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  • Regarding playing media file in Android media player application

    - by Mangesh
    Hi. I am new to android development. I just started with creating my own media player application by looking at the code samples given in Android SDK. While I am trying to play a local media file (m.3gp), I am getting IOException error :: error(1,-4). Please can somebody help me in this regard. Here is my code. package com.mediaPlayer; import java.io.IOException; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.media.MediaPlayer; import android.media.MediaPlayer.OnBufferingUpdateListener; import android.media.MediaPlayer.OnCompletionListener; import android.media.MediaPlayer.OnPreparedListener; import android.media.MediaPlayer.OnVideoSizeChangedListener; import android.view.SurfaceHolder; import android.util.Log; public class MediaPlayer1 extends Activity implements OnBufferingUpdateListener, OnCompletionListener,OnPreparedListener, OnVideoSizeChangedListener,SurfaceHolder.Callback { private static final String TAG = "MediaPlayerByMangesh"; // Widgets in the application private Button btnPlay; private Button btnPause; private Button btnStop; private MediaPlayer mMediaPlayer; private String path = "m.3gp"; private SurfaceHolder holder; private int mVideoWidth; private int mVideoHeight; private boolean mIsVideoSizeKnown = false; private boolean mIsVideoReadyToBePlayed = false; // For the id of radio button selected private int radioCheckedId = -1; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { Log.d(TAG, "Entered OnCreate:"); super.onCreate(savedInstanceState); setContentView(R.layout.main); Log.d(TAG, "Creatinging Buttons:"); btnPlay = (Button) findViewById(R.id.btnPlay); btnPause = (Button) findViewById(R.id.btnPause); // On app load, the Pause button is disabled btnPause.setEnabled(false); btnStop = (Button) findViewById(R.id.btnStop); btnStop.setEnabled(false); /* * Attach a OnCheckedChangeListener to the radio group to monitor radio * buttons selected by user */ Log.d(TAG, "Watching for Click"); /* Attach listener to the Calculate and Reset buttons */ btnPlay.setOnClickListener(mClickListener); btnPause.setOnClickListener(mClickListener); btnStop.setOnClickListener(mClickListener); } /* * ClickListener for the Calculate and Reset buttons. Depending on the * button clicked, the corresponding method is called. */ private OnClickListener mClickListener = new OnClickListener() { @Override public void onClick(View v) { switch (v.getId()) { case R.id.btnPlay: Log.d(TAG, "Clicked Play Button"); Log.d(TAG, "Calling Play Function"); Play(); break; case R.id.btnPause: Pause(); break; case R.id.btnStop: Stop(); break; } } }; /** * Play the Video. */ private void Play() { // Create a new media player and set the listeners mMediaPlayer = new MediaPlayer(); Log.d(TAG, "Entered Play function:"); try { mMediaPlayer.setDataSource(path); } catch(IOException ie) { Log.d(TAG, "IO Exception:" + path); } mMediaPlayer.setDisplay(holder); try { mMediaPlayer.prepare(); } catch(IOException ie) { Log.d(TAG, "IO Exception:" + path); } mMediaPlayer.setOnBufferingUpdateListener(this); mMediaPlayer.setOnCompletionListener(this); mMediaPlayer.setOnPreparedListener(this); //mMediaPlayer.setOnVideoSizeChangedListener(this); //mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC); } public void onBufferingUpdate(MediaPlayer arg0, int percent) { Log.d(TAG, "onBufferingUpdate percent:" + percent); } public void onCompletion(MediaPlayer arg0) { Log.d(TAG, "onCompletion called"); } public void onVideoSizeChanged(MediaPlayer mp, int width, int height) { Log.v(TAG, "onVideoSizeChanged called"); if (width == 0 || height == 0) { Log.e(TAG, "invalid video width(" + width + ") or height(" + height + ")"); return; } mIsVideoSizeKnown = true; mVideoWidth = width; mVideoHeight = height; if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) { startVideoPlayback(); } } public void onPrepared(MediaPlayer mediaplayer) { Log.d(TAG, "onPrepared called"); mIsVideoReadyToBePlayed = true; if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) { startVideoPlayback(); } } public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) { Log.d(TAG, "surfaceChanged called"); } public void surfaceDestroyed(SurfaceHolder surfaceholder) { Log.d(TAG, "surfaceDestroyed called"); } public void surfaceCreated(SurfaceHolder holder) { Log.d(TAG, "surfaceCreated called"); Play(); } private void startVideoPlayback() { Log.v(TAG, "startVideoPlayback"); holder.setFixedSize(176, 144); mMediaPlayer.start(); } /** * Pause the Video */ private void Pause() { ; /* * If all fields are populated with valid values, then proceed to * calculate the tips */ } /** * Stop the Video. */ private void Stop() { ; /* * If all fields are populated with valid values, then proceed to * calculate the tips */ } /** * Shows the error message in an alert dialog * * @param errorMessage * String the error message to show * @param fieldId * the Id of the field which caused the error. This is required * so that the focus can be set on that field once the dialog is * dismissed. */ private void showErrorAlert(String errorMessage, final int fieldId) { new AlertDialog.Builder(this).setTitle("Error") .setMessage(errorMessage).setNeutralButton("Close", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { findViewById(fieldId).requestFocus(); } }).show(); } } Thanks, Mangesh Kumar K.

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  • Bindable richTextBox still hanging in memory {WPF, Caliburn.Micro}

    - by Paul
    Hi, I use in WFP Caliburn.Micro Framework. I need bindable richTextbox for Document property. I found many ways how do it bindable richTextBox. But I have one problem. From parent window I open child window. Child window consist bindable richTextBox user control. After I close child window and use memory profiler view class with bindabelrichTextBox control and view model class is still hanging in memory. - this cause memory leaks. If I use richTextBox from .NET Framework or richTextBox from Extended WPF Toolkit it doesn’t cause this memory leak problem. I can’t identified problem in bindable richTextBox class. Here is ist class for bindable richTextBox: Base class can be from .NET or Extended toolkit. /// <summary> /// Represents a bindable rich editing control which operates on System.Windows.Documents.FlowDocument /// objects. /// </summary> public class BindableRichTextBox : RichTextBox { /// <summary> /// Identifies the <see cref="Document"/> dependency property. /// </summary> public static readonly DependencyProperty DocumentProperty = DependencyProperty.Register("Document", typeof(FlowDocument), typeof(BindableRichTextBox)); /// <summary> /// Initializes a new instance of the <see cref="BindableRichTextBox"/> class. /// </summary> public BindableRichTextBox() : base() { } /// <summary> /// Initializes a new instance of the <see cref="BindableRichTextBox"/> class. /// </summary> /// <param title="document">A <see cref="T:System.Windows.Documents.FlowDocument"></see> to be added as the initial contents of the new <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>.</param> public BindableRichTextBox(FlowDocument document) : base(document) { } /// <summary> /// Raises the <see cref="E:System.Windows.FrameworkElement.Initialized"></see> event. This method is invoked whenever <see cref="P:System.Windows.FrameworkElement.IsInitialized"></see> is set to true internally. /// </summary> /// <param title="e">The <see cref="T:System.Windows.RoutedEventArgs"></see> that contains the event data.</param> protected override void OnInitialized(EventArgs e) { // Hook up to get notified when DocumentProperty changes. DependencyPropertyDescriptor descriptor = DependencyPropertyDescriptor.FromProperty(DocumentProperty, typeof(BindableRichTextBox)); descriptor.AddValueChanged(this, delegate { // If the underlying value of the dependency property changes, // update the underlying document, also. base.Document = (FlowDocument)GetValue(DocumentProperty); }); // By default, we support updates to the source when focus is lost (or, if the LostFocus // trigger is specified explicity. We don't support the PropertyChanged trigger right now. this.LostFocus += new RoutedEventHandler(BindableRichTextBox_LostFocus); base.OnInitialized(e); } /// <summary> /// Handles the LostFocus event of the BindableRichTextBox control. /// </summary> /// <param title="sender">The source of the event.</param> /// <param title="e">The <see cref="System.Windows.RoutedEventArgs"/> instance containing the event data.</param> void BindableRichTextBox_LostFocus(object sender, RoutedEventArgs e) { // If we have a binding that is set for LostFocus or Default (which we are specifying as default) // then update the source. Binding binding = BindingOperations.GetBinding(this, DocumentProperty); if (binding.UpdateSourceTrigger == UpdateSourceTrigger.Default || binding.UpdateSourceTrigger == UpdateSourceTrigger.LostFocus) { BindingOperations.GetBindingExpression(this, DocumentProperty).UpdateSource(); } } /// <summary> /// Gets or sets the <see cref="T:System.Windows.Documents.FlowDocument"></see> that represents the contents of the <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>. /// </summary> /// <value></value> /// <returns>A <see cref="T:System.Windows.Documents.FlowDocument"></see> object that represents the contents of the <see cref="T:System.Windows.Controls.BindableRichTextBox"></see>.By default, this property is set to an empty <see cref="T:System.Windows.Documents.FlowDocument"></see>. Specifically, the empty <see cref="T:System.Windows.Documents.FlowDocument"></see> contains a single <see cref="T:System.Windows.Documents.Paragraph"></see>, which contains a single <see cref="T:System.Windows.Documents.Run"></see> which contains no text.</returns> /// <exception cref="T:System.ArgumentException">Raised if an attempt is made to set this property to a <see cref="T:System.Windows.Documents.FlowDocument"></see> that represents the contents of another <see cref="T:System.Windows.Controls.RichTextBox"></see>.</exception> /// <exception cref="T:System.ArgumentNullException">Raised if an attempt is made to set this property to null.</exception> /// <exception cref="T:System.InvalidOperationException">Raised if this property is set while a change block has been activated.</exception> public new FlowDocument Document { get { return (FlowDocument)GetValue(DocumentProperty); } set { SetValue(DocumentProperty, value); } } } Thank fro help and advice. Qucik example: Child window with .NET richTextBox <Window x:Class="WpfApplication2.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Window1" Height="300" Width="300"> <Grid> <RichTextBox Background="Green" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" FontSize="13" Margin="4,4,4,4" Grid.Row="0"/> </Grid> </Window> This window I open from parent window: var w = new Window1(); w.Show(); Then close this window, check with memory profiler and it memory doesn’t exist any object of window1 - richTextBox. It’s Ok. But then I try bindable richTextBox: Child window 2: <Window x:Class="WpfApplication2.Window2" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Controls="clr-namespace:WpfApplication2.Controls" Title="Window2" Height="300" Width="300"> <Grid> <Controls:BindableRichTextBox Background="Red" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto" FontSize="13" Margin="4,4,4,4" Grid.Row="0" /> </Grid> </Window> Open child window 2, close this child window and in memory are still alive object of this child window also bindable richTextBox object.

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  • Configuring a WCF Client to Use UserName Credentials On the Request and Check Certificate Credential

    - by AlEl
    I'm trying to use WCF to consume a web service provided by a third-party's Oracle Application Server. I pass a username and password in a UsernameToken as part of the request and as part of the response the web service returns a standard security tag in the header which includes a digest and signature. With my current setup, I successfully send a request to the server and the web service sends the expected response data back. However, when parsing the response WCF throws a MessageSecurityException, with an InnerException.Message of "Supporting token signatures not expected." My guess is that WCF wants me to configure it to handle the signature and verify it. I have a certificate from the third party that hosts the web service that I should be able to use to verify the signature, although I'm not sure if I'll need it. Here's a sample header from a response that makes WCF throw the exception: <?xml version="1.0" encoding="UTF-8"?> <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"> <soap:Header> <wsse:Security soap:mustUnderstand="1" xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> <dsig:Signature xmlns="http://www.w3.org/2000/09/xmldsig#" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"> <dsig:SignedInfo> <dsig:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> <dsig:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/> <dsig:Reference URI="#_51IUwNWRVvPOcz12pZHLNQ22"> <dsig:Transforms> <dsig:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> </dsig:Transforms> <dsig:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <dsig:DigestValue> [DigestValue here] </dsig:DigestValue> </dsig:Reference> <dsig:Reference URI="#_dI5j0EqxrVsj0e62J6vd6w22"> <dsig:Transforms> <dsig:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/> </dsig:Transforms> <dsig:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/> <dsig:DigestValue> [DigestValue here] </dsig:DigestValue> </dsig:Reference> </dsig:SignedInfo> <dsig:SignatureValue> [Signature Value Here] </dsig:SignatureValue> <dsig:KeyInfo> <wsse:SecurityTokenReference xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"> <wsse:Reference URI="#BST-9nKWbrE4LRv6maqstrGuUQ22" ValueType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509v3"/> </wsse:SecurityTokenReference> </dsig:KeyInfo> </dsig:Signature> <wsse:BinarySecurityToken ValueType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-x509-token-profile-1.0#X509v3" EncodingType="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-soap-message-security-1.0#Base64Binary" wsu:Id="BST-9nKWbrE4LRv6maqstrGuUQ22" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> [Security Token Here] </wsse:BinarySecurityToken> <wsu:Timestamp wsu:Id="_dI5j0EqxrVsj0e62J6vd6w22" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> <wsu:Created>2010-05-26T18:46:30Z</wsu:Created> </wsu:Timestamp> </wsse:Security> </soap:Header> <soap:Body wsu:Id="_51IUwNWRVvPOcz12pZHLNQ22" xmlns:wsu="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"> [Body content here] </soap:Body> </soap:Envelope> My binding configuration looks like: <basicHttpBinding> <binding name="myBinding" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true"> <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" /> <security mode="TransportWithMessageCredential"> <transport clientCredentialType="None" proxyCredentialType="None" realm="" /> <message clientCredentialType="UserName" algorithmSuite="Default" /> </security> </binding> </basicHttpBinding> I think that basically what I have to do is configure WCF to use UserName client credentials in the request and Certificate client credentials in the response. I don't know how to do this though. I'm new at WCF, so I'm sorry if this is a bit of a dumb question. I've been trying to Google solutions, but there seem to be so many different ways to configure WCF that I'm getting overwhelmed. Thanks in advance!

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  • Need guidance on a Google Map application that has to show 250 000 polylines.

    - by lucian.jp
    I am looking for advice for an application I am developing that uses Google Map. Summary: A user has a list of criteria for searching a street segment that fulfills the criteria. The street segments will be colored with 3 colors for showing those below average, average and over average. Then the user clicks on the street segment to see an information window showing the properties of that specific segment hiding those not selected until he/she closes the window and other polyline becomes visible again. This looks quite like the Monopoly City Streets game Hasbro made some month ago the difference being I do not use Flash, I can’t use Open Street Map because it doesn’t list street segment (if it does the IDs won’t be the same anyway) and I do not have to show Google sketch building over. Information: I have a database of street segments with IDs, polyline points and centroid. The database has 6,000,000 street segment records in it. To narrow the generated data a bit we focus on city. The largest city we must show has 250,000 street segments. This means 250,000 line segment polyline to show. Our longest polyline uses 9600 characters which is stored in two 8000 varchar columns in SQL Server 2008. We need to use the API v3 because it is faster than the API v2 and the application will be ported to iPhone. For now it's an ASP.NET 3.5 with SQl Server 2008 application. Performance is a priority. Problems: Most of the demo projects that do this are made with API v2. So besides tutorial on the Google API v3 reference page I have nothing to compare performance or technology use to achieve my goal. There is no available .NET wrapper for the API v3 yet. Generating a 250,000 line segment polyline creates a heavy file which takes time to transfer and parse. (I have found a demo of one polyline of 390,000 points. I think the encoder would be far less efficient with more polylines with less points since there will be less rounding.) Since streets segments are shown based on criteria, polylines must be dynamically created and cache can't be used. Some thoughts: KML/KMZ: Pros: Since it is a standard we can easily load Bing maps, Yahoo! maps, Google maps, Google Earth, with the same KML file. The data generation would be the same. Cons: LineString in KML cannot be encoded polyline like the Google map API can handle. So it would probably be bigger and slower to display. Zipping the file at the size it will take more processing time and require the client side to uncompress the data and I am not quite sure with 250,000 data how an iPhone would handle this and how a server would handle 40 users browsing at the same time. JavaScript file: Pros: JavaScript file can have encoded polyline and would significantly reduce the file to transfer. Cons: Have to create my own stripped version of API v3 to add overlays, create polyline, etc. It is more complex than just create a KML file and point to the source. GeoRSS: This option isn't adapted for my needs I think, but I could be wrong. MapServer: I saw some post suggesting using MapServer to generate overlays. Not quite sure for the connection with our database and the performance it would give. Plus it requires a plugin for generating KML. It seems to me that it wouldn't allow me to do better than creating my own KML or JavaScript file. Maintenance would be simpler without. Monopoly City Streets: The game is now over, but for those who know what I am talking about Monopoly City Streets was showing at max zoom level only the streets that the centroid was inside the Bounds of the window. Moving the map was sending request to the server for the new streets to show. While I think this was ingenious, I have no idea how to implement something similar. The only thing I thought about was to compare if the long was inside the bound of map area X and same with Y. While this could improve performance significantly at high zoom level, this would give nothing when showing a whole city. Clustering: While cluster is awesome for marker, it seems we cannot cluster polylines. I would have liked something like MarkerClusterer for polylines and be able to cluster by my 3 polyline colors. This will probably stay as a “would have been freaking awesome but forget it”. Arrow: I will have in a future version to show a direction for the polyline and will have to show an arrow at the centroid. Loading an image or marker will only double my data so creating a custom overlay will probably be my only option. I have found that demo for something similar I would like to achieve. Unfortunately, the demo is very slow, but I only wish to show 1 arrow per polyline and not multiple like the demo. This functionality will depend on the format of data since I don't think KML support custom overlays. Criteria: While the application is done with ASP.NET 3.5, the port to the iPhone won't use the web to show the application and be limited in screen size for selecting the criteria. This is why I was more orienting on a service or page generating the file based on criteria passed in parameters. The service would than generate the file I need to display the polylines on the map. I could also create an aspx page that does this. The aspx page is more documented than the service way. There should be a reason. Questions: Should I create a web service to returns the street segments file or create an aspx page that return the file? Should I create a JavaScript file with encoded polyline or a KML with longitude/latitude based on the fact that maximum longitude/latitude polyline have 9600 characters and I have to render maximum 250,000 line segment polyline. Or should I go with a MapServer that generate the overlay? Will I be able to display simple arrow on the polyline on the next version. In case of KML generation is it faster to create the file with XDocument, XmlDocument, XmlWriter and this manually or just serialize the street segment in the stream? This is more a brainstorming Stack Overflow question than an actual code problem. Any answer helping narrow the possibilities is as good as someone having all the knowledge to point me out a better choice.

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  • What is the fastest cyclic synchronization in Java (ExecutorService vs. CyclicBarrier vs. X)?

    - by Alex Dunlop
    Which Java synchronization construct is likely to provide the best performance for a concurrent, iterative processing scenario with a fixed number of threads like the one outlined below? After experimenting on my own for a while (using ExecutorService and CyclicBarrier) and being somewhat surprised by the results, I would be grateful for some expert advice and maybe some new ideas. Existing questions here do not seem to focus primarily on performance, hence this new one. Thanks in advance! The core of the app is a simple iterative data processing algorithm, parallelized to the spread the computational load across 8 cores on a Mac Pro, running OS X 10.6 and Java 1.6.0_07. The data to be processed is split into 8 blocks and each block is fed to a Runnable to be executed by one of a fixed number of threads. Parallelizing the algorithm was fairly straightforward, and it functionally works as desired, but its performance is not yet what I think it could be. The app seems to spend a lot of time in system calls synchronizing, so after some profiling I wonder whether I selected the most appropriate synchronization mechanism(s). A key requirement of the algorithm is that it needs to proceed in stages, so the threads need to sync up at the end of each stage. The main thread prepares the work (very low overhead), passes it to the threads, lets them work on it, then proceeds when all threads are done, rearranges the work (again very low overhead) and repeats the cycle. The machine is dedicated to this task, Garbage Collection is minimized by using per-thread pools of pre-allocated items, and the number of threads can be fixed (no incoming requests or the like, just one thread per CPU core). V1 - ExecutorService My first implementation used an ExecutorService with 8 worker threads. The program creates 8 tasks holding the work and then lets them work on it, roughly like this: // create one thread per CPU executorService = Executors.newFixedThreadPool( 8 ); ... // now process data in cycles while( ...) { // package data into 8 work items ... // create one Callable task per work item ... // submit the Callables to the worker threads executorService.invokeAll( taskList ); } This works well functionally (it does what it should), and for very large work items indeed all 8 CPUs become highly loaded, as much as the processing algorithm would be expected to allow (some work items will finish faster than others, then idle). However, as the work items become smaller (and this is not really under the program's control), the user CPU load shrinks dramatically: blocksize | system | user | cycles/sec 256k 1.8% 85% 1.30 64k 2.5% 77% 5.6 16k 4% 64% 22.5 4096 8% 56% 86 1024 13% 38% 227 256 17% 19% 420 64 19% 17% 948 16 19% 13% 1626 Legend: - block size = size of the work item (= computational steps) - system = system load, as shown in OS X Activity Monitor (red bar) - user = user load, as shown in OS X Activity Monitor (green bar) - cycles/sec = iterations through the main while loop, more is better The primary area of concern here is the high percentage of time spent in the system, which appears to be driven by thread synchronization calls. As expected, for smaller work items, ExecutorService.invokeAll() will require relatively more effort to sync up the threads versus the amount of work being performed in each thread. But since ExecutorService is more generic than it would need to be for this use case (it can queue tasks for threads if there are more tasks than cores), I though maybe there would be a leaner synchronization construct. V2 - CyclicBarrier The next implementation used a CyclicBarrier to sync up the threads before receiving work and after completing it, roughly as follows: main() { // create the barrier barrier = new CyclicBarrier( 8 + 1 ); // create Runable for thread, tell it about the barrier Runnable task = new WorkerThreadRunnable( barrier ); // start the threads for( int i = 0; i < 8; i++ ) { // create one thread per core new Thread( task ).start(); } while( ... ) { // tell threads about the work ... // N threads + this will call await(), then system proceeds barrier.await(); // ... now worker threads work on the work... // wait for worker threads to finish barrier.await(); } } class WorkerThreadRunnable implements Runnable { CyclicBarrier barrier; WorkerThreadRunnable( CyclicBarrier barrier ) { this.barrier = barrier; } public void run() { while( true ) { // wait for work barrier.await(); // do the work ... // wait for everyone else to finish barrier.await(); } } } Again, this works well functionally (it does what it should), and for very large work items indeed all 8 CPUs become highly loaded, as before. However, as the work items become smaller, the load still shrinks dramatically: blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.7% 78% 6.1 16k 5.5% 52% 25 4096 9% 29% 64 1024 11% 15% 117 256 12% 8% 169 64 12% 6.5% 285 16 12% 6% 377 For large work items, synchronization is negligible and the performance is identical to V1. But unexpectedly, the results of the (highly specialized) CyclicBarrier seem MUCH WORSE than those for the (generic) ExecutorService: throughput (cycles/sec) is only about 1/4th of V1. A preliminary conclusion would be that even though this seems to be the advertised ideal use case for CyclicBarrier, it performs much worse than the generic ExecutorService. V3 - Wait/Notify + CyclicBarrier It seemed worth a try to replace the first cyclic barrier await() with a simple wait/notify mechanism: main() { // create the barrier // create Runable for thread, tell it about the barrier // start the threads while( ... ) { // tell threads about the work // for each: workerThreadRunnable.setWorkItem( ... ); // ... now worker threads work on the work... // wait for worker threads to finish barrier.await(); } } class WorkerThreadRunnable implements Runnable { CyclicBarrier barrier; @NotNull volatile private Callable<Integer> workItem; WorkerThreadRunnable( CyclicBarrier barrier ) { this.barrier = barrier; this.workItem = NO_WORK; } final protected void setWorkItem( @NotNull final Callable<Integer> callable ) { synchronized( this ) { workItem = callable; notify(); } } public void run() { while( true ) { // wait for work while( true ) { synchronized( this ) { if( workItem != NO_WORK ) break; try { wait(); } catch( InterruptedException e ) { e.printStackTrace(); } } } // do the work ... // wait for everyone else to finish barrier.await(); } } } Again, this works well functionally (it does what it should). blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.4% 80% 6.3 16k 4.6% 60% 30.1 4096 8.6% 41% 98.5 1024 12% 23% 202 256 14% 11.6% 299 64 14% 10.0% 518 16 14.8% 8.7% 679 The throughput for small work items is still much worse than that of the ExecutorService, but about 2x that of the CyclicBarrier. Eliminating one CyclicBarrier eliminates half of the gap. V4 - Busy wait instead of wait/notify Since this app is the primary one running on the system and the cores idle anyway if they're not busy with a work item, why not try a busy wait for work items in each thread, even if that spins the CPU needlessly. The worker thread code changes as follows: class WorkerThreadRunnable implements Runnable { // as before final protected void setWorkItem( @NotNull final Callable<Integer> callable ) { workItem = callable; } public void run() { while( true ) { // busy-wait for work while( true ) { if( workItem != NO_WORK ) break; } // do the work ... // wait for everyone else to finish barrier.await(); } } } Also works well functionally (it does what it should). blocksize | system | user | cycles/sec 256k 1.9% 85% 1.30 64k 2.2% 81% 6.3 16k 4.2% 62% 33 4096 7.5% 40% 107 1024 10.4% 23% 210 256 12.0% 12.0% 310 64 11.9% 10.2% 550 16 12.2% 8.6% 741 For small work items, this increases throughput by a further 10% over the CyclicBarrier + wait/notify variant, which is not insignificant. But it is still much lower-throughput than V1 with the ExecutorService. V5 - ? So what is the best synchronization mechanism for such a (presumably not uncommon) problem? I am weary of writing my own sync mechanism to completely replace ExecutorService (assuming that it is too generic and there has to be something that can still be taken out to make it more efficient). It is not my area of expertise and I'm concerned that I'd spend a lot of time debugging it (since I'm not even sure my wait/notify and busy wait variants are correct) for uncertain gain. Any advice would be greatly appreciated.

