persistence delegate - Page 138

Programatically add UserControl with events

- by schaermu

Hi everybody I need to add multiple user controls to a panel for further editing of the contained data. My user control contains some panels, dropdown lists and input elements, which are populated in the user control's Page_Load event. protected void Page_Load(object sender, EventArgs e) { // populate comparer ddl from enum string[] enumNames = Enum.GetNames(typeof (SearchComparision)); var al = new ArrayList(); for (int i = 0; i < enumNames.Length; i++) al.Add(new {Value = i, Name = enumNames[i]}); scOperatorSelection.DataValueField = "Value"; scOperatorSelection.DataTextField = "Name"; ... The data to be displayed is added to the user control as a Field, defined above Page_Load. The signature of the events is the following: public delegate void ControlStateChanged(object sender, SearchCriteriaEventArgs eventArgs); public event ControlStateChanged ItemUpdated; public event ControlStateChanged ItemRemoved; public event ControlStateChanged ItemAdded; The update button on the user control triggers the following method: protected void UpdateCriteria(object sender, EventArgs e) { var searchCritCtl = (SearchCriteria) sender; var scEArgs = new SearchCriteriaEventArgs { TargetCriteria = searchCritCtl.CurrentCriteria.CriteriaId, SearchComparision = ParseCurrentComparer(searchCritCtl.scOperatorSelection.SelectedValue), SearchField = searchCritCtl.scFieldSelection.SelectedValue, SearchValue = searchCritCtl.scFilterValue.Text, ClickTarget = SearchCriteriaClickTarget.Update }; if (ItemUpdated != null) ItemUpdated(this, scEArgs); } The rendering page fetches the data objects from a storage backend and displays it in it's Page_Load event. This is the point where it starts getting tricky: i connect to the custom events! int idIt = 0; foreach (var item in _currentSearch.Items) { SearchCriteria sc = (SearchCriteria)LoadControl("~/content/controls/SearchCriteria.ascx"); sc.ID = "scDispCtl_" + idIt; sc.ControlMode = SearchCriteriaMode.Display; sc.CurrentCriteria = item; sc.ItemUpdated += CriteriaUpdated; sc.ItemRemoved += CriteriaRemoved; pnlDisplayCrit.Controls.Add(sc); idIt++; } When first rendering the page, everything is displayed fine, i get all my data. When i trigger an update event, the user control event is fired correctly, but all fields and controls of the user control are NULL. After a bit of research, i had to come to the conclusion that the event is fired before the controls are initialized... Is there any way to prevent such behavior / to override the page lifecycle somehow? I cannot initialize the user controls in the page's Init-event, because i have to access the Session-Store (not initialized in Page_Init). Any advice is welcome... EDIT: Since we hold all criteria informations in the storage backend (including the count of criteria) and that store uses the userid from the session, we cannot use Page_Init... just for clarification EDIT #2: I managed to get past some of the problems. Since i'm now using simple types, im able to bind all the data declaratively (using a repeater with a simple ItemTemplate). It is bound to the control, they are rendered in correct fashion. On Postback, all the data is rebound to the user control, data is available in the OnDataBinding and OnLoad events, everything looks fine. But as soon it enters the real event (bound to the button control of the user control), all field values are lost somehow... Does anybody know, how the page lifecycle continues to process the request after Databinding/Loading ? I'm going crazy about this issue...

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

- by mark

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

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If I use a facade class with generic methods to access the JPA API, how should I provide additional processing for specific types?

