browsers": "ff3_6,ie8,ie9,c8,sf5,es3,es5", "Syntax": "function", "ShortDescription": "Evaluates and executes JavaScript code dynamically", "FullDescription": "<p>\nThe following code evaluates and executes the string \"3+5\" at runtime.\n</p>\n<pre>\nvar result = eval(\"3+5\");\nconsole.log(result); // returns 8\n</pre>\n<p>\nYou can rewrite the code above like this:\n</p>\n<pre>\nvar result;\neval(\"result = 3+5\");\nconsole.log(result);\n</pre>", "LastUpdated": "634298580913817644", "IsDeleted": false, "OwnerId": 1 } … ]} I worried about the amount of time that it would take to transfer the records. According to Google Chome, it takes about 5 seconds to retrieve all 300+ records on a broadband connection over the Internet. 5 seconds is a small price to pay to avoid performing any server fetches of the data in the future. And here are the estimated times using different types of connections using Fiddler: Notice that using a modem, it takes 33 seconds to download the database. 33 seconds is a significant chunk of time. So, I would not use the approach of transferring the entire database up front if you expect a significant portion of your website audience to connect to your website with a modem. Adding Data to HTML5 Local Storage After the JavaScript entries are retrieved from the server, the entries are stored in HTML5 local storage. Here’s the reference documentation for HTML5 storage for Internet Explorer: http://msdn.microsoft.com/en-us/library/cc197062(VS.85).aspx You access local storage by accessing the windows.localStorage object in JavaScript. This object contains key/value pairs. For example, you can use the following JavaScript code to add a new item to local storage: <script type="text/javascript"> window.localStorage.setItem("message", "Hello World!"); </script>   You can use the Google Chrome Storage tab in the Developer Tools (hit CTRL-SHIFT I in Chrome) to view items added to local storage: After you add an item to local storage, you can read it at any time in the future by using the window.localStorage.getItem() method: <script type="text/javascript"> window.localStorage.setItem("message", "Hello World!"); </script>   You only can add strings to local storage and not JavaScript objects such as arrays. Therefore, before adding a JavaScript object to local storage, you need to convert it into a JSON string. In the JavaScript Reference application, I use a wrapper around local storage that looks something like this: function Storage() { this.get = function (name) { return JSON.parse(window.localStorage.getItem(name)); }; this.set = function (name, value) { window.localStorage.setItem(name, JSON.stringify(value)); }; this.clear = function () { window.localStorage.clear(); }; }   If you use the wrapper above, then you can add arbitrary JavaScript objects to local storage like this: var store = new Storage(); // Add array to storage var products = [ {name:"Fish", price:2.33}, {name:"Bacon", price:1.33} ]; store.set("products", products); // Retrieve items from storage var products = store.get("products");   Modern browsers support the JSON object natively. If you need the script above to work with older browsers then you should download the JSON2.js library from: https://github.com/douglascrockford/JSON-js The JSON2 library will use the native JSON object if a browser already supports JSON. Merging Server Changes with Browser Local Storage When you first open the JavaScript Reference application, the entire database of JavaScript entries is transferred from the server to the browser. Two items are added to local storage: entries and entriesLastUpdated. The first item contains the entire entries database (a big JSON string of entries). The second item, a timestamp, represents the version of the entries. Whenever you open the JavaScript Reference in the future, the entriesLastUpdated timestamp is passed to the server. Only records that have been deleted, updated, or added since entriesLastUpdated are transferred to the browser. The OData query to get the latest updates looks like this: http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries?$filter=(LastUpdated%20gt%20634301199890494792L) If you remove URL encoding, the query looks like this: http://superexpert.com/javascriptreference/Services/EntryService.svc/Entries?$filter=(LastUpdated gt 634301199890494792L) This query returns only those entries where the value of LastUpdated > 634301199890494792 (the version timestamp). The changes – new JavaScript entries, deleted entries, and updated entries – are merged with the existing entries in local storage. The JavaScript code for performing the merge is contained in the EntriesHelper.js file. The merge() method looks like this:   merge: function (oldEntries, newEntries) { // concat (this performs the add) oldEntries = oldEntries || []; var mergedEntries = oldEntries.concat(newEntries); // sort this.sortByIdThenLastUpdated(mergedEntries); // prune duplicates (this performs the update) mergedEntries = this.pruneDuplicates(mergedEntries); // delete mergedEntries = this.removeIsDeleted(mergedEntries); // Sort this.sortByName(mergedEntries); return mergedEntries; },   The contents of local storage are then updated with the merged entries. I spent several hours writing the merge() method (much longer than I expected). I found two resources to be extremely useful. First, I wrote extensive unit tests for the merge() method. I wrote the unit tests using server-side JavaScript. I describe this approach to writing unit tests in this blog entry. The unit tests are included in the JavaScript Reference source code. Second, I found the following blog entry to be super useful (thanks Nick!): http://nicksnettravels.builttoroam.com/post/2010/08/03/OData-Synchronization-with-WCF-Data-Services.aspx One big challenge that I encountered involved timestamps. I originally tried to store an actual UTC time as the value of the entriesLastUpdated item. I quickly discovered that trying to work with dates in JSON turned out to be a big can of worms that I did not want to open. Next, I tried to use a SQL timestamp column. However, I learned that OData cannot handle the timestamp data type when doing a filter query. Therefore, I ended up using a bigint column in SQL and manually creating the value when a record is updated. I overrode the SaveChanges() method to look something like this: public override int SaveChanges(SaveOptions options) { var changes = this.ObjectStateManager.GetObjectStateEntries( EntityState.Modified | EntityState.Added | EntityState.Deleted); foreach (var change in changes) { var entity = change.Entity as IEntityTracking; if (entity != null) { entity.LastUpdated = DateTime.Now.Ticks; } } return base.SaveChanges(options); }   Notice that I assign Date.Now.Ticks to the entity.LastUpdated property whenever an entry is modified, added, or deleted. Summary After building the JavaScript Reference application, I am convinced that HTML5 local storage can have a dramatic impact on the performance of any data-driven web application. If you are building a web application that involves extensive interaction with data then I recommend that you take advantage of this new feature included in the HTML5 standard.

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