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  • Simple Adapter error

    - by Rahul Varma
    Hi, I have the following errors when i try to access the simple adapter from my program... Plz can anyone help me solving the error... Desperate to get it done.... android.widget.SimpleAdapter.getCount(SimpleAdapter.java:95) android.widget.ListView.setAdapter(ListView.java:431) com.stellent.gorinka.MusicListActivity.list(MusicListActivity.java:76) com.stellent.gorinka.MusicListActivity$1.run(MusicListActivity.java:67) android.os.Handler.handleCallback(Handler.java:587) android.os.Handler.dispatchMessage(Handler.java:92) at android.os.Looper.loop(Looper.java:123) android.os.Handler.handleCallback(Handler.java:587) android.os.Handler.dispatchMessage(Handler.java:92) android.os.Looper.loop(Looper.java:123) Here' the code for Adapter... public class SongsAdapter extends SimpleAdapter{ static List<HashMap<String,String>> songsList; Context context; LayoutInflater inflater; public SongsAdapter(Context context,List<HashMap<String,String>> imgListWeb,int layout,String[] from,int[] to,LayoutInflater inflater) { super(context,songsList,layout,from,to); this.songsList=songsList; this.context=context; this.inflater=inflater; // TODO Auto-generated constructor stub }@Override public View getView(int postition,View convertView,ViewGroup parent)throws java.lang.OutOfMemoryError{ try { View v = ((LayoutInflater) inflater).inflate(R.layout.row,null); ImageView images=(ImageView)v.findViewById(R.id.image); TextView tvTitle=(TextView)v.findViewById(R.id.text1); TextView tvAlbum=(TextView)v.findViewById(R.id.text2); TextView tvArtist=(TextView)v.findViewById(R.id.text3); HashMap<String,String> songsHash=songsList.get(postition); String path=songsHash.get("path"); String title=songsHash.get("title"); String album=songsHash.get("album"); String artist=songsHash.get("artist"); String imgPath=path; final ImageView imageView = (ImageView) v.findViewById(R.id.image); AsyncImageLoaderv asyncImageLoader=new AsyncImageLoaderv(); Bitmap cachedImage = asyncImageLoader.loadDrawable(imgPath, new AsyncImageLoaderv.ImageCallback() { public void imageLoaded(Bitmap imageDrawable, String imageUrl) { imageView.setImageBitmap(imageDrawable); } }); imageView.setImageBitmap(cachedImage); tvTitle.setText(title); tvAlbum.setText(album); tvArtist.setText(artist); return v; } catch(Exception e){ Log.e("error",e.toString()); } return null; } And also in my main program the focus is not entering the loop... The implementation in the loop isnt getting executed...Here's the code for it... public void list() { Log.d("#####","#####"); LayoutInflater inflater=getLayoutInflater(); String[] from={}; int[] n={}; adapter=new SongsAdapter(getApplicationContext(),songNodeDet,R.layout.row,from,n,inflater); lv.setAdapter(adapter);} private Handler handler = new Handler() { public void handleMessage(Message msg){ Log.d("*****","handler"); removeDialog(0); p.dismiss(); } }; public void webObjectList(Object[] imgListObj,String logInSess) throws XMLRPCException{ songNodeWeb = new HashMap<?,?>[imgListObj.length]; if(imgListObj!=null){ Log.e("completed","completed"); for(int i=0;i<imgListObj.length;i++){ //imgListObj.length songNodeWeb[i]=(HashMap<?,?>)imgListObj[i]; String nodeid=(String) songNodeWeb[i].get("nid"); Log.e("img",i+"completed"); HashMap<String,String> nData=new HashMap<String,String>(); nData.put("nid",nodeid); Object nodeget=client.call("node.get",logInSess,nodeid); HashMap<?,?> imgNode=(HashMap<?,?>)nodeget; String titleName=(String) imgNode.get("titles"); String movieName=(String) imgNode.get("album"); String singerName=(String) imgNode.get("artist"); nData.put("titles", titleName); nData.put("album", movieName); nData.put("artist", singerName); Object[] imgObject=(Object[])imgNode.get("title_format"); HashMap<?,?>[] imgDetails=new HashMap<?,?>[imgObject.length]; imgDetails[0]=(HashMap<?, ?>)imgObject[0]; String path=(String) imgDetails[0].get("filepath"); if(path.contains(" ")){ path=path.replace(" ", "%20"); } String imgPath="http://www.gorinka.com/"+path; paths.add(imgPath); nData.put("path", imgPath); Log.e("my path",path); String mime=(String)imgDetails[0].get("filemime"); nData.put("mime", mime); SongsList songs=new SongsList(titleName,movieName,singerName,imgPath,imgPath); SngList.add(i,songs); songNodeDet.add(i,nData); } Log.e("paths values",paths.toString()); // return imgNodeDet; handler.sendEmptyMessage(0); } } public void getSongs() throws MalformedURLException, XMLRPCException { String ur="http://www.gorinka.com/?q=services/xmlrpc"; URL u=new URL(ur); client = new XMLRPCClient(u); //Connecting to the website HashMap<?, ?> siteConn =(HashMap<?, ?>) client.call("system.connect"); // Getting initial sessio id String initSess=(String)siteConn.get("sessid"); //Login to the site using session id HashMap<?, ?> logInConn =(HashMap<?, ?>) client.call("user.login",initSess,"prakash","stellentsoft2009"); //Getting Login sessid logInSess=(String)logInConn.get("sessid"); websongListObject =(Object[]) client.call("nodetype.get",logInSess,""); webObjectList(websongListObject,logInSess); Log.d("webObjectList","webObjectList"); runOnUiThread(returnRes); } }

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  • Python regex to parse text file, get the items in list and count the list

    - by Nemo
    I have a text file which contains some data. I m particularly interested in finding the count of the number of items in v_dims v_dims pattern in my text file looks like this : v_dims={ "Sales", "Product Family", "Sales Organization", "Region", "Sales Area", "Sales office", "Sales Division", "Sales Person", "Sales Channel", "Sales Order Type", "Sales Number", "Sales Person", "Sales Quantity", "Sales Amount" } So I m thinking of getting all the elements in v_dims and dumping them out in a Python list. Then compute the len(mylist) to get the count of the items. The challenge is in getting all the elements of v_dims from my text file and putting them in an empty list. I m particularly interested in items in v_dims in my text file. The text file has data in the form of v_dims pattern i showed in my original post. Some data has nested patterns of v_dims. Thanks. Here's what I have tried and failed. Any help is appreciated. TIA. import re fname = "C:\Users\XXXX\Test.mrk" with open(fname, "r") as fo: content_as_string = fo.read() match = re.findall(r'v_dims={\"(.+?)\"}',content_as_string) Though I have a big text file, Here's a snippet of what's the structure of my text file version "1"; // Computer generated object language file object 'MRKR' "Main" { Data_Type=2, HeaderBlock={ Version_String="6.3 (25)" }, Printer_Info={ Orientation=0, Page_Width=8.50000000, Page_Height=11.00000000, Page_Header="", Page_Footer="", Margin_type=0, Top_Margin=0.50000000, Left_Margin=0.50000000, Bottom_Margin=0.50000000, Right_Margin=0.50000000 }, Marker_Options={ Close_All="TRUE", Hide_Console="FALSE", Console_Left="FALSE", Console_Width=217, Main_Style="Maximized", MDI_Rect={ 0, 0, 892, 1063 } }, Dives={ { Dive="A", Windows={ { View_Index=0, Window_Info={ Window_Rect={ 0, -288, 400, 1008 }, Window_Style="Maximized Front", Window_Name="Theater [Previous Qtr Diveplan-Dive A]" }, Dependent_bool="FALSE", Colset={ Dive_Type="Normal", Dimension_Name="Theater", Action_List={ Actions={ { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater" }, Key_Indexes={ { "AMERICAS" } } }, { Action_Type="Focus", Focus_Rows="True" }, { Action_Type="Dimensions", v_dims={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag", "Product Item Family" }, Xtab_Bool="False", Xtab_Flip="False" }, { Action_Type="Select", select_type=5 }, { Action_Type="Select", select_type=0, Key_Names={ "Theater", "Product Family", "Division", "Region", "Install at Country Name", "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "PS Flag", "Avalanche Flag" }, Key_Indexes={ { "AMERICAS", "ATMOS", "Latin America CS Division", "37000 CS Region", "Mexico", "", "", "", "", "DIRECT", "EMC", "N", "0" } } } } }, Num_Palette_cols=0, Num_Palette_rows=0 }, Format={ Window_Type="Tabular", Tabular={ Num_row_labels=8 } } } } } }, Widget_Set={ Widget_Layout="Vertical", Go_Button=1, Picklist_Width=0, Sort_Subset_Dimensions="TRUE", Order={ } }, Views={ { Data_Type=1, dbname="Previous Qtr Diveplan", diveline_dbname="Current Qtr Diveplan", logical_name="Current Qtr Diveplan", cols={ { name="Total TSS installs", column_type="Calc[Total TSS installs]", output_type="Number", format_string="." }, { name="TSS Valid Connectivity Records", column_type="Calc[TSS Valid Connectivity Records]", output_type="Number", format_string="." }, { name="% TSS Connectivity Record", column_type="Calc[% TSS Connectivity Record]", output_type="Number" }, { name="TSS Not Applicable", column_type="Calc[TSS Not Applicable]", output_type="Number", format_string="." }, { name="TSS Customer Refusals", column_type="Calc[TSS Customer Refusals]", output_type="Number", format_string="." }, { name="% TSS Refusals", column_type="Calc[% TSS Refusals]", output_type="Number" }, { name="TSS Eligible for Physical Connectivity", column_type="Calc[TSS Eligible for Physical Connectivity]", output_type="Number", format_string="." }, { name="TSS Boxes with Physical Connectivty", column_type="Calc[TSS Boxes with Physical Connectivty]", output_type="Number", format_string="." }, { name="% TSS Physical Connectivity", column_type="Calc[% TSS Physical Connectivity]", output_type="Number" } }, dim_cols={ { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Model", column_type="Dimension[Model]", output_type="None" }, { name="Connect In Type", column_type="Dimension[Connect In Type]", output_type="None" }, { name="Connect Home Type", column_type="Dimension[Connect Home Type]", output_type="None" }, { name="SymmConnect Enabled", column_type="Dimension[SymmConnect Enabled]", output_type="None" }, { name="Theater", column_type="Dimension[Theater]", output_type="None" }, { name="Division", column_type="Dimension[Division]", output_type="None" }, { name="Region", column_type="Dimension[Region]", output_type="None" }, { name="Sales Order Number", column_type="Dimension[Sales Order Number]", output_type="None" }, { name="Product Item Family", column_type="Dimension[Product Item Family]", output_type="None" }, { name="Item Serial Number", column_type="Dimension[Item Serial Number]", output_type="None" }, { name="Sales Order Deal Number", column_type="Dimension[Sales Order Deal Number]", output_type="None" }, { name="Item Install Date", column_type="Dimension[Item Install Date]", output_type="None" }, { name="SYR Last Dial Home Date", column_type="Dimension[SYR Last Dial Home Date]", output_type="None" }, { name="Maintained By Group", column_type="Dimension[Maintained By Group]", output_type="None" }, { name="PS Flag", column_type="Dimension[PS Flag]", output_type="None" }, { name="Connect Home Refusal Reason", column_type="Dimension[Connect Home Refusal Reason]", output_type="None", col_width=177 }, { name="Cust Name", column_type="Dimension[Cust Name]", output_type="None" }, { name="Sales Order Channel Type", column_type="Dimension[Sales Order Channel Type]", output_type="None" }, { name="Sales Order Type", column_type="Dimension[Sales Order Type]", output_type="None" }, { name="Part Model Key", column_type="Dimension[Part Model Key]", output_type="None" }, { name="Ship Date", column_type="Dimension[Ship Date]", output_type="None" }, { name="Model Number", column_type="Dimension[Model Number]", output_type="None" }, { name="Item Description", column_type="Dimension[Item Description]", output_type="None" }, { name="Customer Classification", column_type="Dimension[Customer Classification]", output_type="None" }, { name="CS Customer Name", column_type="Dimension[CS Customer Name]", output_type="None" }, { name="Install At Customer Number", column_type="Dimension[Install At Customer Number]", output_type="None" }, { name="Install at Country Name", column_type="Dimension[Install at Country Name]", output_type="None" }, { name="TLA Serial Number", column_type="Dimension[TLA Serial Number]", output_type="None" }, { name="Product Version", column_type="Dimension[Product Version]", output_type="None" }, { name="Avalanche Flag", column_type="Dimension[Avalanche Flag]", output_type="None" }, { name="Product Family", column_type="Dimension[Product Family]", output_type="None" }, { name="Project Number", column_type="Dimension[Project Number]", output_type="None" }, { name="PROJECT_STATUS", column_type="Dimension[PROJECT_STATUS]", output_type="None" } }, Available_Columns={ "Total TSS installs", "TSS Valid Connectivity Records", "% TSS Connectivity Record", "TSS Not Applicable", "TSS Customer Refusals", "% TSS Refusals", "TSS Eligible for Physical Connectivity", "TSS Boxes with Physical Connectivty", "% TSS Physical Connectivity", "Total Installs", "All Boxes with Valid Connectivty Record", "% All Connectivity Record", "Overall Refusals", "Overall Refusals %", "All Eligible for Physical Connectivty", "Boxes with Physical Connectivity", "% All with Physical Conectivity" }, Remaining_columns={ { name="Total Installs", column_type="Calc[Total Installs]", output_type="Number", format_string="." }, { name="All Boxes with Valid Connectivty Record", column_type="Calc[All Boxes with Valid Connectivty Record]", output_type="Number", format_string="." }, { name="% All Connectivity Record", column_type="Calc[% All Connectivity Record]", output_type="Number" }, { name="Overall Refusals", column_type="Calc[Overall Refusals]", output_type="Number", format_string="." }, { name="Overall Refusals %", column_type="Calc[Overall Refusals %]", output_type="Number" }, { name="All Eligible for Physical Connectivty", column_type="Calc[All Eligible for Physical Connectivty]", output_type="Number" }, { name="Boxes with Physical Connectivity", column_type="Calc[Boxes with Physical Connectivity]", output_type="Number" }, { name="% All with Physical Conectivity", column_type="Calc[% All with Physical Conectivity]", output_type="Number" } }, calcs={ { name="Total TSS installs", definition="Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Valid Connectivity Records", definition="Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% TSS Connectivity Record", definition="Total[PS Boxes w/ valid connectivity record (1=yes)] /Total[Total TSS installs]", ts_flag="Not TS Calc" }, { name="TSS Not Applicable", definition="Total[Bozes w/ valid connectivity record (1=yes)]-Total[Boxes Eligible (1=yes)]-Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="TSS Customer Refusals", definition="Total[TSS Refusals]", ts_flag="Not TS Calc" }, { name="% TSS Refusals", definition="Total[TSS Refusals]/Total[PS Boxes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="TSS Eligible for Physical Connectivity", definition="Total[TSS Eligible]-Total[Exception]", ts_flag="Not TS Calc" }, { name="TSS Boxes with Physical Connectivty", definition="Total[PS Physical Connectivity] - Total[PS Physical Connectivity, SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% TSS Physical Connectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" }, { name="Total Installs", definition="Total[Total Installs]", ts_flag="Not TS Calc" }, { name="All Boxes with Valid Connectivty Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="% All Connectivity Record", definition="Total[Bozes w/ valid connectivity record (1=yes)]/Total[Total Installs]", ts_flag="Not TS Calc" }, { name="Overall Refusals", definition="Total[Overall Refusals]", ts_flag="Not TS Calc" }, { name="Overall Refusals %", definition="Total[Overall Refusals]/Total[Bozes w/ valid connectivity record (1=yes)]", ts_flag="Not TS Calc" }, { name="All Eligible for Physical Connectivty", definition="Total[Boxes Eligible (1=yes)]-Total[Exception]", ts_flag="Not TS Calc" }, { name="Boxes with Physical Connectivity", definition="Total[Boxes w/ phys conn]-Total[Boxes w/ phys conn,SymmConnect Enabled=\"Capable not enabled\"]", ts_flag="Not TS Calc" }, { name="% All with Physical Conectivity", definition="Total[Boxes w/ phys conn]/Total[Boxes Eligible (1=yes)]", ts_flag="Not TS Calc" } }, merge_type="consolidate", merge_dbs={ { dbname="connectivityallproducts.mdl", diveline_dbname="/DI_PSREPORTING/connectivityallproducts.mdl" } }, skip_constant_columns="FALSE", categories={ { name="Geography", dimensions={ "Theater", "Division", "Region", "Install at Country Name" } }, { name="Mappings and Flags", dimensions={ "Connect Home Type", "Connect In Type", "SymmConnect Enabled", "Connect Home Refusal Reason", "Sales Order Channel Type", "Maintained By Group", "Customer Installable", "PS Flag", "Top Level Flag", "Avalanche Flag" } }, { name="Product Information", dimensions={ "Product Family", "Product Item Family", "Product Version", "Item Description" } }, { name="Sales Order Info", dimensions={ "Sales Order Deal Number", "Sales Order Number", "Sales Order Type" } }, { name="Dates", dimensions={ "Item Install Date", "Ship Date", "SYR Last Dial Home Date" } }, { name="Details", dimensions={ "Item Serial Number", "TLA Serial Number", "Part Model Key", "Model Number" } }, { name="Customer Infor", dimensions={ "CS Customer Name", "Install At Customer Number", "Customer Classification", "Cust Name" } }, { name="Other Dimensions", dimensions={ "Model" } } }, Maintain_Category_Order="FALSE", popup_info="false" } } };

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  • Dojo - How to position tooltip close to text?

    - by user244394
    Like the title says i want to be able to display the tooltip close to the text, currently it is displayed far away in the cell. Tobe noted the tooltip positions correctly for large text, only fails for small text. In DOJO How can i position the tooltip close to the text? I have this bit of code snippet that display the tooltip in the grid cells. Screenshot attached, html <div class="some_app claro"></div> ... com.c.widget.EnhancedGrid = function ( aParent, options ) { var grid, options; this.theParentApp = aParent; dojo.require("dojox.grid.EnhancedGrid"); dojo.require("dojox.grid.enhanced.plugins.Menu"); dojo.require("dojox.grid.enhanced.plugins.Selector"); dojo.require("dojox.grid.enhanced.plugins.Pagination"); dojo.require("dojo.store.Memory"); dojo.require("dojo.data.ObjectStore"); dojo.require("dojo._base.xhr"); dojo.require("dojo.domReady!"); dojo.require("dojo.date.locale"); dojo.require("dojo._base.connect"); dojo.require("dojox.data.JsonRestStore"); dojo.require("dojo.data.ItemFileReadStore"); dojo.require("dijit.Menu"); dojo.require("dijit.MenuItem"); dojo.require('dijit.MenuSeparator'); dojo.require('dijit.CheckedMenuItem'); dojo.require('dijit.Tooltip'); dojo.require('dojo/query'); dojo.require("dojox.data.QueryReadStore"); // main initialization function this.init = function( options ) { var me = this; // default options var defaultOptions = { widgetName: ' Enhancedgrid', render: true, // immediately render the grid draggable: true, // disables column dragging containerNode: false, // the Node to hold the Grid (optional) mashupUrl: false, // the URL of the mashup (required) rowsPerPage: 20, //Default number of items per page columns: false, // columns (required) width: "100%", // width of grid height: "100%", // height of grid rowClass: function (rowData) {}, onClick: function () {}, headerMenu: false, // adding a menu pop-up for the header. selectedRegionMenu: false, // adding a menu pop-up for the rows. menusObject: false, //object to start-up the menus using the plug-in. sortInfo: false, // The column default sort infiniteScrolling: false //If true, the enhanced grid will have an infinite scrolling. }; // merge user provided options me.options = jQuery.extend( {}, defaultOptions, options ); // check we have minimum required options if ( ! me.options.mashupUrl ){ throw ("You must supply a mashupUrl"); } if ( ! me.options.columns ){ throw ("You must supply columns"); } // make the column for formatting based on its data type. me.preProcessColumns(); // create the Contextual Menu me.createMenu(); // create the grid object and return me.createGrid(); }; // Loading the data to the grid. this.loadData = function () { var me = this; if (!me.options.infiniteScrolling) { var xhrArgs = { url: me.options.mashupUrl, handleAs: "json", load: function( data ){ var store = new dojo.data.ItemFileReadStore({ data : {items : eval( "data."+me.options.dataRoot)}}); store.fetch({ onComplete : function(items, request) { if (me.grid.selection !== null) { me.grid.selection.clear(); } me.grid.setStore(store); }, onError : function(error) { me.onError(error); } }); }, error: function (error) { me.onError(error); } }; dojo.xhrGet(xhrArgs); } else { dojo.declare('NotificationQueryReadStore', dojox.data.QueryReadStore, { // // hacked -- override to map to proper data structure // from mashup // _xhrFetchHandler : function(data, request, fetchHandler, errorHandler) { // // TODO: need to have error handling here when // data has "error" data structure // // // remap data object before process by super method // var dataRoot = eval ("data."+me.options.dataRoot); var dataTotal = eval ("data."+me.options.dataTotal); data = { numRows : dataTotal, items : dataRoot }; // call to super method to process mapped data and // set rowcount // for proper display this.inherited(arguments); } }); var queryStore = new NotificationQueryReadStore({ url : me.options.mashupUrl, urlPreventCache: true, requestMethod : "get", onError: function (error) { me.onError(error); } }); me.grid.setStore(queryStore); } }; this.preProcessColumns = function () { var me = this; var options = me.options; for (i=0;i<this.options.columns.length;i++) { if (this.options.columns[i].formatter==null) { switch (this.options.columns[i].datatype) { case "string": this.options.columns[i].formatter = me.formatString; break; case "date": this.options.columns[i].formatter = me.formatDate; var todayDate = new Date(); var gmtTime = c.util.Date.parseDate(todayDate.toString()).toString(); var gmtval = gmtTime.substring(gmtTime.indexOf('GMT'),(gmtTime.indexOf('(')-1)); this.options.columns[i].name = this.options.columns[i].name + " ("+gmtval+")"; } } if (this.options.columns[i].sortDefault) { me.options.sortInfo = i+1; } } }; // create GRID object using supplied options this.createGrid = function () { var me = this; var options = me.options; // create a new grid this.grid = new dojox.grid.EnhancedGrid ({ width: options.width, height: options.height, query: { id: "*" }, keepSelection: true, formatterScope: this, structure: options.columns, columnReordering: options.draggable, rowsPerPage: options.rowsPerPage, //sortInfo: options.sortInfo, plugins : { menus: options.menusObject, selector: {"row":"multi", "cell": "disabled" }, }, //Allow the user to decide if a column is sortable by setting sortable = true / false canSort: function(col) { if (options.columns[Math.abs(col)-1].sortable) return true; else return false; }, //Change the row colors depending on severity column. onStyleRow: function (row) { var grid = me.grid; var item = grid.getItem(row.index); if (item && options.rowClass(item)) { row.customClasses += " " +options.rowClass(item); if (grid.selection.selectedIndex == row.index) { row.customClasses += " dojoxGridRowSelected"; } grid.focus.styleRow(row); grid.edit.styleRow(row); } }, onCellMouseOver: function (e){ // var pos = dojo.position(this, true); // alert(pos); console.log( e.rowIndex +" cell node :"+ e.cellNode.innerHTML); // var pos = dojo.position(this, true); console.log( " pos :"+ e.pos); if (e.cellNode.innerHTML!="") { dijit.showTooltip(e.cellNode.innerHTML, e.cellNode); } }, onCellMouseOut: function (e){ dijit.hideTooltip(e.cellNode); }, onHeaderCellMouseOver: function (e){ if (e.cellNode.innerHTML!="") { dijit.showTooltip(e.cellNode.innerHTML, e.cellNode); } }, onHeaderCellMouseOut: function (e){ dijit.hideTooltip(e.cellNode); }, }); // ADDED CODE FOR TOOLTIP var gridTooltip = new Tooltip({ connectId: "grid1", selector: "td", position: ["above"], getContent: function(matchedNode){ var childNode = matchedNode.childNodes[0]; if(childNode.nodeType == 1 && childNode.className == "user") { this.position = ["after"]; this.open(childNode); return false; } if(matchedNode.className && matchedNode.className == "user") { this.position = ["after"]; } else { this.position = ["above"]; } return matchedNode.textContent; } }); ... //Construct the grid this.buildGrid = function(){ var datagrid = new com.emc.widget.EnhancedGrid(this,{ Url: "/dge/api/-resultFormat=json&id="+encodeURIComponent(idUrl), dataRoot: "Root.ATrail", height: '100%', columns: [ { name: 'Time', field: 'Time', width: '20%', datatype: 'date', sortable: true, searchable: true, hidden: false}, { name: 'Type', field: 'Type', width: '20%', datatype: 'string', sortable: true, searchable: true, hidden: false}, { name: 'User ID', field: 'UserID', width: '20%', datatype: 'string', sortable: true, searchable: true, hidden: false } ] }); this.grid = datagrid; };

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  • Edit Contact code worked in 1.6 but doesn't work on Droid 2.1?

    - by user225405
    Hi All, I had some fairly simple code in my app to invoke Edit Contact activity on a known good contact index that worked in Android 1.6 but is broken for me now in Android 2.1 on the Droid. I built a sample activity/app 'EdCon' to show this: package com.jbh; import android.app.Activity; import android.content.Intent; import android.net.Uri; import android.os.Bundle; public class EdCon extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // Build an intent to edit a known good contact index Intent i; i = new Intent(Intent.ACTION_EDIT); i.setData(Uri.parse("content://contacts/people/10")); startActivity(i); } } When I run this on my G1 running 1.6 it works as expected i.e. brings up the Edit Contact screen for the known index and then I can hit BACK to return to "Hello World, EdCon". When I run this on the Droid under 2.1 I get the following: 05-07 15:35:57.787: INFO/ActivityManager(1013): Starting activity: Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.jbh/.EdCon } 05-07 15:35:57.826: DEBUG/AndroidRuntime(13780): Shutting down VM 05-07 15:35:57.826: DEBUG/dalvikvm(13780): DestroyJavaVM waiting for non-daemon threads to exit 05-07 15:35:57.928: DEBUG/dalvikvm(13780): DestroyJavaVM shutting VM down 05-07 15:35:57.928: DEBUG/dalvikvm(13780): HeapWorker thread shutting down 05-07 15:35:57.928: DEBUG/dalvikvm(13780): HeapWorker thread has shut down 05-07 15:35:57.928: DEBUG/jdwp(13780): JDWP shutting down net... 05-07 15:35:57.928: DEBUG/jdwp(13780): Got wake-up signal, bailing out of select 05-07 15:35:57.928: INFO/dalvikvm(13780): Debugger has detached; object registry had 1 entries 05-07 15:35:57.928: DEBUG/dalvikvm(13780): VM cleaning up 05-07 15:35:57.935: INFO/ActivityManager(1013): Start proc com.jbh for activity com.jbh/.EdCon: pid=13802 uid=10052 gids={1015} 05-07 15:35:57.967: ERROR/AndroidRuntime(13780): ERROR: thread attach failed 05-07 15:35:58.053: INFO/ActivityThread(13792): Publishing provider com.android.vending.SuggestionsProvider: com.android.vending.SuggestionsProvider 05-07 15:35:58.154: INFO/dalvikvm(13802): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=38) 05-07 15:35:58.209: DEBUG/dalvikvm(13780): LinearAlloc 0x0 used 639500 of 5242880 (12%) 05-07 15:35:58.365: INFO/dalvikvm(13802): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=18) 05-07 15:35:58.639: INFO/ActivityManager(1013): Starting activity: Intent { act=android.intent.action.EDIT dat=content://contacts/people/10 cmp=com.android.contacts/.ui.EditContactActivity } 05-07 15:35:58.975: DEBUG/dalvikvm(13137): GC freed 2902 objects / 166768 bytes in 61ms 05-07 15:35:59.100: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.run(): Syncing local DB with package manager... 05-07 15:35:59.100: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.syncLocalDbWithPackageManager(): No INSTALLING or UNINSTALLING assets. 05-07 15:35:59.115: INFO/ActivityManager(1013): Displayed activity com.android.contacts/.ui.EditContactActivity: 387 ms (total 1296 ms) 05-07 15:35:59.185: DEBUG/Sources(13137): Creating external source for type=com.facebook.auth.login, packageName=com.facebook.katana 05-07 15:35:59.225: DEBUG/vending(13792): com.android.vending.LocalDbSyncService.run(): Syncing done. 05-07 15:35:59.232: WARN/dalvikvm(13137): threadid=27: thread exiting with uncaught exception (group=0x4001b180) 05-07 15:35:59.232: ERROR/AndroidRuntime(13137): Uncaught handler: thread AsyncTask #1 exiting due to uncaught exception 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): java.lang.RuntimeException: An error occured while executing doInBackground() 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.os.AsyncTask$3.done(AsyncTask.java:200) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.lang.Thread.run(Thread.java:1096) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): Caused by: android.database.sqlite.SQLiteException: no such column: raw_contact_id: , while compiling: SELECT account_name, account_type, sourceid, version, dirty, data_id, res_package, mimetype, data1, data2, data3, data4, data5, data6, data7, data8, data9, data10, data11, data12, data13, data14, data15, data_sync1, data_sync2, data_sync3, data_sync4, _id, is_primary, is_super_primary, data_version, group_sourceid, sync1, sync2, sync3, sync4, deleted, contact_id, starred, is_restricted FROM contact_entities_view WHERE (1) AND (raw_contact_id=10) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.native_compile(Native Method) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.compile(SQLiteProgram.java:110) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteProgram.(SQLiteProgram.java:59) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteQuery.(SQLiteQuery.java:49) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:49) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1221) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:316) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:3850) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:3840) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2$RawContactsEntityIterator.(ContactsProvider2.java:4498) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.providers.contacts.ContactsProvider2.queryEntities(ContactsProvider2.java:4751) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentProvider$Transport.queryEntities(ContentProvider.java:140) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentProviderClient.queryEntities(ContentProviderClient.java:98) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.content.ContentResolver.queryEntities(ContentResolver.java:296) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.model.EntitySet.fromQuery(EntitySet.java:72) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.ui.EditContactActivity$QueryEntitiesTask.doInBackground(EditContactActivity.java:191) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.ui.EditContactActivity$QueryEntitiesTask.doInBackground(EditContactActivity.java:154) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at com.android.contacts.util.WeakAsyncTask.doInBackground(WeakAsyncTask.java:45) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at android.os.AsyncTask$2.call(AsyncTask.java:185) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 05-07 15:35:59.295: ERROR/AndroidRuntime(13137): ... 4 more 05-07 15:35:59.303: INFO/Process(1013): Sending signal. PID: 13137 SIG: 3 05-07 15:35:59.303: INFO/dalvikvm(13137): threadid=7: reacting to signal 3 05-07 15:35:59.303: ERROR/dalvikvm(13137): Unable to open stack trace file '/data/anr/traces.txt': Permission denied 05-07 15:35:59.506: INFO/DumpStateReceiver(1013): Added state dump to 1 crashes 05-07 15:36:07.053: DEBUG/dalvikvm(12901): GC freed 389 objects / 25056 bytes in 145ms 05-07 15:36:17.287: DEBUG/dalvikvm(11649): GC freed 154 objects / 6816 bytes in 136ms 05-07 15:36:22.365: DEBUG/dalvikvm(13574): GC freed 348 objects / 67848 bytes in 112ms 05-07 15:36:27.451: DEBUG/dalvikvm(11836): GC freed 267 objects / 17432 bytes in 65ms 05-07 15:36:32.553: DEBUG/dalvikvm(12757): GC freed 1888 objects / 92440 bytes in 67ms 05-07 15:36:38.803: INFO/power(1013): * set_screen_state 0 05-07 15:36:38.813: DEBUG/SurfaceFlinger(1013): About to give-up screen, flinger = 0x114c30 05-07 15:36:38.826: DEBUG/Sensors(1013): using accelerometer (name=accelerometer) 05-07 15:36:38.834: DEBUG/PhoneWindow(13137): couldn't save which view has focus because the focused view android.widget.ScrollView@44883558 has no id. 05-07 15:36:38.865: DEBUG/WifiService(1013): ACTION_SCREEN_OFF 05-07 15:36:38.889: DEBUG/WifiService(1013): setting ACTION_DEVICE_IDLE timer for 900000ms 05-07 15:36:44.107: DEBUG/dalvikvm(1013): GC freed 7351 objects / 521440 bytes in 130ms 05-07 15:36:49.373: DEBUG/dalvikvm(13553): GC freed 321 objects / 12056 bytes in 102ms The no such column: raw_contact_id: looks like the issue but I'm not sure how or why that would happen or what it means. Any help appreciated! [email protected]

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  • How do I debug this javascript -- I don't get an error in Firebug but it's not working as expected.

