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• Not able to get data from Json completely

  - by Abhinav Raja

  i am getting JSON data from http://abinet.org/?json=1 and displaying the titles in a ListView. the code is working fine but the problem is, it is skipping few titles in my ListView and one title is being repeated. You can see the json data from url given above by copy paste it in JSON editor online http://www.jsoneditoronline.org/ i want titles in the "posts" array to be displayed in ListView, however it is being displayed like this: if you see the JSON data from the link above, its missing like 3 titles (they should come between the first and second title) and 5th title is being repeated. Dont know why this is happening. What minor adjustments i need to do? Please help me. this is my code : public class MainActivity extends Activity { // URL to get contacts JSON private static String url = "http://abinet.org/?json=1"; // JSON Node names private static final String TAG_POSTS = "posts"; static final String TAG_TITLE = "title"; private ProgressDialog pDialog; JSONArray contacts = null; TextView img_url; ArrayList<HashMap<String, Object>> contactList; ListView lv; LazyAdapter adapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); lv = (ListView) findViewById(R.id.newslist); contactList = new ArrayList<HashMap<String, Object>>(); new GetContacts().execute(); } private class GetContacts extends AsyncTask<Void, Void, Void> { protected void onPreExecute() { super.onPreExecute(); // Showing progress dialog pDialog = new ProgressDialog(MainActivity.this); pDialog.setMessage("Please wait..."); pDialog.setCancelable(false); pDialog.show(); } protected Void doInBackground(Void... arg0) { // Making a request to url and getting response JSONParser jParser = new JSONParser(); // Getting JSON from URL JSONObject jsonObj = jParser.getJSONFromUrl(url); // if (jsonStr != null) { try { // Getting JSON Array node contacts = jsonObj.getJSONArray(TAG_POSTS); // looping through All Contacts for (int i = 0; i < contacts.length(); i++) { // JSONObject c = contacts.getJSONObject(i); JSONObject posts = contacts.getJSONObject(i); String title = posts.getString(TAG_TITLE).replace("&#8217;", "'"); JSONArray attachment = posts.getJSONArray("attachments"); for (int j = 0; j< attachment.length(); j++){ JSONObject obj = attachment.getJSONObject(j); JSONObject image = obj.getJSONObject("images"); JSONObject image_small = image.getJSONObject("thumbnail"); String imgurl = image_small.getString("url"); HashMap<String, Object> contact = new HashMap<String, Object>(); contact.put("image_url", imgurl); contact.put(TAG_TITLE, title); contactList.add(contact); } } } catch (JSONException e) { e.printStackTrace(); } return null; } @Override protected void onPostExecute(Void result) { super.onPostExecute(result); // Dismiss the progress dialog if (pDialog.isShowing()) pDialog.dismiss(); adapter=new LazyAdapter(MainActivity.this, contactList); lv.setAdapter(adapter); } } } this is my JsonParser class (although its not required): public JSONParser() { } public JSONObject getJSONFromUrl(String url) { // Making HTTP request try { // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } and this is adapter class: public class LazyAdapter extends BaseAdapter { private Activity activity; private ArrayList<HashMap<String, Object>> data; private static LayoutInflater inflater=null; public LazyAdapter(Activity a,ArrayList<HashMap<String, Object>> d) { activity = a; data=d; inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE); } public int getCount() { return data.size(); } public Object getItem(int position) { return position; } public long getItemId(int position) { return position; } public View getView(int position, View convertView, ViewGroup parent) { View vi=convertView; if(convertView==null) vi = inflater.inflate(R.layout.third_row, null); TextView title = (TextView)vi.findViewById(R.id.headline3); // title SmartImageView iv = (SmartImageView) vi.findViewById(R.id.imageicon); HashMap<String, Object> song = new HashMap<String, Object>(); song = data.get(position); // Setting all values in listview title.setText((CharSequence) song.get(MainActivity.TAG_TITLE)); iv.setImageUrl((String) song.get("image_url")); thumb_image); return vi; } } Please help me. I am stuck at this for more than a week now. I think there is just something to be changed in my MainActivity class.

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• Dynamic Type to do away with Reflection

  - by Rick Strahl

  The dynamic type in C# 4.0 is a welcome addition to the language. One thing I’ve been doing a lot with it is to remove explicit Reflection code that’s often necessary when you ‘dynamically’ need to walk and object hierarchy. In the past I’ve had a number of ReflectionUtils that used string based expressions to walk an object hierarchy. With the introduction of dynamic much of the ReflectionUtils code can be removed for cleaner code that runs considerably faster to boot. The old Way - Reflection Here’s a really contrived example, but assume for a second, you’d want to dynamically retrieve a Page.Request.Url.AbsoluteUrl based on a Page instance in an ASP.NET Web Page request. The strongly typed version looks like this: string path = Page.Request.Url.AbsolutePath; Now assume for a second that Page wasn’t available as a strongly typed instance and all you had was an object reference to start with and you couldn’t cast it (right I said this was contrived :-)) If you’re using raw Reflection code to retrieve this you’d end up writing 3 sets of Reflection calls using GetValue(). Here’s some internal code I use to retrieve Property values as part of ReflectionUtils: /// <summary> /// Retrieve a property value from an object dynamically. This is a simple version /// that uses Reflection calls directly. It doesn't support indexers. /// </summary> /// <param name="instance">Object to make the call on</param> /// <param name="property">Property to retrieve</param> /// <returns>Object - cast to proper type</returns> public static object GetProperty(object instance, string property) { return instance.GetType().GetProperty(property, ReflectionUtils.MemberAccess).GetValue(instance, null); } If you want more control over properties and support both fields and properties as well as array indexers a little more work is required: /// <summary> /// Parses Properties and Fields including Array and Collection references. /// Used internally for the 'Ex' Reflection methods. /// </summary> /// <param name="Parent"></param> /// <param name="Property"></param> /// <returns></returns> private static object GetPropertyInternal(object Parent, string Property) { if (Property == "this" || Property == "me") return Parent; object result = null; string pureProperty = Property; string indexes = null; bool isArrayOrCollection = false; // Deal with Array Property if (Property.IndexOf("[") > -1) { pureProperty = Property.Substring(0, Property.IndexOf("[")); indexes = Property.Substring(Property.IndexOf("[")); isArrayOrCollection = true; } // Get the member MemberInfo member = Parent.GetType().GetMember(pureProperty, ReflectionUtils.MemberAccess)[0]; if (member.MemberType == MemberTypes.Property) result = ((PropertyInfo)member).GetValue(Parent, null); else result = ((FieldInfo)member).GetValue(Parent); if (isArrayOrCollection) { indexes = indexes.Replace("[", string.Empty).Replace("]", string.Empty); if (result is Array) { int Index = -1; int.TryParse(indexes, out Index); result = CallMethod(result, "GetValue", Index); } else if (result is ICollection) { if (indexes.StartsWith("\"")) { // String Index indexes = indexes.Trim('\"'); result = CallMethod(result, "get_Item", indexes); } else { // assume numeric index int index = -1; int.TryParse(indexes, out index); result = CallMethod(result, "get_Item", index); } } } return result; } /// <summary> /// Returns a property or field value using a base object and sub members including . syntax. /// For example, you can access: oCustomer.oData.Company with (this,"oCustomer.oData.Company") /// This method also supports indexers in the Property value such as: /// Customer.DataSet.Tables["Customers"].Rows[0] /// </summary> /// <param name="Parent">Parent object to 'start' parsing from. Typically this will be the Page.</param> /// <param name="Property">The property to retrieve. Example: 'Customer.Entity.Company'</param> /// <returns></returns> public static object GetPropertyEx(object Parent, string Property) { Type type = Parent.GetType(); int at = Property.IndexOf("."); if (at < 0) { // Complex parse of the property return GetPropertyInternal(Parent, Property); } // Walk the . syntax - split into current object (Main) and further parsed objects (Subs) string main = Property.Substring(0, at); string subs = Property.Substring(at + 1); // Retrieve the next . section of the property object sub = GetPropertyInternal(Parent, main); // Now go parse the left over sections return GetPropertyEx(sub, subs); } As you can see there’s a fair bit of code involved into retrieving a property or field value reliably especially if you want to support array indexer syntax. This method is then used by a variety of routines to retrieve individual properties including one called GetPropertyEx() which can walk the dot syntax hierarchy easily. Anyway with ReflectionUtils I can  retrieve Page.Request.Url.AbsolutePath using code like this: string url = ReflectionUtils.GetPropertyEx(Page, "Request.Url.AbsolutePath") as string; This works fine, but is bulky to write and of course requires that I use my custom routines. It’s also quite slow as the code in GetPropertyEx does all sorts of string parsing to figure out which members to walk in the hierarchy. Enter dynamic – way easier! .NET 4.0’s dynamic type makes the above really easy. The following code is all that it takes: object objPage = Page; // force to object for contrivance :) dynamic page = objPage; // convert to dynamic from untyped object string scriptUrl = page.Request.Url.AbsolutePath; The dynamic type assignment in the first two lines turns the strongly typed Page object into a dynamic. The first assignment is just part of the contrived example to force the strongly typed Page reference into an untyped value to demonstrate the dynamic member access. The next line then just creates the dynamic type from the Page reference which allows you to access any public properties and methods easily. It also lets you access any child properties as dynamic types so when you look at Intellisense you’ll see something like this when typing Request.: In other words any dynamic value access on an object returns another dynamic object which is what allows the walking of the hierarchy chain. Note also that the result value doesn’t have to be explicitly cast as string in the code above – the compiler is perfectly happy without the cast in this case inferring the target type based on the type being assigned to. The dynamic conversion automatically handles the cast when making the final assignment which is nice making for natural syntnax that looks *exactly* like the fully typed syntax, but is completely dynamic. Note that you can also use indexers in the same natural syntax so the following also works on the dynamic page instance: string scriptUrl = page.Request.ServerVariables["SCRIPT_NAME"]; The dynamic type is going to make a lot of Reflection code go away as it’s simply so much nicer to be able to use natural syntax to write out code that previously required nasty Reflection syntax. Another interesting thing about the dynamic type is that it actually works considerably faster than Reflection. Check out the following methods that check performance: void Reflection() { Stopwatch stop = new Stopwatch(); stop.Start(); for (int i = 0; i < reps; i++) { // string url = ReflectionUtils.GetProperty(Page,"Title") as string;// "Request.Url.AbsolutePath") as string; string url = Page.GetType().GetProperty("Title", ReflectionUtils.MemberAccess).GetValue(Page, null) as string; } stop.Stop(); Response.Write("Reflection: " + stop.ElapsedMilliseconds.ToString()); } void Dynamic() { Stopwatch stop = new Stopwatch(); stop.Start(); dynamic page = Page; for (int i = 0; i < reps; i++) { string url = page.Title; //Request.Url.AbsolutePath; } stop.Stop(); Response.Write("Dynamic: " + stop.ElapsedMilliseconds.ToString()); } The dynamic code runs in 4-5 milliseconds while the Reflection code runs around 200+ milliseconds! There’s a bit of overhead in the first dynamic object call but subsequent calls are blazing fast and performance is actually much better than manual Reflection. Dynamic is definitely a huge win-win situation when you need dynamic access to objects at runtime.© Rick Strahl, West Wind Technologies, 2005-2010Posted in .NET  CSharp  

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• Silverlight Commands Hacks: Passing EventArgs as CommandParameter to DelegateCommand triggered by Ev

  - by brainbox

  Today I've tried to find a way how to pass EventArgs as CommandParameter to DelegateCommand triggered by EventTrigger. By reverse engineering of default InvokeCommandAction I find that blend team just ignores event args.To resolve this issue I have created my own action for triggering delegate commands.public sealed class InvokeDelegateCommandAction : TriggerAction<DependencyObject>{    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty CommandParameterProperty =        DependencyProperty.Register("CommandParameter", typeof(object), typeof(InvokeDelegateCommandAction), null);    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty CommandProperty = DependencyProperty.Register(        "Command", typeof(ICommand), typeof(InvokeDelegateCommandAction), null);    /// <summary>    ///     /// </summary>    public static readonly DependencyProperty InvokeParameterProperty = DependencyProperty.Register(        "InvokeParameter", typeof(object), typeof(InvokeDelegateCommandAction), null);    private string commandName;    /// <summary>    ///     /// </summary>    public object InvokeParameter    {        get        {            return this.GetValue(InvokeParameterProperty);        }        set        {            this.SetValue(InvokeParameterProperty, value);        }    }    /// <summary>    ///     /// </summary>    public ICommand Command    {        get        {            return (ICommand)this.GetValue(CommandProperty);        }        set        {            this.SetValue(CommandProperty, value);        }    }    /// <summary>    ///     /// </summary>    public string CommandName    {        get        {            return this.commandName;        }        set        {            if (this.CommandName != value)            {                this.commandName = value;            }        }    }    /// <summary>    ///     /// </summary>    public object CommandParameter    {        get        {            return this.GetValue(CommandParameterProperty);        }        set        {            this.SetValue(CommandParameterProperty, value);        }    }    /// <summary>    ///     /// </summary>    /// <param name="parameter"></param>    protected override void Invoke(object parameter)    {        this.InvokeParameter = parameter;                if (this.AssociatedObject != null)        {            ICommand command = this.ResolveCommand();            if ((command != null) && command.CanExecute(this.CommandParameter))            {                command.Execute(this.CommandParameter);            }        }    }    private ICommand ResolveCommand()    {        ICommand command = null;        if (this.Command != null)        {            return this.Command;        }        var frameworkElement = this.AssociatedObject as FrameworkElement;        if (frameworkElement != null)        {            object dataContext = frameworkElement.DataContext;            if (dataContext != null)            {                PropertyInfo commandPropertyInfo = dataContext                    .GetType()                    .GetProperties(BindingFlags.Public | BindingFlags.Instance)                    .FirstOrDefault(                        p =>                        typeof(ICommand).IsAssignableFrom(p.PropertyType) &&                        string.Equals(p.Name, this.CommandName, StringComparison.Ordinal)                    );                if (commandPropertyInfo != null)                {                    command = (ICommand)commandPropertyInfo.GetValue(dataContext, null);                }            }        }        return command;    }}Example:<ComboBox>    <ComboBoxItem Content="Foo option 1" />    <ComboBoxItem Content="Foo option 2" />    <ComboBoxItem Content="Foo option 3" />    <Interactivity:Interaction.Triggers>        <Interactivity:EventTrigger EventName="SelectionChanged" >            <Presentation:InvokeDelegateCommandAction                 Command="{Binding SubmitFormCommand}"                CommandParameter="{Binding RelativeSource={RelativeSource Self}, Path=InvokeParameter}" />        </Interactivity:EventTrigger>    </Interactivity:Interaction.Triggers>                </ComboBox>BTW: InvokeCommanAction CommandName property are trying to find command in properties of view. It very strange, because in MVVM pattern command should be in viewmodel supplied to datacontext.

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• From Binary to Data Structures

  - by Cédric Menzi

  Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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• Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design

  - by SeanMcAlinden

  Creating a dynamic proxy generator – Part 1 – Creating the Assembly builder, Module builder and caching mechanism For the latest code go to http://rapidioc.codeplex.com/ Before getting too involved in generating the proxy, I thought it would be worth while going through the intended design, this is important as the next step is to start creating the constructors for the proxy. Each proxy derives from a specified type The proxy has a corresponding constructor for each of the base type constructors The proxy has overrides for all methods and properties marked as Virtual on the base type For each overridden method, there is also a private method whose sole job is to call the base method. For each overridden method, a delegate is created whose sole job is to call the private method that calls the base method. The following class diagram shows the main classes and interfaces involved in the interception process. I’ll go through each of them to explain their place in the overall proxy.   IProxy Interface The proxy implements the IProxy interface for the sole purpose of adding custom interceptors. This allows the created proxy interface to be cast as an IProxy and then simply add Interceptors by calling it’s AddInterceptor method. This is done internally within the proxy building process so the consumer of the API doesn’t need knowledge of this. IInterceptor Interface The IInterceptor interface has one method: Handle. The handle method accepts a IMethodInvocation parameter which contains methods and data for handling method interception. Multiple classes that implement this interface can be added to the proxy. Each method override in the proxy calls the handle method rather than simply calling the base method. How the proxy fully works will be explained in the next section MethodInvocation. IMethodInvocation Interface & MethodInvocation class The MethodInvocation will contain one main method and multiple helper properties. Continue Method The method Continue() has two functions hidden away from the consumer. When Continue is called, if there are multiple Interceptors, the next Interceptors Handle method is called. If all Interceptors Handle methods have been called, the Continue method then calls the base class method. Properties The MethodInvocation will contain multiple helper properties including at least the following: Method Name (Read Only) Method Arguments (Read and Write) Method Argument Types (Read Only) Method Result (Read and Write) – this property remains null if the method return type is void Target Object (Read Only) Return Type (Read Only) DefaultInterceptor class The DefaultInterceptor class is a simple class that implements the IInterceptor interface. Here is the code: DefaultInterceptor namespace Rapid.DynamicProxy.Interception {     /// <summary>     /// Default interceptor for the proxy.     /// </summary>     /// <typeparam name="TBase">The base type.</typeparam>     public class DefaultInterceptor<TBase> : IInterceptor<TBase> where TBase : class     {         /// <summary>         /// Handles the specified method invocation.         /// </summary>         /// <param name="methodInvocation">The method invocation.</param>         public void Handle(IMethodInvocation<TBase> methodInvocation)         {             methodInvocation.Continue();         }     } } This is automatically created in the proxy and is the first interceptor that each method override calls. It’s sole function is to ensure that if no interceptors have been added, the base method is still called. Custom Interceptor Example A consumer of the Rapid.DynamicProxy API could create an interceptor for logging when the FirstName property of the User class is set. Just for illustration, I have also wrapped a transaction around the methodInvocation.Coninue() method. This means that any overriden methods within the user class will run within a transaction scope. MyInterceptor public class MyInterceptor : IInterceptor<User<int, IRepository>> {     public void Handle(IMethodInvocation<User<int, IRepository>> methodInvocation)     {         if (methodInvocation.Name == "set_FirstName")         {             Logger.Log("First name seting to: " + methodInvocation.Arguments[0]);         }         using (TransactionScope scope = new TransactionScope())         {             methodInvocation.Continue();         }         if (methodInvocation.Name == "set_FirstName")         {             Logger.Log("First name has been set to: " + methodInvocation.Arguments[0]);         }     } } Overridden Method Example To show a taster of what the overridden methods on the proxy would look like, the setter method for the property FirstName used in the above example would look something similar to the following (this is not real code but will look similar): set_FirstName public override void set_FirstName(string value) {     set_FirstNameBaseMethodDelegate callBase =         new set_FirstNameBaseMethodDelegate(this.set_FirstNameProxyGetBaseMethod);     object[] arguments = new object[] { value };     IMethodInvocation<User<IRepository>> methodInvocation =         new MethodInvocation<User<IRepository>>(this, callBase, "set_FirstName", arguments, interceptors);          this.Interceptors[0].Handle(methodInvocation); } As you can see, a delegate instance is created which calls to a private method on the class, the private method calls the base method and would look like the following: calls base setter private void set_FirstNameProxyGetBaseMethod(string value) {     base.set_FirstName(value); } The delegate is invoked when methodInvocation.Continue() is called within an interceptor. The set_FirstName parameters are loaded into an object array. The current instance, delegate, method name and method arguments are passed into the methodInvocation constructor (there will be more data not illustrated here passed in when created including method info, return types, argument types etc.) The DefaultInterceptor’s Handle method is called with the methodInvocation instance as it’s parameter. Obviously methods can have return values, ref and out parameters etc. in these cases the generated method override body will be slightly different from above. I’ll go into more detail on these aspects as we build them. Conclusion I hope this has been useful, I can’t guarantee that the proxy will look exactly like the above, but at the moment, this is pretty much what I intend to do. Always worth downloading the code at http://rapidioc.codeplex.com/ to see the latest. There will also be some tests that you can debug through to help see what’s going on. Cheers, Sean.