- by Shaun

Let's say I'm making a fairly simple web application using JAVA EE specs (I've heard this is possible). In this app, I only have about 10 domain/data objects, and these are represented by JPA Entities. Architecturally, I would consider the JPA API to perform the role of a DAO. Of course, I don't want to use the EntityManager directly in my UI (JSF) and I need to manage transactions, so I delegate these tasks to the so-called service layer. More specifically, I would like to be able to handle these tasks in a single DataService class (often also called CrudService) with generic methods. See this article by Adam Bien for an example interface: http://www.adam-bien.com/roller/abien/entry/generic_crud_service_aka_dao My project differs from that article in that I can't use EJBs, so my service classes are essentially just named beans and I handle transactions manually. Regardless, what I want is a single interface for simple CRUD operations on my data objects because having a different class for each data type would lead to a lot of duplicate and/or unnecessary code. Ideally, my views would be able to use a method such as public <T> List<T> findAll(Class<T> type) { ... } to retrieve data. Using JSF, it might look something like this: <h:dataTable value="#{dataService.findAll(data.class)}" var="d"> ... </h:dataTable> Similarly, after validating forms, my controller could submit the data with a method such as: public <T> void add(T entity) { ... } Granted, you'd probably actually want to return something useful to the caller. In any case, this works well if your data can be treated as homogenous in this manner. Alas, it breaks down when you need to perform additional processing on certain objects before passing them on to JPA. For example, let's say I'm dealing with Books and Authors which have a many-to-many relationship. Each Book has a set of IDs referring to its authors, and each Author has a set of IDs referring to their books. Normally, JPA can manage this kind of relationship for you, but in some cases it can't (for example, the google app engine JPA provider doesn't support this). Thus, when I persist a new book for example, I may need to update the corresponding author entities. My question, then, is if there's an elegant way to handle this or if I should reconsider the sanity of my whole design. Here's a couple ways I see of dealing with it: The instanceof operator. I could use this to target certain classes when special processing is needed. Perhaps maintainability suffers and it isn't beautiful code, but if there's only 10 or so domain objects it can't be all that bad... could it? Make a different service for each entity type (ie, BookService and AuthorService). All services would inherit from a generic DataService base class and override methods if special processing is needed. At this point, you could probably also just call them DAOs instead. As always, I appreciate the help. Let me know if any clarifications are needed, as I left out many smaller details.

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10000's+ UI elements, bind or draw?

- by jpiccolo

I am drawing a header for a timeline control. It looks like this: I go to 0.01 millisecond per line, so for a 10 minute timeline I am looking at drawing 60000 lines + 6000 labels. This takes a while, ~10 seconds. I would like to offload this from the UI thread. My code is currently: private void drawHeader() { Header.Children.Clear(); switch (viewLevel) { case ViewLevel.MilliSeconds100: double hWidth = Header.Width; this.drawHeaderLines(new TimeSpan(0, 0, 0, 0, 10), 100, 5, hWidth); //Was looking into background worker to off load UI //backgroundWorker = new BackgroundWorker(); //backgroundWorker.DoWork += delegate(object sender, DoWorkEventArgs args) // { // this.drawHeaderLines(new TimeSpan(0, 0, 0, 0, 10), 100, 5, hWidth); // }; //backgroundWorker.RunWorkerAsync(); break; } } private void drawHeaderLines(TimeSpan timeStep, int majorEveryXLine, int distanceBetweenLines, double headerWidth) { var currentTime = new TimeSpan(0, 0, 0, 0, 0); const int everyXLine100 = 10; double currentX = 0; var currentLine = 0; while (currentX < headerWidth) { var l = new Line { ToolTip = currentTime.ToString(@"hh\:mm\:ss\.fff"), StrokeThickness = 1, X1 = 0, X2 = 0, Y1 = 30, Y2 = 25 }; if (((currentLine % majorEveryXLine) == 0) && currentLine != 0) { l.StrokeThickness = 2; l.Y2 = 15; var textBlock = new TextBlock { Text = l.ToolTip.ToString(), FontSize = 8, FontFamily = new FontFamily("Tahoma"), Foreground = new SolidColorBrush(Color.FromRgb(255, 255, 255)) }; Canvas.SetLeft(textBlock, (currentX - 22)); Canvas.SetTop(textBlock, 0); Header.Children.Add(textBlock); } if ((((currentLine % everyXLine100) == 0) && currentLine != 0) && (currentLine % majorEveryXLine) != 0) { l.Y2 = 20; var textBlock = new TextBlock { Text = string.Format(".{0}", TimeSpan.Parse(l.ToolTip.ToString()).Milliseconds), FontSize = 8, FontFamily = new FontFamily("Tahoma"), Foreground = new SolidColorBrush(Color.FromRgb(192, 192, 192)) }; Canvas.SetLeft(textBlock, (currentX - 8)); Canvas.SetTop(textBlock, 8); Header.Children.Add(textBlock); } l.Stroke = new SolidColorBrush(Color.FromRgb(255, 255, 255)); Header.Children.Add(l); Canvas.SetLeft(l, currentX); currentX += distanceBetweenLines; currentLine++; currentTime += timeStep; } } I had looked into BackgroundWorker, except you can't create UI elements on a non-UI thread. Is it possible at all to do drawHeaderLines in a non-UI thread? Could I use data binding for drawing the lines? Would this help with UI responsiveness? I would imagine I can use databinding, but the Styling is probably beyond my current WPF ability (coming from winforms and trying to learn what all these style objects are and binding them). Would anyone be able to supply a starting point for tempting this out? Or Google a tutorial that would get me started?