    - by Angela
    I installed the plugin better-edit-in-place (http://github.com/nakajima/better-edit-in-place) but I dont' seem to be able to make it work. The plugin creates javascript, and also automatically creates a rel and class. The expected behavior is to make an edit-in-place, but it currently is not. Nothing happens when I mouse over. When I use firebug, it is rendering the value to be edited correctly: <span rel="/emails/1" id="email_1_days" class="editable">7</span> And it is showing the full javascript which should work on class editable. I didn't copy everything, just the chunks that seemed should be operationable if I have a class name in the DOM. // Editable: Better in-place-editing // http://github.com/nakajima/nakatype/wikis/better-edit-in-place-editable-js var Editable = Class.create({ initialize: function(element, options) { this.element = $(element); Object.extend(this, options); // Set default values for options this.editField = this.editField || {}; this.editField.type = this.editField.type || 'input'; this.onLoading = this.onLoading || Prototype.emptyFunction; this.onComplete = this.onComplete || Prototype.emptyFunction; this.field = this.parseField(); this.value = this.element.innerHTML; this.setupForm(); this.setupBehaviors(); }, // In order to parse the field correctly, it's necessary that the element // you want to edit in place for have an id of (model_name)_(id)_(field_name). // For example, if you want to edit the "caption" field in a "Photo" model, // your id should be something like "photo_#{@photo.id}_caption". // If you want to edit the "comment_body" field in a "MemberBlogPost" model, // it would be: "member_blog_post_#{@member_blog_post.id}_comment_body" parseField: function() { var matches = this.element.id.match(/(.*)_\d*_(.*)/); this.modelName = matches[1]; this.fieldName = matches[2]; if (this.editField.foreignKey) this.fieldName += '_id'; return this.modelName + '[' + this.fieldName + ']'; }, // Create the editing form for the editable and inserts it after the element. // If window._token is defined, then we add a hidden element that contains the // authenticity_token for the AJAX request. setupForm: function() { this.editForm = new Element('form', { 'action': this.element.readAttribute('rel'), 'style':'display:none', 'class':'in-place-editor' }); this.setupInputElement(); if (this.editField.tag != 'select') { this.saveInput = new Element('input', { type:'submit', value: Editable.options.saveText }); if (this.submitButtonClass) this.saveInput.addClassName(this.submitButtonClass); this.cancelLink = new Element('a', { href:'#' }).update(Editable.options.cancelText); if (this.cancelButtonClass) this.cancelLink.addClassName(this.cancelButtonClass); } var methodInput = new Element('input', { type:'hidden', value:'put', name:'_method' }); if (typeof(window._token) != 'undefined') { this.editForm.insert(new Element('input', { type: 'hidden', value: window._token, name: 'authenticity_token' })); } this.editForm.insert(this.editField.element); if (this.editField.type != 'select') { this.editForm.insert(this.saveInput); this.editForm.insert(this.cancelLink); } this.editForm.insert(methodInput); this.element.insert({ after: this.editForm }); }, // Create input element - text input, text area or select box. setupInputElement: function() { this.editField.element = new Element(this.editField.type, { 'name':this.field, 'id':('edit_' + this.element.id) }); if(this.editField['class']) this.editField.element.addClassName(this.editField['class']); if(this.editField.type == 'select') { // Create options var options = this.editField.options.map(function(option) { return new Option(option[0], option[1]); }); // And assign them to select element options.each(function(option, index) { this.editField.element.options[index] = options[index]; }.bind(this)); // Set selected option try { this.editField.element.selectedIndex = $A(this.editField.element.options).find(function(option) { return option.text == this.element.innerHTML; }.bind(this)).index; } catch(e) { this.editField.element.selectedIndex = 0; } // Set event handlers to automaticall submit form when option is changed this.editField.element.observe('blur', this.cancel.bind(this)); this.editField.element.observe('change', this.save.bind(this)); } else { // Copy value of the element to the input this.editField.element.value = this.element.innerHTML; } }, // Sets up event handles for editable. setupBehaviors: function() { this.element.observe('click', this.edit.bindAsEventListener(this)); if (this.saveInput) this.editForm.observe('submit', this.save.bindAsEventListener(this)); if (this.cancelLink) this.cancelLink.observe('click', this.cancel.bindAsEventListener(this)); }, // Event Handler that activates form and hides element. edit: function(event) { this.element.hide(); this.editForm.show(); this.editField.element.activate ? this.editField.element.activate() : this.editField.element.focus(); if (event) event.stop(); }, // Event handler that makes request to server, then handles a JSON response. save: function(event) { var pars = this.editForm.serialize(true); var url = this.editForm.readAttribute('action'); this.editForm.disable(); new Ajax.Request(url + ".json", { method: 'put', parameters: pars, onSuccess: function(transport) { var json = transport.responseText.evalJSON(); var value; if (json[this.modelName]) { value = json[this.modelName][this.fieldName]; } else { value = json[this.fieldName]; } // If we're using foreign key, read value from the form // instead of displaying foreign key ID if (this.editField.foreignKey) { value = $A(this.editField.element.options).find(function(option) { return option.value == value; }).text; } this.value = value; this.editField.element.value = this.value; this.element.update(this.value); this.editForm.enable(); if (Editable.afterSave) { Editable.afterSave(this); } this.cancel(); }.bind(this), onFailure: function(transport) { this.cancel(); alert("Your change could not be saved."); }.bind(this), onLoading: this.onLoading.bind(this), onComplete: this.onComplete.bind(this) }); if (event) { event.stop(); } }, // Event handler that restores original editable value and hides form. cancel: function(event) { this.element.show(); this.editField.element.value = this.value; this.editForm.hide(); if (event) { event.stop(); } }, // Removes editable behavior from an element. clobber: function() { this.element.stopObserving('click'); try { this.editForm.remove(); delete(this); } catch(e) { delete(this); } } }); // Editable class methods. Object.extend(Editable, { options: { saveText: 'Save', cancelText: 'Cancel' }, create: function(element) { new Editable(element); }, setupAll: function(klass) { klass = klass || '.editable'; $$(klass).each(Editable.create); } }); But when I point my mouse at the element, no in-place-editing action!

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  • cannot delete from doubly linked list using visual studios in C

    - by Jesus Sanchez
    hello I am currently doing an assignment that is supposed to read in a file, use the information, and then print out another file. all using doubly linked list. Currently i am trying to just read in the file into a doubly linked list, print it out onto the screen and a file, and finally delete the list and close the program. The program works fine as long as I don't call the dlist_distroy function which is supposed to delete the string. as soon as I do it the program starts running and then a window pops up saying "Windows has triggered a breakpoint in tempfilter.exe. This may be due to a corruption of the heap, which indicates a bug in tempfilter.exe or any of the DLLs it has loaded. This may also be due to the user pressing F12 while tempfilter.exe has focus. The output window may have more diagnostic information." I have revised the destroy and remove functions and cant understand the problem. my program is the following main.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "Dlist.h" #include "dlistdata.h" /**************************************************************************************************/ int main ( int argc, char *argv[] ) { FILE *ifp, *ofp; int hour, min; Dlist *list; DlistElmt *current=NULL, *element; float temp; list = (Dlist *)malloc(sizeof(list)); element = (DlistElmt *)malloc(sizeof(element)); if ( argc != 3 ) /* argc should be 3 for correct execution */ { /* We print argv[0] assuming it is the program name */ /* TODO: This is wrong, it should be: usage: %s inputfile outputfile */ printf( "usage: %s filename", argv[0] ); } else { // We assume argv[1] is a filename to open ifp = fopen( argv[1], "r" ); if (ifp == 0 ){ printf("Could not open file\n"); } else{ ofp = fopen(argv[2], "w"); dlist_init(list);//, (destroy)(hour, min, temp)); while (fscanf(ifp, "%d:%d %f ", &hour, &min, &temp) == 3) { current=list->tail; if(dlist_size(list)==0){ dlist_ins_prev(list, current, hour, min, temp); } else{ dlist_ins_next(list, current, hour, min, temp); } } current = list->head; while(current != NULL){ if(current==list->head){ current=current->next; } else if((current->temp > (current->prev->temp +5)) || (current->temp < (current->prev->temp -5))){ dlist_remove(list, current); current=current->next; } else current=current->next; } current = list->head; while(current != NULL){ printf("%d:%d %2.1lf\n" ,current->time, current->time2, current->temp ); fprintf(ofp, "%d:%d %2.1lf\n", current->time, current->time2, current->temp ); current = current->next; } //dlist_destroy(list); //} fclose(ifp); fclose(ofp); } } getchar(); } dlistdata.c #include <stdlib.h> #include <stdio.h> #include <string.h> #include "dlinklist.h" #include "DlistElmt.h" #include "dlistdata.h" /**************************************************************************************************/ void dlist_init(Dlist *list){ list->size = 0; list->head = NULL; list->tail = NULL; return; } void dlist_destroy(Dlist *list){ while (dlist_size(list) > 0){ dlist_remove(list, list->head); } memset(list, 0, sizeof(Dlist)); return; } int dlist_ins_next(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0) { list->head = new_element; list->head->prev = NULL; list->head->next = NULL; list->tail = new_element; } else { new_element->next = element->next; new_element->prev = element; if(element->next == NULL) list->tail = new_element; else element->next->prev = new_element; element->next = new_element; } list->size++; return 0; } int dlist_ins_prev(Dlist *list, DlistElmt *element, const int time, const int time2, const float temp){ DlistElmt *new_element; if (element == NULL && dlist_size(list) != 0) return -1; if ((new_element = (DlistElmt *)malloc(sizeof(new_element))) == NULL) return -1; new_element->time = (int )time; new_element->time2 = (int )time2; new_element->temp = (float )temp; if (dlist_size(list) == 0){ list->head = new_element; list->head->prev = NULL; list->head->next=NULL; list->tail = new_element; } else{ new_element->next = element; new_element->prev = element->prev; if(element->prev ==NULL) list->head = new_element; else element->prev->next = new_element; element->prev = new_element; } list->size++; return 0; } int dlist_remove(Dlist *list, DlistElmt *element){//, int time, int time2, float temp){ if (element == NULL || dlist_size(list) == 0) return -1; if (element == list->head) { list->head = element->next; if (list->head == NULL) list->tail = NULL; else element->next->prev = NULL; } else{ element->prev->next = element->next; if (element->next = NULL) list->tail = element->prev; else element->next->prev = element->prev; } free(element); list->size--; return 0; }

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  • Assembly - Read next sector of a virtual disk

    - by ali
    As any programmer in the world at least once in his/her life, I am trying to create my "revolutionary", the new and only one operating system. :D Well, I am using a virtual emulator (Oracle VM Virtual Box), for which I create a new unknwon operating system, with a vmdk disk. I like vmdk because they are just plain files, so I can paste my boot-loader over the first 512 bytes of the virtual hard disk. Now, I am trying to read the next sector of this virtual disk, on which I would paste a simple kernel that would display a message. I have two questions: Am I reading the second segment (the first -512 bytes- is occupied by the bootloader) correctly? CODE: CitesteDisc: mov bx, 0x8000 ; segment mov es, bx mov bx, 0x0000 ; offset mov ah, 0x02 ; read function mov al, 0x01 ; sectors - this might be wrong, trying to read from hd mov ch, 0x00 ; cylinder mov cl, 0x02 ; sector mov dh, 0x00 ; head mov dl, 0x80 ; drive - trying to read from hd int 0x13 ; disk int mov si, ErrorMessage ; - This will display an error message jc ShowMessage jmp [es:bx] ; buffer Here, I get the error message, after checking CF. However, if I use INT 13, 1 to get last status message, AL is 0 - so no error is saved. Am I pasting my simple kernel in the correct place inside the vmdk? What I do is pasting it after the 512th byte of the file, the first 512 bytes, as I said, are the boot-loader. The file would look like this: BE 45 7C E8 16 00 EB FE B4 0E B7 00 B3 07 CD 10 <- First sector C3 AC 08 C0 74 05 E8 EF FF EB F6 C3 B4 00 B2 80 CD 13 BE 5D 7C 72 F5 BB 00 80 8E C3 BB 00 00 B4 02 B0 06 B5 00 B1 01 B6 00 B2 07 CD 13 BE 4E 7C 72 CF 26 FF 27 57 65 6C 63 6F 6D 65 21 00 52 65 61 64 69 6E 67 20 65 72 72 6F 72 21 00 52 65 73 65 74 74 69 6E 67 20 65 72 72 6F 72 21 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 AA <- Boot-loader signature B4 0E B0 2E CD 10 EB FE 00 00 00 00 00 00 00 00 <- Start of the second sector 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 So, this is the way I am trying to add the kernel to the second sector. What do you think is wrong with this? Thanks!

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  • How do I control the direction of the scroll on my coda slider?

    - by lightingwrist
    Hello, I have a coda slider and am unable to determine the direction of the scroll. I have 3 panels that I want to scroll left to right. Sometimes it scrolls left to right, sometimes up and down, and sometimes horizontally. How do I lock it down to go the direction I want? Here is the HTML: <body> <div id="slider_home" class="round_10px"> <ul class="navigation_home"> <li><a href="#scroll_Parents" class="round_10px">Information For Parents</a></li> <li><a href="#scroll_Materials" class="round_10px">Print Materials</a></li> <li><a href="#scroll_Resources" class="round_10px">Online Resources</a></li> </ul> <div id="scroll_bg_home"> <div class="scroll_home"> <div class="scrollContainer_home"> <div class="panel_home" id="scroll_Parents"> content </div> <div class="panel_home" id="scroll_Materials"> content </div> <div class="panel_home" id="scroll_Resources"> content </div> </div> </div> </div> </div> </body> Here is the CSS: #wrapper {width:550px;margin:0px auto;} #intro {padding-bottom:10px;} h2 {margin:0;margin-bottom:14px;padding:0;} #slider {width:631px;margin:10px auto 0px auto;position:relative;} #scroll_bg{height:360px;width:590px;overflow:hidden;position:relative;clear:left;background:#FFFFFF url(images/) no-repeat; margin:0px auto 0px auto} .scroll{ background:transparent; width:550px; height:370px; padding:0px; margin:0px auto; overflow:hidden; } .scrollContainer div.panel {padding:20px 0px;height:330px; width:550px;margin:0px;float:left;} #shade {background:#EDEDEC url(images/shade.jpg) no-repeat 0 0;height:50px;} ul.navigation {list-style:none;margin:0px 0px 0px 23px;padding:0px;padding-bottom:0px;} ul.navigation li {display:inline; margin-right:5px;} ul.navigation li a { background:#FFFFFF;font-family:Arial, Helvetica, sans-serif; font-size:16px; font-weight:bold; color:#CCCCCC;padding:5px 5px 5px 5px;border:1px #F4F4F4 solid;text-decoration: none;} ul.navigation a:hover { color:#EDEDEC;border:1px #E6E6E6 solid;} ul.navigation a.selected {color:#333333;} ul.navigation a:focus {outline:none;} .scrollButtons {position:absolute;top:150px;cursor:pointer;} .scrollButtons.left {left:-37px;top:20px} .scrollButtons.right {right:-32px;top:20px;} .hide {display:none;} And here is the Jquery includes file: // when the DOM is ready... $(document).ready(function () { var $panels = $('#slider_home .scrollContainer_home > div.panel_home'); var $container = $('#slider_home .scrollContainer_home'); // if true, we'll float all the panels left and fix the width // of the container var horizontal = true; // float the panels left if we're going horizontal if (horizontal) { $panels.css({ 'float' : 'left', 'position' : 'relative' // IE fix to ensure overflow is hidden }); // calculate a new width for the container (so it holds all panels) $container.css('width', $panels[0].offsetWidth * $panels.length); } // collect the scroll object, at the same time apply the hidden overflow // to remove the default scrollbars that will appear var $scroll_bg = $('#scroll_bg_home'); var $scroll = $('#slider_home .scroll_home').css('overflow', 'hidden'); // apply our left + right buttons $scroll_bg .before('<img class="scrollButtons_home left" src="styles/images/BackFlip.jpg" />') .after('<img class="scrollButtons_home right" src="styles/images/flipForward.jpg" />'); // handle nav selection function selectNav() { $(this) .parents('ul:first') .find('a') .removeClass('selected') .end() .end() .addClass('selected'); } $('.navigation_home').find('a').click(selectNav); // go find the navigation link that has this target and select the nav function trigger(data) { var el = $('.navigation_home').find('a[href$="' + data.id + '"]').get(0); selectNav.call(el); } if (window.location.hash) { trigger({ id : window.location.hash.substr(1) }); } else { $('.navigation_home a:first').click(); } // offset is used to move to *exactly* the right place, since I'm using // padding on my example, I need to subtract the amount of padding to // the offset. Try removing this to get a good idea of the effect var offset = parseInt((horizontal ? $container.css('paddingTop') : $container.css('paddingLeft')) || 0) * -1; var scrollOptions = { target: $scroll, // the element that has the overflow // can be a selector which will be relative to the target items: $panels, navigation: '.navigation_home a', // selectors are NOT relative to document, i.e. make sure they're unique prev: 'img.left', next: 'img.right', // allow the scroll effect to run both directions axis: 'xy', onAfter: trigger, // our final callback offset: offset, // duration of the sliding effect duration: 500, // easing - can be used with the easing plugin: // http://gsgd.co.uk/sandbox/jquery/easing/ easing: 'swing' }; // apply serialScroll to the slider - we chose this plugin because it // supports// the indexed next and previous scroll along with hooking // in to our navigation. $('#slider_home').serialScroll(scrollOptions); // now apply localScroll to hook any other arbitrary links to trigger // the effect $.localScroll(scrollOptions); // finally, if the URL has a hash, move the slider in to position, // setting the duration to 1 because I don't want it to scroll in the // very first page load. We don't always need this, but it ensures // the positioning is absolutely spot on when the pages loads. scrollOptions.duration = 1; $.localScroll.hash(scrollOptions); });

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  • Issue in configuring JPA with Spring 3 in Jboss 4.2.2 server.

    - by KVMKReddy
    Hi, I am facing issues in configuring JPA with Spring 3 in JBoss 4.2.2 server. Please find the below file of persistence.xml. <?xml version="1.0" encoding="UTF-8"?> <persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd" version="1.0"> <persistence-unit name="TestPU"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <jta-data-source>java:/TestDS</jta-data-source> <properties> <property name="hibernate.dialect" value="org.hibernate.dialect.Oracle10gDialect"/> <property name="hibernate.show_sql" value="true"/> </properties> </persistence-unit> </persistence> My spring-beans.xml is as below <bean id="MyAdvise" class=".......Aspect"> <property name="persister"> <bean id="dbPersister" class="..............DataBasePersister"> </bean> </property> </bean> <bean id="localContainerEntityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="jpaVendorAdapter"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"> <property name="showSql" value="true"/> <property name="database" value="ORACLE"/> </bean> </property> <property name="jpaProperties"> <props> <prop key="hibernate.transaction.manager_lookup_class">org.hibernate.transaction.JBossTransactionManagerLookup</prop> </props> </property> </bean> <bean id="myTxManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="localContainerEntityManagerFactory"/> </bean> <tx:annotation-driven transaction-manager="myTxManager" /> My persister bean is as follows. public class DataBasePersister implements IPersister { private static Logger log = Logger.getLogger(DataBasePersister.class); // The Entity Manager @PersistenceContext protected EntityManager entityManager; @Transactional(readOnly = false) public void persist(Object data) { log.info("IN persist() call. Is the data can castable to MethodStats -->:"+(data instanceof MethodStats)); log.info("Entity Manager instance -->:"+(entityManager)); ---------------------- ---------------------- ---------------------- } } I am getting the following exception when the spring container creating my persister bean org.springframework.transaction.CannotCreateTransactionException: Could not open JPA EntityManager for transaction; nested exception is java.lang.IllegalStateException: JTA EntityManager cannot access a transactions at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:382) at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:309) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:166) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy147.getTransaction(Unknown Source) at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) at $Proxy141.persist(Unknown Source) at com.adp.sbs.aop.aspectj.SBSMethodStatsCollectorAspect.doAround(SBSMethodStatsCollectorAspect.java:63) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethodWithGivenArgs(AbstractAspectJAdvice.java:621) at org.springframework.aop.aspectj.AbstractAspectJAdvice.invokeAdviceMethod(AbstractAspectJAdvice.java:610) at org.springframework.aop.aspectj.AspectJAroundAdvice.invoke(AspectJAroundAdvice.java:65) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:161) at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621) at com.adp.sbs.aop.test.TestMethodLevelAnnotationStats$$EnhancerByCGLIB$$efbc78a8.MethodWithOneParamsAndReturnTypeAsString(<generated>) at com.adp.sbs.aop.test.SimpleTestServlet.testMethodAnnotations(SimpleTestServlet.java:46) at com.adp.sbs.aop.test.SimpleTestServlet.doPost(SimpleTestServlet.java:40) at com.adp.sbs.aop.test.SimpleTestServlet.doGet(SimpleTestServlet.java:33) at javax.servlet.http.HttpServlet.service(HttpServlet.java:690) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446) at java.lang.Thread.run(Thread.java:595) Caused by: java.lang.IllegalStateException: JTA EntityManager cannot access a transactions at org.hibernate.ejb.AbstractEntityManagerImpl.getTransaction(AbstractEntityManagerImpl.java:316) at org.springframework.orm.jpa.DefaultJpaDialect.beginTransaction(DefaultJpaDialect.java:70) at org.springframework.orm.jpa.vendor.HibernateJpaDialect.beginTransaction(HibernateJpaDialect.java:57) at org.springframework.orm.jpa.JpaTransactionManager.doBegin(JpaTransactionManager.java:332) Can you somebody please suggest me how to resolve this.

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  • Changing the action of a form with javascript/jquery

    - by Micah
    I'm having an issue that is driving me crazy. I'm trying to modify the openid-selector to support facebook. I'm using RPXNow as my provider so it requires the form to be submitted to a different url than the standard. For example. RpxNow requires me to setup my form like this: <form action="https://wikipediamaze.rpxnow.com/openid/start?token_url=..."> This works for every provider except for facebook and myspace. Those require the form to be posted to a different url like this: <form action="https://wikipediamaze.rpxnow.com/facebook/start?token_url=..."> and <form action="https://wikipediamaze.rpxnow.com/myspace/start?token_url=..."> The open id selector has a bunch of buttons on the form each representing the openid providers. What I'm trying to do is detect when the facebook or myspace button is clicked and changed the action on the form before submitting. However it's not working. Here is my code. I've tried several variations all with the same "not supported" exception $("#openid_form").attr("action", form_url) document.forms[0].action = form_url Any suggestions? Update Here are more details on the code. I've ommitted some for brevity. The only thing i've done is added the facebook section to the "providers_large" object (which successfully adds the logo to the website), and instead of supply a url identifying the user, I'm creating a property called "form_url" which is what I want to set the action of my form to. If you look at the section title "Provider image click" you'll see where I'm checking for the presence of the property "form_url" and using jquery to change the action and submit the form. However when I step through the javascript in debug mode it tells me it's an ivalid operation. var providers_large = { google: { name: 'Google', url: 'https://www.google.com/accounts/o8/id' }, facebook: { name: 'Facebook', form_url: 'http://wikipediamaze.rpxnow.com/facebook/start?token_url=http://www.wikipediamaze.com/Accounts/Logon' }, }; var providers_small = { myopenid: { name: 'MyOpenID', label: 'Enter your MyOpenID username.', url: 'http://{username}.myopenid.com/' }, livejournal: { name: 'LiveJournal', label: 'Enter your Livejournal username.', url: 'http://{username}.livejournal.com/' }, flickr: { name: 'Flickr', label: 'Enter your Flickr username.', url: 'http://flickr.com/{username}/' }, technorati: { name: 'Technorati', label: 'Enter your Technorati username.', url: 'http://technorati.com/people/technorati/{username}/' }, wordpress: { name: 'Wordpress', label: 'Enter your Wordpress.com username.', url: 'http://{username}.wordpress.com/' }, blogger: { name: 'Blogger', label: 'Your Blogger account', url: 'http://{username}.blogspot.com/' }, verisign: { name: 'Verisign', label: 'Your Verisign username', url: 'http://{username}.pip.verisignlabs.com/' }, vidoop: { name: 'Vidoop', label: 'Your Vidoop username', url: 'http://{username}.myvidoop.com/' }, verisign: { name: 'Verisign', label: 'Your Verisign username', url: 'http://{username}.pip.verisignlabs.com/' }, claimid: { name: 'ClaimID', label: 'Your ClaimID username', url: 'http://claimid.com/{username}' } }; var providers = $.extend({}, providers_large, providers_small); var openid = { cookie_expires: 6*30, // 6 months. cookie_name: 'openid_provider', cookie_path: '/', img_path: 'images/', input_id: null, provider_url: null, init: function(input_id) { var openid_btns = $('#openid_btns'); this.input_id = input_id; $('#openid_choice').show(); $('#openid_input_area').empty(); // add box for each provider for (id in providers_large) { openid_btns.append(this.getBoxHTML(providers_large[id], 'large', '.gif')); } if (providers_small) { openid_btns.append('<br/>'); for (id in providers_small) { openid_btns.append(this.getBoxHTML(providers_small[id], 'small', '.ico')); } } $('#openid_form').submit(this.submit); var box_id = this.readCookie(); if (box_id) { this.signin(box_id, true); } }, getBoxHTML: function(provider, box_size, image_ext) { var box_id = provider["name"].toLowerCase(); return '<a title="'+provider["name"]+'" href="javascript: openid.signin(\''+ box_id +'\');"' + ' style="background: #FFF url(' + this.img_path + box_id + image_ext+') no-repeat center center" ' + 'class="' + box_id + ' openid_' + box_size + '_btn"></a>'; }, /* Provider image click */ signin: function(box_id, onload) { var provider = providers[box_id]; if (! provider) { return; } this.highlight(box_id); this.setCookie(box_id); // prompt user for input? if (provider['label']) { this.useInputBox(provider); this.provider_url = provider['url']; } else if(provider['form_url']) { $('#openid_form').attr("action", provider['form_url']); $('#openid_form').submit(); } else { this.setOpenIdUrl(provider['url']); if (! onload) { $('#openid_form').submit(); } } }, /* Sign-in button click */ submit: function() { var url = openid.provider_url; if (url) { url = url.replace('{username}', $('#openid_username').val()); openid.setOpenIdUrl(url); } return true; }, setOpenIdUrl: function (url) { var hidden = $('#'+this.input_id); if (hidden.length > 0) { hidden.value = url; } else { $('#openid_form').append('<input type="hidden" id="' + this.input_id + '" name="' + this.input_id + '" value="'+url+'"/>'); } }, highlight: function (box_id) { // remove previous highlight. var highlight = $('#openid_highlight'); if (highlight) { highlight.replaceWith($('#openid_highlight a')[0]); } // add new highlight. $('.'+box_id).wrap('<div id="openid_highlight"></div>'); }, setCookie: function (value) { var date = new Date(); date.setTime(date.getTime()+(this.cookie_expires*24*60*60*1000)); var expires = "; expires="+date.toGMTString(); document.cookie = this.cookie_name+"="+value+expires+"; path=" + this.cookie_path; }, readCookie: function () { var nameEQ = this.cookie_name + "="; var ca = document.cookie.split(';'); for(var i=0;i < ca.length;i++) { var c = ca[i]; while (c.charAt(0)==' ') c = c.substring(1,c.length); if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length); } return null; }, useInputBox: function (provider) { var input_area = $('#openid_input_area'); var html = ''; var id = 'openid_username'; var value = ''; var label = provider['label']; var style = ''; if (label) { html = '<p>' + label + '</p>'; } if (provider['name'] == 'OpenID') { id = this.input_id; value = 'http://'; style = 'background:#FFF url('+this.img_path+'openid-inputicon.gif) no-repeat scroll 0 50%; padding-left:18px;'; } html += '<input id="'+id+'" type="text" style="'+style+'" name="'+id+'" value="'+value+'" />' + '<input id="openid_submit" type="submit" value="Sign-In"/>'; input_area.empty(); input_area.append(html); $('#'+id).focus(); } };