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• Capturing and Transforming ASP.NET Output with Response.Filter

  - by Rick Strahl

  During one of my Handlers and Modules session at DevConnections this week one of the attendees asked a question that I didn’t have an immediate answer for. Basically he wanted to capture response output completely and then apply some filtering to the output – effectively injecting some additional content into the page AFTER the page had completely rendered. Specifically the output should be captured from anywhere – not just a page and have this code injected into the page. Some time ago I posted some code that allows you to capture ASP.NET Page output by overriding the Render() method, capturing the HtmlTextWriter() and reading its content, modifying the rendered data as text then writing it back out. I’ve actually used this approach on a few occasions and it works fine for ASP.NET pages. But this obviously won’t work outside of the Page class environment and it’s not really generic – you have to create a custom page class in order to handle the output capture. [updated 11/16/2009 – updated ResponseFilterStream implementation and a few additional notes based on comments] Enter Response.Filter However, ASP.NET includes a Response.Filter which can be used – well to filter output. Basically Response.Filter is a stream through which the OutputStream is piped back to the Web Server (indirectly). As content is written into the Response object, the filter stream receives the appropriate Stream commands like Write, Flush and Close as well as read operations although for a Response.Filter that’s uncommon to be hit. The Response.Filter can be programmatically replaced at runtime which allows you to effectively intercept all output generation that runs through ASP.NET. A common Example: Dynamic GZip Encoding A rather common use of Response.Filter hooking up code based, dynamic  GZip compression for requests which is dead simple by applying a GZipStream (or DeflateStream) to Response.Filter. The following generic routines can be used very easily to detect GZip capability of the client and compress response output with a single line of code and a couple of library helper routines: WebUtils.GZipEncodePage(); which is handled with a few lines of reusable code and a couple of static helper methods: /// <summary> ///Sets up the current page or handler to use GZip through a Response.Filter ///IMPORTANT:  ///You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() {     HttpResponse Response = HttpContext.Current.Response;     if(IsGZipSupported())     {         stringAcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"];         if(AcceptEncoding.Contains("deflate"))         {             Response.Filter = newSystem.IO.Compression.DeflateStream(Response.Filter,                                        System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "deflate");         }         else        {             Response.Filter = newSystem.IO.Compression.GZipStream(Response.Filter,                                       System.IO.Compression.CompressionMode.Compress);             Response.AppendHeader("Content-Encoding", "gzip");                            }     }     // Allow proxy servers to cache encoded and unencoded versions separately    Response.AppendHeader("Vary", "Content-Encoding"); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } GZipStream and DeflateStream are streams that are assigned to Response.Filter and by doing so apply the appropriate compression on the active Response. Response.Filter content is chunked So to implement a Response.Filter effectively requires only that you implement a custom stream and handle the Write() method to capture Response output as it’s written. At first blush this seems very simple – you capture the output in Write, transform it and write out the transformed content in one pass. And that indeed works for small amounts of content. But you see, the problem is that output is written in small buffer chunks (a little less than 16k it appears) rather than just a single Write() statement into the stream, which makes perfect sense for ASP.NET to stream data back to IIS in smaller chunks to minimize memory usage en route. Unfortunately this also makes it a more difficult to implement any filtering routines since you don’t directly get access to all of the response content which is problematic especially if those filtering routines require you to look at the ENTIRE response in order to transform or capture the output as is needed for the solution the gentleman in my session asked for. So in order to address this a slightly different approach is required that basically captures all the Write() buffers passed into a cached stream and then making the stream available only when it’s complete and ready to be flushed. As I was thinking about the implementation I also started thinking about the few instances when I’ve used Response.Filter implementations. Each time I had to create a new Stream subclass and create my custom functionality but in the end each implementation did the same thing – capturing output and transforming it. I thought there should be an easier way to do this by creating a re-usable Stream class that can handle stream transformations that are common to Response.Filter implementations. Creating a semi-generic Response Filter Stream Class What I ended up with is a ResponseFilterStream class that provides a handful of Events that allow you to capture and/or transform Response content. The class implements a subclass of Stream and then overrides Write() and Flush() to handle capturing and transformation operations. By exposing events it’s easy to hook up capture or transformation operations via single focused methods. ResponseFilterStream exposes the following events: CaptureStream, CaptureString Captures the output only and provides either a MemoryStream or String with the final page output. Capture is hooked to the Flush() operation of the stream. TransformStream, TransformString Allows you to transform the complete response output with events that receive a MemoryStream or String respectively and can you modify the output then return it back as a return value. The transformed output is then written back out in a single chunk to the response output stream. These events capture all output internally first then write the entire buffer into the response. TransformWrite, TransformWriteString Allows you to transform the Response data as it is written in its original chunk size in the Stream’s Write() method. Unlike TransformStream/TransformString which operate on the complete output, these events only see the current chunk of data written. This is more efficient as there’s no caching involved, but can cause problems due to searched content splitting over multiple chunks. Using this implementation, creating a custom Response.Filter transformation becomes as simple as the following code. To hook up the Response.Filter using the MemoryStream version event: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformStream += filter_TransformStream; Response.Filter = filter; and the event handler to do the transformation: MemoryStream filter_TransformStream(MemoryStream ms) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = encoding.GetString(ms.ToArray()); output = FixPaths(output); ms = new MemoryStream(output.Length); byte[] buffer = encoding.GetBytes(output); ms.Write(buffer,0,buffer.Length); return ms; } private string FixPaths(string output) { string path = HttpContext.Current.Request.ApplicationPath; // override root path wonkiness if (path == "/") path = ""; output = output.Replace("\"~/", "\"" + path + "/").Replace("'~/", "'" + path + "/"); return output; } The idea of the event handler is that you can do whatever you want to the stream and return back a stream – either the same one that’s been modified or a brand new one – which is then sent back to as the final response. The above code can be simplified even more by using the string version events which handle the stream to string conversions for you: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; and the event handler to do the transformation calling the same FixPaths method shown above: string filter_TransformString(string output) { return FixPaths(output); } The events for capturing output and capturing and transforming chunks work in a very similar way. By using events to handle the transformations ResponseFilterStream becomes a reusable component and we don’t have to create a new stream class or subclass an existing Stream based classed. By the way, the example used here is kind of a cool trick which transforms “~/” expressions inside of the final generated HTML output – even in plain HTML controls not HTML controls – and transforms them into the appropriate application relative path in the same way that ResolveUrl would do. So you can write plain old HTML like this: <a href=”~/default.aspx”>Home</a>  and have it turned into: <a href=”/myVirtual/default.aspx”>Home</a>  without having to use an ASP.NET control like Hyperlink or Image or having to constantly use: <img src=”<%= ResolveUrl(“~/images/home.gif”) %>” /> in MVC applications (which frankly is one of the most annoying things about MVC especially given the path hell that extension-less and endpoint-less URLs impose). I can’t take credit for this idea. While discussing the Response.Filter issues on Twitter a hint from Dylan Beattie who pointed me at one of his examples which does something similar. I thought the idea was cool enough to use an example for future demos of Response.Filter functionality in ASP.NET next I time I do the Modules and Handlers talk (which was great fun BTW). How practical this is is debatable however since there’s definitely some overhead to using a Response.Filter in general and especially on one that caches the output and the re-writes it later. Make sure to test for performance anytime you use Response.Filter hookup and make sure it' doesn’t end up killing perf on you. You’ve been warned :-}. How does ResponseFilterStream work? The big win of this implementation IMHO is that it’s a reusable  component – so for implementation there’s no new class, no subclassing – you simply attach to an event to implement an event handler method with a straight forward signature to retrieve the stream or string you’re interested in. The implementation is based on a subclass of Stream as is required in order to handle the Response.Filter requirements. What’s different than other implementations I’ve seen in various places is that it supports capturing output as a whole to allow retrieving the full response output for capture or modification. The exception are the TransformWrite and TransformWrite events which operate only active chunk of data written by the Response. For captured output, the Write() method captures output into an internal MemoryStream that is cached until writing is complete. So Write() is called when ASP.NET writes to the Response stream, but the filter doesn’t pass on the Write immediately to the filter’s internal stream. The data is cached and only when the Flush() method is called to finalize the Stream’s output do we actually send the cached stream off for transformation (if the events are hooked up) and THEN finally write out the returned content in one big chunk. Here’s the implementation of ResponseFilterStream: /// <summary> /// A semi-generic Stream implementation for Response.Filter with /// an event interface for handling Content transformations via /// Stream or String. /// <remarks> /// Use with care for large output as this implementation copies /// the output into a memory stream and so increases memory usage. /// </remarks> /// </summary> public class ResponseFilterStream : Stream { /// <summary> /// The original stream /// </summary> Stream _stream; /// <summary> /// Current position in the original stream /// </summary> long _position; /// <summary> /// Stream that original content is read into /// and then passed to TransformStream function /// </summary> MemoryStream _cacheStream = new MemoryStream(5000); /// <summary> /// Internal pointer that that keeps track of the size /// of the cacheStream /// </summary> int _cachePointer = 0; /// <summary> /// /// </summary> /// <param name="responseStream"></param> public ResponseFilterStream(Stream responseStream) { _stream = responseStream; } /// <summary> /// Determines whether the stream is captured /// </summary> private bool IsCaptured { get { if (CaptureStream != null || CaptureString != null || TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Determines whether the Write method is outputting data immediately /// or delaying output until Flush() is fired. /// </summary> private bool IsOutputDelayed { get { if (TransformStream != null || TransformString != null) return true; return false; } } /// <summary> /// Event that captures Response output and makes it available /// as a MemoryStream instance. Output is captured but won't /// affect Response output. /// </summary> public event Action<MemoryStream> CaptureStream; /// <summary> /// Event that captures Response output and makes it available /// as a string. Output is captured but won't affect Response output. /// </summary> public event Action<string> CaptureString; /// <summary> /// Event that allows you transform the stream as each chunk of /// the output is written in the Write() operation of the stream. /// This means that that it's possible/likely that the input /// buffer will not contain the full response output but only /// one of potentially many chunks. /// /// This event is called as part of the filter stream's Write() /// operation. /// </summary> public event Func<byte[], byte[]> TransformWrite; /// <summary> /// Event that allows you to transform the response stream as /// each chunk of bytep[] output is written during the stream's write /// operation. This means it's possibly/likely that the string /// passed to the handler only contains a portion of the full /// output. Typical buffer chunks are around 16k a piece. /// /// This event is called as part of the stream's Write operation. /// </summary> public event Func<string, string> TransformWriteString; /// <summary> /// This event allows capturing and transformation of the entire /// output stream by caching all write operations and delaying final /// response output until Flush() is called on the stream. /// </summary> public event Func<MemoryStream, MemoryStream> TransformStream; /// <summary> /// Event that can be hooked up to handle Response.Filter /// Transformation. Passed a string that you can modify and /// return back as a return value. The modified content /// will become the final output. /// </summary> public event Func<string, string> TransformString; protected virtual void OnCaptureStream(MemoryStream ms) { if (CaptureStream != null) CaptureStream(ms); } private void OnCaptureStringInternal(MemoryStream ms) { if (CaptureString != null) { string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); OnCaptureString(content); } } protected virtual void OnCaptureString(string output) { if (CaptureString != null) CaptureString(output); } protected virtual byte[] OnTransformWrite(byte[] buffer) { if (TransformWrite != null) return TransformWrite(buffer); return buffer; } private byte[] OnTransformWriteStringInternal(byte[] buffer) { Encoding encoding = HttpContext.Current.Response.ContentEncoding; string output = OnTransformWriteString(encoding.GetString(buffer)); return encoding.GetBytes(output); } private string OnTransformWriteString(string value) { if (TransformWriteString != null) return TransformWriteString(value); return value; } protected virtual MemoryStream OnTransformCompleteStream(MemoryStream ms) { if (TransformStream != null) return TransformStream(ms); return ms; } /// <summary> /// Allows transforming of strings /// /// Note this handler is internal and not meant to be overridden /// as the TransformString Event has to be hooked up in order /// for this handler to even fire to avoid the overhead of string /// conversion on every pass through. /// </summary> /// <param name="responseText"></param> /// <returns></returns> private string OnTransformCompleteString(string responseText) { if (TransformString != null) TransformString(responseText); return responseText; } /// <summary> /// Wrapper method form OnTransformString that handles /// stream to string and vice versa conversions /// </summary> /// <param name="ms"></param> /// <returns></returns> internal MemoryStream OnTransformCompleteStringInternal(MemoryStream ms) { if (TransformString == null) return ms; //string content = ms.GetAsString(); string content = HttpContext.Current.Response.ContentEncoding.GetString(ms.ToArray()); content = TransformString(content); byte[] buffer = HttpContext.Current.Response.ContentEncoding.GetBytes(content); ms = new MemoryStream(); ms.Write(buffer, 0, buffer.Length); //ms.WriteString(content); return ms; } /// <summary> /// /// </summary> public override bool CanRead { get { return true; } } public override bool CanSeek { get { return true; } } /// <summary> /// /// </summary> public override bool CanWrite { get { return true; } } /// <summary> /// /// </summary> public override long Length { get { return 0; } } /// <summary> /// /// </summary> public override long Position { get { return _position; } set { _position = value; } } /// <summary> /// /// </summary> /// <param name="offset"></param> /// <param name="direction"></param> /// <returns></returns> public override long Seek(long offset, System.IO.SeekOrigin direction) { return _stream.Seek(offset, direction); } /// <summary> /// /// </summary> /// <param name="length"></param> public override void SetLength(long length) { _stream.SetLength(length); } /// <summary> /// /// </summary> public override void Close() { _stream.Close(); } /// <summary> /// Override flush by writing out the cached stream data /// </summary> public override void Flush() { if (IsCaptured && _cacheStream.Length > 0) { // Check for transform implementations _cacheStream = OnTransformCompleteStream(_cacheStream); _cacheStream = OnTransformCompleteStringInternal(_cacheStream); OnCaptureStream(_cacheStream); OnCaptureStringInternal(_cacheStream); // write the stream back out if output was delayed if (IsOutputDelayed) _stream.Write(_cacheStream.ToArray(), 0, (int)_cacheStream.Length); // Clear the cache once we've written it out _cacheStream.SetLength(0); } // default flush behavior _stream.Flush(); } /// <summary> /// /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> /// <returns></returns> public override int Read(byte[] buffer, int offset, int count) { return _stream.Read(buffer, offset, count); } /// <summary> /// Overriden to capture output written by ASP.NET and captured /// into a cached stream that is written out later when Flush() /// is called. /// </summary> /// <param name="buffer"></param> /// <param name="offset"></param> /// <param name="count"></param> public override void Write(byte[] buffer, int offset, int count) { if ( IsCaptured ) { // copy to holding buffer only - we'll write out later _cacheStream.Write(buffer, 0, count); _cachePointer += count; } // just transform this buffer if (TransformWrite != null) buffer = OnTransformWrite(buffer); if (TransformWriteString != null) buffer = OnTransformWriteStringInternal(buffer); if (!IsOutputDelayed) _stream.Write(buffer, offset, buffer.Length); } } The key features are the events and corresponding OnXXX methods that handle the event hookups, and the Write() and Flush() methods of the stream implementation. All the rest of the members tend to be plain jane passthrough stream implementation code without much consequence. I do love the way Action<t> and Func<T> make it so easy to create the event signatures for the various events – sweet. A few Things to consider Performance Response.Filter is not great for performance in general as it adds another layer of indirection to the ASP.NET output pipeline, and this implementation in particular adds a memory hit as it basically duplicates the response output into the cached memory stream which is necessary since you may have to look at the entire response. If you have large pages in particular this can cause potentially serious memory pressure in your server application. So be careful of wholesale adoption of this (or other) Response.Filters. Make sure to do some performance testing to ensure it’s not killing your app’s performance. Response.Filter works everywhere A few questions came up in comments and discussion as to capturing ALL output hitting the site and – yes you can definitely do that by assigning a Response.Filter inside of a module. If you do this however you’ll want to be very careful and decide which content you actually want to capture especially in IIS 7 which passes ALL content – including static images/CSS etc. through the ASP.NET pipeline. So it is important to filter only on what you’re looking for – like the page extension or maybe more effectively the Response.ContentType. Response.Filter Chaining Originally I thought that filter chaining doesn’t work at all due to a bug in the stream implementation code. But it’s quite possible to assign multiple filters to the Response.Filter property. So the following actually works to both compress the output and apply the transformed content: WebUtils.GZipEncodePage(); ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; However the following does not work resulting in invalid content encoding errors: ResponseFilterStream filter = new ResponseFilterStream(Response.Filter); filter.TransformString += filter_TransformString; Response.Filter = filter; WebUtils.GZipEncodePage(); In other words multiple Response filters can work together but it depends entirely on the implementation whether they can be chained or in which order they can be chained. In this case running the GZip/Deflate stream filters apparently relies on the original content length of the output and chokes when the content is modified. But if attaching the compression first it works fine as unintuitive as that may seem. Resources Download example code Capture Output from ASP.NET Pages © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Parallelism in .NET – Part 14, The Different Forms of Task

  - by Reed

  Before discussing Task creation and actual usage in concurrent environments, I will briefly expand upon my introduction of the Task class and provide a short explanation of the distinct forms of Task.  The Task Parallel Library includes four distinct, though related, variations on the Task class. In my introduction to the Task class, I focused on the most basic version of Task.  This version of Task, the standard Task class, is most often used with an Action delegate.  This allows you to implement for each task within the task decomposition as a single delegate. Typically, when using the new threading constructs in .NET 4 and the Task Parallel Library, we use lambda expressions to define anonymous methods.  The advantage of using a lambda expression is that it allows the Action delegate to directly use variables in the calling scope.  This eliminates the need to make separate Task classes for Action<T>, Action<T1,T2>, and all of the other Action<…> delegate types.  As an example, suppose we wanted to make a Task to handle the ”Show Splash” task from our earlier decomposition.  Even if this task required parameters, such as a message to display, we could still use an Action delegate specified via a lambda: // Store this as a local variable string messageForSplashScreen = GetSplashScreenMessage(); // Create our task Task showSplashTask = new Task( () => { // We can use variables in our outer scope, // as well as methods scoped to our class! this.DisplaySplashScreen(messageForSplashScreen); }); .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; } This provides a huge amount of flexibility.  We can use this single form of task for any task which performs an operation, provided the only information we need to track is whether the task has completed successfully or not.  This leads to my first observation: Use a Task with a System.Action delegate for any task for which no result is generated. This observation leads to an obvious corollary: we also need a way to define a task which generates a result.  The Task Parallel Library provides this via the Task<TResult> class. Task<TResult> subclasses the standard Task class, providing one additional feature – the ability to return a value back to the user of the task.  This is done by switching from providing an Action delegate to providing a Func<TResult> delegate.  If we decompose our problem, and we realize we have one task where its result is required by a future operation, this can be handled via Task<TResult>.  For example, suppose we want to make a task for our “Check for Update” task, we could do: Task<bool> checkForUpdateTask = new Task<bool>( () => { return this.CheckWebsiteForUpdate(); }); Later, we would start this task, and perform some other work.  At any point in the future, we could get the value from the Task<TResult>.Result property, which will cause our thread to block until the task has finished processing: // This uses Task<bool> checkForUpdateTask generated above... // Start the task, typically on a background thread checkForUpdateTask.Start(); // Do some other work on our current thread this.DoSomeWork(); // Discover, from our background task, whether an update is available // This will block until our task completes bool updateAvailable = checkForUpdateTask.Result; This leads me to my second observation: Use a Task<TResult> with a System.Func<TResult> delegate for any task which generates a result. Task and Task<TResult> provide a much cleaner alternative to the previous Asynchronous Programming design patterns in the .NET framework.  Instead of trying to implement IAsyncResult, and providing BeginXXX() and EndXXX() methods, implementing an asynchronous programming API can be as simple as creating a method that returns a Task or Task<TResult>.  The client side of the pattern also is dramatically simplified – the client can call a method, then either choose to call task.Wait() or use task.Result when it needs to wait for the operation’s completion. While this provides a much cleaner model for future APIs, there is quite a bit of infrastructure built around the current Asynchronous Programming design patterns.  In order to provide a model to work with existing APIs, two other forms of Task exist.  There is a constructor for Task which takes an Action<Object> and a state parameter.  In addition, there is a constructor for creating a Task<TResult> which takes a Func<Object, TResult> as well as a state parameter.  When using these constructors, the state parameter is stored in the Task.AsyncState property. While these two overloads exist, and are usable directly, I strongly recommend avoiding this for new development.  The two forms of Task which take an object state parameter exist primarily for interoperability with traditional .NET Asynchronous Programming methodologies.  Using lambda expressions to capture variables from the scope of the creator is a much cleaner approach than using the untyped state parameters, since lambda expressions provide full type safety without introducing new variables.