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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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Version Assemblies with TFS 2010 Continuous Integration

- by Steve Michelotti

When I first heard that TFS 2010 had moved to Workflow Foundation for Team Build, I was *extremely* skeptical. I’ve loved MSBuild and didn’t quite understand the reasons for this change. In fact, given that I’ve been exclusively using Cruise Control for Continuous Integration (CI) for the last 5+ years of my career, I was skeptical of TFS for CI in general. However, after going through the learning process for TFS 2010 recently, I’m starting to become a believer. I’m also starting to see some of the benefits with Workflow Foundation for the overall processing because it gives you constructs not available in MSBuild such as parallel tasks, better control flow constructs, and a slightly better customization story. The first customization I had to make to the build process was to version the assemblies of my solution. This is not new. In fact, I’d recommend reading Mike Fourie’s well known post on Versioning Code in TFS before you get started. This post describes several foundational aspects of versioning assemblies regardless of your version of TFS. The main points are: 1) don’t use source control operations for your version file, 2) use a schema like <Major>.<Minor>.<IncrementalNumber>.0, and 3) do not keep AssemblyVersion and AssemblyFileVersion in sync. To do this in TFS 2010, the best post I’ve found has been Jim Lamb’s post of building a custom TFS 2010 workflow activity. Overall, this post is excellent but the primary issue I have with it is that the assembly version numbers produced are based in a date and look like this: “2010.5.15.1”. This is definitely not what I want. I want to be able to communicate to the developers and stakeholders that we are producing the “1.1 release” or “1.2 release” – which would have an assembly version number of “1.1.317.0” for example. In this post, I’ll walk through the process of customizing the assembly version number based on this method – customizing the concepts in Lamb’s post to suit my needs. I’ll also be combining this with the concepts of Fourie’s post – particularly with regards to the standards around how to version the assemblies. The first thing I’ll do is add a file called SolutionAssemblyVersionInfo.cs to the root of my solution that looks like this: 1: using System; 2: using System.Reflection; 3: [assembly: AssemblyVersion("1.1.0.0")] 4: [assembly: AssemblyFileVersion("1.1.0.0")] I’ll then add that file as a Visual Studio link file to each project in my solution by right-clicking the project, “Add – Existing Item…” then when I click the SolutionAssemblyVersionInfo.cs file, making sure I “Add As Link”: Now the Solution Explorer will show our file. We can see that it’s a “link” file because of the black arrow in the icon within all our projects. Of course you’ll need to remove the AssemblyVersion and AssemblyFileVersion attributes from the AssemblyInfo.cs files to avoid the duplicate attributes since they now leave in the SolutionAssemblyVersionInfo.cs file. This is an extremely common technique so that all the projects in our solution can be versioned as a unit. At this point, we’re ready to write our custom activity. The primary consideration is that I want the developer and/or tech lead to be able to easily be in control of the Major.Minor and then I want the CI process to add the third number with a unique incremental number. We’ll leave the fourth position always “0” for now – it’s held in reserve in case the day ever comes where we need to do an emergency patch to Production based on a branched version. Writing the Custom Workflow Activity Similar to Lamb’s post, I’m going to write two custom workflow activities. The “outer” activity (a xaml activity) will be pretty straight forward. It will check if the solution version file exists in the solution root and, if so, delegate the replacement of version to the AssemblyVersionInfo activity which is a CodeActivity highlighted in red below: Notice that the arguments of this activity are the “solutionVersionFile” and “tfsBuildNumber” which will be passed in. The tfsBuildNumber passed in will look something like this: “CI_MyApplication.4” and we’ll need to grab the “4” (i.e., the incremental revision number) and put that in the third position. Then we’ll need to honor whatever was specified for Major.Minor in the SolutionAssemblyVersionInfo.cs file. For example, if the SolutionAssemblyVersionInfo.cs file had “1.1.0.0” for the AssemblyVersion (as shown in the first code block near the beginning of this post), then we want to resulting file to have “1.1.4.0”. Before we do anything, let’s put together a unit test for all this so we can know if we get it right: 1: [TestMethod] 2: public void Assembly_version_should_be_parsed_correctly_from_build_name() 3: { 4: // arrange 5: const string versionFile = "SolutionAssemblyVersionInfo.cs"; 6: WriteTestVersionFile(versionFile); 7: var activity = new VersionAssemblies(); 8: var arguments = new Dictionary<string, object> { 9: { "tfsBuildNumber", "CI_MyApplication.4"}, 10: { "solutionVersionFile", versionFile} 11: }; 12: 13: // act 14: var result = WorkflowInvoker.Invoke(activity, arguments); 15: 16: // assert 17: Assert.AreEqual("1.2.4.0", (string)result["newAssemblyFileVersion"]); 18: var