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  • A "Trig" Calculating Class

    - by Clinton Scott
    I have been trying to create a gui that calculates trigonometric functions based off of the user's input. I have had success in the GUI part, but my class that I wrote to hold information using inheritance seems to be messed up, because when I run it gives an error saying: Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - constructor ArcTrigCalcCon in class TrigCalc.ArcTrigCalcCon cannot be applied to given types; required: double,double,double,double,double,double found: java.lang.Double,java.lang.Double,java.lang.Double reason: actual and formal argument lists differ in length at TrigCalc.TrigCalcGUI.(TrigCalcGUI.java:31) at TrigCalc.TrigCalcGUI.main(TrigCalcGUI.java:87) Java Result: 1 and says it is the object causing the problem. Below Will be my code. First I will put up my inheritance class with cosecant secant and cotangent and then my original class with the original 3 trig functions: { public ArcTrigCalcCon(double s, double cs, double t, double csc, double sc, double ct) { // Inherit from the Trig Calc class super(s, cs, t); cosecant = 1/s; secant = 1/cs; cotangent = 1/t; } public void setCsc(double csc) { cosecant = csc; } public void setSec(double sc) { secant = sc; } public void setCot(double ct) { cotangent = ct; } } Here is the first Trigonometric class: public class TrigCalcCon { public double sine; public double cosine; public double tangent; public TrigCalcCon(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public void setSin(double s) { sine = s; } public void setCos(double cs) { cosine = cs; } public void setTan(double t) { tangent = t; } public void set(double s, double cs, double t) { sine = s; cosine = cs; tangent = t; } public double getSin() { return Math.sin(sine); } public double getCos() { return Math.cos(cosine); } public double getTan() { return Math.tan(tangent); } } and here is the demo class to run the gui: public class TrigCalcGUI extends JFrame implements ActionListener { // Instance Variables private String input; private Double s, cs, t, csc, sc, ct; private JPanel mainPanel, sinPanel, cosPanel, tanPanel, cscPanel, secPanel, cotPanel, buttonPanel, inputPanel, displayPanel; // Panel Display private JLabel sinLabel, cosLabel, tanLabel, secLabel, cscLabel, cotLabel, inputLabel; private JTextField sinTF, cosTF, tanTF, secTF, cscTF, cotTF, inputTF; //Text Fields for sin, cos, and tan, and inverse private JButton calcButton, clearButton; // Calculate and Exit Buttons // Object ArcTrigCalcCon trC = new ArcTrigCalcCon(s, cs, t); public TrigCalcGUI() { // title bar text. super("Trig Calculator"); // Corner exit button action. setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Create main panel to add each panel to mainPanel = new JPanel(); mainPanel.setLayout(new GridLayout(3,2)); displayPanel = new JPanel(); displayPanel.setLayout(new GridLayout(3,2)); // Assign Panel to each variable inputPanel = new JPanel(); sinPanel = new JPanel(); cosPanel = new JPanel(); tanPanel = new JPanel(); cscPanel = new JPanel(); secPanel = new JPanel(); cotPanel = new JPanel(); buttonPanel = new JPanel(); // Call each constructor buildInputPanel(); buildSinCosTanPanels(); buildCscSecCotPanels(); buildButtonPanel(); // Add each panel to content pane displayPanel.add(sinPanel); displayPanel.add(cscPanel); displayPanel.add(cosPanel); displayPanel.add(secPanel); displayPanel.add(tanPanel); displayPanel.add(cotPanel); // Add three content panes to GUI mainPanel.add(inputPanel, BorderLayout.NORTH); mainPanel.add(displayPanel, BorderLayout.CENTER); mainPanel.add(buttonPanel, BorderLayout.SOUTH); //add mainPanel this.add(mainPanel); // size of window to content this.pack(); // display window setVisible(true); } public static void main(String[] args) { new TrigCalcGUI(); } private void buildInputPanel() { inputLabel = new JLabel("Enter a Value: "); inputTF = new JTextField(5); inputPanel.add(inputLabel); inputPanel.add(inputTF); } // Building Constructor for sinPanel cosPanel, and tanPanel private void buildSinCosTanPanels() { // Set layout and border for sinPanel sinPanel.setLayout(new GridLayout(2,2)); sinPanel.setBorder(BorderFactory.createTitledBorder("Sine")); // sinTF = new JTextField(5); sinTF.setEditable(false); sinPanel.add(sinTF); // Set layout and border for cosPanel cosPanel.setLayout(new GridLayout(2,2)); cosPanel.setBorder(BorderFactory.createTitledBorder("Cosine")); cosTF = new JTextField(5); cosTF.setEditable(false); cosPanel.add(cosTF); // Set layout and border for tanPanel tanPanel.setLayout(new GridLayout(2,2)); tanPanel.setBorder(BorderFactory.createTitledBorder("Tangent")); tanTF = new JTextField(5); tanTF.setEditable(false); tanPanel.add(tanTF); } // Building Constructor for cscPanel secPanel, and cotPanel private void buildCscSecCotPanels() { // Set layout and border for cscPanel cscPanel.setLayout(new GridLayout(2,2)); cscPanel.setBorder(BorderFactory.createTitledBorder("Cosecant")); // cscTF = new JTextField(5); cscTF.setEditable(false); cscPanel.add(cscTF); // Set layout and border for secPanel secPanel.setLayout(new GridLayout(2,2)); secPanel.setBorder(BorderFactory.createTitledBorder("Secant")); secTF = new JTextField(5); secTF.setEditable(false); secPanel.add(secTF); // Set layout and border for cotPanel cotPanel.setLayout(new GridLayout(2,2)); cotPanel.setBorder(BorderFactory.createTitledBorder("Cotangent")); cotTF = new JTextField(5); cotTF.setEditable(false); cotPanel.add(cotTF); } private void buildButtonPanel() { // Create buttons and add events calcButton = new JButton("Calculate"); calcButton.addActionListener(new CalcButtonListener()); clearButton = new JButton("Clear"); clearButton.addActionListener(new ClearButtonListener()); buttonPanel.add(calcButton); buttonPanel.add(clearButton); } @Override public void actionPerformed(ActionEvent e) { } private class CalcButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Declare boolean variable boolean incorrect = true; // Set input variable to input text field text input = inputTF.getText(); ImageIcon newIcon; ImageIcon frowny = new ImageIcon(TrigCalcGUI.class.getResource("/Sad_Face.png")); Image gm = frowny.getImage(); Image newFrowny = gm.getScaledInstance(100, 100, java.awt.Image.SCALE_FAST); newIcon = new ImageIcon(newFrowny); // If boolean is true, throw exception if(incorrect) { try{Double.parseDouble(input); incorrect = false;} catch(NumberFormatException nfe) { String s = "Invalid Input " + "/n Input Must Be a Numerical value." + "/nPlease Press Ok and Try Again"; JOptionPane.showMessageDialog(null, s, "Invalid", JOptionPane.ERROR_MESSAGE, newIcon); inputTF.setText(""); inputTF.requestFocus(); } } // If boolean is not true, proceed with output if (incorrect != true) { /* Set each text field's output to the String double value * of inputTF */ sinTF.setText(input); cosTF.setText(input); tanTF.setText(input); cscTF.setText(input); secTF.setText(input); cotTF.setText(input); } } } /** * Private inner class that handles the event when * the user clicks the Exit button. */ private class ClearButtonListener implements ActionListener { public void actionPerformed(ActionEvent ae) { // Clear field sinTF.setText(""); cosTF.setText(""); tanTF.setText(""); cscTF.setText(""); secTF.setText(""); cotTF.setText(""); // Clear textfield and set cursor focus to field inputTF.setText(""); inputTF.requestFocus(); } } }

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  • An Introduction to ASP.NET Web API

    - by Rick Strahl
    Microsoft recently released ASP.NET MVC 4.0 and .NET 4.5 and along with it, the brand spanking new ASP.NET Web API. Web API is an exciting new addition to the ASP.NET stack that provides a new, well-designed HTTP framework for creating REST and AJAX APIs (API is Microsoft’s new jargon for a service, in case you’re wondering). Although Web API ships and installs with ASP.NET MVC 4, you can use Web API functionality in any ASP.NET project, including WebForms, WebPages and MVC or just a Web API by itself. And you can also self-host Web API in your own applications from Console, Desktop or Service applications. If you're interested in a high level overview on what ASP.NET Web API is and how it fits into the ASP.NET stack you can check out my previous post: Where does ASP.NET Web API fit? In the following article, I'll focus on a practical, by example introduction to ASP.NET Web API. All the code discussed in this article is available in GitHub: https://github.com/RickStrahl/AspNetWebApiArticle [republished from my Code Magazine Article and updated for RTM release of ASP.NET Web API] Getting Started To start I’ll create a new empty ASP.NET application to demonstrate that Web API can work with any kind of ASP.NET project. Although you can create a new project based on the ASP.NET MVC/Web API template to quickly get up and running, I’ll take you through the manual setup process, because one common use case is to add Web API functionality to an existing ASP.NET application. This process describes the steps needed to hook up Web API to any ASP.NET 4.0 application. Start by creating an ASP.NET Empty Project. Then create a new folder in the project called Controllers. Add a Web API Controller Class Once you have any kind of ASP.NET project open, you can add a Web API Controller class to it. Web API Controllers are very similar to MVC Controller classes, but they work in any kind of project. Add a new item to this folder by using the Add New Item option in Visual Studio and choose Web API Controller Class, as shown in Figure 1. Figure 1: This is how you create a new Controller Class in Visual Studio   Make sure that the name of the controller class includes Controller at the end of it, which is required in order for Web API routing to find it. Here, the name for the class is AlbumApiController. For this example, I’ll use a Music Album model to demonstrate basic behavior of Web API. The model consists of albums and related songs where an album has properties like Name, Artist and YearReleased and a list of songs with a SongName and SongLength as well as an AlbumId that links it to the album. You can find the code for the model (and the rest of these samples) on Github. To add the file manually, create a new folder called Model, and add a new class Album.cs and copy the code into it. There’s a static AlbumData class with a static CreateSampleAlbumData() method that creates a short list of albums on a static .Current that I’ll use for the examples. Before we look at what goes into the controller class though, let’s hook up routing so we can access this new controller. Hooking up Routing in Global.asax To start, I need to perform the one required configuration task in order for Web API to work: I need to configure routing to the controller. Like MVC, Web API uses routing to provide clean, extension-less URLs to controller methods. Using an extension method to ASP.NET’s static RouteTable class, you can use the MapHttpRoute() (in the System.Web.Http namespace) method to hook-up the routing during Application_Start in global.asax.cs shown in Listing 1.using System; using System.Web.Routing; using System.Web.Http; namespace AspNetWebApi { public class Global : System.Web.HttpApplication { protected void Application_Start(object sender, EventArgs e) { RouteTable.Routes.MapHttpRoute( name: "AlbumVerbs", routeTemplate: "albums/{title}", defaults: new { symbol = RouteParameter.Optional, controller="AlbumApi" } ); } } } This route configures Web API to direct URLs that start with an albums folder to the AlbumApiController class. Routing in ASP.NET is used to create extensionless URLs and allows you to map segments of the URL to specific Route Value parameters. A route parameter, with a name inside curly brackets like {name}, is mapped to parameters on the controller methods. Route parameters can be optional, and there are two special route parameters – controller and action – that determine the controller to call and the method to activate respectively. HTTP Verb Routing Routing in Web API can route requests by HTTP Verb in addition to standard {controller},{action} routing. For the first examples, I use HTTP Verb routing, as shown Listing 1. Notice that the route I’ve defined does not include an {action} route value or action value in the defaults. Rather, Web API can use the HTTP Verb in this route to determine the method to call the controller, and a GET request maps to any method that starts with Get. So methods called Get() or GetAlbums() are matched by a GET request and a POST request maps to a Post() or PostAlbum(). Web API matches a method by name and parameter signature to match a route, query string or POST values. In lieu of the method name, the [HttpGet,HttpPost,HttpPut,HttpDelete, etc] attributes can also be used to designate the accepted verbs explicitly if you don’t want to follow the verb naming conventions. Although HTTP Verb routing is a good practice for REST style resource APIs, it’s not required and you can still use more traditional routes with an explicit {action} route parameter. When {action} is supplied, the HTTP verb routing is ignored. I’ll talk more about alternate routes later. When you’re finished with initial creation of files, your project should look like Figure 2.   Figure 2: The initial project has the new API Controller Album model   Creating a small Album Model Now it’s time to create some controller methods to serve data. For these examples, I’ll use a very simple Album and Songs model to play with, as shown in Listing 2. public class Song { public string AlbumId { get; set; } [Required, StringLength(80)] public string SongName { get; set; } [StringLength(5)] public string SongLength { get; set; } } public class Album { public string Id { get; set; } [Required, StringLength(80)] public string AlbumName { get; set; } [StringLength(80)] public string Artist { get; set; } public int YearReleased { get; set; } public DateTime Entered { get; set; } [StringLength(150)] public string AlbumImageUrl { get; set; } [StringLength(200)] public string AmazonUrl { get; set; } public virtual List<Song> Songs { get; set; } public Album() { Songs = new List<Song>(); Entered = DateTime.Now; // Poor man's unique Id off GUID hash Id = Guid.NewGuid().GetHashCode().ToString("x"); } public void AddSong(string songName, string songLength = null) { this.Songs.Add(new Song() { AlbumId = this.Id, SongName = songName, SongLength = songLength }); } } Once the model has been created, I also added an AlbumData class that generates some static data in memory that is loaded onto a static .Current member. The signature of this class looks like this and that's what I'll access to retrieve the base data:public static class AlbumData { // sample data - static list public static List<Album> Current = CreateSampleAlbumData(); /// <summary> /// Create some sample data /// </summary> /// <returns></returns> public static List<Album> CreateSampleAlbumData() { … }} You can check out the full code for the data generation online. Creating an AlbumApiController Web API shares many concepts of ASP.NET MVC, and the implementation of your API logic is done by implementing a subclass of the System.Web.Http.ApiController class. Each public method in the implemented controller is a potential endpoint for the HTTP API, as long as a matching route can be found to invoke it. The class name you create should end in Controller, which is how Web API matches the controller route value to figure out which class to invoke. Inside the controller you can implement methods that take standard .NET input parameters and return .NET values as results. Web API’s binding tries to match POST data, route values, form values or query string values to your parameters. Because the controller is configured for HTTP Verb based routing (no {action} parameter in the route), any methods that start with Getxxxx() are called by an HTTP GET operation. You can have multiple methods that match each HTTP Verb as long as the parameter signatures are different and can be matched by Web API. In Listing 3, I create an AlbumApiController with two methods to retrieve a list of albums and a single album by its title .public class AlbumApiController : ApiController { public IEnumerable<Album> GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); return albums; } public Album GetAlbum(string title) { var album = AlbumData.Current .SingleOrDefault(alb => alb.AlbumName.Contains(title)); return album; }} To access the first two requests, you can use the following URLs in your browser: http://localhost/aspnetWebApi/albumshttp://localhost/aspnetWebApi/albums/Dirty%20Deeds Note that you’re not specifying the actions of GetAlbum or GetAlbums in these URLs. Instead Web API’s routing uses HTTP GET verb to route to these methods that start with Getxxx() with the first mapping to the parameterless GetAlbums() method and the latter to the GetAlbum(title) method that receives the title parameter mapped as optional in the route. Content Negotiation When you access any of the URLs above from a browser, you get either an XML or JSON result returned back. The album list result for Chrome 17 and Internet Explorer 9 is shown Figure 3. Figure 3: Web API responses can vary depending on the browser used, demonstrating Content Negotiation in action as these two browsers send different HTTP Accept headers.   Notice that the results are not the same: Chrome returns an XML response and IE9 returns a JSON response. Whoa, what’s going on here? Shouldn’t we see the same result in both browsers? Actually, no. Web API determines what type of content to return based on Accept headers. HTTP clients, like browsers, use Accept headers to specify what kind of content they’d like to see returned. Browsers generally ask for HTML first, followed by a few additional content types. Chrome (and most other major browsers) ask for: Accept: text/html, application/xhtml+xml,application/xml; q=0.9,*/*;q=0.8 IE9 asks for: Accept: text/html, application/xhtml+xml, */* Note that Chrome’s Accept header includes application/xml, which Web API finds in its list of supported media types and returns an XML response. IE9 does not include an Accept header type that works on Web API by default, and so it returns the default format, which is JSON. This is an important and very useful feature that was missing from any previous Microsoft REST tools: Web API automatically switches output formats based on HTTP Accept headers. Nowhere in the server code above do you have to explicitly specify the output format. Rather, Web API determines what format the client is requesting based on the Accept headers and automatically returns the result based on the available formatters. This means that a single method can handle both XML and JSON results.. Using this simple approach makes it very easy to create a single controller method that can return JSON, XML, ATOM or even OData feeds by providing the appropriate Accept header from the client. By default you don’t have to worry about the output format in your code. Note that you can still specify an explicit output format if you choose, either globally by overriding the installed formatters, or individually by returning a lower level HttpResponseMessage instance and setting the formatter explicitly. More on that in a minute. Along the same lines, any content sent to the server via POST/PUT is parsed by Web API based on the HTTP Content-type of the data sent. The same formats allowed for output are also allowed on input. Again, you don’t have to do anything in your code – Web API automatically performs the deserialization from the content. Accessing Web API JSON Data with jQuery A very common scenario for Web API endpoints is to retrieve data for AJAX calls from the Web browser. Because JSON is the default format for Web API, it’s easy to access data from the server using jQuery and its getJSON() method. This example receives the albums array from GetAlbums() and databinds it into the page using knockout.js.$.getJSON("albums/", function (albums) { // make knockout template visible $(".album").show(); // create view object and attach array var view = { albums: albums }; ko.applyBindings(view); }); Figure 4 shows this and the next example’s HTML output. You can check out the complete HTML and script code at http://goo.gl/Ix33C (.html) and http://goo.gl/tETlg (.js). Figu Figure 4: The Album Display sample uses JSON data loaded from Web API.   The result from the getJSON() call is a JavaScript object of the server result, which comes back as a JavaScript array. In the code, I use knockout.js to bind this array into the UI, which as you can see, requires very little code, instead using knockout’s data-bind attributes to bind server data to the UI. Of course, this is just one way to use the data – it’s entirely up to you to decide what to do with the data in your client code. Along the same lines, I can retrieve a single album to display when the user clicks on an album. The response returns the album information and a child array with all the songs. The code to do this is very similar to the last example where we pulled the albums array:$(".albumlink").live("click", function () { var id = $(this).data("id"); // title $.getJSON("albums/" + id, function (album) { ko.applyBindings(album, $("#divAlbumDialog")[0]); $("#divAlbumDialog").show(); }); }); Here the URL looks like this: /albums/Dirty%20Deeds, where the title is the ID captured from the clicked element’s data ID attribute. Explicitly Overriding Output Format When Web API automatically converts output using content negotiation, it does so by matching Accept header media types to the GlobalConfiguration.Configuration.Formatters and the SupportedMediaTypes of each individual formatter. You can add and remove formatters to globally affect what formats are available and it’s easy to create and plug in custom formatters.The example project includes a JSONP formatter that can be plugged in to provide JSONP support for requests that have a callback= querystring parameter. Adding, removing or replacing formatters is a global option you can use to manipulate content. It’s beyond the scope of this introduction to show how it works, but you can review the sample code or check out my blog entry on the subject (http://goo.gl/UAzaR). If automatic processing is not desirable in a particular Controller method, you can override the response output explicitly by returning an HttpResponseMessage instance. HttpResponseMessage is similar to ActionResult in ASP.NET MVC in that it’s a common way to return an abstract result message that contains content. HttpResponseMessage s parsed by the Web API framework using standard interfaces to retrieve the response data, status code, headers and so on[MS2] . Web API turns every response – including those Controller methods that return static results – into HttpResponseMessage instances. Explicitly returning an HttpResponseMessage instance gives you full control over the output and lets you mostly bypass WebAPI’s post-processing of the HTTP response on your behalf. HttpResponseMessage allows you to customize the response in great detail. Web API’s attention to detail in the HTTP spec really shows; many HTTP options are exposed as properties and enumerations with detailed IntelliSense comments. Even if you’re new to building REST-based interfaces, the API guides you in the right direction for returning valid responses and response codes. For example, assume that I always want to return JSON from the GetAlbums() controller method and ignore the default media type content negotiation. To do this, I can adjust the output format and headers as shown in Listing 4.public HttpResponseMessage GetAlbums() { var albums = AlbumData.Current.OrderBy(alb => alb.Artist); // Create a new HttpResponse with Json Formatter explicitly var resp = new HttpResponseMessage(HttpStatusCode.OK); resp.Content = new ObjectContent<IEnumerable<Album>>( albums, new JsonMediaTypeFormatter()); // Get Default Formatter based on Content Negotiation //var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); resp.Headers.ConnectionClose = true; resp.Headers.CacheControl = new CacheControlHeaderValue(); resp.Headers.CacheControl.Public = true; return resp; } This example returns the same IEnumerable<Album> value, but it wraps the response into an HttpResponseMessage so you can control the entire HTTP message result including the headers, formatter and status code. In Listing 4, I explicitly specify the formatter using the JsonMediaTypeFormatter to always force the content to JSON.  If you prefer to use the default content negotiation with HttpResponseMessage results, you can create the Response instance using the Request.CreateResponse method:var resp = Request.CreateResponse<IEnumerable<Album>>(HttpStatusCode.OK, albums); This provides you an HttpResponse object that's pre-configured with the default formatter based on Content Negotiation. Once you have an HttpResponse object you can easily control most HTTP aspects on this object. What's sweet here is that there are many more detailed properties on HttpResponse than the core ASP.NET Response object, with most options being explicitly configurable with enumerations that make it easy to pick the right headers and response codes from a list of valid codes. It makes HTTP features available much more discoverable even for non-hardcore REST/HTTP geeks. Non-Serialized Results The output returned doesn’t have to be a serialized value but can also be raw data, like strings, binary data or streams. You can use the HttpResponseMessage.Content object to set a number of common Content classes. Listing 5 shows how to return a binary image using the ByteArrayContent class from a Controller method. [HttpGet] public HttpResponseMessage AlbumArt(string title) { var album = AlbumData.Current.FirstOrDefault(abl => abl.AlbumName.StartsWith(title)); if (album == null) { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found")); return resp; } // kinda silly - we would normally serve this directly // but hey - it's a demo. var http = new WebClient(); var imageData = http.DownloadData(album.AlbumImageUrl); // create response and return var result = new HttpResponseMessage(HttpStatusCode.OK); result.Content = new ByteArrayContent(imageData); result.Content.Headers.ContentType = new MediaTypeHeaderValue("image/jpeg"); return result; } The image retrieval from Amazon is contrived, but it shows how to return binary data using ByteArrayContent. It also demonstrates that you can easily return multiple types of content from a single controller method, which is actually quite common. If an error occurs - such as a resource can’t be found or a validation error – you can return an error response to the client that’s very specific to the error. In GetAlbumArt(), if the album can’t be found, we want to return a 404 Not Found status (and realistically no error, as it’s an image). Note that if you are not using HTTP Verb-based routing or not accessing a method that starts with Get/Post etc., you have to specify one or more HTTP Verb attributes on the method explicitly. Here, I used the [HttpGet] attribute to serve the image. Another option to handle the error could be to return a fixed placeholder image if no album could be matched or the album doesn’t have an image. When returning an error code, you can also return a strongly typed response to the client. For example, you can set the 404 status code and also return a custom error object (ApiMessageError is a class I defined) like this:return Request.CreateResponse<ApiMessageError>( HttpStatusCode.NotFound, new ApiMessageError("Album not found") );   If the album can be found, the image will be returned. The image is downloaded into a byte[] array, and then assigned to the result’s Content property. I created a new ByteArrayContent instance and assigned the image’s bytes and the content type so that it displays properly in the browser. There are other content classes available: StringContent, StreamContent, ByteArrayContent, MultipartContent, and ObjectContent are at your disposal to return just about any kind of content. You can create your own Content classes if you frequently return custom types and handle the default formatter assignments that should be used to send the data out . Although HttpResponseMessage results require more code than returning a plain .NET value from a method, it allows much more control over the actual HTTP processing than automatic processing. It also makes it much easier to test your controller methods as you get a response object that you can check for specific status codes and output messages rather than just a result value. Routing Again Ok, let’s get back to the image example. Using the original routing we have setup using HTTP Verb routing there's no good way to serve the image. In order to return my album art image I’d like to use a URL like this: http://localhost/aspnetWebApi/albums/Dirty%20Deeds/image In order to create a URL like this, I have to create a new Controller because my earlier routes pointed to the AlbumApiController using HTTP Verb routing. HTTP Verb based routing is great for representing a single set of resources such as albums. You can map operations like add, delete, update and read easily using HTTP Verbs. But you cannot mix action based routing into a an HTTP Verb routing controller - you can only map HTTP Verbs and each method has to be unique based on parameter signature. You can't have multiple GET operations to methods with the same signature. So GetImage(string id) and GetAlbum(string title) are in conflict in an HTTP GET routing scenario. In fact, I was unable to make the above Image URL work with any combination of HTTP Verb plus Custom routing using the single Albums controller. There are number of ways around this, but all involve additional controllers.  Personally, I think it’s easier to use explicit Action routing and then add custom routes if you need to simplify your URLs further. So in order to accommodate some of the other examples, I created another controller – AlbumRpcApiController – to handle all requests that are explicitly routed via actions (/albums/rpc/AlbumArt) or are custom routed with explicit routes defined in the HttpConfiguration. I added the AlbumArt() method to this new AlbumRpcApiController class. For the image URL to work with the new AlbumRpcApiController, you need a custom route placed before the default route from Listing 1.RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); Now I can use either of the following URLs to access the image: Custom route: (/albums/rpc/{title}/image)http://localhost/aspnetWebApi/albums/PowerAge/image Action route: (/albums/rpc/action/{title})http://localhost/aspnetWebAPI/albums/rpc/albumart/PowerAge Sending Data to the Server To send data to the server and add a new album, you can use an HTTP POST operation. Since I’m using HTTP Verb-based routing in the original AlbumApiController, I can implement a method called PostAlbum()to accept a new album from the client. Listing 6 shows the Web API code to add a new album.public HttpResponseMessage PostAlbum(Album album) { if (!this.ModelState.IsValid) { // my custom error class var error = new ApiMessageError() { message = "Model is invalid" }; // add errors into our client error model for client foreach (var prop in ModelState.Values) { var modelError = prop.Errors.FirstOrDefault(); if (!string.IsNullOrEmpty(modelError.ErrorMessage)) error.errors.Add(modelError.ErrorMessage); else error.errors.Add(modelError.Exception.Message); } return Request.CreateResponse<ApiMessageError>(HttpStatusCode.Conflict, error); } // update song id which isn't provided foreach (var song in album.Songs) song.AlbumId = album.Id; // see if album exists already var matchedAlbum = AlbumData.Current .SingleOrDefault(alb => alb.Id == album.Id || alb.AlbumName == album.AlbumName); if (matchedAlbum == null) AlbumData.Current.Add(album); else matchedAlbum = album; // return a string to show that the value got here var resp = Request.CreateResponse(HttpStatusCode.OK, string.Empty); resp.Content = new StringContent(album.AlbumName + " " + album.Entered.ToString(), Encoding.UTF8, "text/plain"); return resp; } The PostAlbum() method receives an album parameter, which is automatically deserialized from the POST buffer the client sent. The data passed from the client can be either XML or JSON. Web API automatically figures out what format it needs to deserialize based on the content type and binds the content to the album object. Web API uses model binding to bind the request content to the parameter(s) of controller methods. Like MVC you can check the model by looking at ModelState.IsValid. If it’s not valid, you can run through the ModelState.Values collection and check each binding for errors. Here I collect the error messages into a string array that gets passed back to the client via the result ApiErrorMessage object. When a binding error occurs, you’ll want to return an HTTP error response and it’s best to do that with an HttpResponseMessage result. In Listing 6, I used a custom error class that holds a message and an array of detailed error messages for each binding error. I used this object as the content to return to the client along with my Conflict HTTP Status Code response. If binding succeeds, the example returns a string with the name and date entered to demonstrate that you captured the data. Normally, a method like this should return a Boolean or no response at all (HttpStatusCode.NoConent). The sample uses a simple static list to hold albums, so once you’ve added the album using the Post operation, you can hit the /albums/ URL to see that the new album was added. The client jQuery code to call the POST operation from the client with jQuery is shown in Listing 7. var id = new Date().getTime().toString(); var album = { "Id": id, "AlbumName": "Power Age", "Artist": "AC/DC", "YearReleased": 1977, "Entered": "2002-03-11T18:24:43.5580794-10:00", "AlbumImageUrl": http://ecx.images-amazon.com/images/…, "AmazonUrl": http://www.amazon.com/…, "Songs": [ { "SongName": "Rock 'n Roll Damnation", "SongLength": 3.12}, { "SongName": "Downpayment Blues", "SongLength": 4.22 }, { "SongName": "Riff Raff", "SongLength": 2.42 } ] } $.ajax( { url: "albums/", type: "POST", contentType: "application/json", data: JSON.stringify(album), processData: false, beforeSend: function (xhr) { // not required since JSON is default output xhr.setRequestHeader("Accept", "application/json"); }, success: function (result) { // reload list of albums page.loadAlbums(); }, error: function (xhr, status, p3, p4) { var err = "Error"; if (xhr.responseText && xhr.responseText[0] == "{") err = JSON.parse(xhr.responseText).message; alert(err); } }); The code in Listing 7 creates an album object in JavaScript to match the structure of the .NET Album class. This object is passed to the $.ajax() function to send to the server as POST. The data is turned into JSON and the content type set to application/json so that the server knows what to convert when deserializing in the Album instance. The jQuery code hooks up success and failure events. Success returns the result data, which is a string that’s echoed back with an alert box. If an error occurs, jQuery returns the XHR instance and status code. You can check the XHR to see if a JSON object is embedded and if it is, you can extract it by de-serializing it and accessing the .message property. REST standards suggest that updates to existing resources should use PUT operations. REST standards aside, I’m not a big fan of separating out inserts and updates so I tend to have a single method that handles both. But if you want to follow REST suggestions, you can create a PUT method that handles updates by forwarding the PUT operation to the POST method:public HttpResponseMessage PutAlbum(Album album) { return PostAlbum(album); } To make the corresponding $.ajax() call, all you have to change from Listing 7 is the type: from POST to PUT. Model Binding with UrlEncoded POST Variables In the example in Listing 7 I used JSON objects to post a serialized object to a server method that accepted an strongly typed object with the same structure, which is a common way to send data to the server. However, Web API supports a number of different ways that data can be received by server methods. For example, another common way is to use plain UrlEncoded POST  values to send to the server. Web API supports Model Binding that works similar (but not the same) as MVC's model binding where POST variables are mapped to properties of object parameters of the target method. This is actually quite common for AJAX calls that want to avoid serialization and the potential requirement of a JSON parser on older browsers. For example, using jQUery you might use the $.post() method to send a new album to the server (albeit one without songs) using code like the following:$.post("albums/",{AlbumName: "Dirty Deeds", YearReleased: 1976 … },albumPostCallback); Although the code looks very similar to the client code we used before passing JSON, here the data passed is URL encoded values (AlbumName=Dirty+Deeds&YearReleased=1976 etc.). Web API then takes this POST data and maps each of the POST values to the properties of the Album object in the method's parameter. Although the client code is different the server can both handle the JSON object, or the UrlEncoded POST values. Dynamic Access to POST Data There are also a few options available to dynamically access POST data, if you know what type of data you're dealing with. If you have POST UrlEncoded values, you can dynamically using a FormsDataCollection:[HttpPost] public string PostAlbum(FormDataCollection form) { return string.Format("{0} - released {1}", form.Get("AlbumName"),form.Get("RearReleased")); } The FormDataCollection is a very simple object, that essentially provides the same functionality as Request.Form[] in ASP.NET. Request.Form[] still works if you're running hosted in an ASP.NET application. However as a general rule, while ASP.NET's functionality is always available when running Web API hosted inside of an  ASP.NET application, using the built in classes specific to Web API makes it possible to run Web API applications in a self hosted environment outside of ASP.NET. If your client is sending JSON to your server, and you don't want to map the JSON to a strongly typed object because you only want to retrieve a few simple values, you can also accept a JObject parameter in your API methods:[HttpPost] public string PostAlbum(JObject jsonData) { dynamic json = jsonData; JObject jalbum = json.Album; JObject juser = json.User; string token = json.UserToken; var album = jalbum.ToObject<Album>(); var user = juser.ToObject<User>(); return String.Format("{0} {1} {2}", album.AlbumName, user.Name, token); } There quite a few options available to you to receive data with Web API, which gives you more choices for the right tool for the job. Unfortunately one shortcoming of Web API is that POST data is always mapped to a single parameter. This means you can't pass multiple POST parameters to methods that receive POST data. It's possible to accept multiple parameters, but only one can map to the POST content - the others have to come from the query string or route values. I have a couple of Blog POSTs that explain what works and what doesn't here: Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API   Handling Delete Operations Finally, to round out the server API code of the album example we've been discussin, here’s the DELETE verb controller method that allows removal of an album by its title:public HttpResponseMessage DeleteAlbum(string title) { var matchedAlbum = AlbumData.Current.Where(alb => alb.AlbumName == title) .SingleOrDefault(); if (matchedAlbum == null) return new HttpResponseMessage(HttpStatusCode.NotFound); AlbumData.Current.Remove(matchedAlbum); return new HttpResponseMessage(HttpStatusCode.NoContent); } To call this action method using jQuery, you can use:$(".removeimage").live("click", function () { var $el = $(this).parent(".album"); var txt = $el.find("a").text(); $.ajax({ url: "albums/" + encodeURIComponent(txt), type: "Delete", success: function (result) { $el.fadeOut().remove(); }, error: jqError }); }   Note the use of the DELETE verb in the $.ajax() call, which routes to DeleteAlbum on the server. DELETE is a non-content operation, so you supply a resource ID (the title) via route value or the querystring. Routing Conflicts In all requests with the exception of the AlbumArt image example shown so far, I used HTTP Verb routing that I set up in Listing 1. HTTP Verb Routing is a recommendation that is in line with typical REST access to HTTP resources. However, it takes quite a bit of effort to create REST-compliant API implementations based only on HTTP Verb routing only. You saw one example that didn’t really fit – the return of an image where I created a custom route albums/{title}/image that required creation of a second controller and a custom route to work. HTTP Verb routing to a controller does not mix with custom or action routing to the same controller because of the limited mapping of HTTP verbs imposed by HTTP Verb routing. To understand some of the problems with verb routing, let’s look at another example. Let’s say you create a GetSortableAlbums() method like this and add it to the original AlbumApiController accessed via HTTP Verb routing:[HttpGet] public IQueryable<Album> SortableAlbums() { var albums = AlbumData.Current; // generally should be done only on actual queryable results (EF etc.) // Done here because we're running with a static list but otherwise might be slow return albums.AsQueryable(); } If you compile this code and try to now access the /albums/ link, you get an error: Multiple Actions were found that match the request. HTTP Verb routing only allows access to one GET operation per parameter/route value match. If more than one method exists with the same parameter signature, it doesn’t work. As I mentioned earlier for the image display, the only solution to get this method to work is to throw it into another controller. Because I already set up the AlbumRpcApiController I can add the method there. First, I should rename the method to SortableAlbums() so I’m not using a Get prefix for the method. This also makes the action parameter look cleaner in the URL - it looks less like a method and more like a noun. I can then create a new route that handles direct-action mapping:RouteTable.Routes.MapHttpRoute( name: "AlbumRpcApiAction", routeTemplate: "albums/rpc/{action}/{title}", defaults: new { title = RouteParameter.Optional, controller = "AlbumRpcApi", action = "GetAblums" } ); As I am explicitly adding a route segment – rpc – into the route template, I can now reference explicit methods in the Web API controller using URLs like this: http://localhost/AspNetWebApi/rpc/SortableAlbums Error Handling I’ve already done some minimal error handling in the examples. For example in Listing 6, I detected some known-error scenarios like model validation failing or a resource not being found and returning an appropriate HttpResponseMessage result. But what happens if your code just blows up or causes an exception? If you have a controller method, like this:[HttpGet] public void ThrowException() { throw new UnauthorizedAccessException("Unauthorized Access Sucka"); } You can call it with this: http://localhost/AspNetWebApi/albums/rpc/ThrowException The default exception handling displays a 500-status response with the serialized exception on the local computer only. When you connect from a remote computer, Web API throws back a 500  HTTP Error with no data returned (IIS then adds its HTML error page). The behavior is configurable in the GlobalConfiguration:GlobalConfiguration .Configuration .IncludeErrorDetailPolicy = IncludeErrorDetailPolicy.Never; If you want more control over your error responses sent from code, you can throw explicit error responses yourself using HttpResponseException. When you throw an HttpResponseException the response parameter is used to generate the output for the Controller action. [HttpGet] public void ThrowError() { var resp = Request.CreateResponse<ApiMessageError>( HttpStatusCode.BadRequest, new ApiMessageError("Your code stinks!")); throw new HttpResponseException(resp); } Throwing an HttpResponseException stops the processing of the controller method and immediately returns the response you passed to the exception. Unlike other Exceptions fired inside of WebAPI, HttpResponseException bypasses the Exception Filters installed and instead just outputs the response you provide. In this case, the serialized ApiMessageError result string is returned in the default serialization format – XML or JSON. You can pass any content to HttpResponseMessage, which includes creating your own exception objects and consistently returning error messages to the client. Here’s a small helper method on the controller that you might use to send exception info back to the client consistently:private void ThrowSafeException(string message, HttpStatusCode statusCode = HttpStatusCode.BadRequest) { var errResponse = Request.CreateResponse<ApiMessageError>(statusCode, new ApiMessageError() { message = message }); throw new HttpResponseException(errResponse); } You can then use it to output any captured errors from code:[HttpGet] public void ThrowErrorSafe() { try { List<string> list = null; list.Add("Rick"); } catch (Exception ex) { ThrowSafeException(ex.Message); } }   Exception Filters Another more global solution is to create an Exception Filter. Filters in Web API provide the ability to pre- and post-process controller method operations. An exception filter looks at all exceptions fired and then optionally creates an HttpResponseMessage result. Listing 8 shows an example of a basic Exception filter implementation.public class UnhandledExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { HttpStatusCode status = HttpStatusCode.InternalServerError; var exType = context.Exception.GetType(); if (exType == typeof(UnauthorizedAccessException)) status = HttpStatusCode.Unauthorized; else if (exType == typeof(ArgumentException)) status = HttpStatusCode.NotFound; var apiError = new ApiMessageError() { message = context.Exception.Message }; // create a new response and attach our ApiError object // which now gets returned on ANY exception result var errorResponse = context.Request.CreateResponse<ApiMessageError>(status, apiError); context.Response = errorResponse; base.OnException(context); } } Exception Filter Attributes can be assigned to an ApiController class like this:[UnhandledExceptionFilter] public class AlbumRpcApiController : ApiController or you can globally assign it to all controllers by adding it to the HTTP Configuration's Filters collection:GlobalConfiguration.Configuration.Filters.Add(new UnhandledExceptionFilter()); The latter is a great way to get global error trapping so that all errors (short of hard IIS errors and explicit HttpResponseException errors) return a valid error response that includes error information in the form of a known-error object. Using a filter like this allows you to throw an exception as you normally would and have your filter create a response in the appropriate output format that the client expects. For example, an AJAX application can on failure expect to see a JSON error result that corresponds to the real error that occurred rather than a 500 error along with HTML error page that IIS throws up. You can even create some custom exceptions so you can differentiate your own exceptions from unhandled system exceptions - you often don't want to display error information from 'unknown' exceptions as they may contain sensitive system information or info that's not generally useful to users of your application/site. This is just one example of how ASP.NET Web API is configurable and extensible. Exception filters are just one example of how you can plug-in into the Web API request flow to modify output. Many more hooks exist and I’ll take a closer look at extensibility in Part 2 of this article in the future. Summary Web API is a big improvement over previous Microsoft REST and AJAX toolkits. The key features to its usefulness are its ease of use with simple controller based logic, familiar MVC-style routing, low configuration impact, extensibility at all levels and tight attention to exposing and making HTTP semantics easily discoverable and easy to use. Although none of the concepts used in Web API are new or radical, Web API combines the best of previous platforms into a single framework that’s highly functional, easy to work with, and extensible to boot. I think that Microsoft has hit a home run with Web API. Related Resources Where does ASP.NET Web API fit? Sample Source Code on GitHub Passing multiple POST parameters to Web API Controller Methods Mapping UrlEncoded POST Values in ASP.NET Web API Creating a JSONP Formatter for ASP.NET Web API Removing the XML Formatter from ASP.NET Web API Applications© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • Tip/Trick: Fix Common SEO Problems Using the URL Rewrite Extension