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• Parallelism in .NET – Part 11, Divide and Conquer via Parallel.Invoke

  - by Reed

  Many algorithms are easily written to work via recursion.  For example, most data-oriented tasks where a tree of data must be processed are much more easily handled by starting at the root, and recursively “walking” the tree.  Some algorithms work this way on flat data structures, such as arrays, as well.  This is a form of divide and conquer: an algorithm design which is based around breaking up a set of work recursively, “dividing” the total work in each recursive step, and “conquering” the work when the remaining work is small enough to be solved easily. Recursive algorithms, especially ones based on a form of divide and conquer, are often a very good candidate for parallelization. This is apparent from a common sense standpoint.  Since we’re dividing up the total work in the algorithm, we have an obvious, built-in partitioning scheme.  Once partitioned, the data can be worked upon independently, so there is good, clean isolation of data. Implementing this type of algorithm is fairly simple.  The Parallel class in .NET 4 includes a method suited for this type of operation: Parallel.Invoke.  This method works by taking any number of delegates defined as an Action, and operating them all in parallel.  The method returns when every delegate has completed: Parallel.Invoke( () => { Console.WriteLine("Action 1 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); }, () => { Console.WriteLine("Action 2 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); }, () => { Console.WriteLine("Action 3 executing in thread {0}", Thread.CurrentThread.ManagedThreadId); } ); .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; } Running this simple example demonstrates the ease of using this method.  For example, on my system, I get three separate thread IDs when running the above code.  By allowing any number of delegates to be executed directly, concurrently, the Parallel.Invoke method provides us an easy way to parallelize any algorithm based on divide and conquer.  We can divide our work in each step, and execute each task in parallel, recursively. For example, suppose we wanted to implement our own quicksort routine.  The quicksort algorithm can be designed based on divide and conquer.  In each iteration, we pick a pivot point, and use that to partition the total array.  We swap the elements around the pivot, then recursively sort the lists on each side of the pivot.  For example, let’s look at this simple, sequential implementation of quicksort: public static void QuickSort<T>(T[] array) where T : IComparable<T> { QuickSortInternal(array, 0, array.Length - 1); } private static void QuickSortInternal<T>(T[] array, int left, int right) where T : IComparable<T> { if (left >= right) { return; } SwapElements(array, left, (left + right) / 2); int last = left; for (int current = left + 1; current <= right; ++current) { if (array[current].CompareTo(array[left]) < 0) { ++last; SwapElements(array, last, current); } } SwapElements(array, left, last); QuickSortInternal(array, left, last - 1); QuickSortInternal(array, last + 1, right); } static void SwapElements<T>(T[] array, int i, int j) { T temp = array[i]; array[i] = array[j]; array[j] = temp; } Here, we implement the quicksort algorithm in a very common, divide and conquer approach.  Running this against the built-in Array.Sort routine shows that we get the exact same answers (although the framework’s sort routine is slightly faster).  On my system, for example, I can use framework’s sort to sort ten million random doubles in about 7.3s, and this implementation takes about 9.3s on average. Looking at this routine, though, there is a clear opportunity to parallelize.  At the end of QuickSortInternal, we recursively call into QuickSortInternal with each partition of the array after the pivot is chosen.  This can be rewritten to use Parallel.Invoke by simply changing it to: // Code above is unchanged... SwapElements(array, left, last); Parallel.Invoke( () => QuickSortInternal(array, left, last - 1), () => QuickSortInternal(array, last + 1, right) ); } This routine will now run in parallel.  When executing, we now see the CPU usage across all cores spike while it executes.  However, there is a significant problem here – by parallelizing this routine, we took it from an execution time of 9.3s to an execution time of approximately 14 seconds!  We’re using more resources as seen in the CPU usage, but the overall result is a dramatic slowdown in overall processing time. This occurs because parallelization adds overhead.  Each time we split this array, we spawn two new tasks to parallelize this algorithm!  This is far, far too many tasks for our cores to operate upon at a single time.  In effect, we’re “over-parallelizing” this routine.  This is a common problem when working with divide and conquer algorithms, and leads to an important observation: When parallelizing a recursive routine, take special care not to add more tasks than necessary to fully utilize your system. This can be done with a few different approaches, in this case.  Typically, the way to handle this is to stop parallelizing the routine at a certain point, and revert back to the serial approach.  Since the first few recursions will all still be parallelized, our “deeper” recursive tasks will be running in parallel, and can take full advantage of the machine.  This also dramatically reduces the overhead added by parallelizing, since we’re only adding overhead for the first few recursive calls.  There are two basic approaches we can take here.  The first approach would be to look at the total work size, and if it’s smaller than a specific threshold, revert to our serial implementation.  In this case, we could just check right-left, and if it’s under a threshold, call the methods directly instead of using Parallel.Invoke. The second approach is to track how “deep” in the “tree” we are currently at, and if we are below some number of levels, stop parallelizing.  This approach is a more general-purpose approach, since it works on routines which parse trees as well as routines working off of a single array, but may not work as well if a poor partitioning strategy is chosen or the tree is not balanced evenly. This can be written very easily.  If we pass a maxDepth parameter into our internal routine, we can restrict the amount of times we parallelize by changing the recursive call to: // Code above is unchanged... SwapElements(array, left, last); if (maxDepth < 1) { QuickSortInternal(array, left, last - 1, maxDepth); QuickSortInternal(array, last + 1, right, maxDepth); } else { --maxDepth; Parallel.Invoke( () => QuickSortInternal(array, left, last - 1, maxDepth), () => QuickSortInternal(array, last + 1, right, maxDepth)); } We no longer allow this to parallelize indefinitely – only to a specific depth, at which time we revert to a serial implementation.  By starting the routine with a maxDepth equal to Environment.ProcessorCount, we can restrict the total amount of parallel operations significantly, but still provide adequate work for each processing core. With this final change, my timings are much better.  On average, I get the following timings: Framework via Array.Sort: 7.3 seconds Serial Quicksort Implementation: 9.3 seconds Naive Parallel Implementation: 14 seconds Parallel Implementation Restricting Depth: 4.7 seconds Finally, we are now faster than the framework’s Array.Sort implementation.

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• 17 new features in Visual Studio 2010

  - by vik20000in

  Visual studio 2010 has been released to RTM a few days back. This release of Visual studio 2010 comes with a big number of improvements on many fronts. In this post I will try and point out some of the major improvements in Visual Studio 2010. 1)      Visual studio IDE Improvement. Visual studio IDE has been rewritten in WPF. The look and feel of the studio has been improved for improved readability. Start page has been redesigned and template so that anyone can change the start page as they wish. 2)      Multiple Monitor - Support for Multiple Monitor was already there in Visual studio. But in this edition it has been improved as much that we can now place the document, design and code window outside the IDE in another monitor. 3)      ZOOM in Code Editor – Making the editors in WPF has made significant improvement for them. The best one that I like is the ZOOM feature. We can now zoom in the code editor with the help of the ctrl + Mouse scroll. The zoom feature does not work on the Design surface or windows with icon like solution view and toolbox. 4)      Box Selection - Another Important improvement in the Visual studio 2010 is the box selection. We can select a rectangular by holding down the Alt Key and selecting with mouse.  Now in the rectangular selection we can insert text, Paste same code in different line etc. This is helpful if you want to convert a number of variables from public to private etc… 5)      New Improved Search – One of the best productivity improvements in Visual studio 2010 is its new search as you type support. This has been done in the Navigate To window which can be brought up by pressing (Ctrl + ,). The navigate To windows also take help of the Camel casing and will be able to search with the help of camel casing when character is entered in upper case. For example we can search AOH for AddOrederHeader. 6)      Call Hierarchy – This feature is only available to the Visual C# and Visual C++ editor. The call hierarchy windows displays the calls made to and from (yes both to and from) a selected method property or a constructor. The call hierarchy also shows the implementation of interface and the overrides of virtual or abstract methods. This window is very helpful in understanding the code flow, and evaluating the effect of making changes. The best part is it is available at design time and not at runtime only like a debugger. 7)      Highlighting references – One of the very cool stuff in Visual Studio 2010 is the fact if you select a variable then all the use of that variable will be highlighted alongside. This should work for all the result of symbols returned by Find all reference. This also works for Name of class, objects variable, properties and methods. We can also use the Ctrl + Shift + Down Arrow or Up Arror to move through them. 8)      Generate from usage - The Generate from usage feature lets you use classes and members before you define them. You can generate a stub for any undefined class, constructor, method, property, field, or enum that you want to use but have not yet defined. You can generate new types and members without leaving your current location in code, This minimizes interruption to your workflow.9)      IntelliSense Suggestion Mode - IntelliSense now provides two alternatives for IntelliSense statement completion, completion mode and suggestion mode. Use suggestion mode for situations where classes and members are used before they are defined. In suggestion mode, when you type in the editor and then commit the entry, the text you typed is inserted into the code. When you commit an entry in completion mode, the editor shows the entry that is highlighted on the members list. When an IntelliSense window is open, you can press CTRL+ALT+SPACEBAR to toggle between completion mode and suggestion mode. 10)   Application Lifecycle Management – A client application for management of application lifecycle like version control, work item tracking, build automation, team portal etc is available for free (this is not available for express edition.). 11)   Start Page – The start page has been redesigned with WPF for new functionality and look. Tabbed areas are provided for content from different source including MSDN. Once you open some project the start page closes automatically. The list of recent project also lets you remove project from the list. And above all the start page is customizable enough to be changed as per individual requirement. 12)   Extension Manager – Visual Studio 2010 has provided good ways to be extended. We can also use MEF to extend most of the features of Visual Studio. The new extension manager now can go the visual studio gallery and install the extension without even opening any explorer. 13)   Code snippets – Visual studio 2010 for HTML, Jscript and Asp.net also. 14)   Improved Intelligence for JavaScript has been improved vastly (around 2-5 times). Intelligence now also shows the XML documentation comment on the go. 15)   Web Deployment – Web Deployment has been vastly improved. We can package and publish the web application in one click. Three major supported deployment scenarios are Web packages, one click deployment and Web configuration Transformation. 16)   SharePoint - Visual Studio 2010 also brings vastly improved development experience for SharePoint. We can create, edit, debug, package, deploy and activate SharePoint project from within Visual Studio. Deployment of Site is as easy as hitting F5. 17)   Azure – Visual Studio 2010 also comes with handy improvement for developing on windows Azure environment. Vikram

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• Implementing a generic repository for WCF data services

  - by cibrax

  The repository implementation I am going to discuss here is not exactly what someone would call repository in terms of DDD, but it is an abstraction layer that becomes handy at the moment of unit testing the code around this repository. In other words, you can easily create a mock to replace the real repository implementation. The WCF Data Services update for .NET 3.5 introduced a nice feature to support two way data bindings, which is very helpful for developing WPF or Silverlight based application but also for implementing the repository I am going to talk about. As part of this feature, the WCF Data Services Client library introduced a new collection DataServiceCollection<T> that implements INotifyPropertyChanged to notify the data context (DataServiceContext) about any change in the association links. This means that it is not longer necessary to manually set or remove the links in the data context when an item is added or removed from a collection. Before having this new collection, you basically used the following code to add a new item to a collection. Order order = new Order {   Name = "Foo" }; OrderItem item = new OrderItem {   Name = "bar",   UnitPrice = 10,   Qty = 1 }; var context = new OrderContext(); context.AddToOrders(order); context.AddToOrderItems(item); context.SetLink(item, "Order", order); context.SaveChanges(); Now, thanks to this new collection, everything is much simpler and similar to what you have in other ORMs like Entity Framework or L2S. Order order = new Order {   Name = "Foo" }; OrderItem item = new OrderItem {   Name = "bar",   UnitPrice = 10,   Qty = 1 }; order.Items.Add(item); var context = new OrderContext(); context.AddToOrders(order); context.SaveChanges(); In order to use this new feature, you first need to enable V2 in the data service, and then use some specific arguments in the datasvcutil tool (You can find more information about this new feature and how to use it in this post). DataSvcUtil /uri:"http://localhost:3655/MyDataService.svc/" /out:Reference.cs /dataservicecollection /version:2.0 Once you use those two arguments, the generated proxy classes will use DataServiceCollection<T> rather than a simple ObjectCollection<T>, which was the default collection in V1. There are some aspects that you need to know to use this feature correctly. 1. All the entities retrieved directly from the data context with a query track the changes and report those to the data context automatically. 2. A entity created with “new” does not track any change in the properties or associations. In order to enable change tracking in this entity, you need to do the following trick. public Order CreateOrder() {   var collection = new DataServiceCollection<Order>(this.context);   var order = new Order();   collection.Add(order);   return order; } You basically need to create a collection, and add the entity to that collection with the “Add” method to enable change tracking on that entity. 3. If you need to attach an existing entity (For example, if you created the entity with the “new” operator rather than retrieving it from the data context with a query) to a data context for tracking changes, you can use the “Load” method in the DataServiceCollection. var order = new Order {   Id = 1 }; var collection = new DataServiceCollection<Order>(this.context); collection.Load(order); In this case, the order with Id = 1 must exist on the data source exposed by the Data service. Otherwise, you will get an error because the entity did not exist. These cool extensions methods discussed by Stuart Leeks in this post to replace all the magic strings in the “Expand” operation with Expression Trees represent another feature I am going to use to implement this generic repository. Thanks to these extension methods, you could replace the following query with magic strings by a piece of code that only uses expressions. Magic strings, var customers = dataContext.Customers .Expand("Orders")         .Expand("Orders/Items") Expressions, var customers = dataContext.Customers .Expand(c => c.Orders.SubExpand(o => o.Items)) That query basically returns all the customers with their orders and order items. Ok, now that we have the automatic change tracking support and the expression support for explicitly loading entity associations, we are ready to create the repository. The interface for this repository looks like this,public interface IRepository { T Create<T>() where T : new(); void Update<T>(T entity); void Delete<T>(T entity); IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties); IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties); void Attach<T>(T entity); void SaveChanges(); } The Retrieve and RetrieveAll methods are used to execute queries against the data service context. While both methods receive an array of expressions to load associations explicitly, only the Retrieve method receives a predicate representing the “where” clause. The following code represents the final implementation of this repository.public class DataServiceRepository: IRepository { ResourceRepositoryContext context; public DataServiceRepository() : this (new DataServiceContext()) { } public DataServiceRepository(DataServiceContext context) { this.context = context; } private static string ResolveEntitySet(Type type) { var entitySetAttribute = (EntitySetAttribute)type.GetCustomAttributes(typeof(EntitySetAttribute), true).FirstOrDefault(); if (entitySetAttribute != null) return entitySetAttribute.EntitySet; return null; } public T Create<T>() where T : new() { var collection = new DataServiceCollection<T>(this.context); var entity = new T(); collection.Add(entity); return entity; } public void Update<T>(T entity) { this.context.UpdateObject(entity); } public void Delete<T>(T entity) { this.context.DeleteObject(entity); } public void Attach<T>(T entity) { var collection = new DataServiceCollection<T>(this.context); collection.Load(entity); } public IQueryable<T> Retrieve<T>(Expression<Func<T, bool>> predicate, params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query.Where(predicate); } public IQueryable<T> RetrieveAll<T>(params Expression<Func<T, object>>[] eagerProperties) { var entitySet = ResolveEntitySet(typeof(T)); var query = context.CreateQuery<T>(entitySet); foreach (var e in eagerProperties) { query = query.Expand(e); } return query; } public void SaveChanges() { this.context.SaveChanges(SaveChangesOptions.Batch); } } For instance, you can use the following code to retrieve customers with First name equal to “John”, and all their orders in a single call. repository.Retrieve<Customer>(    c => c.FirstName == “John”, //Where    c => c.Orders.SubExpand(o => o.Items)); In case, you want to have some pre-defined queries that you are going to use across several places, you can put them in an specific class. public static class CustomerQueries {   public static Expression<Func<Customer, bool>> LastNameEqualsTo(string lastName)   {     return c => c.LastName == lastName;   } } And then, use it with the repository. repository.Retrieve<Customer>(    CustomerQueries.LastNameEqualsTo("foo"),    c => c.Orders.SubExpand(o => o.Items));

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• Cleaner HTML Markup with ASP.NET 4 Web Forms - Client IDs (VS 2010 and .NET 4.0 Series)