lines = File.ReadAllLines(versionFile); 19: Assert.IsTrue(lines.Contains("[assembly: AssemblyVersion(\"1.2.0.0\")]")); 20: Assert.IsTrue(lines.Contains("[assembly: AssemblyFileVersion(\"1.2.4.0\")]")); 21: } 22: 23: private void WriteTestVersionFile(string versionFile) 24: { 25: var fileContents = "using System.Reflection;\n" + 26: "[assembly: AssemblyVersion(\"1.2.0.0\")]\n" + 27: "[assembly: AssemblyFileVersion(\"1.2.0.0\")]"; 28: File.WriteAllText(versionFile, fileContents); 29: } At this point, the code for our AssemblyVersion activity is pretty straight forward: 1: [BuildActivity(HostEnvironmentOption.Agent)] 2: public class AssemblyVersionInfo : CodeActivity 3: { 4: [RequiredArgument] 5: public InArgument<string> FileName { get; set; } 6: 7: [RequiredArgument] 8: public InArgument<string> TfsBuildNumber { get; set; } 9: 10: public OutArgument<string> NewAssemblyFileVersion { get; set; } 11: 12: protected override void Execute(CodeActivityContext context) 13: { 14: var solutionVersionFile = this.FileName.Get(context); 15: 16: // Ensure that the file is writeable 17: var fileAttributes = File.GetAttributes(solutionVersionFile); 18: File.SetAttributes(solutionVersionFile, fileAttributes & ~FileAttributes.ReadOnly); 19: 20: // Prepare assembly versions 21: var majorMinor = GetAssemblyMajorMinorVersionBasedOnExisting(solutionVersionFile); 22: var newBuildNumber = GetNewBuildNumber(this.TfsBuildNumber.Get(context)); 23: var newAssemblyVersion = string.Format("{0}.{1}.0.0", majorMinor.Item1, majorMinor.Item2); 24: var newAssemblyFileVersion = string.Format("{0}.{1}.{2}.0", majorMinor.Item1, majorMinor.Item2, newBuildNumber); 25: this.NewAssemblyFileVersion.Set(context, newAssemblyFileVersion); 26: 27: // Perform the actual replacement 28: var contents = this.GetFileContents(newAssemblyVersion, newAssemblyFileVersion); 29: File.WriteAllText(solutionVersionFile, contents); 30: 31: // Restore the file's original attributes 32: File.SetAttributes(solutionVersionFile, fileAttributes); 33: } 34: 35: #region Private Methods 36: 37: private string GetFileContents(string newAssemblyVersion, string newAssemblyFileVersion) 38: { 39: var cs = new StringBuilder(); 40: cs.AppendLine("using System.Reflection;"); 41: cs.AppendFormat("[assembly: AssemblyVersion(\"{0}\")]", newAssemblyVersion); 42: cs.AppendLine(); 43: cs.AppendFormat("[assembly: AssemblyFileVersion(\"{0}\")]", newAssemblyFileVersion); 44: return cs.ToString(); 45: } 46: 47: private Tuple<string, string> GetAssemblyMajorMinorVersionBasedOnExisting(string filePath) 48: { 49: var lines = File.ReadAllLines(filePath); 50: var versionLine = lines.Where(x => x.Contains("AssemblyVersion")).FirstOrDefault(); 51: 52: if (versionLine == null) 53: { 54: throw new InvalidOperationException("File does not contain [assembly: AssemblyVersion] attribute"); 55: } 56: 57: return ExtractMajorMinor(versionLine); 58: } 59: 60: private static Tuple<string, string> ExtractMajorMinor(string versionLine) 61: { 62: var firstQuote = versionLine.IndexOf('"') + 1; 63: var secondQuote = versionLine.IndexOf('"', firstQuote); 64: var version = versionLine.Substring(firstQuote, secondQuote - firstQuote); 65: var versionParts = version.Split('.'); 66: return new Tuple<string, string>(versionParts[0], versionParts[1]); 67: } 68: 69: private string GetNewBuildNumber(string buildName) 70: { 71: return buildName.Substring(buildName.LastIndexOf(".") + 1); 72: } 73: 74: #endregion 75: } At this point the final step is to incorporate this activity into the overall build template. Make a copy of the DefaultTempate.xaml – we’ll call it DefaultTemplateWithVersioning.xaml. Before the build and labeling happens, drag the VersionAssemblies activity in. Then set the LabelName variable to “BuildDetail.BuildDefinition.Name + "-" + newAssemblyFileVersion since the newAssemblyFileVersion was produced by our activity. Configuring CI Once you add your solution to source control, you can configure CI with the build definition window as shown here. The main difference is that we’ll change the Process tab to reflect a different build number format and choose our custom build process file: When the build completes, we’ll see the name of our project with the unique revision number: If we look at the detailed build log for the latest build, we’ll see the label being created with our custom task: We can now look at the history labels in TFS and see the project name with the labels (the Assignment activity I added to the workflow): Finally, if we look at the physical assemblies that are produced, we can right-click on any assembly in Windows Explorer and see the assembly version in its properties: Full Traceability We now have full traceability for our code. There will never be a question of what code was deployed to Production. You can always see the assembly version in the properties of the physical assembly. That can be traced back to a label in TFS where the unique revision number matches. The label in TFS gives you the complete snapshot of the code in your source control repository at the time the code was built. This type of process for full traceability has been used for many years for CI – in fact, I’ve done similar things with CCNet and SVN for quite some time. This is simply the TFS implementation of that pattern. The new features that TFS 2010 give you to make these types of customizations in your build process are quite easy once you get over the initial curve.