    - by ScottGu
    Search engine optimization (SEO) is important for any publically facing web-site.  A large % of traffic to sites now comes directly from search engines, and improving your site’s search relevancy will lead to more users visiting your site from search engine queries.  This can directly or indirectly increase the money you make through your site. This blog post covers how you can use the free Microsoft URL Rewrite Extension to fix a bunch of common SEO problems that your site might have.  It takes less than 15 minutes (and no code changes) to apply 4 simple URL Rewrite rules to your site, and in doing so cause search engines to drive more visitors and traffic to your site.  The techniques below work equally well with both ASP.NET Web Forms and ASP.NET MVC based sites.  They also works with all versions of ASP.NET (and even work with non-ASP.NET content). [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Measuring the SEO of your website with the Microsoft SEO Toolkit A few months ago I blogged about the free SEO Toolkit that we’ve shipped.  This useful tool enables you to automatically crawl/scan your site for SEO correctness, and it then flags any SEO issues it finds.  I highly recommend downloading and using the tool against any public site you work on.  It makes it easy to spot SEO issues you might have in your site, and pinpoint ways to optimize it further. Below is a simple example of a report I ran against one of my sites (www.scottgu.com) prior to applying the URL Rewrite rules I’ll cover later in this blog post:   Search Relevancy and URL Splitting Two of the important things that search engines evaluate when assessing your site’s “search relevancy” are: How many other sites link to your content.  Search engines assume that if a lot of people around the web are linking to your content, then it is likely useful and so weight it higher in relevancy. The uniqueness of the content it finds on your site.  If search engines find that the content is duplicated in multiple places around the Internet (or on multiple URLs on your site) then it is likely to drop the relevancy of the content. One of the things you want to be very careful to avoid when building public facing sites is to not allow different URLs to retrieve the same content within your site.  Doing so will hurt with both of the situations above.  In particular, allowing external sites to link to the same content with multiple URLs will cause your link-count and page-ranking to be split up across those different URLs (and so give you a smaller page rank than what it would otherwise be if it was just one URL).  Not allowing external sites to link to you in different ways sounds easy in theory – but you might wonder what exactly this means in practice and how you avoid it. 4 Really Common SEO Problems Your Sites Might Have Below are 4 really common scenarios that can cause your site to inadvertently expose multiple URLs for the same content.  When this happens external sites linking to yours will end up splitting their page links across multiple URLs - and as a result cause you to have a lower page ranking with search engines than you deserve. SEO Problem #1: Default Document IIS (and other web servers) supports the concept of a “default document”.  This allows you to avoid having to explicitly specify the page you want to serve at either the root of the web-site/application, or within a sub-directory.  This is convenient – but means that by default this content is available via two different publically exposed URLs (which is bad).  For example: http://scottgu.com/ http://scottgu.com/default.aspx SEO Problem #2: Different URL Casings Web developers often don’t realize URLs are case sensitive to search engines on the web.  This means that search engines will treat the following links as two completely different URLs: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx SEO Problem #3: Trailing Slashes Consider the below two URLs – they might look the same at first, but they are subtly different. The trailing slash creates yet another situation that causes search engines to treat the URLs as different and so split search rankings: http://scottgu.com http://scottgu.com/ SEO Problem #4: Canonical Host Names Sometimes sites support scenarios where they support a web-site with both a leading “www” hostname prefix as well as just the hostname itself.  This causes search engines to treat the URLs as different and split search rankling: http://scottgu.com/albums.aspx/ http://www.scottgu.com/albums.aspx/ How to Easily Fix these SEO Problems in 10 minutes (or less) using IIS Rewrite If you haven’t been careful when coding your sites, chances are you are suffering from one (or more) of the above SEO problems.  Addressing these issues will improve your search engine relevancy ranking and drive more traffic to your site. The “good news” is that fixing the above 4 issues is really easy using the URL Rewrite Extension.  This is a completely free Microsoft extension available for IIS 7.x (on Windows Server 2008, Windows Server 2008 R2, Windows 7 and Windows Vista).  The great thing about using the IIS Rewrite extension is that it allows you to fix the above problems *without* having to change any code within your applications.  You can easily install the URL Rewrite Extension in under 3 minutes using the Microsoft Web Platform Installer (a free tool we ship that automates setting up web servers and development machines).  Just click the green “Install Now” button on the URL Rewrite Spotlight page to install it on your Windows Server 2008, Windows 7 or Windows Vista machine: Once installed you’ll find that a new “URL Rewrite” icon is available within the IIS 7 Admin Tool: Double-clicking the icon will open up the URL Rewrite admin panel – which will display the list of URL Rewrite rules configured for a particular application or site: Notice that our rewrite rule list above is currently empty (which is the default when you first install the extension).  We can click the “Add Rule…” link button in the top-right of the panel to add and enable new URL Rewriting logic for our site.  Scenario 1: Handling Default Document Scenarios One of the SEO problems I discussed earlier in this post was the scenario where the “default document” feature of IIS causes you to inadvertently expose two URLs for the same content on your site.  For example: http://scottgu.com/ http://scottgu.com/default.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the second URL to instead go to the first one.  We will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve.  Let’s look at how we can create such a rule.  We’ll begin by clicking the “Add Rule” link in the screenshot above.  This will cause the below dialog to display: We’ll select the “Blank Rule” template within the “Inbound rules” section to create a new custom URL Rewriting rule.  This will display an empty pane like below: Don’t worry – setting up the above rule is easy.  The following 4 steps explain how to do so: Step 1: Name the Rule Our first step will be to name the rule we are creating.  Naming it with a descriptive name will make it easier to find and understand later.  Let’s name this rule our “Default Document URL Rewrite” rule: Step 2: Setup the Regular Expression that Matches this Rule Our second step will be to specify a regular expression filter that will cause this rule to execute when an incoming URL matches the regex pattern.   Don’t worry if you aren’t good with regular expressions - I suck at them too. The trick is to know someone who is good at them or copy/paste them from a web-site.  Below we are going to specify the following regular expression as our pattern rule: (.*?)/?Default\.aspx$ This pattern will match any URL string that ends with Default.aspx. The "(.*?)" matches any preceding character zero or more times. The "/?" part says to match the slash symbol zero or one times. The "$" symbol at the end will ensure that the pattern will only match strings that end with Default.aspx.  Combining all these regex elements allows this rule to work not only for the root of your web site (e.g. http://scottgu.com/default.aspx) but also for any application or subdirectory within the site (e.g. http://scottgu.com/photos/default.aspx.  Because the “ignore case” checkbox is selected it will match both “Default.aspx” as well as “default.aspx” within the URL.   One nice feature built-into the rule editor is a “Test pattern” button that you can click to bring up a dialog that allows you to test out a few URLs with the rule you are configuring: Above I've added a “products/default.aspx” URL and clicked the “Test” button.  This will give me immediate feedback on whether the rule will execute for it.  Step 3: Setup a Permanent Redirect Action We’ll then setup an action to occur when our regular expression pattern matches the incoming URL: In the dialog above I’ve changed the “Action Type” drop down to be a “Redirect” action.  The “Redirect Type” will be a HTTP 301 Permanent redirect – which means search engines will follow it. I’ve also set the “Redirect URL” property to be: {R:1}/ This indicates that we want to redirect the web client requesting the original URL to a new URL that has the originally requested URL path - minus the "Default.aspx" in it.  For example, requests for http://scottgu.com/default.aspx will be redirected to http://scottgu.com/, and requests for http://scottgu.com/photos/default.aspx will be redirected to http://scottgu.com/photos/ The "{R:N}" regex construct, where N >= 0, is called a back-reference and N is the back-reference index. In the case of our pattern "(.*?)/?Default\.aspx$", if the input URL is "products/Default.aspx" then {R:0} will contain "products/Default.aspx" and {R:1} will contain "products".  We are going to use this {R:1}/ value to be the URL we redirect users to.  Step 4: Apply and Save the Rule Our final step is to click the “Apply” button in the top right hand of the IIS admin tool – which will cause the tool to persist the URL Rewrite rule into our application’s root web.config file (under a <system.webServer/rewrite> configuration section): <configuration>     <system.webServer>         <rewrite>             <rules>                 <rule name="Default Document" stopProcessing="true">                     <match url="(.*?)/?Default\.aspx$" />                     <action type="Redirect" url="{R:1}/" />                 </rule>             </rules>         </rewrite>     </system.webServer> </configuration> Because IIS 7.x and ASP.NET share the same web.config files, you can actually just copy/paste the above code into your web.config files using Visual Studio and skip the need to run the admin tool entirely.  This also makes adding/deploying URL Rewrite rules with your ASP.NET applications really easy. Step 5: Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site.  Try the following two URLs on my site: http://scottgu.com/ http://scottgu.com/default.aspx Notice that the second URL automatically redirects to the first one.  Because it is a permanent redirect, search engines will follow the URL and should update the page ranking of http://scottgu.com to include links to http://scottgu.com/default.aspx as well. Scenario 2: Different URL Casing Another common SEO problem I discussed earlier in this post is that URLs are case sensitive to search engines on the web.  This means that search engines will treat the following links as two completely different URLs: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL to instead go to the second (all lower-case) one.  Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve. To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again.  This will cause the “Add Rule” dialog to appear again: Unlike the previous scenario (where we created a “Blank Rule”), with this scenario we can take advantage of a built-in “Enforce lowercase URLs” rule template.  When we click the “ok” button we’ll see the following dialog which asks us if we want to create a rule that enforces the use of lowercase letters in URLs: When we click the “Yes” button we’ll get a pre-written rule that automatically performs a permanent redirect if an incoming URL has upper-case characters in it – and automatically send users to a lower-case version of the URL: We can click the “Apply” button to use this rule “as-is” and have it apply to all incoming URLs to our site.  Because my www.scottgu.com site uses ASP.NET Web Forms, I’m going to make one small change to the rule we generated above – which is to add a condition that will ensure that URLs to ASP.NET’s built-in “WebResource.axd” handler are excluded from our case-sensitivity URL Rewrite logic.  URLs to the WebResource.axd handler will only come from server-controls emitted from my pages – and will never be linked to from external sites.  While my site will continue to function fine if we redirect these URLs to automatically be lower-case – doing so isn’t necessary and will add an extra HTTP redirect to many of my pages.  The good news is that adding a condition that prevents my URL Rewriting rule from happening with certain URLs is easy.  We simply need to expand the “Conditions” section of the form above We can then click the “Add” button to add a condition clause.  This will bring up the “Add Condition” dialog: Above I’ve entered {URL} as the Condition input – and said that this rule should only execute if the URL does not match a regex pattern which contains the string “WebResource.axd”.  This will ensure that WebResource.axd URLs to my site will be allowed to execute just fine without having the URL be re-written to be all lower-case. Note: If you have static resources (like references to .jpg, .css, and .js files) within your site that currently use upper-case characters you’ll probably want to add additional condition filter clauses so that URLs to them also don’t get redirected to be lower-case (just add rules for patterns like .jpg, .gif, .js, etc).  Your site will continue to work fine if these URLs get redirected to be lower case (meaning the site won’t break) – but it will cause an extra HTTP redirect to happen on your site for URLs that don’t need to be redirected for SEO reasons.  So setting up a condition clause makes sense to add. When I click the “ok” button above and apply our lower-case rewriting rule the admin tool will save the following additional rule to our web.config file: <configuration>     <system.webServer>         <rewrite>             <rules>                 <rule name="Default Document" stopProcessing="true">                     <match url="(.*?)/?Default\.aspx$" />                     <action type="Redirect" url="{R:1}/" />                 </rule>                 <rule name="Lower Case URLs" stopProcessing="true">                     <match url="[A-Z]" ignoreCase="false" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{URL}" pattern="WebResource.axd" negate="true" />                     </conditions>                     <action type="Redirect" url="{ToLower:{URL}}" />                 </rule>             </rules>         </rewrite>     </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site.  Try the following two URLs on my site: http://scottgu.com/Albums.aspx http://scottgu.com/albums.aspx Notice that the first URL (which has a capital “A”) automatically does a redirect to a lower-case version of the URL.  Scenario 3: Trailing Slashes Another common SEO problem I discussed earlier in this post is the scenario of trailing slashes within URLs.  The trailing slash creates yet another situation that causes search engines to treat the URLs as different and so split search rankings: http://scottgu.com http://scottgu.com/ We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL (that does not have a trailing slash) to instead go to the second one that does.  Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve.  To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again.  This will cause the “Add Rule” dialog to appear again: The URL Rewrite admin tool has a built-in “Append or remove the trailing slash symbol” rule template.  When we select it and click the “ok” button we’ll see the following dialog which asks us if we want to create a rule that automatically redirects users to a URL with a trailing slash if one isn’t present: Like within our previous lower-casing rewrite rule we’ll add one additional condition clause that will exclude WebResource.axd URLs from being processed by this rule.  This will avoid an unnecessary redirect for happening for those URLs. When we click the “OK” button we’ll get a pre-written rule that automatically performs a permanent redirect if the URL doesn’t have a trailing slash – and if the URL is not processed by either a directory or a file.  This will save the following additional rule to our web.config file: <configuration>     <system.webServer>         <rewrite>             <rules>                 <rule name="Default Document" stopProcessing="true">                     <match url="(.*?)/?Default\.aspx$" />                     <action type="Redirect" url="{R:1}/" />                 </rule>                 <rule name="Lower Case URLs" stopProcessing="true">                     <match url="[A-Z]" ignoreCase="false" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{URL}" pattern="WebResource.axd" negate="true" />                     </conditions>                     <action type="Redirect" url="{ToLower:{URL}}" />                 </rule>                 <rule name="Trailing Slash" stopProcessing="true">                     <match url="(.*[^/])$" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />                         <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />                         <add input="{URL}" pattern="WebResource.axd" negate="true" />                     </conditions>                     <action type="Redirect" url="{R:1}/" />                 </rule>             </rules>         </rewrite>     </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site.  Try the following two URLs on my site: http://scottgu.com http://scottgu.com/ Notice that the first URL (which has no trailing slash) automatically does a redirect to a URL with the trailing slash.  Because it is a permanent redirect, search engines will follow the URL and update the page ranking. Scenario 4: Canonical Host Names The final SEO problem I discussed earlier are scenarios where a site works with both a leading “www” hostname prefix as well as just the hostname itself.  This causes search engines to treat the URLs as different and split search rankling: http://www.scottgu.com/albums.aspx http://scottgu.com/albums.aspx We can fix this by adding a new IIS Rewrite rule that automatically redirects anyone who navigates to the first URL (that has a www prefix) to instead go to the second URL.  Like before, we will setup the HTTP redirect to be a “permanent redirect” – which will indicate to search engines that they should follow the redirect and use the new URL they are redirected to as the identifier of the content they retrieve.  To create such a rule we’ll click the “Add Rule” link in the URL Rewrite admin tool again.  This will cause the “Add Rule” dialog to appear again: The URL Rewrite admin tool has a built-in “Canonical domain name” rule template.  When we select it and click the “ok” button we’ll see the following dialog which asks us if we want to create a redirect rule that automatically redirects users to a primary host name URL: Above I’m entering the primary URL address I want to expose to the web: scottgu.com.  When we click the “OK” button we’ll get a pre-written rule that automatically performs a permanent redirect if the URL has another leading domain name prefix.  This will save the following additional rule to our web.config file: <configuration>     <system.webServer>         <rewrite>             <rules>                 <rule name="Cannonical Hostname">                     <match url="(.*)" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{HTTP_HOST}" pattern="^scottgu\.com$" negate="true" />                     </conditions>                     <action type="Redirect" url="http://scottgu.com/{R:1}" />                 </rule>                 <rule name="Default Document" stopProcessing="true">                     <match url="(.*?)/?Default\.aspx$" />                     <action type="Redirect" url="{R:1}/" />                 </rule>                 <rule name="Lower Case URLs" stopProcessing="true">                     <match url="[A-Z]" ignoreCase="false" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{URL}" pattern="WebResource.axd" negate="true" />                     </conditions>                     <action type="Redirect" url="{ToLower:{URL}}" />                 </rule>                 <rule name="Trailing Slash" stopProcessing="true">                     <match url="(.*[^/])$" />                     <conditions logicalGrouping="MatchAll" trackAllCaptures="false">                         <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />                         <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />                         <add input="{URL}" pattern="WebResource.axd" negate="true" />                     </conditions>                     <action type="Redirect" url="{R:1}/" />                 </rule>             </rules>         </rewrite>     </system.webServer> </configuration> Try the Rule Out Now that we’ve saved the rule, let’s try it out on our site.  Try the following two URLs on my site: http://www.scottgu.com/albums.aspx http://scottgu.com/albums.aspx Notice that the first URL (which has the “www” prefix) now automatically does a redirect to the second URL which does not have the www prefix.  Because it is a permanent redirect, search engines will follow the URL and update the page ranking. 4 Simple Rules for Improved SEO The above 4 rules are pretty easy to setup and should take less than 15 minutes to configure on existing sites you already have.  The beauty of using a solution like the URL Rewrite Extension is that you can take advantage of it without having to change code within your web-site – and without having to break any existing links already pointing at your site.  Users who follow existing links will be automatically redirected to the new URLs you wish to publish.  And search engines will start to give your site a higher search relevancy ranking – which will list your site higher in search results and drive more traffic to it. Customizing your URL Rewriting rules further is easy to-do either by editing the web.config file directly, or alternatively, just double click the URL Rewrite icon within the IIS 7.x admin tool and it will list all the active rules for your web-site or application: Clicking any of the rules above will open the rules editor back up and allow you to tweak/customize/save them further. Summary Measuring and improving SEO is something every developer building a public-facing web-site needs to think about and focus on.  If you haven’t already, download and use the SEO Toolkit to analyze the SEO of your sites today. New URL Routing features in ASP.NET MVC and ASP.NET Web Forms 4 make it much easier to build applications that have more control over the URLs that are published.  Tools like the URL Rewrite Extension that I’ve talked about in this blog post make it much easier to improve the URLs that are published from sites you already have built today – without requiring you to change a lot of code. The URL Rewrite Extension provides a bunch of additional great capabilities – far beyond just SEO - as well.  I’ll be covering these additional capabilities more in future blog posts. Hope this helps, Scott