  - by ScottGu

  This is the sixteenth in a series of blog posts I’m doing on the upcoming VS 2010 and .NET 4 release. Today’s post is the first of a few blog posts I’ll be doing that talk about some of the important changes we’ve made to make Web Forms in ASP.NET 4 generate clean, standards-compliant, CSS-friendly markup.  Today I’ll cover the work we are doing to provide better control over the “ID” attributes rendered by server controls to the client. [In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu] Clean, Standards-Based, CSS-Friendly Markup One of the common complaints developers have often had with ASP.NET Web Forms is that when using server controls they don’t have the ability to easily generate clean, CSS-friendly output and markup.  Some of the specific complaints with previous ASP.NET releases include: Auto-generated ID attributes within HTML make it hard to write JavaScript and style with CSS Use of tables instead of semantic markup for certain controls (in particular the asp:menu control) make styling ugly Some controls render inline style properties even if no style property on the control has been set ViewState can often be bigger than ideal ASP.NET 4 provides better support for building standards-compliant pages out of the box.  The built-in <asp:> server controls with ASP.NET 4 now generate cleaner markup and support CSS styling – and help address all of the above issues.  Markup Compatibility When Upgrading Existing ASP.NET Web Forms Applications A common question people often ask when hearing about the cleaner markup coming with ASP.NET 4 is “Great - but what about my existing applications?  Will these changes/improvements break things when I upgrade?” To help ensure that we don’t break assumptions around markup and styling with existing ASP.NET Web Forms applications, we’ve enabled a configuration flag – controlRenderingCompatbilityVersion – within web.config that let’s you decide if you want to use the new cleaner markup approach that is the default with new ASP.NET 4 applications, or for compatibility reasons render the same markup that previous versions of ASP.NET used:   When the controlRenderingCompatbilityVersion flag is set to “3.5” your application and server controls will by default render output using the same markup generation used with VS 2008 and .NET 3.5.  When the controlRenderingCompatbilityVersion flag is set to “4.0” your application and server controls will strictly adhere to the XHTML 1.1 specification, have cleaner client IDs, render with semantic correctness in mind, and have extraneous inline styles removed. This flag defaults to 4.0 for all new ASP.NET Web Forms applications built using ASP.NET 4. Any previous application that is upgraded using VS 2010 will have the controlRenderingCompatbilityVersion flag automatically set to 3.5 by the upgrade wizard to ensure backwards compatibility.  You can then optionally change it (either at the application level, or scope it within the web.config file to be on a per page or directory level) if you move your pages to use CSS and take advantage of the new markup rendering. Today’s Cleaner Markup Topic: Client IDs The ability to have clean, predictable, ID attributes on rendered HTML elements is something developers have long asked for with Web Forms (ID values like “ctl00_ContentPlaceholder1_ListView1_ctrl0_Label1” are not very popular).  Having control over the ID values rendered helps make it much easier to write client-side JavaScript against the output, makes it easier to style elements using CSS, and on large pages can help reduce the overall size of the markup generated. New ClientIDMode Property on Controls ASP.NET 4 supports a new ClientIDMode property on the Control base class.  The ClientIDMode property indicates how controls should generate client ID values when they render.  The ClientIDMode property supports four possible values: AutoID—Renders the output as in .NET 3.5 (auto-generated IDs which will still render prefixes like ctrl00 for compatibility) Predictable (Default)— Trims any “ctl00” ID string and if a list/container control concatenates child ids (example: id=”ParentControl_ChildControl”) Static—Hands over full ID naming control to the developer – whatever they set as the ID of the control is what is rendered (example: id=”JustMyId”) Inherit—Tells the control to defer to the naming behavior mode of the parent container control The ClientIDMode property can be set directly on individual controls (or within container controls – in which case the controls within them will by default inherit the setting): Or it can be specified at a page or usercontrol level (using the <%@ Page %> or <%@ Control %> directives) – in which case controls within the pages/usercontrols inherit the setting (and can optionally override it): Or it can be set within the web.config file of an application – in which case pages within the application inherit the setting (and can optionally override it): This gives you the flexibility to customize/override the naming behavior however you want. Example: Using the ClientIDMode property to control the IDs of Non-List Controls Let’s take a look at how we can use the new ClientIDMode property to control the rendering of “ID” elements within a page.  To help illustrate this we can create a simple page called “SingleControlExample.aspx” that is based on a master-page called “Site.Master”, and which has a single <asp:label> control with an ID of “Message” that is contained with an <asp:content> container control called “MainContent”: Within our code-behind we’ll then add some simple code like below to dynamically populate the Label’s Text property at runtime:   If we were running this application using ASP.NET 3.5 (or had our ASP.NET 4 application configured to run using 3.5 rendering or ClientIDMode=AutoID), then the generated markup sent down to the client would look like below: This ID is unique (which is good) – but rather ugly because of the “ct100” prefix (which is bad). Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Predictable” With ASP.NET 4, server controls by default now render their ID’s using ClientIDMode=”Predictable”.  This helps ensure that ID values are still unique and don’t conflict on a page, but at the same time it makes the IDs less verbose and more predictable.  This means that the generated markup of our <asp:label> control above will by default now look like below with ASP.NET 4: Notice that the “ct100” prefix is gone. Because the “Message” control is embedded within a “MainContent” container control, by default it’s ID will be prefixed “MainContent_Message” to avoid potential collisions with other controls elsewhere within the page. Markup Rendering when using ASP.NET 4 and the ClientIDMode is set to “Static” Sometimes you don’t want your ID values to be nested hierarchically, though, and instead just want the ID rendered to be whatever value you set it as.  To enable this you can now use ClientIDMode=static, in which case the ID rendered will be exactly the same as what you set it on the server-side on your control.  This will cause the below markup to be rendered with ASP.NET 4: This option now gives you the ability to completely control the client ID values sent down by controls. Example: Using the ClientIDMode property to control the IDs of Data-Bound List Controls Data-bound list/grid controls have historically been the hardest to use/style when it comes to working with Web Form’s automatically generated IDs.  Let’s now take a look at a scenario where we’ll customize the ID’s rendered using a ListView control with ASP.NET 4. The code snippet below is an example of a ListView control that displays the contents of a data-bound collection — in this case, airports: We can then write code like below within our code-behind to dynamically databind a list of airports to the ListView above: At runtime this will then by default generate a <ul> list of airports like below.  Note that because the <ul> and <li> elements in the ListView’s template are not server controls, no IDs are rendered in our markup: Adding Client ID’s to Each Row Item Now, let’s say that we wanted to add client-ID’s to the output so that we can programmatically access each <li> via JavaScript.  We want these ID’s to be unique, predictable, and identifiable. A first approach would be to mark each <li> element within the template as being a server control (by giving it a runat=server attribute) and by giving each one an id of “airport”: By default ASP.NET 4 will now render clean IDs like below (no ctl001-like ids are rendered):   Using the ClientIDRowSuffix Property Our template above now generates unique ID’s for each <li> element – but if we are going to access them programmatically on the client using JavaScript we might want to instead have the ID’s contain the airport code within them to make them easier to reference.  The good news is that we can easily do this by taking advantage of the new ClientIDRowSuffix property on databound controls in ASP.NET 4 to better control the ID’s of our individual row elements. To do this, we’ll set the ClientIDRowSuffix property to “Code” on our ListView control.  This tells the ListView to use the databound “Code” property from our Airport class when generating the ID: And now instead of having row suffixes like “1”, “2”, and “3”, we’ll instead have the Airport.Code value embedded within the IDs (e.g: _CLE, _CAK, _PDX, etc): You can use this ClientIDRowSuffix approach with other databound controls like the GridView as well. It is useful anytime you want to program row elements on the client – and use clean/identified IDs to easily reference them from JavaScript code. Summary ASP.NET 4 enables you to generate much cleaner HTML markup from server controls and from within your Web Forms applications.  In today’s post I covered how you can now easily control the client ID values that are rendered by server controls.  In upcoming posts I’ll cover some of the other markup improvements that are also coming with the ASP.NET 4 release. Hope this helps, Scott

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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• CodePlex Daily Summary for Monday, April 12, 2010

  CodePlex Daily Summary for Monday, April 12, 2010New Projects3 Hour Game Design Contest: The 3 Hour Game Design Contest is a programming contest for making simple games in 3 hours. 3 hours may not seem like enough time to make a game, b...BI Monkey SSIS ETL Framework: The BI Monkey SSIS ETL Framework is an ETL Execution, Control and Logging system for ETL projects using SSIS. It is supported by a SQL Server metad...Blend Sample Data Helpers: Helper behavior classes to generate sample images and data from Internet sources such as Flickr images. Bold TCP for Delphi 7: Open Sourcing the Bold TCP for Delphi 7.cfThreadingTools: This library project contains classes and extensions which will allow easy handling of multi-threaded UI-accesses.CuBiX_SDL: CuBiX_SDL : CuBiX est un projet personnel.Draglets: Draglets makes it easier for editors and CMS-developers to move and reorder content at their web sites. It's developed in ASP.NET, C# with WCF and ...DSQLT - Dynamic SQL Templates: DSQLT - Dynamic SQL Templates Use Stored Procedures as templates for dynamic SQL statements. Substitute parameters @0-@9 with values like objectna...Edtter: Edtter is a sample web application built on ASP.NET MVC 2 Framework. (Japanese Version Only)Forms Based Authentication Management - SharePoint2007FBA: This is my own update to Stacy Draper's FBABasic project for Forms Based Authentication in MOSS 2007. In additon to managing your fba user's roles,...Height Map to 3D World at XNA: Height Map to 3D World is a XNA project that developed firstly by Eric Grossinger and secondly improved by Karadeniz Technical University Computer ...HouseFly: A simple contact and note taking applicationITM 495 - iPhone Web App: School ProjectKaufleute: This will be finished laterLR: this project is about connecting toPowerShell Integration Services: A set of tools aimed at Extract Transform and Load tasks. Focused on getting the most common ETL tasks done without SSIS. Salient: A collection of, hopefully, useful libraries.Samurai.Validation: Extensible and flexible .Net object validation frameworkSamurai.Workflow: Samurai Workflow is a slim, easy-to-use workflow framework for WPF applications.SharePoint User Management WebPart: SharePoint User Management WebPartUrl shorte(ne)r: It's simple Url Shortener (like: http://tinyurl.com) Currently only Polish language is supported. In future will be provided multi language suppor...Yasbg: Yasbg (pronounced yas-bug) is Yet Another Static Blog Generator. It is made in C# using MarkdownSharp for markdown. Currently in alpha. New Releases.NET Extensions - Extension Methods Library: Release 2010.06: Added an universal approach for grouping extension methods like conversions. Conversion are now available on any data type (it's actually extension...3 Hour Game Design Contest: 3H-GDC mVII: This is the collection of game files for the 7th 3H-GDCB&W Port Scanner: Black`n`White Port Scanner 3.0: B&W Port Scanner 3 includes FTP Server detection tool, Better stability, Optimized memory management, Saving & Opening Result sets ... and more new...BI Monkey SSIS ETL Framework: Framework v1 Alpha: This Alpha release is not fully tested and some functionality is not operating as intended.Bluetooth Radar: Version 1.7: UI Changes Device UserControl Randomly placed devices.BugTracker.NET: BugTracker.NET 3.4.1: For the tasks/time tracking feature, added a way of viewing all the tasks at once, not just the tasks for one bug. Also added a way of exporting a...cfThreadingTools: cfThreadingTools 0.1.1.8: This is the first public available release. Following items are included: BaseTools-class which allows thread-safe setting of properties and callin...DeepZoom Pivot Constructor: DeepZoom Pivot Constructor v0.1: This is a test release of the library platform - Targets .NET 3.5 No samples yet, etc., but it works well :-)DSQLT - Dynamic SQL Templates: Initial release with License Included: nothing changed but license print procedure included the zip file contains database backup SQL script readmeForms Based Authentication Management - SharePoint2007FBA: SharePoint2007FBA 1.0.0.0: Downloads for the Project solution and the WSP package. Please read the Setup Guide. If you are unfamiliar with setting up Forms Based Authenticati...Foursquare BlogEngine Widget: foursquare widget for BlogEngine.NET version 0.3: To see the changes which have been made, visit http://philippkueng.ch/post/Foursquare-BlogEngineNET-widget-version-03.aspx For installation instruc...Framework Detector: FrameworkDetect Support .NET 4 v2: FrameworkDetect Support .NET 4Happy Turtle Plugins for BVI :: Repository Based Versioning for Visual Studio: Happy Turtle 1.0.46860: This is the second beta release of the SVN based version incrementor. Please feel free to create a thread in the discussion tabs and provide feedb...Height Map to 3D World at XNA: 3DWorld: Just open .rar file and extract it any folder and run Proje2Dto3D.exe file.HTML Ruby: 6.20.2: Removed rubyLineSpace option Improved options panel Fixed ruby text font-size rendering issue with complex ruby annotation Removed more waste...HTML Ruby: 6.20.3: Removed unused code Temporary partial fix for Firefox 3.7a4pre nightly buildHTML Ruby: 6.21.0: Added support for current HTML5 ruby annotation format. All ruby annotations are converted to XHTML 1.1 complex ruby annotation.Kooboo HTML form: Kooboo HTML Form Module for 2.1.0.0: Compatible with Kooboo cms 2.1.0.0 Upgrade to MVC 2Kooboo Menu: Kooboo CMS Menu for 2.1.0.0: Compatible with Kooboo cms 2.1.0.0 Upgrade to MVC 2Kooboo Meta: Kooboo Meta Module for 2.1.0.0: Compatible with Kooboo cms 2.1.0.0 Upgrade to MVC 2Kooboo PageMenu: Kooboo CMS PageMenu for 2.1.0.0: Compatible with Kooboo cms 2.1.0.0 Upgrade to MVC 2Kooboo Search: Kooboo CMS Search module for 2.1.0.0: Compatible with Kooboo cms 2.1.0.0 Upgrade to MVC 2Numina Application/Security Framework: Numina.Framework Core 50212: Added bulk import user page Added General settings page for updating Company Name, Theme, and API Key Add/Edit application calls Full URL to h...Rawr: Rawr 2.3.14: - Rawr3: Tons of fixes for Rawr3 compatability and UI. - Significant performance improvements all around. - More fixes and improvements to Wowhea...Rich Ajax empowered Web/Cloud Applications: 6.4 beta 2: The first fully featured version of Visual webGui offering web/cloud development tool that puts all ASP.NET Ajax limits behind with enhanced perfor...SharePoint User Management WebPart: User Management Web part 1.0: Most of the organization have one SharePoint Site which is configured with windows authenticated which is for internal employees having AD authenti...SkeinLibManaged: SkeinLibManaged 1.1.0.0 (Beta): This is the compiled DLL with XML documentation, so there should be plenty of context sensitive help and Intellisense. This is the Release version,...VCC: Latest build, v2.1.30411.0: Automatic drop of latest buildVFPX: Code References 1.1 Beta: Visit the Code References Info Page for complete information about this release.VisioAutomation: VisioAutomation 2.5.0: VisioAutomation 2.5.0- General cleanup/bugfixes - Many low-level changes the the VisioAutomation extension methods - these are far fewer now - This...Visual Studio DSite: English To Spanish Translator (Visual C++ 2008): A simple english to spanish translator made in visual c 2008, using the Google Translate API.WatchersNET CKEditor™ Provider for DotNetNuke: CKEditor Provider 1.10.00: Whats NewFile Browser: Inherits Folder Permissions from DotNetNuke Updated the Editor to Version 3.2.1 revision 5372 Added CkEditor jQuery Adap...Web/Cloud Applications Development Framework | Visual WebGui: 6.4 beta 2: The first fully featured version of Visual webGui offering web/cloud development tool that puts all ASP.NET Ajax limits behind with unique develope...WPF Data Virtualization: 1.0.0.0: First ReleaseYasbg: Yasbg Alpha: ReadmeYet Another Static Blog Generator is a command line utility that generates static html files for blogs. Currently, it is NOT feed enabled. I...異世界の新着動画: Ver. 10-04-12: ニコ生の仕様変更に対応 アンケート時間の設定追加Most Popular ProjectsWBFS ManagerRawrASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseAJAX Control ToolkitSilverlight ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesFacebook Developer ToolkitMost Active ProjectsRawrnopCommerce. Open Source online shop e-commerce solution.AutoPocopatterns & practices – Enterprise LibraryShweet: SharePoint 2010 Team Messaging built with PexFarseer Physics EngineNB_Store - Free DotNetNuke Ecommerce Catalog ModuleIonics Isapi Rewrite FilterBlogEngine.NETBeanProxy

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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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• Errors trying to run MongoDB