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

- by Reed

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

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Creating a dynamic proxy generator with c# – Part 4 – Calling the base method

- by SeanMcAlinden

Creating a dynamic proxy generator with c# – Part 1 – Creating the Assembly builder, Module builder and caching mechanism Creating a dynamic proxy generator with c# – Part 2 – Interceptor Design Creating a dynamic proxy generator with c# – Part 3 – Creating the constructors The plan for calling the base methods from the proxy is to create a private method for each overridden proxy method, this will allow the proxy to use a delegate to simply invoke the private method when required. Quite a few helper classes have been created to make this possible so as usual I would suggest download or viewing the code at http://rapidioc.codeplex.com/. In this post I’m just going to cover the main points for when creating methods. Getting the methods to override The first two notable methods are for getting the methods. private static MethodInfo[] GetMethodsToOverride<TBase>() where TBase : class { return typeof(TBase).GetMethods().Where(x => !methodsToIgnore.Contains(x.Name) && (x.Attributes & MethodAttributes.Final) == 0) .ToArray(); } private static StringCollection GetMethodsToIgnore() { return new StringCollection() { "ToString", "GetHashCode", "Equals", "GetType" }; } The GetMethodsToIgnore method string collection contains an array of methods that I don’t want to override. In the GetMethodsToOverride method, you’ll notice a binary AND which is basically saying not to include any methods marked final i.e. not virtual. Creating the MethodInfo for calling the base method This method should hopefully be fairly easy to follow, it’s only function is to create a MethodInfo which points to the correct base method, and with the correct parameters. private static MethodInfo CreateCallBaseMethodInfo<TBase>(MethodInfo method) where TBase : class { Type[] baseMethodParameterTypes = ParameterHelper.GetParameterTypes(method, method.GetParameters()); return typeof(TBase).GetMethod( method.Name, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, baseMethodParameterTypes, null ); } /// <summary> /// Get the parameter types. /// </summary> /// <param name="method">The method.</param> /// <param name="parameters">The parameters.</param> public static Type[] GetParameterTypes(MethodInfo method, ParameterInfo[] parameters) { Type[] parameterTypesList = Type.EmptyTypes; if (parameters.Length > 0) { parameterTypesList = CreateParametersList(parameters); } return parameterTypesList; } Creating the new private methods for calling the base method The following method outline how I’ve created the private methods for calling the base class method. private static MethodBuilder CreateCallBaseMethodBuilder(TypeBuilder typeBuilder, MethodInfo method) { string callBaseSuffix = "GetBaseMethod"; if (method.IsGenericMethod || method.IsGenericMethodDefinition) { return MethodHelper.SetUpGenericMethod ( typeBuilder, method, method.Name + callBaseSuffix, MethodAttributes.Private | MethodAttributes.HideBySig ); } else { return MethodHelper.SetupNonGenericMethod ( typeBuilder, method, method.Name + callBaseSuffix, MethodAttributes.Private | MethodAttributes.HideBySig ); } } The CreateCallBaseMethodBuilder is the entry point method for creating the call base method. I’ve added a suffix to the base classes method name to keep it unique. Non Generic Methods Creating a non generic method is fairly simple public static MethodBuilder SetupNonGenericMethod( TypeBuilder typeBuilder, MethodInfo method, string methodName, MethodAttributes methodAttributes) { ParameterInfo[] parameters = method.GetParameters(); Type[] parameterTypes = ParameterHelper.GetParameterTypes(method, parameters); Type returnType = method.ReturnType; MethodBuilder methodBuilder = CreateMethodBuilder ( typeBuilder, method, methodName, methodAttributes, parameterTypes, returnType ); ParameterHelper.SetUpParameters(parameterTypes, parameters, methodBuilder); return methodBuilder; } private static MethodBuilder CreateMethodBuilder ( TypeBuilder typeBuilder, MethodInfo method, string methodName, MethodAttributes methodAttributes, Type[] parameterTypes, Type returnType ) { MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName, methodAttributes, returnType, parameterTypes); return methodBuilder; } As you can see, you simply have to declare a method builder, get the parameter types, and set the method attributes you want. Generic Methods Creating generic methods takes a little bit more work. /// <summary> /// Sets up generic method. /// </summary> /// <param name="typeBuilder">The type builder.