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  • Upload File to Windows Azure Blob in Chunks through ASP.NET MVC, JavaScript and HTML5

    - by Shaun
    Originally posted on: http://geekswithblogs.net/shaunxu/archive/2013/07/01/upload-file-to-windows-azure-blob-in-chunks-through-asp.net.aspxMany people are using Windows Azure Blob Storage to store their data in the cloud. Blob storage provides 99.9% availability with easy-to-use API through .NET SDK and HTTP REST. For example, we can store JavaScript files, images, documents in blob storage when we are building an ASP.NET web application on a Web Role in Windows Azure. Or we can store our VHD files in blob and mount it as a hard drive in our cloud service. If you are familiar with Windows Azure, you should know that there are two kinds of blob: page blob and block blob. The page blob is optimized for random read and write, which is very useful when you need to store VHD files. The block blob is optimized for sequential/chunk read and write, which has more common usage. Since we can upload block blob in blocks through BlockBlob.PutBlock, and them commit them as a whole blob with invoking the BlockBlob.PutBlockList, it is very powerful to upload large files, as we can upload blocks in parallel, and provide pause-resume feature. There are many documents, articles and blog posts described on how to upload a block blob. Most of them are focus on the server side, which means when you had received a big file, stream or binaries, how to upload them into blob storage in blocks through .NET SDK.  But the problem is, how can we upload these large files from client side, for example, a browser. This questioned to me when I was working with a Chinese customer to help them build a network disk production on top of azure. The end users upload their files from the web portal, and then the files will be stored in blob storage from the Web Role. My goal is to find the best way to transform the file from client (end user’s machine) to the server (Web Role) through browser. In this post I will demonstrate and describe what I had done, to upload large file in chunks with high speed, and save them as blocks into Windows Azure Blob Storage.   Traditional Upload, Works with Limitation The simplest way to implement this requirement is to create a web page with a form that contains a file input element and a submit button. 1: @using (Html.BeginForm("About", "Index", FormMethod.Post, new { enctype = "multipart/form-data" })) 2: { 3: <input type="file" name="file" /> 4: <input type="submit" value="upload" /> 5: } And then in the backend controller, we retrieve the whole content of this file and upload it in to the blob storage through .NET SDK. We can split the file in blocks and upload them in parallel and commit. The code had been well blogged in the community. 1: [HttpPost] 2: public ActionResult About(HttpPostedFileBase file) 3: { 4: var container = _client.GetContainerReference("test"); 5: container.CreateIfNotExists(); 6: var blob = container.GetBlockBlobReference(file.FileName); 7: var blockDataList = new Dictionary<string, byte[]>(); 8: using (var stream = file.InputStream) 9: { 10: var blockSizeInKB = 1024; 11: var offset = 0; 12: var index = 0; 13: while (offset < stream.Length) 14: { 15: var readLength = Math.Min(1024 * blockSizeInKB, (int)stream.Length - offset); 16: var blockData = new byte[readLength]; 17: offset += stream.Read(blockData, 0, readLength); 18: blockDataList.Add(Convert.ToBase64String(BitConverter.GetBytes(index)), blockData); 19:  20: index++; 21: } 22: } 23:  24: Parallel.ForEach(blockDataList, (bi) => 25: { 26: blob.PutBlock(bi.Key, new MemoryStream(bi.Value), null); 27: }); 28: blob.PutBlockList(blockDataList.Select(b => b.Key).ToArray()); 29:  30: return RedirectToAction("About"); 31: } This works perfect if we selected an image, a music or a small video to upload. But if I selected a large file, let’s say a 6GB HD-movie, after upload for about few minutes the page will be shown as below and the upload will be terminated. In ASP.NET there is a limitation of request length and the maximized request length is defined in the web.config file. It’s a number which less than about 4GB. So if we want to upload a really big file, we cannot simply implement in this way. Also, in Windows Azure, a cloud service network load balancer will terminate the connection if exceed the timeout period. From my test the timeout looks like 2 - 3 minutes. Hence, when we need to upload a large file we cannot just use the basic HTML elements. Besides the limitation mentioned above, the simple HTML file upload cannot provide rich upload experience such as chunk upload, pause and pause-resume. So we need to find a better way to upload large file from the client to the server.   Upload in Chunks through HTML5 and JavaScript In order to break those limitation mentioned above we will try to upload the large file in chunks. This takes some benefit to us such as - No request size limitation: Since we upload in chunks, we can define the request size for each chunks regardless how big the entire file is. - No timeout problem: The size of chunks are controlled by us, which means we should be able to make sure request for each chunk upload will not exceed the timeout period of both ASP.NET and Windows Azure load balancer. It was a big challenge to upload big file in chunks until we have HTML5. There are some new features and improvements introduced in HTML5 and we will use them to implement our solution.   In HTML5, the File interface had been improved with a new method called “slice”. It can be used to read part of the file by specifying the start byte index and the end byte index. For example if the entire file was 1024 bytes, file.slice(512, 768) will read the part of this file from the 512nd byte to 768th byte, and return a new object of interface called "Blob”, which you can treat as an array of bytes. In fact,  a Blob object represents a file-like object of immutable, raw data. The File interface is based on Blob, inheriting blob functionality and expanding it to support files on the user's system. For more information about the Blob please refer here. File and Blob is very useful to implement the chunk upload. We will use File interface to represent the file the user selected from the browser and then use File.slice to read the file in chunks in the size we wanted. For example, if we wanted to upload a 10MB file with 512KB chunks, then we can read it in 512KB blobs by using File.slice in a loop.   Assuming we have a web page as below. User can select a file, an input box to specify the block size in KB and a button to start upload. 1: <div> 2: <input type="file" id="upload_files" name="files[]" /><br /> 3: Block Size: <input type="number" id="block_size" value="512" name="block_size" />KB<br /> 4: <input type="button" id="upload_button_blob" name="upload" value="upload (blob)" /> 5: </div> Then we can have the JavaScript function to upload the file in chunks when user clicked the button. 1: <script type="text/javascript"> 1: 2: $(function () { 3: $("#upload_button_blob").click(function () { 4: }); 5: });</script> Firstly we need to ensure the client browser supports the interfaces we are going to use. Just try to invoke the File, Blob and FormData from the “window” object. If any of them is “undefined” the condition result will be “false” which means your browser doesn’t support these premium feature and it’s time for you to get your browser updated. FormData is another new feature we are going to use in the future. It could generate a temporary form for us. We will use this interface to create a form with chunk and associated metadata when invoked the service through ajax. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: if (window.File && window.Blob && window.FormData) { 4: alert("Your brwoser is awesome, let's rock!"); 5: } 6: else { 7: alert("Oh man plz update to a modern browser before try is cool stuff out."); 8: return; 9: } 10: }); Each browser supports these interfaces by their own implementation and currently the Blob, File and File.slice are supported by Chrome 21, FireFox 13, IE 10, Opera 12 and Safari 5.1 or higher. After that we worked on the files the user selected one by one since in HTML5, user can select multiple files in one file input box. 1: var files = $("#upload_files")[0].files; 2: for (var i = 0; i < files.length; i++) { 3: var file = files[i]; 4: var fileSize = file.size; 5: var fileName = file.name; 6: } Next, we calculated the start index and end index for each chunks based on the size the user specified from the browser. We put them into an array with the file name and the index, which will be used when we upload chunks into Windows Azure Blob Storage as blocks since we need to specify the target blob name and the block index. At the same time we will store the list of all indexes into another variant which will be used to commit blocks into blob in Azure Storage once all chunks had been uploaded successfully. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10:  11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: var blockSizeInKB = $("#block_size").val(); 14: var blockSize = blockSizeInKB * 1024; 15: var blocks = []; 16: var offset = 0; 17: var index = 0; 18: var list = ""; 19: while (offset < fileSize) { 20: var start = offset; 21: var end = Math.min(offset + blockSize, fileSize); 22:  23: blocks.push({ 24: name: fileName, 25: index: index, 26: start: start, 27: end: end 28: }); 29: list += index + ","; 30:  31: offset = end; 32: index++; 33: } 34: } 35: }); Now we have all chunks’ information ready. The next step should be upload them one by one to the server side, and at the server side when received a chunk it will upload as a block into Blob Storage, and finally commit them with the index list through BlockBlobClient.PutBlockList. But since all these invokes are ajax calling, which means not synchronized call. So we need to introduce a new JavaScript library to help us coordinate the asynchronize operation, which named “async.js”. You can download this JavaScript library here, and you can find the document here. I will not explain this library too much in this post. We will put all procedures we want to execute as a function array, and pass into the proper function defined in async.js to let it help us to control the execution sequence, in series or in parallel. Hence we will define an array and put the function for chunk upload into this array. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4:  5: // start to upload each files in chunks 6: var files = $("#upload_files")[0].files; 7: for (var i = 0; i < files.length; i++) { 8: var file = files[i]; 9: var fileSize = file.size; 10: var fileName = file.name; 11: // calculate the start and end byte index for each blocks(chunks) 12: // with the index, file name and index list for future using 13: ... ... 14:  15: // define the function array and push all chunk upload operation into this array 16: blocks.forEach(function (block) { 17: putBlocks.push(function (callback) { 18: }); 19: }); 20: } 21: }); 22: }); As you can see, I used File.slice method to read each chunks based on the start and end byte index we calculated previously, and constructed a temporary HTML form with the file name, chunk index and chunk data through another new feature in HTML5 named FormData. Then post this form to the backend server through jQuery.ajax. This is the key part of our solution. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: blocks.forEach(function (block) { 15: putBlocks.push(function (callback) { 16: // load blob based on the start and end index for each chunks 17: var blob = file.slice(block.start, block.end); 18: // put the file name, index and blob into a temporary from 19: var fd = new FormData(); 20: fd.append("name", block.name); 21: fd.append("index", block.index); 22: fd.append("file", blob); 23: // post the form to backend service (asp.net mvc controller action) 24: $.ajax({ 25: url: "/Home/UploadInFormData", 26: data: fd, 27: processData: false, 28: contentType: "multipart/form-data", 29: type: "POST", 30: success: function (result) { 31: if (!result.success) { 32: alert(result.error); 33: } 34: callback(null, block.index); 35: } 36: }); 37: }); 38: }); 39: } 40: }); Then we will invoke these functions one by one by using the async.js. And once all functions had been executed successfully I invoked another ajax call to the backend service to commit all these chunks (blocks) as the blob in Windows Azure Storage. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.series(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); That’s all in the client side. The outline of our logic would be - Calculate the start and end byte index for each chunks based on the block size. - Defined the functions of reading the chunk form file and upload the content to the backend service through ajax. - Execute the functions defined in previous step with “async.js”. - Commit the chunks by invoking the backend service in Windows Azure Storage finally.   Save Chunks as Blocks into Blob Storage In above we finished the client size JavaScript code. It uploaded the file in chunks to the backend service which we are going to implement in this step. We will use ASP.NET MVC as our backend service, and it will receive the chunks, upload into Windows Azure Bob Storage in blocks, then finally commit as one blob. As in the client side we uploaded chunks by invoking the ajax call to the URL "/Home/UploadInFormData", I created a new action under the Index controller and it only accepts HTTP POST request. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: } 8: catch (Exception e) 9: { 10: error = e.ToString(); 11: } 12:  13: return new JsonResult() 14: { 15: Data = new 16: { 17: success = string.IsNullOrWhiteSpace(error), 18: error = error 19: } 20: }; 21: } Then I retrieved the file name, index and the chunk content from the Request.Form object, which was passed from our client side. And then, used the Windows Azure SDK to create a blob container (in this case we will use the container named “test”.) and create a blob reference with the blob name (same as the file name). Then uploaded the chunk as a block of this blob with the index, since in Blob Storage each block must have an index (ID) associated with so that finally we can put all blocks as one blob by specifying their block ID list. 1: [HttpPost] 2: public JsonResult UploadInFormData() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var index = int.Parse(Request.Form["index"]); 9: var file = Request.Files[0]; 10: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 11:  12: var container = _client.GetContainerReference("test"); 13: container.CreateIfNotExists(); 14: var blob = container.GetBlockBlobReference(name); 15: blob.PutBlock(id, file.InputStream, null); 16: } 17: catch (Exception e) 18: { 19: error = e.ToString(); 20: } 21:  22: return new JsonResult() 23: { 24: Data = new 25: { 26: success = string.IsNullOrWhiteSpace(error), 27: error = error 28: } 29: }; 30: } Next, I created another action to commit the blocks into blob once all chunks had been uploaded. Similarly, I retrieved the blob name from the Request.Form. I also retrieved the chunks ID list, which is the block ID list from the Request.Form in a string format, split them as a list, then invoked the BlockBlob.PutBlockList method. After that our blob will be shown in the container and ready to be download. 1: [HttpPost] 2: public JsonResult Commit() 3: { 4: var error = string.Empty; 5: try 6: { 7: var name = Request.Form["name"]; 8: var list = Request.Form["list"]; 9: var ids = list 10: .Split(',') 11: .Where(id => !string.IsNullOrWhiteSpace(id)) 12: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 13: .ToArray(); 14:  15: var container = _client.GetContainerReference("test"); 16: container.CreateIfNotExists(); 17: var blob = container.GetBlockBlobReference(name); 18: blob.PutBlockList(ids); 19: } 20: catch (Exception e) 21: { 22: error = e.ToString(); 23: } 24:  25: return new JsonResult() 26: { 27: Data = new 28: { 29: success = string.IsNullOrWhiteSpace(error), 30: error = error 31: } 32: }; 33: } Now we finished all code we need. The whole process of uploading would be like this below. Below is the full client side JavaScript code. 1: <script type="text/javascript" src="~/Scripts/async.js"></script> 2: <script type="text/javascript"> 3: $(function () { 4: $("#upload_button_blob").click(function () { 5: // assert the browser support html5 6: if (window.File && window.Blob && window.FormData) { 7: alert("Your brwoser is awesome, let's rock!"); 8: } 9: else { 10: alert("Oh man plz update to a modern browser before try is cool stuff out."); 11: return; 12: } 13:  14: // start to upload each files in chunks 15: var files = $("#upload_files")[0].files; 16: for (var i = 0; i < files.length; i++) { 17: var file = files[i]; 18: var fileSize = file.size; 19: var fileName = file.name; 20:  21: // calculate the start and end byte index for each blocks(chunks) 22: // with the index, file name and index list for future using 23: var blockSizeInKB = $("#block_size").val(); 24: var blockSize = blockSizeInKB * 1024; 25: var blocks = []; 26: var offset = 0; 27: var index = 0; 28: var list = ""; 29: while (offset < fileSize) { 30: var start = offset; 31: var end = Math.min(offset + blockSize, fileSize); 32:  33: blocks.push({ 34: name: fileName, 35: index: index, 36: start: start, 37: end: end 38: }); 39: list += index + ","; 40:  41: offset = end; 42: index++; 43: } 44:  45: // define the function array and push all chunk upload operation into this array 46: var putBlocks = []; 47: blocks.forEach(function (block) { 48: putBlocks.push(function (callback) { 49: // load blob based on the start and end index for each chunks 50: var blob = file.slice(block.start, block.end); 51: // put the file name, index and blob into a temporary from 52: var fd = new FormData(); 53: fd.append("name", block.name); 54: fd.append("index", block.index); 55: fd.append("file", blob); 56: // post the form to backend service (asp.net mvc controller action) 57: $.ajax({ 58: url: "/Home/UploadInFormData", 59: data: fd, 60: processData: false, 61: contentType: "multipart/form-data", 62: type: "POST", 63: success: function (result) { 64: if (!result.success) { 65: alert(result.error); 66: } 67: callback(null, block.index); 68: } 69: }); 70: }); 71: }); 72:  73: // invoke the functions one by one 74: // then invoke the commit ajax call to put blocks into blob in azure storage 75: async.series(putBlocks, function (error, result) { 76: var data = { 77: name: fileName, 78: list: list 79: }; 80: $.post("/Home/Commit", data, function (result) { 81: if (!result.success) { 82: alert(result.error); 83: } 84: else { 85: alert("done!"); 86: } 87: }); 88: }); 89: } 90: }); 91: }); 92: </script> And below is the full ASP.NET MVC controller code. 1: public class HomeController : Controller 2: { 3: private CloudStorageAccount _account; 4: private CloudBlobClient _client; 5:  6: public HomeController() 7: : base() 8: { 9: _account = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("DataConnectionString")); 10: _client = _account.CreateCloudBlobClient(); 11: } 12:  13: public ActionResult Index() 14: { 15: ViewBag.Message = "Modify this template to jump-start your ASP.NET MVC application."; 16:  17: return View(); 18: } 19:  20: [HttpPost] 21: public JsonResult UploadInFormData() 22: { 23: var error = string.Empty; 24: try 25: { 26: var name = Request.Form["name"]; 27: var index = int.Parse(Request.Form["index"]); 28: var file = Request.Files[0]; 29: var id = Convert.ToBase64String(BitConverter.GetBytes(index)); 30:  31: var container = _client.GetContainerReference("test"); 32: container.CreateIfNotExists(); 33: var blob = container.GetBlockBlobReference(name); 34: blob.PutBlock(id, file.InputStream, null); 35: } 36: catch (Exception e) 37: { 38: error = e.ToString(); 39: } 40:  41: return new JsonResult() 42: { 43: Data = new 44: { 45: success = string.IsNullOrWhiteSpace(error), 46: error = error 47: } 48: }; 49: } 50:  51: [HttpPost] 52: public JsonResult Commit() 53: { 54: var error = string.Empty; 55: try 56: { 57: var name = Request.Form["name"]; 58: var list = Request.Form["list"]; 59: var ids = list 60: .Split(',') 61: .Where(id => !string.IsNullOrWhiteSpace(id)) 62: .Select(id => Convert.ToBase64String(BitConverter.GetBytes(int.Parse(id)))) 63: .ToArray(); 64:  65: var container = _client.GetContainerReference("test"); 66: container.CreateIfNotExists(); 67: var blob = container.GetBlockBlobReference(name); 68: blob.PutBlockList(ids); 69: } 70: catch (Exception e) 71: { 72: error = e.ToString(); 73: } 74:  75: return new JsonResult() 76: { 77: Data = new 78: { 79: success = string.IsNullOrWhiteSpace(error), 80: error = error 81: } 82: }; 83: } 84: } And if we selected a file from the browser we will see our application will upload chunks in the size we specified to the server through ajax call in background, and then commit all chunks in one blob. Then we can find the blob in our Windows Azure Blob Storage.   Optimized by Parallel Upload In previous example we just uploaded our file in chunks. This solved the problem that ASP.NET MVC request content size limitation as well as the Windows Azure load balancer timeout. But it might introduce the performance problem since we uploaded chunks in sequence. In order to improve the upload performance we could modify our client side code a bit to make the upload operation invoked in parallel. The good news is that, “async.js” library provides the parallel execution function. If you remembered the code we invoke the service to upload chunks, it utilized “async.series” which means all functions will be executed in sequence. Now we will change this code to “async.parallel”. This will invoke all functions in parallel. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallel(putBlocks, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: }); In this way all chunks will be uploaded to the server side at the same time to maximize the bandwidth usage. This should work if the file was not very large and the chunk size was not very small. But for large file this might introduce another problem that too many ajax calls are sent to the server at the same time. So the best solution should be, upload the chunks in parallel with maximum concurrency limitation. The code below specified the concurrency limitation to 4, which means at the most only 4 ajax calls could be invoked at the same time. 1: $("#upload_button_blob").click(function () { 2: // assert the browser support html5 3: ... ... 4: // start to upload each files in chunks 5: var files = $("#upload_files")[0].files; 6: for (var i = 0; i < files.length; i++) { 7: var file = files[i]; 8: var fileSize = file.size; 9: var fileName = file.name; 10: // calculate the start and end byte index for each blocks(chunks) 11: // with the index, file name and index list for future using 12: ... ... 13: // define the function array and push all chunk upload operation into this array 14: ... ... 15: // invoke the functions one by one 16: // then invoke the commit ajax call to put blocks into blob in azure storage 17: async.parallelLimit(putBlocks, 4, function (error, result) { 18: var data = { 19: name: fileName, 20: list: list 21: }; 22: $.post("/Home/Commit", data, function (result) { 23: if (!result.success) { 24: alert(result.error); 25: } 26: else { 27: alert("done!"); 28: } 29: }); 30: }); 31: } 32: });   Summary In this post we discussed how to upload files in chunks to the backend service and then upload them into Windows Azure Blob Storage in blocks. We focused on the frontend side and leverage three new feature introduced in HTML 5 which are - File.slice: Read part of the file by specifying the start and end byte index. - Blob: File-like interface which contains the part of the file content. - FormData: Temporary form element that we can pass the chunk alone with some metadata to the backend service. Then we discussed the performance consideration of chunk uploading. Sequence upload cannot provide maximized upload speed, but the unlimited parallel upload might crash the browser and server if too many chunks. So we finally came up with the solution to upload chunks in parallel with the concurrency limitation. We also demonstrated how to utilize “async.js” JavaScript library to help us control the asynchronize call and the parallel limitation.   Regarding the chunk size and the parallel limitation value there is no “best” value. You need to test vary composition and find out the best one for your particular scenario. It depends on the local bandwidth, client machine cores and the server side (Windows Azure Cloud Service Virtual Machine) cores, memory and bandwidth. Below is one of my performance test result. The client machine was Windows 8 IE 10 with 4 cores. I was using Microsoft Cooperation Network. The web site was hosted on Windows Azure China North data center (in Beijing) with one small web role (1.7GB 1 core CPU, 1.75GB memory with 100Mbps bandwidth). The test cases were - Chunk size: 512KB, 1MB, 2MB, 4MB. - Upload Mode: Sequence, parallel (unlimited), parallel with limit (4 threads, 8 threads). - Chunk Format: base64 string, binaries. - Target file: 100MB. - Each case was tested 3 times. Below is the test result chart. Some thoughts, but not guidance or best practice: - Parallel gets better performance than series. - No significant performance improvement between parallel 4 threads and 8 threads. - Transform with binaries provides better performance than base64. - In all cases, chunk size in 1MB - 2MB gets better performance.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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  • New features of C# 4.0