  - by SomeKittens

  I'm running Ubuntu Server 12.04 (32 bit) on an old (1998) computer. Everything's working fine until I try and start MongoDB. somekittens@DLserver01:~$ mongo MongoDB shell version: 2.2.2 connecting to: test Sun Dec 16 22:47:50 Error: couldn't connect to server 127.0.0.1:27017 src/mongo/shell/mongo.js:91 exception: connect failed Googling the error lead me to all sorts of "repair" options, none of which fixed anything. I've also removed MongoDB and installed it again (using apt-get, have not built from source). Mongo's log shows the following error: Thu Dec 13 18:36:32 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability. Thu Dec 13 18:36:32 Thu Dec 13 18:36:32 [initandlisten] MongoDB starting : pid=758 port=27017 dbpath=/var/lib/mongodb 32-bit host=DLserver01 Thu Dec 13 18:36:32 [initandlisten] Thu Dec 13 18:36:32 [initandlisten] ** NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data Thu Dec 13 18:36:32 [initandlisten] ** see http://blog.mongodb.org/post/137788967/32-bit-limitations Thu Dec 13 18:36:32 [initandlisten] ** with --journal, the limit is lower Thu Dec 13 18:36:32 [initandlisten] Thu Dec 13 18:36:32 [initandlisten] db version v2.2.2, pdfile version 4.5 Thu Dec 13 18:36:32 [initandlisten] git version: d1b43b61a5308c4ad0679d34b262c5af9d664267 Thu Dec 13 18:36:32 [initandlisten] build info: Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_49 Thu Dec 13 18:36:32 [initandlisten] options: { config: "/etc/mongodb.conf", dbpath: "/var/lib/mongodb", logappend: "true", logpath: "/var/log/mongodb/mongodb.log" } Thu Dec 13 18:36:32 [initandlisten] Unable to check for journal files due to: boost::filesystem::basic_directory_iterator constructor: No such file or directory: "/var/lib/mongodb/journal" ************** Unclean shutdown detected. Please visit http://dochub.mongodb.org/core/repair for recovery instructions. ************* Thu Dec 13 18:36:32 [initandlisten] exception in initAndListen: 12596 old lock file, terminating Thu Dec 13 18:36:32 dbexit: Thu Dec 13 18:36:32 [initandlisten] shutdown: going to close listening sockets... Thu Dec 13 18:36:32 [initandlisten] shutdown: going to flush diaglog... Thu Dec 13 18:36:32 [initandlisten] shutdown: going to close sockets... Thu Dec 13 18:36:32 [initandlisten] shutdown: waiting for fs preallocator... Thu Dec 13 18:36:32 [initandlisten] shutdown: closing all files... Thu Dec 13 18:36:32 [initandlisten] closeAllFiles() finished Thu Dec 13 18:36:32 dbexit: really exiting now Running through the recovery instructions lead to the following adventure: somekittens@DLserver01:/var/log/mongodb$ mongod --repair Sun Dec 16 22:42:54 Sun Dec 16 22:42:54 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability. Sun Dec 16 22:42:54 Sun Dec 16 22:42:54 [initandlisten] MongoDB starting : pid=1887 port=27017 dbpath=/data/db/ 32-bit host=DLserver01 Sun Dec 16 22:42:54 [initandlisten] Sun Dec 16 22:42:54 [initandlisten] ** NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data Sun Dec 16 22:42:54 [initandlisten] ** see http://blog.mongodb.org/post/137788967/32-bit-limitations Sun Dec 16 22:42:54 [initandlisten] ** with --journal, the limit is lower Sun Dec 16 22:42:54 [initandlisten] Sun Dec 16 22:42:54 [initandlisten] db version v2.2.2, pdfile version 4.5 Sun Dec 16 22:42:54 [initandlisten] git version: d1b43b61a5308c4ad0679d34b262c5af9d664267 Sun Dec 16 22:42:54 [initandlisten] build info: Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_49 Sun Dec 16 22:42:54 [initandlisten] options: { repair: true } Sun Dec 16 22:42:54 [initandlisten] exception in initAndListen: 10296 ********************************************************************* ERROR: dbpath (/data/db/) does not exist. Create this directory or give existing directory in --dbpath. See http://dochub.mongodb.org/core/startingandstoppingmongo ********************************************************************* , terminating Sun Dec 16 22:42:54 dbexit: Sun Dec 16 22:42:54 [initandlisten] shutdown: going to close listening sockets... Sun Dec 16 22:42:54 [initandlisten] shutdown: going to flush diaglog... Sun Dec 16 22:42:54 [initandlisten] shutdown: going to close sockets... Sun Dec 16 22:42:54 [initandlisten] shutdown: waiting for fs preallocator... Sun Dec 16 22:42:54 [initandlisten] shutdown: closing all files... Sun Dec 16 22:42:54 [initandlisten] closeAllFiles() finished Sun Dec 16 22:42:54 dbexit: really exiting now somekittens@DLserver01:/var/log/mongodb$ sudo mkdir /data somekittens@DLserver01:/var/log/mongodb$ sudo mkdir /data/db somekittens@DLserver01:/var/log/mongodb$ mongod --repair Sun Dec 16 22:43:51 Sun Dec 16 22:43:51 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability. Sun Dec 16 22:43:51 Sun Dec 16 22:43:51 [initandlisten] MongoDB starting : pid=1909 port=27017 dbpath=/data/db/ 32-bit host=DLserver01 Sun Dec 16 22:43:51 [initandlisten] Sun Dec 16 22:43:51 [initandlisten] ** NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data Sun Dec 16 22:43:51 [initandlisten] ** see http://blog.mongodb.org/post/137788967/32-bit-limitations Sun Dec 16 22:43:51 [initandlisten] ** with --journal, the limit is lower Sun Dec 16 22:43:51 [initandlisten] Sun Dec 16 22:43:51 [initandlisten] db version v2.2.2, pdfile version 4.5 Sun Dec 16 22:43:51 [initandlisten] git version: d1b43b61a5308c4ad0679d34b262c5af9d664267 Sun Dec 16 22:43:51 [initandlisten] build info: Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_49 Sun Dec 16 22:43:51 [initandlisten] options: { repair: true } Sun Dec 16 22:43:51 [initandlisten] exception in initAndListen: 10309 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating Sun Dec 16 22:43:51 dbexit: Sun Dec 16 22:43:51 [initandlisten] shutdown: going to close listening sockets... Sun Dec 16 22:43:51 [initandlisten] shutdown: going to flush diaglog... Sun Dec 16 22:43:51 [initandlisten] shutdown: going to close sockets... Sun Dec 16 22:43:51 [initandlisten] shutdown: waiting for fs preallocator... Sun Dec 16 22:43:51 [initandlisten] shutdown: closing all files... Sun Dec 16 22:43:51 [initandlisten] closeAllFiles() finished Sun Dec 16 22:43:51 [initandlisten] shutdown: removing fs lock... Sun Dec 16 22:43:51 [initandlisten] couldn't remove fs lock errno:9 Bad file descriptor Sun Dec 16 22:43:51 dbexit: really exiting now somekittens@DLserver01:/var/log/mongodb$ service mongodb stop stop: Unknown instance: somekittens@DLserver01:/var/log/mongodb$ sudo mongod --repair Sun Dec 16 22:45:04 Sun Dec 16 22:45:04 warning: 32-bit servers don't have journaling enabled by default. Please use --journal if you want durability. Sun Dec 16 22:45:04 Sun Dec 16 22:45:04 [initandlisten] MongoDB starting : pid=1921 port=27017 dbpath=/data/db/ 32-bit host=DLserver01 Sun Dec 16 22:45:04 [initandlisten] Sun Dec 16 22:45:04 [initandlisten] ** NOTE: when using MongoDB 32 bit, you are limited to about 2 gigabytes of data Sun Dec 16 22:45:04 [initandlisten] ** see http://blog.mongodb.org/post/137788967/32-bit-limitations Sun Dec 16 22:45:04 [initandlisten] ** with --journal, the limit is lower Sun Dec 16 22:45:04 [initandlisten] Sun Dec 16 22:45:04 [initandlisten] db version v2.2.2, pdfile version 4.5 Sun Dec 16 22:45:04 [initandlisten] git version: d1b43b61a5308c4ad0679d34b262c5af9d664267 Sun Dec 16 22:45:04 [initandlisten] build info: Linux domU-12-31-39-01-70-B4 2.6.21.7-2.fc8xen #1 SMP Fri Feb 15 12:39:36 EST 2008 i686 BOOST_LIB_VERSION=1_49 Sun Dec 16 22:45:04 [initandlisten] options: { repair: true } Sun Dec 16 22:45:04 [initandlisten] Unable to check for journal files due to: boost::filesystem::basic_directory_iterator constructor: No such file or directory: "/data/db/journal" Sun Dec 16 22:45:04 [initandlisten] finished checking dbs Sun Dec 16 22:45:04 dbexit: Sun Dec 16 22:45:04 [initandlisten] shutdown: going to close listening sockets... Sun Dec 16 22:45:04 [initandlisten] shutdown: going to flush diaglog... Sun Dec 16 22:45:04 [initandlisten] shutdown: going to close sockets... Sun Dec 16 22:45:04 [initandlisten] shutdown: waiting for fs preallocator... Sun Dec 16 22:45:04 [initandlisten] shutdown: closing all files... Sun Dec 16 22:45:04 [initandlisten] closeAllFiles() finished Sun Dec 16 22:45:04 [initandlisten] shutdown: removing fs lock... Sun Dec 16 22:45:04 dbexit: really exiting now Which didn't change anything. What can I do to resolve this? It's an old computer (640MB RAM, single-core P2). Could that be causing it?

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• An Xml Serializable PropertyBag Dictionary Class for .NET

  - by Rick Strahl

  I don't know about you but I frequently need property bags in my applications to store and possibly cache arbitrary data. Dictionary<T,V> works well for this although I always seem to be hunting for a more specific generic type that provides a string key based dictionary. There's string dictionary, but it only works with strings. There's Hashset<T> but it uses the actual values as keys. In most key value pair situations for me string is key value to work off. Dictionary<T,V> works well enough, but there are some issues with serialization of dictionaries in .NET. The .NET framework doesn't do well serializing IDictionary objects out of the box. The XmlSerializer doesn't support serialization of IDictionary via it's default serialization, and while the DataContractSerializer does support IDictionary serialization it produces some pretty atrocious XML. What doesn't work? First off Dictionary serialization with the Xml Serializer doesn't work so the following fails: [TestMethod] public void DictionaryXmlSerializerTest() { var bag = new Dictionary<string, object>(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42, 45, 66 }); TestContext.WriteLine(this.ToXml(bag)); } public string ToXml(object obj) { if (obj == null) return null; StringWriter sw = new StringWriter(); XmlSerializer ser = new XmlSerializer(obj.GetType()); ser.Serialize(sw, obj); return sw.ToString(); } The error you get with this is: System.NotSupportedException: The type System.Collections.Generic.Dictionary`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] is not supported because it implements IDictionary. Got it! BTW, the same is true with binary serialization. Running the same code above against the DataContractSerializer does work: [TestMethod] public void DictionaryDataContextSerializerTest() { var bag = new Dictionary<string, object>(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42, 45, 66 }); TestContext.WriteLine(this.ToXmlDcs(bag)); } public string ToXmlDcs(object value, bool throwExceptions = false) { var ser = new DataContractSerializer(value.GetType(), null, int.MaxValue, true, false, null); MemoryStream ms = new MemoryStream(); ser.WriteObject(ms, value); return Encoding.UTF8.GetString(ms.ToArray(), 0, (int)ms.Length); } This DOES work but produces some pretty heinous XML (formatted with line breaks and indentation here): <ArrayOfKeyValueOfstringanyType xmlns="http://schemas.microsoft.com/2003/10/Serialization/Arrays" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"> <KeyValueOfstringanyType> <Key>key</Key> <Value i:type="a:string" xmlns:a="http://www.w3.org/2001/XMLSchema">Value</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key2</Key> <Value i:type="a:decimal" xmlns:a="http://www.w3.org/2001/XMLSchema">100.10</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key3</Key> <Value i:type="a:guid" xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/">2cd46d2a-a636-4af4-979b-e834d39b6d37</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key4</Key> <Value i:type="a:dateTime" xmlns:a="http://www.w3.org/2001/XMLSchema">2011-09-19T17:17:05.4406999-07:00</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key5</Key> <Value i:type="a:boolean" xmlns:a="http://www.w3.org/2001/XMLSchema">true</Value> </KeyValueOfstringanyType> <KeyValueOfstringanyType> <Key>Key7</Key> <Value i:type="a:base64Binary" xmlns:a="http://www.w3.org/2001/XMLSchema">Ki1C</Value> </KeyValueOfstringanyType> </ArrayOfKeyValueOfstringanyType> Ouch! That seriously hurts the eye! :-) Worse though it's extremely verbose with all those repetitive namespace declarations. It's good to know that it works in a pinch, but for a human readable/editable solution or something lightweight to store in a database it's not quite ideal. Why should I care? As a little background, in one of my applications I have a need for a flexible property bag that is used on a free form database field on an otherwise static entity. Basically what I have is a standard database record to which arbitrary properties can be added in an XML based string field. I intend to expose those arbitrary properties as a collection from field data stored in XML. The concept is pretty simple: When loading write the data to the collection, when the data is saved serialize the data into an XML string and store it into the database. When reading the data pick up the XML and if the collection on the entity is accessed automatically deserialize the XML into the Dictionary. (I'll talk more about this in another post). While the DataContext Serializer would work, it's verbosity is problematic both for size of the generated XML strings and the fact that users can manually edit this XML based property data in an advanced mode. A clean(er) layout certainly would be preferable and more user friendly. Custom XMLSerialization with a PropertyBag Class So… after a bunch of experimentation with different serialization formats I decided to create a custom PropertyBag class that provides for a serializable Dictionary. It's basically a custom Dictionary<TType,TValue> implementation with the keys always set as string keys. The result are PropertyBag<TValue> and PropertyBag (which defaults to the object type for values). The PropertyBag<TType> and PropertyBag classes provide these features: Subclassed from Dictionary<T,V> Implements IXmlSerializable with a cleanish XML format ToXml() and FromXml() methods to export and import to and from XML strings Static CreateFromXml() method to create an instance It's simple enough as it's merely a Dictionary<string,object> subclass but that supports serialization to a - what I think at least - cleaner XML format. The class is super simple to use: [TestMethod] public void PropertyBagTwoWayObjectSerializationTest() { var bag = new PropertyBag(); bag.Add("key", "Value"); bag.Add("Key2", 100.10M); bag.Add("Key3", Guid.NewGuid()); bag.Add("Key4", DateTime.Now); bag.Add("Key5", true); bag.Add("Key7", new byte[3] { 42,45,66 } ); bag.Add("Key8", null); bag.Add("Key9", new ComplexObject() { Name = "Rick", Entered = DateTime.Now, Count = 10 }); string xml = bag.ToXml(); TestContext.WriteLine(bag.ToXml()); bag.Clear(); bag.FromXml(xml); Assert.IsTrue(bag["key"] as string == "Value"); Assert.IsInstanceOfType( bag["Key3"], typeof(Guid)); Assert.IsNull(bag["Key8"]); //Assert.IsNull(bag["Key10"]); Assert.IsInstanceOfType(bag["Key9"], typeof(ComplexObject)); } This uses the PropertyBag class which uses a PropertyBag<string,object> - which means it returns untyped values of type object. I suspect for me this will be the most common scenario as I'd want to store arbitrary values in the PropertyBag rather than one specific type. The same code with a strongly typed PropertyBag<decimal> looks like this: [TestMethod] public void PropertyBagTwoWayValueTypeSerializationTest() { var bag = new PropertyBag<decimal>(); bag.Add("key", 10M); bag.Add("Key1", 100.10M); bag.Add("Key2", 200.10M); bag.Add("Key3", 300.10M); string xml = bag.ToXml(); TestContext.WriteLine(bag.ToXml()); bag.Clear(); bag.FromXml(xml); Assert.IsTrue(bag.Get("Key1") == 100.10M); Assert.IsTrue(bag.Get("Key3") == 300.10M); } and produces typed results of type decimal. The types can be either value or reference types the combination of which actually proved to be a little more tricky than anticipated due to null and specific string value checks required - getting the generic typing right required use of default(T) and Convert.ChangeType() to trick the compiler into playing nice. Of course the whole raison d'etre for this class is the XML serialization. You can see in the code above that we're doing a .ToXml() and .FromXml() to serialize to and from string. The XML produced for the first example looks like this: <?xml version="1.0" encoding="utf-8"?> <properties> <item> <key>key</key> <value>Value</value> </item> <item> <key>Key2</key> <value type="decimal">100.10</value> </item> <item> <key>Key3</key> <value type="___System.Guid"> <guid>f7a92032-0c6d-4e9d-9950-b15ff7cd207d</guid> </value> </item> <item> <key>Key4</key> <value type="datetime">2011-09-26T17:45:58.5789578-10:00</value> </item> <item> <key>Key5</key> <value type="boolean">true</value> </item> <item> <key>Key7</key> <value type="base64Binary">Ki1C</value> </item> <item> <key>Key8</key> <value type="nil" /> </item> <item> <key>Key9</key> <value type="___Westwind.Tools.Tests.PropertyBagTest+ComplexObject"> <ComplexObject> <Name>Rick</Name> <Entered>2011-09-26T17:45:58.5789578-10:00</Entered> <Count>10</Count> </ComplexObject> </value> </item> </properties>   The format is a bit cleaner than the DataContractSerializer. Each item is serialized into <key> <value> pairs. If the value is a string no type information is written. Since string tends to be the most common type this saves space and serialization processing. All other types are attributed. Simple types are mapped to XML types so things like decimal, datetime, boolean and base64Binary are encoded using their Xml type values. All other types are embedded with a hokey format that describes the .NET type preceded by a three underscores and then are encoded using the XmlSerializer. You can see this best above in the ComplexObject encoding. For custom types this isn't pretty either, but it's more concise than the DCS and it works as long as you're serializing back and forth between .NET clients at least. The XML generated from the second example that uses PropertyBag<decimal> looks like this: <?xml version="1.0" encoding="utf-8"?> <properties> <item> <key>key</key> <value type="decimal">10</value> </item> <item> <key>Key1</key> <value type="decimal">100.10</value> </item> <item> <key>Key2</key> <value type="decimal">200.10</value> </item> <item> <key>Key3</key> <value type="decimal">300.10</value> </item> </properties>   How does it work As I mentioned there's nothing fancy about this solution - it's little more than a subclass of Dictionary<T,V> that implements custom Xml Serialization and a couple of helper methods that facilitate getting the XML in and out of the class more easily. But it's proven very handy for a number of projects for me where dynamic data storage is required. Here's the code: /// <summary> /// Creates a serializable string/object dictionary that is XML serializable /// Encodes keys as element names and values as simple values with a type /// attribute that contains an XML type name. Complex names encode the type /// name with type='___namespace.classname' format followed by a standard xml /// serialized format. The latter serialization can be slow so it's not recommended /// to pass complex types if performance is critical. /// </summary> [XmlRoot("properties")] public class PropertyBag : PropertyBag<object> { /// <summary> /// Creates an instance of a propertybag from an Xml string /// </summary> /// <param name="xml">Serialize</param> /// <returns></returns> public static PropertyBag CreateFromXml(string xml) { var bag = new PropertyBag(); bag.FromXml(xml); return bag; } } /// <summary> /// Creates a serializable string for generic types that is XML serializable. /// /// Encodes keys as element names and values as simple values with a type /// attribute that contains an XML type name. Complex names encode the type /// name with type='___namespace.classname' format followed by a standard xml /// serialized format. The latter serialization can be slow so it's not recommended /// to pass complex types if performance is critical. /// </summary> /// <typeparam name="TValue">Must be a reference type. For value types use type object</typeparam> [XmlRoot("properties")] public class PropertyBag<TValue> : Dictionary<string, TValue>, IXmlSerializable { /// <summary> /// Not implemented - this means no schema information is passed /// so this won't work with ASMX/WCF services. /// </summary> /// <returns></returns> public System.Xml.Schema.XmlSchema GetSchema() { return null; } /// <summary> /// Serializes the dictionary to XML. Keys are /// serialized to element names and values as /// element values. An xml type attribute is embedded /// for each serialized element - a .NET type /// element is embedded for each complex type and /// prefixed with three underscores. /// </summary> /// <param name="writer"></param> public void WriteXml(System.Xml.XmlWriter writer) { foreach (string key in this.Keys) { TValue value = this[key]; Type type = null; if (value != null) type = value.GetType(); writer.WriteStartElement("item"); writer.WriteStartElement("key"); writer.WriteString(key as string); writer.WriteEndElement(); writer.WriteStartElement("value"); string xmlType = XmlUtils.MapTypeToXmlType(type); bool isCustom = false; // Type information attribute if not string if (value == null) { writer.WriteAttributeString("type", "nil"); } else if (!string.IsNullOrEmpty(xmlType)) { if (xmlType != "string") { writer.WriteStartAttribute("type"); writer.WriteString(xmlType); writer.WriteEndAttribute(); } } else { isCustom = true; xmlType = "___" + value.GetType().FullName; writer.WriteStartAttribute("type"); writer.WriteString(xmlType); writer.WriteEndAttribute(); } // Actual deserialization if (!isCustom) { if (value != null) writer.WriteValue(value); } else { XmlSerializer ser = new XmlSerializer(value.GetType()); ser.Serialize(writer, value); } writer.WriteEndElement(); // value writer.WriteEndElement(); // item } } /// <summary> /// Reads the custom serialized format /// </summary> /// <param name="reader"></param> public void ReadXml(System.Xml.XmlReader reader) { this.Clear(); while (reader.Read()) { if (reader.NodeType == XmlNodeType.Element && reader.Name == "key") { string xmlType = null; string name = reader.ReadElementContentAsString(); // item element reader.ReadToNextSibling("value"); if (reader.MoveToNextAttribute()) xmlType = reader.Value; reader.MoveToContent(); TValue value; if (xmlType == "nil") value = default(TValue); // null else if (string.IsNullOrEmpty(xmlType)) { // value is a string or object and we can assign TValue to value string strval = reader.ReadElementContentAsString(); value = (TValue) Convert.ChangeType(strval, typeof(TValue)); } else if (xmlType.StartsWith("___")) { while (reader.Read() && reader.NodeType != XmlNodeType.Element) { } Type type = ReflectionUtils.GetTypeFromName(xmlType.Substring(3)); //value = reader.ReadElementContentAs(type,null); XmlSerializer ser = new XmlSerializer(type); value = (TValue)ser.Deserialize(reader); } else value = (TValue)reader.ReadElementContentAs(XmlUtils.MapXmlTypeToType(xmlType), null); this.Add(name, value); } } } /// <summary> /// Serializes this dictionary to an XML string /// </summary> /// <returns>XML String or Null if it fails</returns> public string ToXml() { string xml = null; SerializationUtils.SerializeObject(this, out xml); return xml; } /// <summary> /// Deserializes from an XML string /// </summary> /// <param name="xml"></param> /// <returns>true or false</returns> public bool FromXml(string xml) { this.Clear(); // if xml string is empty we return an empty dictionary if (string.IsNullOrEmpty(xml)) return true; var result = SerializationUtils.DeSerializeObject(xml, this.GetType()) as PropertyBag<TValue>; if (result != null) { foreach (var item in result) { this.Add(item.Key, item.Value); } } else // null is a failure return false; return true; } /// <summary> /// Creates an instance of a propertybag from an Xml string /// </summary> /// <param name="xml"></param> /// <returns></returns> public static PropertyBag<TValue> CreateFromXml(string xml) { var bag = new PropertyBag<TValue>(); bag.FromXml(xml); return bag; } } } The code uses a couple of small helper classes SerializationUtils and XmlUtils for mapping Xml types to and from .NET, both of which are from the WestWind,Utilities project (which is the same project where PropertyBag lives) from the West Wind Web Toolkit. The code implements ReadXml and WriteXml for the IXmlSerializable implementation using old school XmlReaders and XmlWriters (because it's pretty simple stuff - no need for XLinq here). Then there are two helper methods .ToXml() and .FromXml() that basically allow your code to easily convert between XML and a PropertyBag object. In my code that's what I use to actually to persist to and from the entity XML property during .Load() and .Save() operations. It's sweet to be able to have a string key dictionary and then be able to turn around with 1 line of code to persist the whole thing to XML and back. Hopefully some of you will find this class as useful as I've found it. It's a simple solution to a common requirement in my applications and I've used the hell out of it in the  short time since I created it. Resources You can find the complete code for the two classes plus the helpers in the Subversion repository for Westwind.Utilities. You can grab the source files from there or download the whole project. You can also grab the full Westwind.Utilities assembly from NuGet and add it to your project if that's easier for you. PropertyBag Source Code SerializationUtils and XmlUtils Westwind.Utilities Assembly on NuGet (add from Visual Studio) © Rick Strahl, West Wind Technologies, 2005-2011Posted in .NET  CSharp   Tweet (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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• Routing Issue in ASP.NET MVC 3 RC 2