</param> /// <param name="method">The method.</param> /// <param name="methodName">Name of the method.</param> /// <param name="methodAttributes">The method attributes.</param> public static MethodBuilder SetUpGenericMethod ( TypeBuilder typeBuilder, MethodInfo method, string methodName, MethodAttributes methodAttributes ) { ParameterInfo[] parameters = method.GetParameters(); Type[] parameterTypes = ParameterHelper.GetParameterTypes(method, parameters); MethodBuilder methodBuilder = typeBuilder.DefineMethod(methodName, methodAttributes); Type[] genericArguments = method.GetGenericArguments(); GenericTypeParameterBuilder[] genericTypeParameters = GetGenericTypeParameters(methodBuilder, genericArguments); ParameterHelper.SetUpParameterConstraints(parameterTypes, genericTypeParameters); SetUpReturnType(method, methodBuilder, genericTypeParameters); if (method.IsGenericMethod) { methodBuilder.MakeGenericMethod(genericArguments); } ParameterHelper.SetUpParameters(parameterTypes, parameters, methodBuilder); return methodBuilder; } private static GenericTypeParameterBuilder[] GetGenericTypeParameters ( MethodBuilder methodBuilder, Type[] genericArguments ) { return methodBuilder.DefineGenericParameters(GenericsHelper.GetArgumentNames(genericArguments)); } private static void SetUpReturnType(MethodInfo method, MethodBuilder methodBuilder, GenericTypeParameterBuilder[] genericTypeParameters) { if (method.IsGenericMethodDefinition) { SetUpGenericDefinitionReturnType(method, methodBuilder, genericTypeParameters); } else { methodBuilder.SetReturnType(method.ReturnType); } } private static void SetUpGenericDefinitionReturnType(MethodInfo method, MethodBuilder methodBuilder, GenericTypeParameterBuilder[] genericTypeParameters) { if (method.ReturnType == null) { methodBuilder.SetReturnType(typeof(void)); } else if (method.ReturnType.IsGenericType) { methodBuilder.SetReturnType(genericTypeParameters.Where (x => x.Name == method.ReturnType.Name).First()); } else { methodBuilder.SetReturnType(method.ReturnType); } } Ok, there are a few helper methods missing, basically there is way to much code to put in this post, take a look at the code at http://rapidioc.codeplex.com/ to follow it through completely. Basically though, when dealing with generics there is extra work to do in terms of getting the generic argument types setting up any generic parameter constraints setting up the return type setting up the method as a generic All of the information is easy to get via reflection from the MethodInfo. Emitting the new private method Emitting the new private method is relatively simple as it’s only function is calling the base method and returning a result if the return type is not void. ILGenerator il = privateMethodBuilder.GetILGenerator(); EmitCallBaseMethod(method, callBaseMethod, il); private static void EmitCallBaseMethod(MethodInfo method, MethodInfo callBaseMethod, ILGenerator il) { int privateParameterCount = method.GetParameters().Length; il.Emit(OpCodes.Ldarg_0); if (privateParameterCount > 0) { for (int arg = 0; arg < privateParameterCount; arg++) { il.Emit(OpCodes.Ldarg_S, arg + 1); } } il.Emit(OpCodes.Call, callBaseMethod); il.Emit(OpCodes.Ret); } So in the main method building method, an ILGenerator is created from the method builder. The ILGenerator performs the following actions: Load the class (this) onto the stack using the hidden argument Ldarg_0. Create an argument on the stack for each of the method parameters (starting at 1 because 0 is the hidden argument) Call the base method using the Opcodes.Call code and the MethodInfo we created earlier. Call return on the method Conclusion Now we have the private methods prepared for calling the base method, we have reached the last of the relatively easy part of the proxy building. Hopefully, it hasn’t been too hard to follow so far, there is a lot of code so I haven’t been able to post it all so please check it out at http://rapidioc.codeplex.com/. The next section should be up fairly soon, it’s going to cover creating the delegates for calling the private methods created in this post. Kind Regards, Sean.