    This article covers New features of C# 4.0. Article has been divided into below sections. Introduction. Dynamic Lookup. Named and Optional Arguments. Features for COM interop. Variance. Relationship with Visual Basic. Resources. Other interested readings… 22 New Features of Visual Studio 2008 for .NET Professionals 50 New Features of SQL Server 2008 IIS 7.0 New features Introduction It is now close to a year since Microsoft Visual C# 3.0 shipped as part of Visual Studio 2008. In the VS Managed Languages team we are hard at work on creating the next version of the language (with the unsurprising working title of C# 4.0), and this document is a first public description of the planned language features as we currently see them. Please be advised that all this is in early stages of production and is subject to change. Part of the reason for sharing our plans in public so early is precisely to get the kind of feedback that will cause us to improve the final product before it rolls out. Simultaneously with the publication of this whitepaper, a first public CTP (community technology preview) of Visual Studio 2010 is going out as a Virtual PC image for everyone to try. Please use it to play and experiment with the features, and let us know of any thoughts you have. We ask for your understanding and patience working with very early bits, where especially new or newly implemented features do not have the quality or stability of a final product. The aim of the CTP is not to give you a productive work environment but to give you the best possible impression of what we are working on for the next release. The CTP contains a number of walkthroughs, some of which highlight the new language features of C# 4.0. Those are excellent for getting a hands-on guided tour through the details of some common scenarios for the features. You may consider this whitepaper a companion document to these walkthroughs, complementing them with a focus on the overall language features and how they work, as opposed to the specifics of the concrete scenarios. C# 4.0 The major theme for C# 4.0 is dynamic programming. Increasingly, objects are “dynamic” in the sense that their structure and behavior is not captured by a static type, or at least not one that the compiler knows about when compiling your program. Some examples include a. objects from dynamic programming languages, such as Python or Ruby b. COM objects accessed through IDispatch c. ordinary .NET types accessed through reflection d. objects with changing structure, such as HTML DOM objects While C# remains a statically typed language, we aim to vastly improve the interaction with such objects. A secondary theme is co-evolution with Visual Basic. Going forward we will aim to maintain the individual character of each language, but at the same time important new features should be introduced in both languages at the same time. They should be differentiated more by style and feel than by feature set. The new features in C# 4.0 fall into four groups: Dynamic lookup Dynamic lookup allows you to write method, operator and indexer calls, property and field accesses, and even object invocations which bypass the C# static type checking and instead gets resolved at runtime. Named and optional parameters Parameters in C# can now be specified as optional by providing a default value for them in a member declaration. When the member is invoked, optional arguments can be omitted. Furthermore, any argument can be passed by parameter name instead of position. COM specific interop features Dynamic lookup as well as named and optional parameters both help making programming against COM less painful than today. On top of that, however, we are adding a number of other small features that further improve the interop experience. Variance It used to be that an IEnumerable<string> wasn’t an IEnumerable<object>. Now it is – C# embraces type safe “co-and contravariance” and common BCL types are updated to take advantage of that. Dynamic Lookup Dynamic lookup allows you a unified approach to invoking things dynamically. With dynamic lookup, when you have an object in your hand you do not need to worry about whether it comes from COM, IronPython, the HTML DOM or reflection; you just apply operations to it and leave it to the runtime to figure out what exactly those operations mean for that particular object. This affords you enormous flexibility, and can greatly simplify your code, but it does come with a significant drawback: Static typing is not maintained for these operations. A dynamic object is assumed at compile time to support any operation, and only at runtime will you get an error if it wasn’t so. Oftentimes this will be no loss, because the object wouldn’t have a static type anyway, in other cases it is a tradeoff between brevity and safety. In order to facilitate this tradeoff, it is a design goal of C# to allow you to opt in or opt out of dynamic behavior on every single call. The dynamic type C# 4.0 introduces a new static type called dynamic. When you have an object of type dynamic you can “do things to it” that are resolved only at runtime: dynamic d = GetDynamicObject(…); d.M(7); The C# compiler allows you to call a method with any name and any arguments on d because it is of type dynamic. At runtime the actual object that d refers to will be examined to determine what it means to “call M with an int” on it. The type dynamic can be thought of as a special version of the type object, which signals that the object can be used dynamically. It is easy to opt in or out of dynamic behavior: any object can be implicitly converted to dynamic, “suspending belief” until runtime. Conversely, there is an “assignment conversion” from dynamic to any other type, which allows implicit conversion in assignment-like constructs: dynamic d = 7; // implicit conversion int i = d; // assignment conversion Dynamic operations Not only method calls, but also field and property accesses, indexer and operator calls and even delegate invocations can be dispatched dynamically: dynamic d = GetDynamicObject(…); d.M(7); // calling methods d.f = d.P; // getting and settings fields and properties d[“one”] = d[“two”]; // getting and setting thorugh indexers int i = d + 3; // calling operators string s = d(5,7); // invoking as a delegate The role of the C# compiler here is simply to package up the necessary information about “what is being done to d”, so that the runtime can pick it up and determine what the exact meaning of it is given an actual object d. Think of it as deferring part of the compiler’s job to runtime. The result of any dynamic operation is itself of type dynamic. Runtime lookup At runtime a dynamic operation is dispatched according to the nature of its target object d: COM objects If d is a COM object, the operation is dispatched dynamically through COM IDispatch. This allows calling to COM types that don’t have a Primary Interop Assembly (PIA), and relying on COM features that don’t have a counterpart in C#, such as indexed properties and default properties. Dynamic objects If d implements the interface IDynamicObject d itself is asked to perform the operation. Thus by implementing IDynamicObject a type can completely redefine the meaning of dynamic operations. This is used intensively by dynamic languages such as IronPython and IronRuby to implement their own dynamic object models. It will also be used by APIs, e.g. by the HTML DOM to allow direct access to the object’s properties using property syntax. Plain objects Otherwise d is a standard .NET object, and the operation will be dispatched using reflection on its type and a C# “runtime binder” which implements C#’s lookup and overload resolution semantics at runtime. This is essentially a part of the C# compiler running as a runtime component to “finish the work” on dynamic operations that was deferred by the static compiler. Example Assume the following code: dynamic d1 = new Foo(); dynamic d2 = new Bar(); string s; d1.M(s, d2, 3, null); Because the receiver of the call to M is dynamic, the C# compiler does not try to resolve the meaning of the call. Instead it stashes away information for the runtime about the call. This information (often referred to as the “payload”) is essentially equivalent to: “Perform an instance method call of M with the following arguments: 1. a string 2. a dynamic 3. a literal int 3 4. a literal object null” At runtime, assume that the actual type Foo of d1 is not a COM type and does not implement IDynamicObject. In this case the C# runtime binder picks up to finish the overload resolution job based on runtime type information, proceeding as follows: 1. Reflection is used to obtain the actual runtime types of the two objects, d1 and d2, that did not have a static type (or rather had the static type dynamic). The result is Foo for d1 and Bar for d2. 2. Method lookup and overload resolution is performed on the type Foo with the call M(string,Bar,3,null) using ordinary C# semantics. 3. If the method is found it is invoked; otherwise a runtime exception is thrown. Overload resolution with dynamic arguments Even if the receiver of a method call is of a static type, overload resolution can still happen at runtime. This can happen if one or more of the arguments have the type dynamic: Foo foo = new Foo(); dynamic d = new Bar(); var result = foo.M(d); The C# runtime binder will choose between the statically known overloads of M on Foo, based on the runtime type of d, namely Bar. The result is again of type dynamic. The Dynamic Language Runtime An important component in the underlying implementation of dynamic lookup is the Dynamic Language Runtime (DLR), which is a new API in .NET 4.0. The DLR provides most of the infrastructure behind not only C# dynamic lookup but also the implementation of several dynamic programming languages on .NET, such as IronPython and IronRuby. Through this common infrastructure a high degree of interoperability is ensured, but just as importantly the DLR provides excellent caching mechanisms which serve to greatly enhance the efficiency of runtime dispatch. To the user of dynamic lookup in C#, the DLR is invisible except for the improved efficiency. However, if you want to implement your own dynamically dispatched objects, the IDynamicObject interface allows you to interoperate with the DLR and plug in your own behavior. This is a rather advanced task, which requires you to understand a good deal more about the inner workings of the DLR. For API writers, however, it can definitely be worth the trouble in order to vastly improve the usability of e.g. a library representing an inherently dynamic domain. Open issues There are a few limitations and things that might work differently than you would expect. · The DLR allows objects to be created from objects that represent classes. However, the current implementation of C# doesn’t have syntax to support this. · Dynamic lookup will not be able to find extension methods. Whether extension methods apply or not depends on the static context of the call (i.e. which using clauses occur), and this context information is not currently kept as part of the payload. · Anonymous functions (i.e. lambda expressions) cannot appear as arguments to a dynamic method call. The compiler cannot bind (i.e. “understand”) an anonymous function without knowing what type it is converted to. One consequence of these limitations is that you cannot easily use LINQ queries over dynamic objects: dynamic collection = …; var result = collection.Select(e => e + 5); If the Select method is an extension method, dynamic lookup will not find it. Even if it is an instance method, the above does not compile, because a lambda expression cannot be passed as an argument to a dynamic operation. There are no plans to address these limitations in C# 4.0. Named and Optional Arguments Named and optional parameters are really two distinct features, but are often useful together. Optional parameters allow you to omit arguments to member invocations, whereas named arguments is a way to provide an argument using the name of the corresponding parameter instead of relying on its position in the parameter list. Some APIs, most notably COM interfaces such as the Office automation APIs, are written specifically with named and optional parameters in mind. Up until now it has been very painful to call into these APIs from C#, with sometimes as many as thirty arguments having to be explicitly passed, most of which have reasonable default values and could be omitted. Even in APIs for .NET however you sometimes find yourself compelled to write many overloads of a method with different combinations of parameters, in order to provide maximum usability to the callers. Optional parameters are a useful alternative for these situations. Optional parameters A parameter is declared optional simply by providing a default value for it: public void M(int x, int y = 5, int z = 7); Here y and z are optional parameters and can be omitted in calls: M(1, 2, 3); // ordinary call of M M(1, 2); // omitting z – equivalent to M(1, 2, 7) M(1); // omitting both y and z – equivalent to M(1, 5, 7) Named and optional arguments C# 4.0 does not permit you to omit arguments between commas as in M(1,,3). This could lead to highly unreadable comma-counting code. Instead any argument can be passed by name. Thus if you want to omit only y from a call of M you can write: M(1, z: 3); // passing z by name or M(x: 1, z: 3); // passing both x and z by name or even M(z: 3, x: 1); // reversing the order of arguments All forms are equivalent, except that arguments are always evaluated in the order they appear, so in the last example the 3 is evaluated before the 1. Optional and named arguments can be used not only with methods but also with indexers and constructors. Overload resolution Named and optional arguments affect overload resolution, but the changes are relatively simple: A signature is applicable if all its parameters are either optional or have exactly one corresponding argument (by name or position) in the call which is convertible to the parameter type. Betterness rules on conversions are only applied for arguments that are explicitly given – omitted optional arguments are ignored for betterness purposes. If two signatures are equally good, one that does not omit optional parameters is preferred. M(string s, int i = 1); M(object o); M(int i, string s = “Hello”); M(int i); M(5); Given these overloads, we can see the working of the rules above. M(string,int) is not applicable because 5 doesn’t convert to string. M(int,string) is applicable because its second parameter is optional, and so, obviously are M(object) and M(int). M(int,string) and M(int) are both better than M(object) because the conversion from 5 to int is better than the conversion from 5 to object. Finally M(int) is better than M(int,string) because no optional arguments are omitted. Thus the method that gets called is M(int). Features for COM interop Dynamic lookup as well as named and optional parameters greatly improve the experience of interoperating with COM APIs such as the Office Automation APIs. In order to remove even more of the speed bumps, a couple of small COM-specific features are also added to C# 4.0. Dynamic import Many COM methods accept and return variant types, which are represented in the PIAs as object. In the vast majority of cases, a programmer calling these methods already knows the static type of a returned object from context, but explicitly has to perform a cast on the returned value to make use of that knowledge. These casts are so common that they constitute a major nuisance. In order to facilitate a smoother experience, you can now choose to import these COM APIs in such a way that variants are instead represented using the type dynamic. In other words, from your point of view, COM signatures now have occurrences of dynamic instead of object in them. This means that you can easily access members directly off a returned object, or you can assign it to a strongly typed local variable without having to cast. To illustrate, you can now say excel.Cells[1, 1].Value = "Hello"; instead of ((Excel.Range)excel.Cells[1, 1]).Value2 = "Hello"; and Excel.Range range = excel.Cells[1, 1]; instead of Excel.Range range = (Excel.Range)excel.Cells[1, 1]; Compiling without PIAs Primary Interop Assemblies are large .NET assemblies generated from COM interfaces to facilitate strongly typed interoperability. They provide great support at design time, where your experience of the interop is as good as if the types where really defined in .NET. However, at runtime these large assemblies can easily bloat your program, and also cause versioning issues because they are distributed independently of your application. The no-PIA feature allows you to continue to use PIAs at design time without having them around at runtime. Instead, the C# compiler will bake the small part of the PIA that a program actually uses directly into its assembly. At runtime the PIA does not have to be loaded. Omitting ref Because of a different programming model, many COM APIs contain a lot of reference parameters. Contrary to refs in C#, these are typically not meant to mutate a passed-in argument for the subsequent benefit of the caller, but are simply another way of passing value parameters. It therefore seems unreasonable that a C# programmer should have to create temporary variables for all such ref parameters and pass these by reference. Instead, specifically for COM methods, the C# compiler will allow you to pass arguments by value to such a method, and will automatically generate temporary variables to hold the passed-in values, subsequently discarding these when the call returns. In this way the caller sees value semantics, and will not experience any side effects, but the called method still gets a reference. Open issues A few COM interface features still are not surfaced in C#. Most notably these include indexed properties and default properties. As mentioned above these will be respected if you access COM dynamically, but statically typed C# code will still not recognize them. There are currently no plans to address these remaining speed bumps in C# 4.0. Variance An aspect of generics that often comes across as surprising is that the following is illegal: IList<string> strings = new List<string>(); IList<object> objects = strings; The second assignment is disallowed because strings does not have the same element type as objects. There is a perfectly good reason for this. If it were allowed you could write: objects[0] = 5; string s = strings[0]; Allowing an int to be inserted into a list of strings and subsequently extracted as a string. This would be a breach of type safety. However, there are certain interfaces where the above cannot occur, notably where there is no way to insert an object into the collection. Such an interface is IEnumerable<T>. If instead you say: IEnumerable<object> objects = strings; There is no way we can put the wrong kind of thing into strings through objects, because objects doesn’t have a method that takes an element in. Variance is about allowing assignments such as this in cases where it is safe. The result is that a lot of situations that were previously surprising now just work. Covariance In .NET 4.0 the IEnumerable<T> interface will be declared in the following way: public interface IEnumerable<out T> : IEnumerable { IEnumerator<T> GetEnumerator(); } public interface IEnumerator<out T> : IEnumerator { bool MoveNext(); T Current { get; } } The “out” in these declarations signifies that the T can only occur in output position in the interface – the compiler will complain otherwise. In return for this restriction, the interface becomes “covariant” in T, which means that an IEnumerable<A> is considered an IEnumerable<B> if A has a reference conversion to B. As a result, any sequence of strings is also e.g. a sequence of objects. This is useful e.g. in many LINQ methods. Using the declarations above: var result = strings.Union(objects); // succeeds with an IEnumerable<object> This would previously have been disallowed, and you would have had to to some cumbersome wrapping to get the two sequences to have the same element type. Contravariance Type parameters can also have an “in” modifier, restricting them to occur only in input positions. An example is IComparer<T>: public interface IComparer<in T> { public int Compare(T left, T right); } The somewhat baffling result is that an IComparer<object> can in fact be considered an IComparer<string>! It makes sense when you think about it: If a comparer can compare any two objects, it can certainly also compare two strings. This property is referred to as contravariance. A generic type can have both in and out modifiers on its type parameters, as is the case with the Func<…> delegate types: public delegate TResult Func<in TArg, out TResult>(TArg arg); Obviously the argument only ever comes in, and the result only ever comes out. Therefore a Func<object,string> can in fact be used as a Func<string,object>. Limitations Variant type parameters can only be declared on interfaces and delegate types, due to a restriction in the CLR. Variance only applies when there is a reference conversion between the type arguments. For instance, an IEnumerable<int> is not an IEnumerable<object> because the conversion from int to object is a boxing conversion, not a reference conversion. Also please note that the CTP does not contain the new versions of the .NET types mentioned above. In order to experiment with variance you have to declare your own variant interfaces and delegate types. COM Example Here is a larger Office automation example that shows many of the new C# features in action. using System; using System.Diagnostics; using System.Linq; using Excel = Microsoft.Office.Interop.Excel; using Word = Microsoft.Office.Interop.Word; class Program { static void Main(string[] args) { var excel = new Excel.Application(); excel.Visible = true; excel.Workbooks.Add(); // optional arguments omitted excel.Cells[1, 1].Value = "Process Name"; // no casts; Value dynamically excel.Cells[1, 2].Value = "Memory Usage"; // accessed var processes = Process.GetProcesses() .OrderByDescending(p =&gt; p.WorkingSet) .Take(10); int i = 2; foreach (var p in processes) { excel.Cells[i, 1].Value = p.ProcessName; // no casts excel.Cells[i, 2].Value = p.WorkingSet; // no casts i++; } Excel.Range range = excel.Cells[1, 1]; // no casts Excel.Chart chart = excel.ActiveWorkbook.Charts. Add(After: excel.ActiveSheet); // named and optional arguments chart.ChartWizard( Source: range.CurrentRegion, Title: "Memory Usage in " + Environment.MachineName); //named+optional chart.ChartStyle = 45; chart.CopyPicture(Excel.XlPictureAppearance.xlScreen, Excel.XlCopyPictureFormat.xlBitmap, Excel.XlPictureAppearance.xlScreen); var word = new Word.Application(); word.Visible = true; word.Documents.Add(); // optional arguments word.Selection.Paste(); } } The code is much more terse and readable than the C# 3.0 counterpart. Note especially how the Value property is accessed dynamically. This is actually an indexed property, i.e. a property that takes an argument; something which C# does not understand. However the argument is optional. Since the access is dynamic, it goes through the runtime COM binder which knows to substitute the default value and call the indexed property. Thus, dynamic COM allows you to avoid accesses to the puzzling Value2 property of Excel ranges. Relationship with Visual Basic A number of the features introduced to C# 4.0 already exist or will be introduced in some form or other in Visual Basic: · Late binding in VB is similar in many ways to dynamic lookup in C#, and can be expected to make more use of the DLR in the future, leading to further parity with C#. · Named and optional arguments have been part of Visual Basic for a long time, and the C# version of the feature is explicitly engineered with maximal VB interoperability in mind. · NoPIA and variance are both being introduced to VB and C# at the same time. VB in turn is adding a number of features that have hitherto been a mainstay of C#. As a result future versions of C# and VB will have much better feature parity, for the benefit of everyone. Resources All available resources concerning C# 4.0 can be accessed through the C# Dev Center. Specifically, this white paper and other resources can be found at the Code Gallery site. Enjoy! span.fullpost {display:none;}

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  • Design by Contract with Microsoft .Net Code Contract

    - by Fredrik N
    I have done some talks on different events and summits about Defensive Programming and Design by Contract, last time was at Cornerstone’s Developer Summit 2010. Next time will be at SweNug (Sweden .Net User Group). I decided to write a blog post about of some stuffs I was talking about. Users are a terrible thing! Protect your self from them ”Human users have a gift for doing the worst possible thing at the worst possible time.” – Michael T. Nygard, Release It! The kind of users Michael T. Nygard are talking about is the users of a system. We also have users that uses our code, the users I’m going to focus on is the users of our code. Me and you and another developers. “Any fool can write code that a computer can understand. Good programmers write code that humans can understand.” – Martin Fowler Good programmers also writes code that humans know how to use, good programmers also make sure software behave in a predictable manner despise inputs or user actions. Design by Contract   Design by Contract (DbC) is a way for us to make a contract between us (the code writer) and the users of our code. It’s about “If you give me this, I promise to give you this”. It’s not about business validations, that is something completely different that should be part of the domain model. DbC is to make sure the users of our code uses it in a correct way, and that we can rely on the contract and write code in a way where we know that the users will follow the contract. It will make it much easier for us to write code with a contract specified. Something like the following code is something we may see often: public void DoSomething(Object value) { value.DoIKnowThatICanDoThis(); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Where “value” can be uses directly or passed to other methods and later be used. What some of us can easily forget here is that the “value” can be “null”. We will probably not passing a null value, but someone else that uses our code maybe will do it. I think most of you (including me) have passed “null” into a method because you don’t know if the argument need to be specified to a valid value etc. I bet most of you also have got the “Null reference exception”. Sometimes this “Null reference exception” can be hard and take time to fix, because we need to search among our code to see where the “null” value was passed in etc. Wouldn’t it be much better if we can as early as possible specify that the value can’t not be null, so the users of our code also know it when the users starts to use our code, and before run time execution of the code? This is where DbC comes into the picture. We can use DbC to specify what we need, and by doing so we can rely on the contract when we write our code. So the code above can actually use the DoIKnowThatICanDoThis() method on the value object without being worried that the “value” can be null. The contract between the users of the code and us writing the code, says that the “value” can’t be null.   Pre- and Postconditions   When working with DbC we are specifying pre- and postconditions.  Precondition is a condition that should be met before a query or command is executed. An example of a precondition is: “The Value argument of the method can’t be null”, and we make sure the “value” isn’t null before the method is called. Postcondition is a condition that should be met when a command or query is completed, a postcondition will make sure the result is correct. An example of a postconditon is “The method will return a list with at least 1 item”. Commands an Quires When using DbC, we need to know what a Command and a Query is, because some principles that can be good to follow are based on commands and queries. A Command is something that will not return anything, like the SQL’s CREATE, UPDATE and DELETE. There are two kinds of Commands when using DbC, the Creation commands (for example a Constructor), and Others. Others can for example be a Command to add a value to a list, remove or update a value etc. //Creation commands public Stack(int size) //Other commands public void Push(object value); public void Remove(); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   A Query, is something that will return something, for example an Attribute, Property or a Function, like the SQL’s SELECT.   There are two kinds of Queries, the Basic Queries  (Quires that aren’t based on another queries), and the Derived Queries, queries that is based on another queries. Here is an example of queries of a Stack: //Basic Queries public int Count; public object this[int index] { get; } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To understand about some principles that are good to follow when using DbC, we need to know about the Commands and different Queries. The 6 Principles When working with DbC, it’s advisable to follow some principles to make it easier to define and use contracts. The following DbC principles are: Separate commands and queries. Separate basic queries from derived queries. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries. For each command, write a postcondition that specifies the value of every basic query. For every query and command, decide on a suitable precondition. Write invariants to define unchanging properties of objects. Before I will write about each of them I want you to now that I’m going to use .Net 4.0 Code Contract. I will in the rest of the post uses a simple Stack (Yes I know, .Net already have a Stack class) to give you the basic understanding about using DbC. A Stack is a data structure where the first item in, will be the first item out. Here is a basic implementation of a Stack where not contract is specified yet: public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } //Is related to Count and this[] Query public object Top() { return this[Count]; } //Creation commands public Stack(uint size) { Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { this[++Count] = value; } public void Remove() { this[Count] = null; Count--; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The Stack is implemented in a way to demonstrate the use of Code Contract in a simple way, the implementation may not look like how you would implement it, so don’t think this is the perfect Stack implementation, only used for demonstration.   Before I will go deeper into the principles I will simply mention how we can use the .Net Code Contract. I mention before about pre- and postcondition, is about “Require” something and to “Ensure” something. When using Code Contract, we will use a static class called “Contract” and is located in he “System.Diagnostics.Contracts” namespace. The contract must be specified at the top or our member statement block. To specify a precondition with Code Contract we uses the Contract.Requires method, and to specify a postcondition, we uses the Contract.Ensure method. Here is an example where both a pre- and postcondition are used: public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The contract above requires that the Count is greater than 0, if not we can’t get the item at the Top of a Stack. We also Ensures that the results (By using the Contract.Result method, we can specify a postcondition that will check if the value returned from a method is correct) of the Top query is equal to this[Count].   1. Separate Commands and Queries   When working with DbC, it’s important to separate Command and Quires. A method should either be a command that performs an Action, or returning information to the caller, not both. By asking a question the answer shouldn’t be changed. The following is an example of a Command and a Query of a Stack: public void Push(object value) public object Top() .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The Push is a command and will not return anything, just add a value to the Stack, the Top is a query to get the item at the top of the stack.   2. Separate basic queries from derived queries There are two different kinds of queries,  the basic queries that doesn’t rely on another queries, and derived queries that uses a basic query. The “Separate basic queries from derived queries” principle is about about that derived queries can be specified in terms of basic queries. So this principles is more about recognizing that a query is a derived query or a basic query. It will then make is much easier to follow the other principles. The following code shows a basic query and a derived query: //Basic Queries public uint Count; //Derived Queries //Is related to Count Query public bool IsEmpty() { return Count == 0; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   We can see that IsEmpty will use the Count query, and that makes the IsEmpty a Derived query.   3. For each derived query, write a postcondition that specifies what result will be returned, in terms of one or more basic queries.   When the derived query is recognize we can follow the 3ed principle. For each derived query, we can create a postcondition that specifies what result our derived query will return in terms of one or more basic queries. Remember that DbC is about contracts between the users of the code and us writing the code. So we can’t use demand that the users will pass in a valid value, we must also ensure that we will give the users what the users wants, when the user is following our contract. The IsEmpty query of the Stack will use a Count query and that will make the IsEmpty a Derived query, so we should now write a postcondition that specified what results will be returned, in terms of using a basic query and in this case the Count query, //Basic Queries public uint Count; //Derived Queries public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } The Contract.Ensures is used to create a postcondition. The above code will make sure that the results of the IsEmpty (by using the Contract.Result to get the result of the IsEmpty method) is correct, that will say that the IsEmpty will be either true or false based on Count is equal to 0 or not. The postcondition are using a basic query, so the IsEmpty is now following the 3ed principle. We also have another Derived Query, the Top query, it will also need a postcondition and it uses all basic queries. The Result of the Top method must be the same value as the this[] query returns. //Basic Queries public uint Count; public object this[uint index] { get { return _array[index]; } set { _array[index] = value; } } //Derived Queries //Is related to Count and this[] Query public object Top() { Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   4. For each command, write a postcondition that specifies the value of every basic query.   For each command we will create a postconditon that specifies the value of basic queries. If we look at the Stack implementation we will have three Commands, one Creation command, the Constructor, and two others commands, Push and Remove. Those commands need a postcondition and they should include basic query to follow the 4th principle. //Creation commands public Stack(uint size) { Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   As you can see the Create command will Ensures that Count will be 0 when the Stack is created, when a Stack is created there shouldn’t be any items in the stack. The Push command will take a value and put it into the Stack, when an item is pushed into the Stack, the Count need to be increased to know the number of items added to the Stack, and we must also make sure the item is really added to the Stack. The postconditon of the Push method will make sure the that old value of the Count (by using the Contract.OldValue we can get the value a Query has before the method is called)  plus 1 will be equal to the Count query, this is the way we can ensure that the Push will increase the Count with one. We also make sure the this[] query will now contain the item we pushed into the Stack. The Remove method must make sure the Count is decreased by one when the top item is removed from the Stack. The Commands is now following the 4th principle, where each command now have a postcondition that used the value of basic queries. Note: The principle says every basic Query, the Remove only used one Query the Count, it’s because this command can’t use the this[] query because an item is removed, so the only way to make sure an item is removed is to just use the Count query, so the Remove will still follow the principle.   5. For every query and command, decide on a suitable precondition.   We have now focused only on postcondition, now time for some preconditons. The 5th principle is about deciding a suitable preconditon for every query and command. If we starts to look at one of our basic queries (will not go through all Queries and commands here, just some of them) the this[] query, we can’t pass an index that is lower then 1 (.Net arrays and list are zero based, but not the stack in this blog post ;)) and the index can’t be lesser than the number of items in the stack. So here we will need a preconditon. public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Think about the Contract as an documentation about how to use the code in a correct way, so if the contract could be specified elsewhere (not part of the method body), we could simply write “return _array[index]” and there is no need to check if index is greater or lesser than Count, because that is specified in a “contract”. The implementation of Code Contract, requires that the contract is specified in the code. As a developer I would rather have this contract elsewhere (Like Spec#) or implemented in a way Eiffel uses it as part of the language. Now when we have looked at one Query, we can also look at one command, the Remove command (You can see the whole implementation of the Stack at the end of this blog post, where precondition is added to more queries and commands then what I’m going to show in this section). We can only Remove an item if the Count is greater than 0. So we can write a precondition that will require that Count must be greater than 0. public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   6. Write invariants to define unchanging properties of objects.   The last principle is about making sure the object are feeling great! This is done by using invariants. When using Code Contract we can specify invariants by adding a method with the attribute ContractInvariantMethod, the method must be private or public and can only contains calls to Contract.Invariant. To make sure the Stack feels great, the Stack must have 0 or more items, the Count can’t never be a negative value to make sure each command and queries can be used of the Stack. Here is our invariant for the Stack object: [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: The ObjectInvariant method will be called every time after a Query or Commands is called. Here is the full example using Code Contract:   public class Stack { private object[] _array; //Basic Queries public uint Count; public object this[uint index] { get { Contract.Requires(index >= 1); Contract.Requires(index <= Count); return _array[index]; } set { Contract.Requires(index >= 1); Contract.Requires(index <= Count); _array[index] = value; } } //Derived Queries //Is related to Count Query public bool IsEmpty() { Contract.Ensures(Contract.Result<bool>() == (Count == 0)); return Count == 0; } //Is related to Count and this[] Query public object Top() { Contract.Requires(Count > 0, "Stack is empty"); Contract.Ensures(Contract.Result<object>() == this[Count]); return this[Count]; } //Creation commands public Stack(uint size) { Contract.Requires(size > 0); Contract.Ensures(Count == 0); Count = 0; _array = new object[size]; } //Other commands public void Push(object value) { Contract.Requires(value != null); Contract.Ensures(Count == Contract.OldValue<uint>(Count) + 1); Contract.Ensures(this[Count] == value); this[++Count] = value; } public void Remove() { Contract.Requires(Count > 0); Contract.Ensures(Count == Contract.OldValue<uint>(Count) - 1); this[Count] = null; Count--; } [ContractInvariantMethod] private void ObjectInvariant() { Contract.Invariant(Count >= 0); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Summary By using Design By Contract we can make sure the users are using our code in a correct way, and we must also make sure the users will get the expected results when they uses our code. This can be done by specifying contracts. To make it easy to use Design By Contract, some principles may be good to follow like the separation of commands an queries. With .Net 4.0 we can use the Code Contract feature to specify contracts.