  - by imran_ku07

       Introduction:             Two weeks ago, ASP.NET MVC team shipped the ASP.NET MVC 3 RC 2 release. This release includes some new features and some performance optimization. This release also fixes most of the bugs but still some minor issues are present in this release. Some of these issues are already discussed by Scott Guthrie at Update on ASP.NET MVC 3 RC2 (and a workaround for a bug in it). In addition to these issues, I have found another issue in this release regarding routing. In this article, I will show you the issue regarding routing and a simple workaround for this issue.       Description:             The easiest way to understand an issue is to reproduce it in the application. So create a MVC 2 application and a MVC 3 RC 2 application. Then in both applications, just open global.asax file and update the default route as below,     routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id1}/{id2}", // URL with parameters new { controller = "Home", action = "Index", id1 = UrlParameter.Optional, id2 = UrlParameter.Optional } // Parameter defaults );              Then just open Index View and add the following lines,    <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Home Page </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <% Html.RenderAction("About"); %> </asp:Content>             The above view will issue a child request to About action method. Now run both applications. ASP.NET MVC 2 application will run just fine. But ASP.NET MVC 3 RC 2 application will throw an exception as shown below,                  You may think that this is a routing issue but this is not the case here as both ASP.NET MVC 2 and ASP.NET MVC  3 RC 2 applications(created above) are built with .NET Framework 4.0 and both will use the same routing defined in System.Web. Something is wrong in ASP.NET MVC 3 RC 2. So after digging into ASP.NET MVC source code, I have found that the UrlParameter class in ASP.NET MVC 3 RC 2 overrides the ToString method which simply return an empty string.     public sealed class UrlParameter { public static readonly UrlParameter Optional = new UrlParameter(); private UrlParameter() { } public override string ToString() { return string.Empty; } }             In MVC 2 the ToString method was not overridden. So to quickly fix the above problem just replace UrlParameter.Optional default value with a different value other than null or empty(for example, a single white space) or replace UrlParameter.Optional default value with a new class object containing the same code as UrlParameter class have except the ToString method is not overridden (or with a overridden ToString method that return a string value other than null or empty). But by doing this you will loose the benefit of ASP.NET MVC 2 Optional URL Parameters. There may be many different ways to fix the above problem and not loose the benefit of optional parameters. Here I will create a new class MyUrlParameter with the same code as UrlParameter class have except the ToString method is not overridden. Then I will create a base controller class which contains a constructor to remove all MyUrlParameter route data parameters, same like ASP.NET MVC doing with UrlParameter route data parameters early in the request.     public class BaseController : Controller { public BaseController() { if (System.Web.HttpContext.Current.CurrentHandler is MvcHandler) { RouteValueDictionary rvd = ((MvcHandler)System.Web.HttpContext.Current.CurrentHandler).RequestContext.RouteData.Values; string[] matchingKeys = (from entry in rvd where entry.Value == MyUrlParameter.Optional select entry.Key).ToArray(); foreach (string key in matchingKeys) { rvd.Remove(key); } } } } public class HomeController : BaseController { public ActionResult Index(string id1) { ViewBag.Message = "Welcome to ASP.NET MVC!"; return View(); } public ActionResult About() { return Content("Child Request Contents"); } }     public sealed class MyUrlParameter { public static readonly MyUrlParameter Optional = new MyUrlParameter(); private MyUrlParameter() { } }     routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id1}/{id2}", // URL with parameters new { controller = "Home", action = "Index", id1 = MyUrlParameter.Optional, id2 = MyUrlParameter.Optional } // Parameter defaults );             MyUrlParameter class is a copy of UrlParameter class except that MyUrlParameter class not overrides the ToString method. Note that the default route is modified to use MyUrlParameter.Optional instead of UrlParameter.Optional. Also note that BaseController class constructor is removing MyUrlParameter parameters from the current request route data so that the model binder will not bind these parameters with action method parameters. Now just run the ASP.NET MVC 3 RC 2 application again, you will find that it runs just fine.             In case if you are curious to know that why ASP.NET MVC 3 RC 2 application throws an exception if UrlParameter class contains a ToString method which returns an empty string, then you need to know something about a feature of routing for url generation. During url generation, routing will call the ParsedRoute.Bind method internally. This method includes a logic to match the route and build the url. During building the url, ParsedRoute.Bind method will call the ToString method of the route values(in our case this will call the UrlParameter.ToString method) and then append the returned value into url. This method includes a logic after appending the returned value into url that if two continuous returned values are empty then don't match the current route otherwise an incorrect url will be generated. Here is the snippet from ParsedRoute.Bind method which will prove this statement.       if ((builder2.Length > 0) && (builder2[builder2.Length - 1] == '/')) { return null; } builder2.Append("/"); ........................................................... ........................................................... ........................................................... ........................................................... if (RoutePartsEqual(obj3, obj4)) { builder2.Append(UrlEncode(Convert.ToString(obj3, CultureInfo.InvariantCulture))); continue; }             In the above example, both id1 and id2 parameters default values are set to UrlParameter object and UrlParameter class include a ToString method that returns an empty string. That's why this route will not matched.            Summary:             In this article I showed you the issue regarding routing and also showed you how to workaround this problem. I explained this issue with an example by creating a ASP.NET MVC 2 and a ASP.NET MVC 3 RC 2 application. Finally I also explained the reason for this issue. Hopefully you will enjoy this article too.   SyntaxHighlighter.all()

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• Creating a Dynamic DataRow for easier DataRow Syntax

  - by Rick Strahl

  I've been thrown back into an older project that uses DataSets and DataRows as their entity storage model. I have several applications internally that I still maintain that run just fine (and I sometimes wonder if this wasn't easier than all this ORM crap we deal with with 'newer' improved technology today - but I disgress) but use this older code. For the most part DataSets/DataTables/DataRows are abstracted away in a pseudo entity model, but in some situations like queries DataTables and DataRows are still surfaced to the business layer. Here's an example. Here's a business object method that runs dynamic query and the code ends up looping over the result set using the ugly DataRow Array syntax:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { string title = row["title"] as string; string safeTitle = row["safeTitle"] as string; int pk = (int)row["pk"]; string newSafeTitle = this.GetSafeTitle(title); if (newSafeTitle != safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",pk) ); result++; } } return result; } The problem with looping over DataRow objecs is two fold: The array syntax is tedious to type and not real clear to look at, and explicit casting is required in order to do anything useful with the values. I've highlighted the place where this matters. Using the DynamicDataRow class I'll show in a minute this code can be changed to look like this:public int UpdateAllSafeTitles() { int result = this.Execute("select pk, title, safetitle from " + Tablename + " where EntryType=1", "TPks"); if (result < 0) return result; result = 0; foreach (DataRow row in this.DataSet.Tables["TPks"].Rows) { dynamic entry = new DynamicDataRow(row); string newSafeTitle = this.GetSafeTitle(entry.title); if (newSafeTitle != entry.safeTitle) { this.ExecuteNonQuery("update " + this.Tablename + " set safeTitle=@safeTitle where pk=@pk", this.CreateParameter("@safeTitle",newSafeTitle), this.CreateParameter("@pk",entry.pk) ); result++; } } return result; } The code looks much a bit more natural and describes what's happening a little nicer as well. Well, using the new dynamic features in .NET it's actually quite easy to implement the DynamicDataRow class. Creating your own custom Dynamic Objects .NET 4.0 introduced the Dynamic Language Runtime (DLR) and opened up a whole bunch of new capabilities for .NET applications. The dynamic type is an easy way to avoid Reflection and directly access members of 'dynamic' or 'late bound' objects at runtime. There's a lot of very subtle but extremely useful stuff that dynamic does (especially for COM Interop scenearios) but in its simplest form it often allows you to do away with manual Reflection at runtime. In addition you can create DynamicObject implementations that can perform  custom interception of member accesses and so allow you to provide more natural access to more complex or awkward data structures like the DataRow that I use as an example here. Bascially you can subclass DynamicObject and then implement a few methods (TryGetMember, TrySetMember, TryInvokeMember) to provide the ability to return dynamic results from just about any data structure using simple property/method access. In the code above, I created a custom DynamicDataRow class which inherits from DynamicObject and implements only TryGetMember and TrySetMember. Here's what simple class looks like:/// <summary> /// This class provides an easy way to turn a DataRow /// into a Dynamic object that supports direct property /// access to the DataRow fields. /// /// The class also automatically fixes up DbNull values /// (null into .NET and DbNUll to DataRow) /// </summary> public class DynamicDataRow : DynamicObject { /// <summary> /// Instance of object passed in /// </summary> DataRow DataRow; /// <summary> /// Pass in a DataRow to work off /// </summary> /// <param name="instance"></param> public DynamicDataRow(DataRow dataRow) { DataRow = dataRow; } /// <summary> /// Returns a value from a DataRow items array. /// If the field doesn't exist null is returned. /// DbNull values are turned into .NET nulls. /// /// </summary> /// <param name="binder"></param> /// <param name="result"></param> /// <returns></returns> public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; try { result = DataRow[binder.Name]; if (result == DBNull.Value) result = null; return true; } catch { } result = null; return false; } /// <summary> /// Property setter implementation tries to retrieve value from instance /// first then into this object /// </summary> /// <param name="binder"></param> /// <param name="value"></param> /// <returns></returns> public override bool TrySetMember(SetMemberBinder binder, object value) { try { if (value == null) value = DBNull.Value; DataRow[binder.Name] = value; return true; } catch {} return false; } } To demonstrate the basic features here's a short test: [TestMethod] [ExpectedException(typeof(RuntimeBinderException))] public void BasicDataRowTests() { DataTable table = new DataTable("table"); table.Columns.Add( new DataColumn() { ColumnName = "Name", DataType=typeof(string) }); table.Columns.Add( new DataColumn() { ColumnName = "Entered", DataType=typeof(DateTime) }); table.Columns.Add(new DataColumn() { ColumnName = "NullValue", DataType = typeof(string) }); DataRow row = table.NewRow(); DateTime now = DateTime.Now; row["Name"] = "Rick"; row["Entered"] = now; row["NullValue"] = null; // converted in DbNull dynamic drow = new DynamicDataRow(row); string name = drow.Name; DateTime entered = drow.Entered; string nulled = drow.NullValue; Assert.AreEqual(name, "Rick"); Assert.AreEqual(entered,now); Assert.IsNull(nulled); // this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); } The DynamicDataRow requires a custom constructor that accepts a single parameter that sets the DataRow. Once that's done you can access property values that match the field names. Note that types are automatically converted - no type casting is needed in the code you write. The class also automatically converts DbNulls to regular nulls and vice versa which is something that makes it much easier to deal with data returned from a database. What's cool here isn't so much the functionality - even if I'd prefer to leave DataRow behind ASAP -  but the fact that we can create a dynamic type that uses a DataRow as it's 'DataSource' to serve member values. It's pretty useful feature if you think about it, especially given how little code it takes to implement. By implementing these two simple methods we get to provide two features I was complaining about at the beginning that are missing from the DataRow: Direct Property Syntax Automatic Type Casting so no explicit casts are required Caveats As cool and easy as this functionality is, it's important to understand that it doesn't come for free. The dynamic features in .NET are - well - dynamic. Which means they are essentially evaluated at runtime (late bound). Rather than static typing where everything is compiled and linked by the compiler/linker, member invokations are looked up at runtime and essentially call into your custom code. There's some overhead in this. Direct invocations - the original code I showed - is going to be faster than the equivalent dynamic code. However, in the above code the difference of running the dynamic code and the original data access code was very minor. The loop running over 1500 result records took on average 13ms with the original code and 14ms with the dynamic code. Not exactly a serious performance bottleneck. One thing to remember is that Microsoft optimized the DLR code significantly so that repeated calls to the same operations are routed very efficiently which actually makes for very fast evaluation. The bottom line for performance with dynamic code is: Make sure you test and profile your code if you think that there might be a performance issue. However, in my experience with dynamic types so far performance is pretty good for repeated operations (ie. in loops). While usually a little slower the perf hit is a lot less typically than equivalent Reflection work. Although the code in the second example looks like standard object syntax, dynamic is not static code. It's evaluated at runtime and so there's no type recognition until runtime. This means no Intellisense at development time, and any invalid references that call into 'properties' (ie. fields in the DataRow) that don't exist still cause runtime errors. So in the case of the data row you still get a runtime error if you mistype a column name:// this should throw a RuntimeBinderException Assert.AreEqual(entered,drow.enteredd); Dynamic - Lots of uses The arrival of Dynamic types in .NET has been met with mixed emotions. Die hard .NET developers decry dynamic types as an abomination to the language. After all what dynamic accomplishes goes against all that a static language is supposed to provide. On the other hand there are clearly scenarios when dynamic can make life much easier (COM Interop being one place). Think of the possibilities. What other data structures would you like to expose to a simple property interface rather than some sort of collection or dictionary? And beyond what I showed here you can also implement 'Method missing' behavior on objects with InvokeMember which essentially allows you to create dynamic methods. It's all very flexible and maybe just as important: It's easy to do. There's a lot of power hidden in this seemingly simple interface. Your move…© Rick Strahl, West Wind Technologies, 2005-2011Posted in CSharp  .NET   Tweet (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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• Launching a WPF Window in a Separate Thread, Part 1

  - by Reed

  Typically, I strongly recommend keeping the user interface within an application’s main thread, and using multiple threads to move the actual “work” into background threads.  However, there are rare times when creating a separate, dedicated thread for a Window can be beneficial.  This is even acknowledged in the MSDN samples, such as the Multiple Windows, Multiple Threads sample.  However, doing this correctly is difficult.  Even the referenced MSDN sample has major flaws, and will fail horribly in certain scenarios.  To ease this, I wrote a small class that alleviates some of the difficulties involved. The MSDN Multiple Windows, Multiple Threads Sample shows how to launch a new thread with a WPF Window, and will work in most cases.  The sample code (commented and slightly modified) works out to the following: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create and show the Window Window1 tempWindow = new Window1(); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Set the apartment state newWindowThread.SetApartmentState(ApartmentState.STA); // Make the thread a background thread newWindowThread.IsBackground = true; // Start the thread newWindowThread.Start(); .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; } This sample creates a thread, marks it as single threaded apartment state, and starts the Dispatcher on that thread. That is the minimum requirements to get a Window displaying and handling messages correctly, but, unfortunately, has some serious flaws. The first issue – the created thread will run continuously until the application shuts down, given the code in the sample.  The problem is that the ThreadStart delegate used ends with running the Dispatcher.  However, nothing ever stops the Dispatcher processing.  The thread was created as a Background thread, which prevents it from keeping the application alive, but the Dispatcher will continue to pump dispatcher frames until the application shuts down. In order to fix this, we need to call Dispatcher.InvokeShutdown after the Window is closed.  This would require modifying the above sample to subscribe to the Window’s Closed event, and, at that point, shutdown the Dispatcher: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This eliminates the first issue.  Now, when the Window is closed, the new thread’s Dispatcher will shut itself down, which in turn will cause the thread to complete. The above code will work correctly for most situations.  However, there is still a potential problem which could arise depending on the content of the Window1 class.  This is particularly nasty, as the code could easily work for most windows, but fail on others. The problem is, at the point where the Window is constructed, there is no active SynchronizationContext.  This is unlikely to be a problem in most cases, but is an absolute requirement if there is code within the constructor of Window1 which relies on a context being in place. While this sounds like an edge case, it’s fairly common.  For example, if a BackgroundWorker is started within the constructor, or a TaskScheduler is built using TaskScheduler.FromCurrentSynchronizationContext() with the expectation of synchronizing work to the UI thread, an exception will be raised at some point.  Both of these classes rely on the existence of a proper context being installed to SynchronizationContext.Current, which happens automatically, but not until Dispatcher.Run is called.  In the above case, SynchronizationContext.Current will return null during the Window’s construction, which can cause exceptions to occur or unexpected behavior. Luckily, this is fairly easy to correct.  We need to do three things, in order, prior to creating our Window: Create and initialize the Dispatcher for the new thread manually Create a synchronization context for the thread which uses the Dispatcher Install the synchronization context Creating the Dispatcher is quite simple – The Dispatcher.CurrentDispatcher property gets the current thread’s Dispatcher and “creates a new Dispatcher if one is not already associated with the thread.”  Once we have the correct Dispatcher, we can create a SynchronizationContext which uses the dispatcher by creating a DispatcherSynchronizationContext.  Finally, this synchronization context can be installed as the current thread’s context via SynchronizationContext.SetSynchronizationContext.  These three steps can easily be added to the above via a single line of code: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create our context, and install it: SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext( Dispatcher.CurrentDispatcher)); Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This now forces the synchronization context to be in place before the Window is created and correctly shuts down the Dispatcher when the window closes. However, there are quite a few steps.  In my next post, I’ll show how to make this operation more reusable by creating a class with a far simpler API…

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• Java JRE 7 Certified with Oracle E-Business Suite

  - by Steven Chan (Oracle Development)