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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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Toorcon 15 (2013)

- by danx

The Toorcon gang (senior staff): h1kari (founder), nfiltr8, and Geo Introduction to Toorcon 15 (2013) A Tale of One Software Bypass of MS Windows 8 Secure Boot Breaching SSL, One Byte at a Time Running at 99%: Surviving an Application DoS Security Response in the Age of Mass Customized Attacks x86 Rewriting: Defeating RoP and other Shinanighans Clowntown Express: interesting bugs and running a bug bounty program Active Fingerprinting of Encrypted VPNs Making Attacks Go Backwards Mask Your Checksums—The Gorry Details Adventures with weird machines thirty years after "Reflections on Trusting Trust" Introduction to Toorcon 15 (2013) Toorcon 15 is the 15th annual security conference held in San Diego. I've attended about a third of them and blogged about previous conferences I attended here starting in 2003. As always, I've only summarized the talks I attended and interested me enough to write about them. Be aware that I may have misrepresented the speaker's remarks and that they are not my remarks or opinion, or those of my employer, so don't quote me or them. Those seeking further details may contact the speakers directly or use The Google. For some talks, I have a URL for further information. A Tale of One Software Bypass of MS Windows 8 Secure Boot Andrew Furtak and Oleksandr Bazhaniuk Yuri Bulygin, Oleksandr ("Alex") Bazhaniuk, and (not present) Andrew Furtak Yuri and Alex talked about UEFI and Bootkits and bypassing MS Windows 8 Secure Boot, with vendor recommendations. They previously gave this talk at the BlackHat 2013 conference. MS Windows 8 Secure Boot Overview UEFI (Unified Extensible Firmware Interface) is interface between hardware and OS. UEFI is processor and architecture independent. Malware can replace bootloader (bootx64.efi, bootmgfw.efi). Once replaced can modify kernel. Trivial to replace bootloader. Today many legacy bootkits—UEFI replaces them most of them. MS Windows 8 Secure Boot verifies everything you load, either through signatures or hashes. UEFI firmware relies on secure update (with signed update). You would think Secure Boot would rely on ROM (such as used for phones0, but you can't do that for PCs—PCs use writable memory with signatures DXE core verifies the UEFI boat loader(s) OS Loader (winload.efi, winresume.efi) verifies the OS kernel A chain of trust is established with a root key (Platform Key, PK), which is a cert belonging to the platform vendor. Key Exchange Keys (KEKs) verify an "authorized" database (db), and "forbidden" database (dbx). X.509 certs with SHA-1/SHA-256 hashes. Keys are stored in non-volatile (NV) flash-based NVRAM. Boot Services (BS) allow adding/deleting keys (can't be accessed once OS starts—which uses Run-Time (RT)). Root cert uses RSA-2048 public keys and PKCS#7 format signatures. SecureBoot — enable disable image signature checks SetupMode — update keys, self-signed keys, and secure boot variables CustomMode — allows updating keys Secure Boot policy settings are: always execute, never execute, allow execute on security violation, defer execute on security violation, deny execute on security violation, query user on security violation Attacking MS Windows 8 Secure Boot Secure Boot does NOT protect from physical access. Can disable from console. Each BIOS vendor implements Secure Boot differently. There are several platform and BIOS vendors. It becomes a "zoo" of implementations—which can be taken advantage of. Secure Boot is secure only when all vendors implement it correctly. Allow only UEFI firmware signed updates protect UEFI firmware from direct modification in flash memory protect FW update components program SPI controller securely protect secure boot policy settings in nvram protect runtime api disable compatibility support module which allows unsigned legacy Can corrupt the Platform Key (PK) EFI root certificate variable in SPI flash. If PK is not found, FW enters setup mode wich secure boot turned off. Can also