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  • AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

    - by Varun Chatterji
    Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an anti­pattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/starter­template/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ng­app=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ng­view attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/Extending­HTML­with­AngularJS­Directives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ng­click=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/Understanding­Scopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial: <!--­­ If model.errorMessage is defined, then render the error div -­­> <div class="alert alert-­danger alert-­dismissable" style="margin­-top: 30px;" ng­-show="model.errorMessage != undefined"> <button type="button" class="close" data­dismiss="alert" aria­hidden="true">&times;</button> <strong>Error!</strong> <br /> {{ model.errorMessage }} </div> <!--­­ The input fields bound to the model --­­> <div class="well" style="margin-­top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng­-model="model.phoneNumber" class="form-­control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-­align: center;"> <input type="text" placeholder="Message" ng­-model="model.message" class="form-­control" style="width: 90%" /> </td> <td style="text-­align: center;"> <button class="btn btn-­danger" ng-­click="sendMessage();" ng-­disabled="model.isAjaxInProgress" style="margin­right: 5px;">Send</button> <img src="/Content/ajax-­loader.gif" ng­-show="model.isAjaxInProgress" /> </td> </tr> </table> </div> <!--­­ The past messages ­­--> <div style="margin-­top: 30px;"> <!­­-- The following div is shown if there are no past messages --­­> <div ng­-show="model.allMessages.length == 0"> No messages have been sent yet! </div> <!--­­ The following div is shown if there are some past messages --­­> <div ng-­show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-­striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr> <!--­­ The ng-­repeat directive is line the repeater control in .NET, but as you can see this partial is pure HTML which is much cleaner --> <tr ng-­repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-­danger" ng-­click="delete(message.smsId);" ng­-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-­show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ng­click=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-­disabled directive which is added as an attribute to the buttons. The ng-­repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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  • 10 Essential Tools for building ASP.NET Websites

    - by Stephen Walther
    I recently put together a simple public website created with ASP.NET for my company at Superexpert.com. I was surprised by the number of free tools that I ended up using to put together the website. Therefore, I thought it would be interesting to create a list of essential tools for building ASP.NET websites. These tools work equally well with both ASP.NET Web Forms and ASP.NET MVC. Performance Tools After reading Steve Souders two (very excellent) books on front-end website performance High Performance Web Sites and Even Faster Web Sites, I have been super sensitive to front-end website performance. According to Souders’ Performance Golden Rule: “Optimize front-end performance first, that's where 80% or more of the end-user response time is spent” You can use the tools below to reduce the size of the images, JavaScript files, and CSS files used by an ASP.NET application. 1. Sprite and Image Optimization Framework CSS sprites were first described in an article written for A List Apart entitled CSS sprites: Image Slicing’s Kiss of Death. When you use sprites, you combine multiple images used by a website into a single image. Next, you use CSS trickery to display particular sub-images from the combined image in a webpage. The primary advantage of sprites is that they reduce the number of requests required to display a webpage. Requesting a single large image is faster than requesting multiple small images. In general, the more resources – images, JavaScript files, CSS files – that must be moved across the wire, the slower your website. However, most people avoid using sprites because they require a lot of work. You need to combine all of the images and write just the right CSS rules to display the sub-images. The Microsoft Sprite and Image Optimization Framework enables you to avoid all of this work. The framework combines the images for you automatically. Furthermore, the framework includes an ASP.NET Web Forms control and an ASP.NET MVC helper that makes it easy to display the sub-images. You can download the Sprite and Image Optimization Framework from CodePlex at http://aspnet.codeplex.com/releases/view/50869. The Sprite and Image Optimization Framework was written by Morgan McClean who worked in the office next to mine at Microsoft. Morgan was a scary smart Intern from Canada and we discussed the Framework while he was building it (I was really excited to learn that he was working on it). Morgan added some great advanced features to this framework. For example, the Sprite and Image Optimization Framework supports something called image inlining. When you use image inlining, the actual image is stored in the CSS file. Here’s an example of what image inlining looks like: .Home_StephenWalther_small-jpg { width:75px; height:100px; background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEsAAABkCAIAAABB1lpeAAAAB GdBTUEAALGOfPtRkwAAACBjSFJNAACHDwAAjA8AAP1SAACBQAAAfXkAAOmLAAA85QAAGcxzPIV3AAAKL s+zNfREAAAAASUVORK5CYII=) no-repeat 0% 0%; } The actual image (in this case a picture of me that is displayed on the home page of the Superexpert.com website) is stored in the CSS file. If you visit the Superexpert.com website then very few separate images are downloaded. For example, all of the images with a red border in the screenshot below take advantage of CSS sprites: Unfortunately, there are some significant Gotchas that you need to be aware of when using the Sprite and Image Optimization Framework. There are workarounds for these Gotchas. I plan to write about these Gotchas and workarounds in a future blog entry. 2. Microsoft Ajax Minifier Whenever possible you should combine, minify, compress, and cache with a far future header all of your JavaScript and CSS files. The Microsoft Ajax Minifier makes it easy to minify JavaScript and CSS files. Don’t confuse minification and compression. You need to do both. According to Souders, you can reduce the size of a JavaScript file by an additional 20% (on average) by minifying a JavaScript file after you compress the file. When you minify a JavaScript or CSS file, you use various tricks to reduce the size of the file before you compress the file. For example, you can minify a JavaScript file by replacing long JavaScript variables names with short variables names and removing unnecessary white space and comments. You can minify a CSS file by doing such things as replacing long color names such as #ffffff with shorter equivalents such as #fff. The Microsoft Ajax Minifier was created by Microsoft employee Ron Logan. Internally, this tool was being used by several large Microsoft websites. We also used the tool heavily on the ASP.NET team. I convinced Ron to publish the tool on CodePlex so that everyone in the world could take advantage of it. You can download the tool from the ASP.NET Ajax website and read documentation for the tool here. I created the installer for the Microsoft Ajax Minifier. When creating the installer, I also created a Visual Studio build task to make it easy to minify all of your JavaScript and CSS files whenever you do a build within Visual Studio automatically. Read the Ajax Minifier Quick Start to learn how to configure the build task. 3. ySlow The ySlow tool is a free add-on for Firefox created by Yahoo that enables you to test the front-end of your website. For example, here are the current test results for the Superexpert.com website: The Superexpert.com website has an overall score of B (not perfect but not bad). The ySlow tool is not perfect. For example, the Superexpert.com website received a failing grade of F for not using a Content Delivery Network even though the website using the Microsoft Ajax Content Delivery Network for JavaScript files such as jQuery. Uptime After publishing a website live to the world, you want to ensure that the website does not encounter any issues and that it stays live. I use the following tools to monitor the Superexpert.com website now that it is live. 4. ELMAH ELMAH stands for Error Logging Modules and Handlers for ASP.NET. ELMAH enables you to record any errors that happen at your website so you can review them in the future. You can download ELMAH for free from the ELMAH project website. ELMAH works great with both ASP.NET Web Forms and ASP.NET MVC. You can configure ELMAH to store errors in a number of different stores including XML files, the Event Log, an Access database, a SQL database, an Oracle database, or in computer RAM. You also can configure ELMAH to email error messages to you when they happen. By default, you can access ELMAH by requesting the elmah.axd page from a website with ELMAH installed. Here’s what the elmah page looks like from the Superexpert.com website (this page is password-protected because secret information can be revealed in an error message): If you click on a particular error message, you can view the original Yellow Screen ASP.NET error message (even when the error message was never displayed to the actual user). I installed ELMAH by taking advantage of the new package manager for ASP.NET named NuGet (originally named NuPack). You can read the details about NuGet in the following blog entry by Scott Guthrie. You can download NuGet from CodePlex. 5. Pingdom I use Pingdom to verify that the Superexpert.com website is always up. You can sign up for Pingdom by visiting Pingdom.com. You can use Pingdom to monitor a single website for free. At the Pingdom website, you configure the frequency that your website gets pinged. I verify that the Superexpert.com website is up every 5 minutes. I have the Pingdom service verify that it can retrieve the string “Contact Us” from the website homepage. If your website goes down, you can configure Pingdom so that it sends an email, Twitter, SMS, or iPhone alert. I use the Pingdom iPhone app which looks like this: 6. Host Tracker If your website does go down then you need some way of determining whether it is a problem with your local network or if your website is down for everyone. I use a website named Host-Tracker.com to check how badly a website is down. Here’s what the Host-Tracker website displays for the Superexpert.com website when the website can be successfully pinged from everywhere in the world: Notice that Host-Tracker pinged the Superexpert.com website from 68 locations including Roubaix, France and Scranton, PA. Debugging I mean debugging in the broadest possible sense. I use the following tools when building a website to verify that I have not made a mistake. 7. HTML Spell Checker Why doesn’t Visual Studio have a built-in spell checker? Don’t know – I’ve always found this mysterious. Fortunately, however, a former member of the ASP.NET team wrote a free spell checker that you can use with your ASP.NET pages. I find a spell checker indispensible. It is easy to delude yourself that you are capable of perfect spelling. I’m always super embarrassed when I actually run the spell checking tool and discover all of my spelling mistakes. The fastest way to add the HTML Spell Checker extension to Visual Studio is to select the menu option Tools, Extension Manager within Visual Studio. Click on Online Gallery and search for HTML Spell Checker: 8. IIS SEO Toolkit If people cannot find your website through Google then you should not even bother to create it. Microsoft has a great extension for IIS named the IIS Search Engine Optimization Toolkit that you can use to identify issue with your website that would hurt its page rank. You also can use this tool to quickly create a sitemap for your website that you can submit to Google or Bing. You can even generate the sitemap for an ASP.NET MVC website. Here’s what the report overview for the Superexpert.com website looks like: Notice that the Sueprexpert.com website had plenty of violations. For example, there are 65 cases in which a page has a broken hyperlink. You can drill into these violations to identity the exact page and location where these violations occur. 9. LinqPad If your ASP.NET website accesses a database then you should be using LINQ to Entities with the Entity Framework. Using LINQ involves some magic. LINQ queries written in C# get converted into SQL queries for you. If you are not careful about how you write your LINQ queries, you could unintentionally build a really badly performing website. LinqPad is a free tool that enables you to experiment with your LINQ queries. It even works with Microsoft SQL CE 4 and Azure. You can use LinqPad to execute a LINQ to Entities query and see the results. You also can use it to see the resulting SQL that gets executed against the database: 10. .NET Reflector I use .NET Reflector daily. The .NET Reflector tool enables you to take any assembly and disassemble the assembly into C# or VB.NET code. You can use .NET Reflector to see the “Source Code” of an assembly even when you do not have the actual source code. You can download a free version of .NET Reflector from the Redgate website. I use .NET Reflector primarily to help me understand what code is doing internally. For example, I used .NET Reflector with the Sprite and Image Optimization Framework to better understand how the MVC Image helper works. Here’s part of the disassembled code from the Image helper class: Summary In this blog entry, I’ve discussed several of the tools that I used to create the Superexpert.com website. These are tools that I use to improve the performance, improve the SEO, verify the uptime, or debug the Superexpert.com website. All of the tools discussed in this blog entry are free. Furthermore, all of these tools work with both ASP.NET Web Forms and ASP.NET MVC. Let me know if there are any tools that you use daily when building ASP.NET websites.

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  • CodePlex Daily Summary for Wednesday, December 15, 2010

    CodePlex Daily Summary for Wednesday, December 15, 2010Popular ReleasesTweetSharp: TweetSharp v2.0.0.0 - Preview 5: Documentation for this release may be found at http://tweetsharp.codeplex.com/wikipage?title=UserGuide&referringTitle=Documentation. Note: This code is currently preview quality. Preview 5 ChangesMaintenance release with user reported fixes Preview 4 ChangesReintroduced fluent interface support via satellite assembly Added entities support, entity segmentation, and ITweetable/ITweeter interfaces for client development Numerous fixes reported by preview users Preview 3 ChangesNumerous ...SQL Monitor: SQL Monitor 2.8: 1. redesigned the object explorer, support multiple serversEnhSim: EnhSim 2.2.2 ALPHA: 2.2.2 ALPHAThis release adds in the changes for 4.03a at level 85 To use this release, you must have the Microsoft Visual C++ 2010 Redistributable Package installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=A7B7A05E-6DE6-4D3A-A423-37BF0912DB84 To use the GUI you must have the .NET 4.0 Framework installed. This can be downloaded from http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9cfb2d51-5ff4-4491-b0e5-b386f32c0992 - The spirit ...FlickrNet API Library: 3.1.4000: Newest release. Now contains dedicated Windows Phone 7 DLL as well as all previous DLLs. Also contains Windows Help file documentation now as standard.mojoPortal: 2.3.5.8: see release notes on mojoportal.com http://www.mojoportal.com/mojoportal-2358-released.aspx Note that we have separate deployment packages for .NET 3.5 and .NET 4.0 The deployment package downloads on this page are pre-compiled and ready for production deployment, they contain no C# source code. To download the source code see the Source Code Tab I recommend getting the latest source code using TortoiseHG, you can get the source code corresponding to this release here.Microsoft All-In-One Code Framework: Visual Studio 2010 Code Samples 2010-12-13: Code samples for Visual Studio 2010SuperSocket, an extensible socket application framework: SuperSocket 1.3 beta 1: SuperSocket 1.3 is built on .NET 4.0 framework. Bug fixes: fixed a potential bug that the running state hadn't been updated after socket server stopped fixed a synchronization issue when clearing timeout session fixed a bug in ArraySegmentList fixed a bug on getting configuration value Third-part library upgrades: upgraded SuperSocket to .NET 4.0 upgraded EntLib 4.1 to 5.0 New features: supported UDP socket support custom protocol (can support binary protocol and other complecate...Wii Backup Fusion: Wii Backup Fusion 0.9 Beta: - Aqua or brushed metal style for Mac OS X - Shows selection count beside ID - Game list selection mode via settings - Compare Files <-> WBFS game lists - Verify game images/DVD/WBFS - WIT command line for log (via settings) - Cancel possibility for loading games process - Progress infos while loading games - Localization for dates - UTF-8 support - Shortcuts added - View game infos in browser - Transfer infos for log - All transfer routines rewritten - Extract image from image/WBFS - Support....NETTER Code Starter Pack: v1.0.beta: '.NETTER Code Starter Pack ' contains a gallery of Visual Studio 2010 solutions leveraging latest and new technologies and frameworks based on Microsoft .NET Framework. Each Visual Studio solution included here is focused to provide a very simple starting point for cutting edge development technologies and framework, using well known Northwind database (for database driven scenarios). The current release of this project includes starter samples for the following technologies: ASP.NET Dynamic...WPF Multiple Document Interface (MDI): Beta Release v1.1: WPF.MDI is a library to imitate the traditional Windows Forms Multiple Document Interface (MDI) features in WPF. This is Beta release, means there's still work to do. Please provide feedback, so next release will be better. Features: Position dependency property MdiLayout dependency property Menu dependency property Ctrl + F4, Ctrl + Tab shortcuts should work Behavior: don’t allow negative values for MdiChild position minimized windows: remember position, tile multiple windows, ...SQL Server PowerShell Extensions: 2.3.1 Production: Release 2.3.1 implements SQLPSX as PowersShell version 2.0 modules. SQLPSX consists of 12 modules with 155 advanced functions, 2 cmdlets and 7 scripts for working with ADO.NET, SMO, Agent, RMO, SSIS, SQL script files, PBM, Performance Counters, SQLProfiler and using Powershell ISE as a SQL and Oracle query tool. In addition optional backend databases and SQL Server Reporting Services 2008 reports are provided with SQLServer and PBM modules. See readme file for details.NuGet (formerly NuPack): NuGet 1.0 Release Candidate: NuGet is a free, open source developer focused package management system for the .NET platform intent on simplifying the process of incorporating third party libraries into a .NET application during development. This release is a Visual Studio 2010 extension and contains the the Package Manager Console and the Add Package Dialog. This new build targets the newer feed (http://go.microsoft.com/fwlink/?LinkID=206669) and package format. See http://nupack.codeplex.com/documentation?title=Nuspe...Free Silverlight & WPF Chart Control - Visifire: Visifire Silverlight, WPF Charts v3.6.5 Released: Hi, Today we are releasing final version of Visifire, v3.6.5 with the following new feature: * New property AutoFitToPlotArea has been introduced in DataSeries. AutoFitToPlotArea will bring bubbles inside the PlotArea in order to avoid clipping of bubbles in bubble chart. You can visit Visifire documentation to know more. http://www.visifire.com/visifirechartsdocumentation.php Also this release includes few bug fixes: * Chart threw exception while adding new Axis in Chart using Vi...PHPExcel: PHPExcel 1.7.5 Production: DonationsDonate via PayPal via PayPal. If you want to, we can also add your name / company on our Donation Acknowledgements page. PEAR channelWe now also have a full PEAR channel! Here's how to use it: New installation: pear channel-discover pear.pearplex.net pear install pearplex/PHPExcel Or if you've already installed PHPExcel before: pear upgrade pearplex/PHPExcel The official page can be found at http://pearplex.net. Want to contribute?Please refer the Contribute page.SwapWin: SwapWin 0.2: Updates: Bring all windows that are swapped to foreground. Make the window sent to primary screen active.??????????: All-In-One Code Framework ??? 2010-12-10: ?????All-In-One Code Framework(??) 2010?12??????!!http://i3.codeplex.com/Project/Download/FileDownload.aspx?ProjectName=1code&DownloadId=128165 ?????release?,???????ASP.NET, WinForm, Silverlight????12?Sample Code。???,??????????sample code。 ?????:http://blog.csdn.net/sjb5201/archive/2010/12/13/6072675.aspx ??,??????MSDN????????????。 http://social.msdn.microsoft.com/Forums/zh-CN/codezhchs/threads ?????????????????,??Email ????DNN Simple Article: DNNSimpleArticle Module V00.00.03: The initial release of the DNNSimpleArticle module (labelled V00.00.03) There are C# and VB versions of this module for this initial release. No promises that going forward there will be packages for both languages provided for future releases. This module provides the following functionality Create and display articles Display a paged list of articles Articles get created as DNN ContentItems Categorization provided through DNN Taxonomy SEO functionality for article display providi...AutoLoL: AutoLoL v1.4.3: AutoLoL now supports importing the build pages from Mobafire.com as well! Just insert the url to the build and voila. (For example: http://www.mobafire.com/league-of-legends/build/unforgivens-guide-how-to-build-a-successful-mordekaiser-24061) Stable release of AutoChat (It is still recommended to use with caution and to read the documentation) It is now possible to associate *.lolm files with AutoLoL to quickly open them The selected spells are now displayed in the masteries tab for qu...SubtitleTools: SubtitleTools 1.2: - Added auto insertion of RLE (RIGHT-TO-LEFT EMBEDDING) Unicode character for the RTL languages. - Fixed delete rows issue.PHP Manager for IIS: PHP Manager 1.1 for IIS 7: This is a final stable release of PHP Manager 1.1 for IIS 7. This is a minor incremental release that contains all the functionality available in 53121 plus additional features listed below: Improved detection logic for existing PHP installations. Now PHP Manager detects the location to php.ini file in accordance to the PHP specifications Configuring date.timezone. PHP Manager can automatically set the date.timezone directive which is required to be set starting from PHP 5.3 Ability to ...New Projectscomplile: compiler is bestComputer Graphics: Esercitazioni di Computer GraficaDocsVision WorkFlow Extended Library: ?????? ??????, ???????????? ????? ??????????, ??????????? ????? ?????? ? DocsVision.WorkFlow.Gates. ?????????? ?????????? ????????????? ???????-????????? ? ????? DocsVision. ??????????? ??????: - DVTypeConverter; - DVCardProperty.DotNetNuke Razor Forum Profile: A razor based module for DotNetNuke that displays a user's forum profile information (based on the core forum). Excel AddIn to reset the last worksheet cell: This is a sample Excel AddIn to reset the last worsheet cell in an Excel Workbook.FriendFeed Backup Creator: FriendFeed Backup Creator makes it easier for friendfeed users to backup their feeds including likes and comments. You'll no longer have to worry about your old feeds.Gerins: Sistema Gerencial InsolGoodreads for Windows Phone 7: Goodreads client for Windows Phone 7HyperView for DotNetNuke: HyperView for DotNetNuke is a port of the MIT Exhibit project for DotNetNuke. Exhibit enables web site authors to easily create dynamic exhibits of collections. The collections can be searched and browsed using faceted browsing.Ladder Ranking System: A ladder ranking system as a DotNetNuke moduleLive Office Tools: <LOT - Live Office Tools> makes it easier for <target user group> to <Escritórios>. You'll no longer have to <activity>. It's developed in <C#>. LostMamory: ???????GIS??My WP7 Brand: My WP7 Brand is a simple Windows Phone 7 Template that allows users to view your rss feed, your tweet and your contact's info.Network Adapter/ Interface Analyzer, viewer, Speed Calculator: Simple .Net Application to give information about all network adapters in the system, their running status, max speed, download upload speed, etcOnlineenquete: Online enquete is an application based based on BeeldbankMVC. This project will be used as a starting point for creating my online survay toolOpalis Extension Exchange Mail: A Opalis Integration Pack allowing for Exachange 2007 and 2010 mail manipulation functions. Uses Exchange Webservices.PAK: A Sample project for windows Phone 7, Azure and K2 blackpearl.Persephone CMS: // TODO: Some description to be displayed here!!!Perspectives: Perspectives makes it easier for Visual Studio 2010 users to manage window configurations. It's developed in C#. It was modeled after the Eclipse Perspectives window management system.Photo Studio: Photo studio for storing family albumsPorto Alegre Dojo: Porto Alegre DojoRazor's Edge DotNetNuke User Map: Razor's Edge User Map allows you to load your DotnetNuke user's locations on to a map dynamically based on the address in their user profile. It uses the razor scripting language to retrieve user data and display that data on the page.RestUpMVC: RestUpMVC is a library that allows developers to easily expose a RESTful interface from an ASP.NET MVC application. The library was written in C#.Rocket Framework for Windows Form: Rocket Framework winform .net 4.0 WPF generic entity framework repositoryRPG Maplestory XNA SDK C#: a RPG Maplestory XNA SDK makes it easier for all people want to devolopded a Platform rpg in XNA - C# Sistema para Manejo de Maquinas: Sistema para controlar, insertar y almacenar datos.SoloForum: SoloForumUpdate SharePoint 2010 User Personal Settings: Every SharePoint user will have his/her personal settings for a site collection. Each user can view their details by clicking on Logged-in User link and select My Settings menu item. This tool helps to update user personal settings for a particular site collection.uREST 4 Umbraco: uREST is an Umbraco package for adding a set of RESTful web services to an Umbraco website.Veller: This is a high speed game where speed is your ally. The faster you go the more damage you do. You are vulnerable when moving slow, but gain momentum. Windows Forms Wizard: Oddly, the Windows Forms libraries don't provide any support for writing wizards. Here's one way to do it. Yes!gama NewCMS: Yes!gama NewCMS is a simple news CMS Builded by asp.net + access very very simple... maybe u like simlpe tings...

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  • iPhone SDK vs Windows Phone 7 Series SDK Challenge, Part 1: Hello World!

    In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. Hello World! Of course no first post would be allowed if it didnt focus on the hello world scenario.  The iPhone SDK follows that tradition with the Your First iPhone Application walkthrough.  I will say that the developer documentation for iPhone is pretty good.  There are plenty of walkthoughs and they break things down into nicely sized steps and do a good job of bringing the user along.  As expected, this application is quite simple.  It comprises of a text box, a label, and a button.  When you push the button, the label changes to Hello plus the  word you typed into the text box.  Makes perfect sense for a starter application.  Theres not much to this but it covers a few basic elements: Laying out basic UI Handling user input Hooking up events Formatting text     So, lets get started building a similar app for Windows Phone 7 Series! Implementing the UI: UI in Silverlight (and therefore Windows Phone 7) is defined in XAML, which is a declarative XML language also used by WPF on the desktop.  For anyone thats familiar with similar types of markup, its relatively straightforward to learn, but has a lot of power in it once you get it figured out.  Well talk more about that. This UI is very simple.  When I look at this, I note a couple of things: Elements are arranged vertically They are all centered So, lets create our Application and then start with the UI.  Once you have the the VS 2010 Express for Windows Phone tool running, create a new Windows Phone Project, and call it Hello World: Once created, youll see the designer on one side and your XAML on the other: Now, we can create our UI in one of three ways: Use the designer in Visual Studio to drag and drop the components Use the designer in Expression Blend 4 to drag and drop the components Enter the XAML by hand in either of the above Well start with (1), then kind of move to (3) just for instructional value. To develop this UI in the designer: First, delete all of the markup between inside of the Grid element (LayoutRoot).  You should be left with just this XAML for your MainPage.xaml (i shortened all the xmlns declarations below for brevity): 1: <phoneNavigation:PhoneApplicationPage 2: x:Class="HelloWorld.MainPage" 3: xmlns="...[snip]" 4: FontFamily="{StaticResource PhoneFontFamilyNormal}" 5: FontSize="{StaticResource PhoneFontSizeNormal}" 6: Foreground="{StaticResource PhoneForegroundBrush}"> 7:   8: <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}"> 9:   10: </Grid> 11:   12: </phoneNavigation:PhoneApplicationPage> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Well be adding XAML at line 9, so thats the important part. Now, Click on the center area of the phone surface Open the Toolbox and double click StackPanel Double click TextBox Double click TextBlock Double click Button That will create the necessary UI elements but they wont be arranged quite right.  Well fix it in a second.    Heres the XAML that we end up with: 1: <StackPanel Height="100" HorizontalAlignment="Left" Margin="10,10,0,0" Name="stackPanel1" VerticalAlignment="Top" Width="200"> 2: <TextBox Height="32" Name="textBox1" Text="TextBox" Width="100" /> 3: <TextBlock Height="23" Name="textBlock1" Text="TextBlock" /> 4: <Button Content="Button" Height="70" Name="button1" Width="160" /> 5: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The designer does its best at guessing what we want, but in this case we want things to be a bit simpler. So well just clean it up a bit.  We want the items to be centered and we want them to have a little bit of a margin on either side, so heres what we end up with.  Ive also made it match the values and style from the iPhone app: 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <TextBlock Name="textBlock1" HorizontalAlignment="Center" Margin="0,100,0,0" Text="Hello You!" /> 4: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello"/> 5: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now lets take a look at what weve done there. Line 1: We removed all of the formatting from the StackPanel, except for Margin, as thats all we need.  Since our parent element is a Grid, by default the StackPanel will be sized to fit in that space.  The Margin says that we want to reserve 10 pixels on each side of the StackPanel. Line 2: Weve set the HorizontalAlignment of the TextBox to Stretch, which says that it should fill its parents size horizontally.  We want to do this so the TextBox is always full-width.  We also set TextAlignment to Center, to center the text. Line 3: In contrast to the TextBox above, we dont care how wide the TextBlock is, just so long as it is big enough for its text.  Thatll happen automatically, so we just set its Horizontal alignment to Center.  We also set a Margin above the TextBlock of 100 pixels to bump it down a bit, per the iPhone UI. Line 4: We do the same things here as in Line 3. Heres how the UI looks in the designer: Believe it or not, were almost done! Implementing the App Logic Now, we want the TextBlock to change its text when the Button is clicked.  In the designer, double click the Button to be taken to the Event Handler for the Buttons Click event.  In that event handler, we take the Text property from the TextBox, and format it into a string, then set it into the TextBlock.  Thats it! 1: private void button1_Click(object sender, RoutedEventArgs e) 2: { 3: string name = textBox1.Text; 4:   5: // if there isn't a name set, just use "World" 6: if (String.IsNullOrEmpty(name)) 7: { 8: name = "World"; 9: } 10:   11: // set the value into the TextBlock 12: textBlock1.Text = String.Format("Hello {0}!", name); 13:   14: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We use the String.Format() method to handle the formatting for us.    Now all thats left is to test the app in the Windows Phone Emulator and verify it does what we think it does! And it does! Comparing against the iPhone Looking at the iPhone example, there are basically three things that you have to touch as the developer: 1) The UI in the Nib file 2) The app delegate 3) The view controller Counting lines is a bit tricky here, but to try to keep this even, Im going to only count lines of code that I could not have (or would not have) generated with the tooling.  Meaning, Im not counting XAML and Im not counting operations that happen in the Nib file with the XCode designer tool.  So in the case of the above, even though I modified the XAML, I could have done all of those operations using the visual designer tool.  And normally I would have, but the XAML is more instructive (and less steps!).  Im interested in things that I, as the developer have to figure out in code.  Im also not counting lines that just have a curly brace on them, or lines that are generated for me (e.g. method names that are generated for me when I make a connection, etc.) So, by that count, heres what I get from the code listing for the iPhone app found here: HelloWorldAppDelegate.h: 6 HelloWorldAppDelegate.m: 12 MyViewController.h: 8 MyViewController.m: 18 Which gives me a grand total of about 44 lines of code on iPhone.  I really do recommend looking at the iPhone code for a comparison to the above. Now, for the Windows Phone 7 Series application, the only code I typed was in the event handler above Main.Xaml.cs: 4 So a total of 4 lines of code on Windows Phone 7.  And more importantly, the process is just A LOT simpler.  For example, I was surprised that the User Interface Designer in XCode doesnt automatically create instance variables for me and wire them up to the corresponding elements.  I assumed I wouldnt have to write this code myself (and risk getting it wrong!).  I dont need to worry about view controllers or anything.  I just write my code.  This blog post up to this point has covered almost every aspect of this apps development in a few pages.  The iPhone tutorial has 5 top level steps with 2-3 sub sections of each. Now, its worth pointing out that the iPhone development model uses the Model View Controller (MVC) pattern, which is a very flexible and powerful pattern that enforces proper separation of concerns.  But its fairly complex and difficult to understand when you first walk up to it.  Here at Microsoft weve dabbled in MVC a bit, with frameworks like MFC on Visual C++ and with the ASP.NET MVC framework now.  Both are very powerful frameworks.  But one of the reasons weve stayed away from MVC with client UI frameworks is that its difficult to tool.  We havent seen the type of value that beats double click, write code! for the broad set of scenarios. Another thing to think about is how many of those lines of code were focused on my apps functionality?.  Or, the converse of How many lines of code were boilerplate plumbing?  In both examples, the actual number of functional code lines is similar.  I count most of them in MyViewController.m, in the changeGreeting method.  Its about 7 lines of code that do the work of taking the value from the TextBox and putting it into the label.  Versus 4 on the Windows Phone 7 side.  But, unfortunately, on iPhone I still have to write that other 37 lines of code, just to get there. 10% of the code, 1 file instead of 4, its just much simpler. Making Some Tweaks It turns out, I can actually do this application with ZERO  lines of code, if Im willing to change the spec a bit. The data binding functionality in Silverlight is incredibly powerful.  And what I can do is databind the TextBoxs value directly to the TextBlock.  Take some time looking at this XAML below.  Youll see that I have added another nested StackPanel and two more TextBlocks.  Why?  Because thats how I build that string, and the nested StackPanel will lay things out Horizontally for me, as specified by the Orientation property. 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,100,0,0" > 4: <TextBlock Text="Hello " /> 5: <TextBlock Name="textBlock1" Text="{Binding ElementName=textBox1, Path=Text}" /> 6: <TextBlock Text="!" /> 7: </StackPanel> 8: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello" Click="button1_Click" /> 9: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now, the real action is there in the bolded TextBlock.Text property: Text="{Binding ElementName=textBox1, Path=Text}" .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } That does all the heavy lifting.  It sets up a databinding between the TextBox.Text property on textBox1 and the TextBlock.Text property on textBlock1. As I change the text of the TextBox, the label updates automatically. In fact, I dont even need the button any more, so I could get rid of that altogether.  And no button means no event handler.  No event handler means no C# code at all.  Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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