  Java Runtime Environment 7u10 (a.k.a. JRE 1.7.0_10 build 18) and later updates on the JRE 7 codeline are now certified with Oracle E-Business Suite Release 11i and 12 Windows-based desktop clients. What's needed to enable EBS environments for JRE 7? EBS customers should ensure that they are running JRE 7u10, at minimum, on Windows desktop clients. Of the compatibility issues identified with JRE 7, the most critical is an issue that prevents E-Business Suite Forms-based products from launching on Windows desktops that are running JRE 7.  Customers can prevent this issue -- and all other JRE 7 compatibility issues -- by ensuring that they have applied the latest certified patches documented for JRE 7 configurations to their EBS application tier servers.  These are summarized here for convenience. If the requirements change over time, please check the Notes for the authoritative list of patches: Apply Forms patch 14615390 to EBS 11i environments (Note 125767.1) Apply Forms patch 14614795 to EBS 12.0 and 12.1 environments (Note 437878.1) These patches are compatible with JRE 6 and 7, production ready, and fully-tested with the E-Business Suite.  These patches may be applied immediately to all E-Business Suite environments. All other Forms prerequisites documented in the Notes above should also be applied.  Where are the official patch requirements documented? All patches required for ensuring full compatibility of the E-Business Suite with JRE 7 are documented in these Notes: For EBS 11i: Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 11i (Note 290807.1) Upgrading Developer 6i with Oracle E-Business Suite 11i (Note 125767.1) For EBS 12 Deploying Sun JRE (Native Plug-in) for Windows Clients in Oracle E-Business Suite Release 12 (Note 393931.1) Upgrading OracleAS 10g Forms and Reports in Oracle E-Business Suite Release 12 (Note 437878.1) Prerequisites for 32-bit and 64-bit JRE certifications JRE 1.70_10 32-bit + EBS 11.5.10.2 Windows XP SP3 Windows Vista SP1 and SP2 Windows 7 and Windows 7 SP1  Forms 6.0.8.28.x patch 14615390 (Note 125767.1) JRE 1.70_10 32-bit + EBS 12.0 & 12.1 Windows XP SP3 Windows Vista SP1 and SP2 Windows 7 and Windows 7 SP1 Forms 10g overlay patch 14614795 (Note 437878.1) SSL Users:  10.1.0.5 version of Patch 6370967 applied to AS 10.1.3 with OPatch. Note: This fix is already included in the April 2011 AS 10.1.3.5 CPU patch and later. JRE 1.7.0_10 64-bit + EBS 11.5.10.2 Windows 7 (64-bit) and Windows 7 SP1 (64-bit) Forms 6.0.8.28.x patch 14615390 (Note 125767.1) JRE 1.70_10 64-bit + EBS 12.0 & 12.1 Windows 7 (64-bit) and Windows 7 SP1 (64-bit) Forms 10g overlay patch 14614795 (Note 437878.1) SSL Users:  10.1.0.5 version of Patch 6370967 applied to AS 10.1.3 with OPatch. Note: This fix is already included in the April 2011 AS 10.1.3.5 CPU patch and later.  EBS + Discoverer 11g Users JRE 1.7.0_10 (7u10) is certified for Discoverer 11g in E-Business Suite environments with the following minimum requirements: Discoverer (11g) 11.1.1.6 plus Patch 13877486 and later  Reference: How To Find Oracle BI Discoverer 10g and 11g Certification Information (Document 233047.1) Worried about the 'mismanaged session cookie' issue? No need to worry -- it's fixed.  To recap: JRE releases 1.6.0_18 through 1.6.0_22 had issues with mismanaging session cookies that affected some users in some circumstances. The fix for those issues was first included in JRE 1.6.0_23. These fixes will carry forward and continue to be fixed in all future JRE releases on the JRE 6 and 7 codelines.  In other words, if you wish to avoid the mismanaged session cookie issue, you should apply any release after JRE 1.6.0_22 on the JRE 6 codeline, and JRE 7u10 and later JRE 7 codeline updates. All JRE 6 and 7 releases are certified with EBS upon release Our standard policy is that all E-Business Suite customers can apply all JRE updates to end-user desktops from JRE 1.6.0_03 and later updates on the 1.6 codeline, and from JRE 7u10 and later updates on the JRE 7 codeline.  We test all new JRE 1.6 and JRE 7 releases in parallel with the JRE development process, so all new JRE 1.6 and 7 releases are considered certified with the E-Business Suite on the same day that they're released by our Java team.  You do not need to wait for a certification announcement before applying new JRE 1.6 or JRE 7 releases to your EBS users' desktops. Implications of Java 6 End of Public Updates for EBS Users The Support Roadmap for Oracle Java is published here: Oracle Java SE Support Roadmap The latest updates to that page (as of Sept. 19, 2012) state (emphasis added): Java SE 6 End of Public Updates Notice After February 2013, Oracle will no longer post updates of Java SE 6 to its public download sites. Existing Java SE 6 downloads already posted as of February 2013 will remain accessible in the Java Archive on Oracle Technology Network. Developers and end-users are encouraged to update to more recent Java SE versions that remain available for public download. For enterprise customers, who need continued access to critical bug fixes and security fixes as well as general maintenance for Java SE 6 or older versions, long term support is available through Oracle Java SE Support . What does this mean for Oracle E-Business Suite users? EBS users fall under the category of "enterprise users" above.  Java is an integral part of the Oracle E-Business Suite technology stack, so EBS users will continue to receive Java SE 6 updates after February 2013. In other words, nothing will change for EBS users after February 2013.  EBS users will continue to receive critical bug fixes and security fixes as well as general maintenance for Java SE 6. These Java SE 6 updates will be made available to EBS users for the Extended Support periods documented in the Oracle Lifetime Support policy document for Oracle Applications (PDF): EBS 11i Extended Support ends November 2013 EBS 12.0 Extended Support ends January 2015 EBS 12.1 Extended Support ends December 2018 Will EBS users be forced to upgrade to JRE 7 for Windows desktop clients? No. This upgrade is highly recommended but currently remains optional. JRE 6 will be available to Windows users to run with EBS for the duration of your respective EBS Extended Support period.  Updates will be delivered via My Oracle Support, where you can continue to receive critical bug fixes and security fixes as well as general maintenance for JRE 6 desktop clients.  Coexistence of JRE 6 and JRE 7 on Windows desktops The upgrade to JRE 7 is highly recommended for EBS users, but some users may need to run both JRE 6 and 7 on their Windows desktops for reasons unrelated to the E-Business Suite. Most EBS configurations with IE and Firefox use non-static versioning by default. JRE 7 will be invoked instead of JRE 6 if both are installed on a Windows desktop. For more details, see "Appendix B: Static vs. Non-static Versioning and Set Up Options" in Notes 290801.1 and 393931.1. Applying Updates to JRE 6 and JRE 7 to Windows desktops Auto-update will keep JRE 7 up-to-date for Windows users with JRE 7 installed. Auto-update will only keep JRE 7 up-to-date for Windows users with both JRE 6 and 7 installed.  JRE 6 users are strongly encouraged to apply the latest Critical Patch Updates as soon as possible after each release. The Jave SE CPUs will be available via My Oracle Support.  EBS users can find more information about JRE 6 and 7 updates here: Information Center: Installation & Configuration for Oracle Java SE (Note 1412103.2) The dates for future Java SE CPUs can be found on the Critical Patch Updates, Security Alerts and Third Party Bulletin.  An RSS feed is available on that site for those who would like to be kept up-to-date. What will Mac users need? Oracle will provide updates to JRE 7 for Mac OS X users. EBS users running Macs will need to upgrade to JRE 7 to receive JRE updates. The certification of Oracle E-Business Suite with JRE 7 for Mac-based desktop clients accessing EBS Forms-based content is underway. Mac users waiting for that certification may find this article useful: How to Reenable Apple Java 6 Plug-in for Mac EBS Users Will EBS users be forced to upgrade to JDK 7 for EBS application tier servers? No. This upgrade will be highly recommended but will be optional for EBS application tier servers running on Windows, Linux, and Solaris.  You can choose to remain on JDK 6 for the duration of your respective EBS Extended Support period.  If you remain on JDK 6, you will continue to receive critical bug fixes and security fixes as well as general maintenance for JDK 6. The certification of Oracle E-Business Suite with JDK 7 for EBS application tier servers on Windows, Linux, and Solaris as well as other platforms such as IBM AIX and HP-UX is planned.  Customers running platforms other than Windows, Linux, and Solaris should refer to their Java vendors's sites for more information about their support policies. References Recommended Browsers for Oracle Applications 11i (Metalink Note 285218.1) Upgrading Sun JRE (Native Plug-in) with Oracle Applications 11i for Windows Clients (Metalink Note 290807.1) Recommended Browsers for Oracle Applications 12 (MetaLink Note 389422.1) Upgrading JRE Plugin with Oracle Applications R12 (MetaLink Note 393931.1) Related Articles Mismanaged Session Cookie Issue Fixed for EBS in JRE 1.6.0_23 Roundup: Oracle JInitiator 1.3 Desupported for EBS Customers in July 2009

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• Performance Optimization &ndash; It Is Faster When You Can Measure It

  - by Alois Kraus

  Performance optimization in bigger systems is hard because the measured numbers can vary greatly depending on the measurement method of your choice. To measure execution timing of specific methods in your application you usually use Time Measurement Method Potential Pitfalls Stopwatch Most accurate method on recent processors. Internally it uses the RDTSC instruction. Since the counter is processor specific you can get greatly different values when your thread is scheduled to another core or the core goes into a power saving mode. But things do change luckily: Intel's Designer's vol3b, section 16.11.1 "16.11.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor's support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource." DateTime.Now Good but it has only a resolution of 16ms which can be not enough if you want more accuracy.   Reporting Method Potential Pitfalls Console.WriteLine Ok if not called too often. Debug.Print Are you really measuring performance with Debug Builds? Shame on you. Trace.WriteLine Better but you need to plug in some good output listener like a trace file. But be aware that the first time you call this method it will read your app.config and deserialize your system.diagnostics section which does also take time.   In general it is a good idea to use some tracing library which does measure the timing for you and you only need to decorate some methods with tracing so you can later verify if something has changed for the better or worse. In my previous article I did compare measuring performance with quantum mechanics. This analogy does work surprising well. When you measure a quantum system there is a lower limit how accurately you can measure something. The Heisenberg uncertainty relation does tell us that you cannot measure of a quantum system the impulse and location of a particle at the same time with infinite accuracy. For programmers the two variables are execution time and memory allocations. If you try to measure the timings of all methods in your application you will need to store them somewhere. The fastest storage space besides the CPU cache is the memory. But if your timing values do consume all available memory there is no memory left for the actual application to run. On the other hand if you try to record all memory allocations of your application you will also need to store the data somewhere. This will cost you memory and execution time. These constraints are always there and regardless how good the marketing of tool vendors for performance and memory profilers are: Any measurement will disturb the system in a non predictable way. Commercial tool vendors will tell you they do calculate this overhead and subtract it from the measured values to give you the most accurate values but in reality it is not entirely true. After falling into the trap to trust the profiler timings several times I have got into the habit to Measure with a profiler to get an idea where potential bottlenecks are. Measure again with tracing only the specific methods to check if this method is really worth optimizing. Optimize it Measure again. Be surprised that your optimization has made things worse. Think harder Implement something that really works. Measure again Finished! - Or look for the next bottleneck. Recently I have looked into issues with serialization performance. For serialization DataContractSerializer was used and I was not sure if XML is really the most optimal wire format. After looking around I have found protobuf-net which uses Googles Protocol Buffer format which is a compact binary serialization format. What is good for Google should be good for us. A small sample app to check out performance was a matter of minutes: using ProtoBuf; using System; using System.Diagnostics; using System.IO; using System.Reflection; using System.Runtime.Serialization; [DataContract, Serializable] class Data { [DataMember(Order=1)] public int IntValue { get; set; } [DataMember(Order = 2)] public string StringValue { get; set; } [DataMember(Order = 3)] public bool IsActivated { get; set; } [DataMember(Order = 4)] public BindingFlags Flags { get; set; } } class Program { static MemoryStream _Stream = new MemoryStream(); static MemoryStream Stream { get { _Stream.Position = 0; _Stream.SetLength(0); return _Stream; } } static void Main(string[] args) { DataContractSerializer ser = new DataContractSerializer(typeof(Data)); Data data = new Data { IntValue = 100, IsActivated = true, StringValue = "Hi this is a small string value to check if serialization does work as expected" }; var sw = Stopwatch.StartNew(); int Runs = 1000 * 1000; for (int i = 0; i < Runs; i++) { //ser.WriteObject(Stream, data); Serializer.Serialize<Data>(Stream, data); } sw.Stop(); Console.WriteLine("Did take {0:N0}ms for {1:N0} objects", sw.Elapsed.TotalMilliseconds, Runs); Console.ReadLine(); } } The results are indeed promising: Serializer Time in ms N objects protobuf-net   807 1000000 DataContract 4402 1000000 Nearly a factor 5 faster and a much more compact wire format. Lets use it! After switching over to protbuf-net the transfered wire data has dropped by a factor two (good) and the performance has worsened by nearly a factor two. How is that possible? We have measured it? Protobuf-net is much faster! As it turns out protobuf-net is faster but it has a cost: For the first time a type is de/serialized it does use some very smart code-gen which does not come for free. Lets try to measure this one by setting of our performance test app the Runs value not to one million but to 1. Serializer Time in ms N objects protobuf-net 85 1 DataContract 24 1 The code-gen overhead is significant and can take up to 200ms for more complex types. The break even point where the code-gen cost is amortized by its faster serialization performance is (assuming small objects) somewhere between 20.000-40.000 serialized objects. As it turned out my specific scenario involved about 100 types and 1000 serializations in total. That explains why the good old DataContractSerializer is not so easy to take out of business. The final approach I ended up was to reduce the number of types and to serialize primitive types via BinaryWriter directly which turned out to be a pretty good alternative. It sounded good until I measured again and found that my optimizations so far do not help much. After looking more deeper at the profiling data I did found that one of the 1000 calls did take 50% of the time. So how do I find out which call it was? Normal profilers do fail short at this discipline. A (totally undeserved) relatively unknown profiler is SpeedTrace which does unlike normal profilers create traces of your applications by instrumenting your IL code at runtime. This way you can look at the full call stack of the one slow serializer call to find out if this stack was something special. Unfortunately the call stack showed nothing special. But luckily I have my own tracing as well and I could see that the slow serializer call did happen during the serialization of a bool value. When you encounter after much analysis something unreasonable you cannot explain it then the chances are good that your thread was suspended by the garbage collector. If there is a problem with excessive GCs remains to be investigated but so far the serialization performance seems to be mostly ok.  When you do profile a complex system with many interconnected processes you can never be sure that the timings you just did measure are accurate at all. Some process might be hitting the disc slowing things down for all other processes for some seconds as well. There is a big difference between warm and cold startup. If you restart all processes you can basically forget the first run because of the OS disc cache, JIT and GCs make the measured timings very flexible. When you are in need of a random number generator you should measure cold startup times of a sufficiently complex system. After the first run you can try again getting different and much lower numbers. Now try again at least two times to get some feeling how stable the numbers are. Oh and try to do the same thing the next day. It might be that the bottleneck you found yesterday is gone today. Thanks to GC and other random stuff it can become pretty hard to find stuff worth optimizing if no big bottlenecks except bloatloads of code are left anymore. When I have found a spot worth optimizing I do make the code changes and do measure again to check if something has changed. If it has got slower and I am certain that my change should have made it faster I can blame the GC again. The thing is that if you optimize stuff and you allocate less objects the GC times will shift to some other location. If you are unlucky it will make your faster working code slower because you see now GCs at times where none were before. This is where the stuff does get really tricky. A safe escape hatch is to create a repro of the slow code in an isolated application so you can change things fast in a reliable manner. Then the normal profilers do also start working again. As Vance Morrison does point out it is much more complex to profile a system against the wall clock compared to optimize for CPU time. The reason is that for wall clock time analysis you need to understand how your system does work and which threads (if you have not one but perhaps 20) are causing a visible delay to the end user and which threads can wait a long time without affecting the user experience at all. Next time: Commercial profiler shootout.

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• Caching NHibernate Named Queries

  - by TStewartDev

  I recently started a new job and one of my first tasks was to implement a "popular products" design. The parameters were that it be done with NHibernate and be cached for 24 hours at a time because the query will be pretty taxing and the results do not need to be constantly up to date. This ended up being tougher than it sounds. The database schema meant a minimum of four joins with filtering and ordering criteria. I decided to use a stored procedure rather than letting NHibernate create the SQL for me. Here is a summary of what I learned (even if I didn't ultimately use all of it): You can't, at the time of this writing, use Fluent NHibernate to configure SQL named queries or imports You can return persistent entities from a stored procedure and there are a couple ways to do that You can populate POCOs using the results of a stored procedure, but it isn't quite as obvious You can reuse your named query result mapping other places (avoid duplication) Caching your query results is not at all obvious Testing to see if your cache is working is a pain NHibernate does a lot of things right. Having unified, up-to-date, comprehensive, and easy-to-find documentation is not one of them. By the way, if you're new to this, I'll use the terms "named query" and "stored procedure" (from NHibernate's perspective) fairly interchangeably. Technically, a named query can execute any SQL, not just a stored procedure, and a stored procedure doesn't have to be executed from a named query, but for reusability, it seems to me like the best practice. If you're here, chances are good you're looking for answers to a similar problem. You don't want to read about the path, you just want the result. So, here's how to get this thing going. The Stored Procedure NHibernate has some guidelines when using stored procedures. For Microsoft SQL Server, you have to return a result set. The scalar value that the stored procedure returns is ignored as are any result sets after the first. Other than that, it's nothing special. CREATE PROCEDURE GetPopularProducts @StartDate DATETIME, @MaxResults INT AS BEGIN SELECT [ProductId], [ProductName], [ImageUrl] FROM SomeTableWithJoinsEtc END The Result Class - PopularProduct You have two options to transport your query results to your view (or wherever is the final destination): you can populate an existing mapped entity class in your model, or you can create a new entity class. If you go with the existing model, the advantage is that the query will act as a loader and you'll get full proxied access to the domain model. However, this can be a disadvantage if you require access to the related entities that aren't loaded by your results. For example, my PopularProduct has image references. Unless I tie them into the query (thus making it even more complicated and expensive to run), they'll have to be loaded on access, requiring more trips to the database. Since we're trying to avoid trips to the database by using a second-level cache, we should use the second option, which is to create a separate entity for results. This approach is (I believe) in the spirit of the Command-Query Separation principle, and it allows us to flatten our data and optimize our report-generation process from data source to view. public class PopularProduct { public virtual int ProductId { get; set; } public virtual string ProductName { get; set; } public virtual string ImageUrl { get; set; } } The NHibernate Mappings (hbm) Next up, we need to let NHibernate know about the query and where the results will go. Below is the markup for the PopularProduct class. Notice that I'm using the <resultset> element and that it has a name attribute. The name allows us to drop this into our query map and any others, giving us reusability. Also notice the <import> element which lets NHibernate know about our entity class. <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <import class="PopularProduct, Infrastructure.NHibernate, Version=1.0.0.0"/> <resultset name="PopularProductResultSet"> <return-scalar column="ProductId" type="System.Int32"/> <return-scalar column="ProductName" type="System.String"/> <return-scalar column="ImageUrl" type="System.String"/> </resultset> </hibernate-mapping>  And now the PopularProductsMap: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"> <sql-query name="GetPopularProducts" resultset-ref="PopularProductResultSet" cacheable="true" cache-mode="normal"> <query-param name="StartDate" type="System.DateTime" /> <query-param name="MaxResults" type="System.Int32" /> exec GetPopularProducts @StartDate = :StartDate, @MaxResults = :MaxResults </sql-query> </hibernate-mapping>  The two most important things to notice here are the resultset-ref attribute, which links in our resultset mapping, and the cacheable attribute. The Query Class – PopularProductsQuery So far, this has been fairly obvious if you're familiar with NHibernate. This next part, maybe not so much. You can implement your query however you want to; for me, I wanted a self-encapsulated Query class, so here's what it looks like: public class PopularProductsQuery : IPopularProductsQuery { private static readonly IResultTransformer ResultTransformer; private readonly ISessionBuilder _sessionBuilder;   static PopularProductsQuery() { ResultTransformer = Transformers.AliasToBean<PopularProduct>(); }   public PopularProductsQuery(ISessionBuilder sessionBuilder) { _sessionBuilder = sessionBuilder; }   public IList<PopularProduct> GetPopularProducts(DateTime startDate, int maxResults) { var session = _sessionBuilder.GetSession(); var popularProducts = session .GetNamedQuery("GetPopularProducts") .SetCacheable(true) .SetCacheRegion("PopularProductsCacheRegion") .SetCacheMode(CacheMode.Normal) .SetReadOnly(true) .SetResultTransformer(ResultTransformer) .SetParameter("StartDate", startDate.Date) .SetParameter("MaxResults", maxResults) .List<PopularProduct>();   return popularProducts; } }  Okay, so let's look at each line of the query execution. The first, GetNamedQuery, matches up with our NHibernate mapping for the sql-query. Next, we set it as cacheable (this is probably redundant since our mapping also specified it, but it can't hurt, right?). Then we set the cache region which we'll get to in the next section. Set the cache mode (optional, I believe), and my cache is read-only, so I set that as well. The result transformer is very important. This tells NHibernate how to transform your query results into a non-persistent entity. You can see I've defined ResultTransformer in the static constructor using the AliasToBean transformer. The name is obviously leftover from Java/Hibernate. Finally, set your parameters and then call a result method which will execute the query. Because this is set to cached, you execute this statement every time you run the query and NHibernate will know based on your parameters whether to use its cached version or a fresh version. The Configuration – hibernate.cfg.xml and Web.config You need to explicitly enable second-level caching in your hibernate configuration: <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> <session-factory> [...] <property name="dialect">NHibernate.Dialect.MsSql2005Dialect</property> <property name="cache.provider_class">NHibernate.Caches.SysCache.SysCacheProvider,NHibernate.Caches.SysCache</property> <property name="cache.use_query_cache">true</property> <property name="cache.use_second_level_cache">true</property> [...] </session-factory> </hibernate-configuration> Both properties "use_query_cache" and "use_second_level_cache" are necessary. As this is for a web deployement, we're using SysCache which relies on ASP.NET's caching. Be aware of this if you're not deploying to the web! You'll have to use a different cache provider. We also need to tell our cache provider (in this cache, SysCache) about our caching region: <syscache> <cache region="PopularProductsCacheRegion" expiration="86400" priority="5" /> </syscache> Here I've set the cache to be valid for 24 hours. This XML snippet goes in your Web.config (or in a separate file referenced by Web.config, which helps keep things tidy). The Payoff That should be it! At this point, your queries should run once against the database for a given set of parameters and then use the cache thereafter until it expires. You can, of course, adjust settings to work in your particular environment. Testing Testing your application to ensure it is using the cache is a pain, but if you're like me, you want to know that it's actually working. It's a bit involved, though, so I'll create a separate post for it if comments indicate there is interest.

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• Authenticating clients in the new WCF Http stack

  - by cibrax

  About this time last year, I wrote a couple of posts about how to use the “Interceptors” from the REST starker kit for implementing several authentication mechanisms like “SAML”, “Basic Authentication” or “OAuth” in the WCF Web programming model. The things have changed a lot since then, and Glenn finally put on our hands a new version of the Web programming model that deserves some attention and I believe will help us a lot to build more Http oriented services in the .NET stack. What you can get today from wcf.codeplex.com is a preview with some cool features like Http Processors (which I already discussed here), a new and improved version of the HttpClient library, Dependency injection and better TDD support among others. However, the framework still does not support an standard way of doing client authentication on the services (This is something planned for the upcoming releases I believe). For that reason, moving the existing authentication interceptors to this new programming model was one of the things I did in the last few days. In order to make authentication simple and easy to extend,  I first came up with a model based on what I called “Authentication Interceptors”. An authentication interceptor maps to an existing Http authentication mechanism and implements the following interface, public interface IAuthenticationInterceptor{ string Scheme { get; } bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal);} An authentication interceptors basically needs to returns the http authentication schema that implements in the property “Scheme”, and implements the authentication mechanism in the method “DoAuthentication”. As you can see, this last method “DoAuthentication” only relies on the HttpRequestMessage and HttpResponseMessage classes, making the testing of this interceptor very simple (There is no need to do some black magic with the WCF context or messages). After this, I implemented a couple of interceptors for supporting basic authentication and brokered authentication with SAML (using WIF) in my services. The following code illustrates how the basic authentication interceptors looks like. public class BasicAuthenticationInterceptor : IAuthenticationInterceptor{ Func<UsernameAndPassword, bool> userValidation; string realm;  public BasicAuthenticationInterceptor(Func<UsernameAndPassword, bool> userValidation, string realm) { if (userValidation == null) throw new ArgumentNullException("userValidation");  if (string.IsNullOrEmpty(realm)) throw new ArgumentNullException("realm");  this.userValidation = userValidation; this.realm = realm; }  public string Scheme { get { return "Basic"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { string[] credentials = ExtractCredentials(request); if (credentials.Length == 0 || !AuthenticateUser(credentials[0], credentials[1])) { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied"); response.Headers.WwwAuthenticate.Add(new AuthenticationHeaderValue("Basic", "realm=" + this.realm));  principal = null;  return false; } else { principal = new GenericPrincipal(new GenericIdentity(credentials[0]), new string[] {});  return true; } }  private string[] ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme.StartsWith("Basic")) { string encodedUserPass = request.Headers.Authorization.Parameter.Trim();  Encoding encoding = Encoding.GetEncoding("iso-8859-1"); string userPass = encoding.GetString(Convert.FromBase64String(encodedUserPass)); int separator = userPass.IndexOf(':');  string[] credentials = new string[2]; credentials[0] = userPass.Substring(0, separator); credentials[1] = userPass.Substring(separator + 1);  return credentials; }  return new string[] { }; }  private bool AuthenticateUser(string username, string password) { var usernameAndPassword = new UsernameAndPassword { Username = username, Password = password };  if (this.userValidation(usernameAndPassword)) { return true; }  return false; }} This interceptor receives in the constructor a callback in the form of a Func delegate for authenticating the user and the “realm”, which is required as part of the implementation. The rest is a general implementation of the basic authentication mechanism using standard http request and response messages. I also implemented another interceptor for authenticating a SAML token with WIF. public class SamlAuthenticationInterceptor : IAuthenticationInterceptor{ SecurityTokenHandlerCollection handlers = null;  public SamlAuthenticationInterceptor(SecurityTokenHandlerCollection handlers) { if (handlers == null) throw new ArgumentNullException("handlers");  this.handlers = handlers; }  public string Scheme { get { return "saml"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { SecurityToken token = ExtractCredentials(request);  if (token != null) { ClaimsIdentityCollection claims = handlers.ValidateToken(token);  principal = new ClaimsPrincipal(claims);  return true; } else { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied");  principal = null;  return false; } }  private SecurityToken ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme == "saml") { XmlTextReader xmlReader = new XmlTextReader(new StringReader(request.Headers.Authorization.Parameter));  var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection(); SecurityToken token = col.ReadToken(xmlReader);  return token; }  return null; }}This implementation receives a “SecurityTokenHandlerCollection” instance as part of the constructor. This class is part of WIF, and basically represents a collection of token managers to know how to handle specific xml authentication tokens (SAML is one of them). I also created a set of extension methods for injecting these interceptors as part of a service route when the service is initialized. var basicAuthentication = new BasicAuthenticationInterceptor((u) => true, "ContactManager");var samlAuthentication = new SamlAuthenticationInterceptor(serviceConfiguration.SecurityTokenHandlers); // use MEF for providing instancesvar catalog = new AssemblyCatalog(typeof(Global).Assembly);var container = new CompositionContainer(catalog);var configuration = new ContactManagerConfiguration(container); RouteTable.Routes.AddServiceRoute<ContactResource>("contact", configuration, basicAuthentication, samlAuthentication);RouteTable.Routes.AddServiceRoute<ContactsResource>("contacts", configuration, basicAuthentication, samlAuthentication); In the code above, I am injecting the basic authentication and saml authentication interceptors in the “contact” and “contacts” resource implementations that come as samples in the code preview. I will use another post to discuss more in detail how the brokered authentication with SAML model works with this new WCF Http bits. The code is available to download in this location.

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• Integrating NetBeans for Raspberry Pi Java Development

  - by speakjava

  Raspberry Pi IDE Java Development The Raspberry Pi is an incredible device for building embedded Java applications but, despite being able to run an IDE on the Pi it really pushes things to the limit.  It's much better to use a PC or laptop to develop the code and then deploy and test on the Pi.  What I thought I'd do in this blog entry was to run through the steps necessary to set up NetBeans on a PC for Java code development, with automatic deployment to the Raspberry Pi as part of the build process. I will assume that your starting point is a Raspberry Pi with an SD card that has one of the latest Raspbian images on it.  This is good because this now includes the JDK 7 as part of the distro, so no need to download and install a separate JDK.  I will also assume that you have installed the JDK and NetBeans on your PC.  These can be downloaded here. There are numerous approaches you can take to this including mounting the file system from the Raspberry Pi remotely on your development machine.  I tried this and I found that NetBeans got rather upset if the file system disappeared either through network interruption or the Raspberry Pi being turned off.  The following method uses copying over SSH, which will fail more gracefully if the Pi is not responding. Step 1: Enable SSH on the Raspberry Pi To run the Java applications you create you will need to start Java on the Raspberry Pi with the appropriate class name, classpath and parameters.  For non-JavaFX applications you can either do this from the Raspberry Pi desktop or, if you do not have a monitor connected through a remote command line.  To execute the remote command line you need to enable SSH (a secure shell login over the network) and connect using an application like PuTTY. You can enable SSH when you first boot the Raspberry Pi, as the raspi-config program runs automatically.  You can also run it at any time afterwards by running the command: sudo raspi-config This will bring up a menu of options.  Select '8 Advanced Options' and on the next screen select 'A$ SSH'.  Select 'Enable' and the task is complete. Step 2: Configure Raspberry Pi Networking By default, the Raspbian distribution configures the ethernet connection to use DHCP rather than a static IP address.  You can continue to use DHCP if you want, but to avoid having to potentially change settings whenever you reboot the Pi using a static IP address is simpler. To configure this on the Pi you need to edit the /etc/network/interfaces file.  You will need to do this as root using the sudo command, so something like sudo vi /etc/network/interfaces.  In this file you will see this line: iface eth0 inet dhcp This needs to be changed to the following: iface eth0 inet static     address 10.0.0.2     gateway 10.0.0.254     netmask 255.255.255.0 You will need to change the values in red to an appropriate IP address and to match the address of your gateway. Step 3: Create a Public-Private Key Pair On Your Development Machine How you do this will depend on which Operating system you are using: Mac OSX or Linux Run the command: ssh-keygen -t rsa Press ENTER/RETURN to accept the default destination for saving the key.  We do not need a passphrase so simply press ENTER/RETURN for an empty one and once more to confirm. The key will be created in the file .ssh/id_rsa.pub in your home directory.  Display the contents of this file using the cat command: cat ~/.ssh/id_rsa.pub Open a window, SSH to the Raspberry Pi and login.  Change directory to .ssh and edit the authorized_keys file (don't worry if the file does not exist).  Copy and paste the contents of the id_rsa.pub file to the authorized_keys file and save it. Windows Since Windows is not a UNIX derivative operating system it does not include the necessary key generating software by default.  To generate the key I used puttygen.exe which is available from the same site that provides the PuTTY application, here. Download this and run it on your Windows machine.  Follow the instructions to generate a key.  I remove the key comment, but you can leave that if you want. Click "Save private key", confirm that you don't want to use a passphrase and select a filename and location for the key. Copy the public key from the part of the window marked, "Public key for pasting into OpenSSH authorized_keys file".  Use PuTTY to connect to the Raspberry Pi and login.  Change directory to .ssh and edit the authorized_keys file (don't worry if this does not exist).  Paste the key information at the end of this file and save it. Logout and then start PuTTY again.  This time we need to create a saved session using the private key.  Type in the IP address of the Raspberry Pi in the "Hostname (or IP address)" field and expand "SSH" under the "Connection" category.  Select "Auth" (see the screen shot below). Click the "Browse" button under "Private key file for authentication" and select the file you saved from puttygen. Go back to the "Session" category and enter a short name in the saved sessions field, as shown below.  Click "Save" to save the session. Step 4: Test The Configuration You should now have the ability to use scp (Mac/Linux) or pscp.exe (Windows) to copy files from your development machine to the Raspberry Pi without needing to authenticate by typing in a password (so we can automate the process in NetBeans).  It's a good idea to test this using something like: scp /tmp/foo [email protected]:/tmp on Linux or Mac or pscp.exe foo pi@raspi:/tmp on Windows (Note that we use the saved configuration name instead of the IP address or hostname so the public key is picked up). pscp.exe is another tool available from the creators of PuTTY. Step 5: Configure the NetBeans Build Script Start NetBeans and create a new project (or open an existing one that you want to deploy automatically to the Raspberry Pi). Select the Files tab in the explorer window and expand your project.  You will see a build.xml file.  Double click this to edit it. This file will mostly be comments.  At the end (but within the </project> tag) add the XML for <target name="-post-jar">, shown below Here's the code again in case you want to use cut-and-paste: <target name="-post-jar">   <echo level="info" message="Copying dist directory to remote Pi"/>   <exec executable="scp" dir="${basedir}">     <arg line="-r"/>     <arg value="dist"/>     <arg value="[email protected]:NetBeans/CopyTest"/>   </exec>  </target> For Windows it will be slightly different: <target name="-post-jar">   <echo level="info" message="Copying dist directory to remote Pi"/>   <exec executable="C:\pi\putty\pscp.exe" dir="${basedir}">     <arg line="-r"/>     <arg value="dist"/>     <arg value="pi@raspi:NetBeans/CopyTest"/>   </exec> </target> You will also need to ensure that pscp.exe is in your PATH (or specify a fully qualified pathname). From now on when you clean and build the project the dist directory will automatically be copied to the Raspberry Pi ready for testing.

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• CodePlex Daily Summary for Tuesday, March 23, 2010

  CodePlex Daily Summary for Tuesday, March 23, 2010New Projects.NET StarCraft II Replay Parser: A .NET 3.5 Library used to parse StarCraft II replays. Developed in C# 3.5.BackToBasics "B2B" Chat: With technology and software getting more and more complicated, why not get back to basics with BackToBasicsChat. B2B allows you to chat over a ser...Dark Neuron Game Engine: Dark Neuron allows you to easily create fun and interesting games with no need of developing basic game components. This engine is developed for C#...DeepZoom Pivot Constructor: Library to make building DeepZoom images and Pivot displays simpler.ePaper reader: The project is aimed at creating a tool which helps in reading electronic editions of news papers(pdf/flash)FSharpPageProvider for EPiServer CMS 6: This project starts as the port of EPiServer XmlPageProvider to F# programming language. Hammock for REST: Hammock is a REST library for .NET that greatly simplifies consuming and wrapping RESTful services.Kirill Osenkov: Various small projects, tools, utilities and samples by Kirill OsenkovliveDB: liveDB - web client for sql serverLucilla Framework: lucilla frameworkMVC Foolproof Validation: MVC Foolproof Validation aims to extend the Data Annotation validation provided in ASP.NET MVC. Initial efforts are focused on adding contingent va...MVC2Forums: MVC2Forums is simply a forum system based upon MVC2.Mvvm Foundation Silverlight: Mvvm Foundation Silverlight is a library of classes that are helpful when building Silverlight applications based in the MVVM pattern. This librar...MyPersonalWebsite: This is my personal web site developed using ASP.NET MVC 2Planner: Planner makes it easier for all peoples to plan your tasks. It's developed in Delphi.Prose: Prose is an playground for an experimental JavaScript like language compiler. Eventually it will implement 0-CFA, CFA2, and a Tracing JITQuestTracker: QuestTracker is a todo list presented in the format of a quest tracking list such as the one in World of Warcraft.SevenZipLib: SevenZipLib is a C# interface to the 7-zip library.SimpleGeo .Net: .Net Client library for the SimpleGeo.com serviceNew ReleasesAutenticar no OpenLDAP utilizando pGIna: DLL LDAPAuth Plus: New Group: No LoginBMap.NET: BMap.NET 2: This is the 2nd version of BMap.NET. It has included these tags: Bing Maps, and "About BMap.NET".Cronos: Version 2.04: This is primarily a bug-fix release. Several numerical issues have been resolved, and a resource leak (of MS Windows graphics objects) has been fi...EV Dashboard: v1.0: This release includes support for an App.config file and Auto Connect, which will connect to the specified BMS at startup. Note: You still have to ...GKO Libraries: GKO Libraries 0.1 Beta: 0.1 Beta Added More utilities and functions RefactoringsGLB Virtual Player Builder: 0.4.2 Beta: Beta build that includes a new player creator.HKGolden Express: HKGoldenExpress (Build 201003222215): New features: (None) Bug fix: Fixed bugs of unable to parse XML file stream returned from HKGolden API, as the encoding of XML file stream chang...jQuery Web Controls ASP.Net: jQueryWebControls 1.1.1.2: En esta versión se han corregido problemas existentes en la ejecución de los scripts de jquery cuando se utilizaban MasterPage y/o Ajax Control Too...LightKit: Version 0.2.2: Fixed: fixed bug when CollectionItemsEditor ditermines IsChanged property incorrectly fixed ObjectEditor`a thisstring propertyName method wrong l...LINQ to Twitter: LINQ to Twitter Beta v2.0.8: New items added since v1.1 include: Support for OAuth (via DotNetOpenAuth), secure communication via https, VB language support, serialization of ...MapWindow6: MapWindow 6.0 msi (March 22): This version fixes the icons for the desktop installer and changes the install directory to Program Files\MapWindow instead of Program Files\ISU.Math.NET Numerics: 2010.3.22.1334 Build: Latest alpha buildMiniCalendar Web Part: MiniCalendar Web Part 1.8: A small web part to display links to events stored in a list (or document library) in a mini calendar (in month view mode). It shows tooltips for t...OCInject: Release Two: This release brings some missing features such as Singleton support, Func<T> factories and child containers. It, also, has an updated constructor ...Phalanger - The PHP Language Compiler for the .NET Framework: 2.0 (March 2010): Installer of the latest binaries of Phalanger 2.0 (March 2010) and its integration into Visual Studio 2008. Easy installer with automatic IIS int...Planner: Planner: firstQuestTracker: QuestTracker 0.1: This is the preliminary release of QuestTracker. There's not much documentation or many features yet, but it is functional. Any feedback would be a...QuestTracker: QuestTracker 0.1.1: Bugfix for QuestTracker 0.1QuestTracker: QuestTracker 0.1.2: Fixes an issue with saving the quest list.Rawr: Rawr 2.3.13: We're pleased to announce that, after long last, Rawr3 has entered public beta. You're still welcome to continue using Rawr2 (that's what you're re...Single Web Session: Alpha Model Plugin: !How to use Single Web Session add following line into your web config <httpModules> <add name="SingleSession" type="SingleWebSession.Model.W...SMIL - SharePoint Map Integration Layer: SMIL 1.0: Custom data field Extracts Lat/Lon from EXIF from images being uploaded. Map Web Part Filter with SharePoint views Filter by connecting to...sTASKedit: sTASKedit 42532 (Developer Alpha): This release is only to verify the currently decoded task structure... Supported files: tasks.data (v1.3.6 client)VCC: Latest build, v2.1.30322.0: Automatic drop of latest buildVisual Studio DSite: Advanced Notepad (Visual C++ 2008): An notepad written in c that can save in a rich text file format.Wallpaper Rotator: Wallpaper Rotator 0.5: Wallpaper Rotator 0.5 This version includes the following improvements: Saving the choice of "Random Order (Shuffle Mode)" Updating the configu...Most Popular ProjectsMetaSharpRawrWBFS ManagerSilverlight ToolkitASP.NET Ajax LibraryMicrosoft SQL Server Product Samples: DatabaseAJAX Control ToolkitLiveUpload to FacebookWindows Presentation Foundation (WPF)ASP.NETMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesBlogEngine.NETLINQ to TwitterPHPExcelFarseer Physics EngineFacebook Developer ToolkitNB_Store - Free DotNetNuke Ecommerce Catalog Modulepatterns & practices: Composite WPF and SilverlightN2 CMS

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