exploit TPM in a similar manner. One is not supposed to be able to directly modify the PK in SPI flash from the OS though. But they found a bug that they can exploit from User Mode (undisclosed) and demoed the exploit. It loaded and ran their own bootkit. The exploit requires a reboot. Multiple vendors are vulnerable. They will disclose this exploit to vendors in the future. Recommendations: allow only signed updates protect UEFI fw in ROM protect EFI variable store in ROM Breaching SSL, One Byte at a Time Yoel Gluck and Angelo Prado Angelo Prado and Yoel Gluck, Salesforce.com CRIME is software that performs a "compression oracle attack." This is possible because the SSL protocol doesn't hide length, and because SSL compresses the header. CRIME requests with every possible character and measures the ciphertext length. Look for the plaintext which compresses the most and looks for the cookie one byte-at-a-time. SSL Compression uses LZ77 to reduce redundancy. Huffman coding replaces common byte sequences with shorter codes. US CERT thinks the SSL compression problem is fixed, but it isn't. They convinced CERT that it wasn't fixed and they issued a CVE. BREACH, breachattrack.com BREACH exploits the SSL response body (Accept-Encoding response, Content-Encoding). It takes advantage of the fact that the response is not compressed. BREACH uses gzip and needs fairly "stable" pages that are static for ~30 seconds. It needs attacker-supplied content (say from a web form or added to a URL parameter). BREACH listens to a session's requests and responses, then inserts extra requests and responses. Eventually, BREACH guesses a session's secret key. Can use compression to guess contents one byte at-a-time. For example, "Supersecret SupersecreX" (a wrong guess) compresses 10 bytes, and "Supersecret Supersecret" (a correct guess) compresses 11 bytes, so it can find each character by guessing every character. To start the guess, BREACH needs at least three known initial characters in the response sequence. Compression length then "leaks" information. Some roadblocks include no winners (all guesses wrong) or too many winners (multiple possibilities that compress the same). The solutions include: lookahead (guess 2 or 3 characters at-a-time instead of 1 character). Expensive rollback to last known conflict check compression ratio can brute-force first 3 "bootstrap" characters, if needed (expensive) block ciphers hide exact plain text length. Solution is to align response in advance to block size Mitigations length: use variable padding secrets: dynamic CSRF tokens per request secret: change over time separate secret to input-less servlets Future work eiter understand DEFLATE/GZIP HTTPS extensions Running at 99%: Surviving an Application DoS Ryan Huber Ryan Huber, Risk I/O Ryan first discussed various ways to do a denial of service (DoS) attack against web services. One usual method is to find a slow web page and do several wgets. Or download large files. Apache is not well suited at handling a large number of connections, but one can put something in front of it Can use Apache alternatives, such as nginx How to identify malicious hosts short, sudden web requests user-agent is obvious (curl, python) same url requested repeatedly no web page referer (not normal) hidden links. hide a link and see if a bot gets it restricted access if not your geo IP (unless the website is global) missing common headers in request regular timing first seen IP at beginning of attack count requests per hosts (usually a very large number) Use of captcha can mitigate attacks, but you'll lose a lot of genuine users. Bouncer, goo.gl/c2vyEc and www.github.com/rawdigits/Bouncer Bouncer is software written by Ryan in netflow. Bouncer has a small, unobtrusive footprint and detects DoS attempts. It closes blacklisted sockets immediately (not nice about it, no proper close connection). Aggregator collects requests and controls your web proxies. Need NTP on the front end web servers for clean data for use by bouncer. Bouncer is also useful for a popularity storm ("Slashdotting") and scraper storms. Future features: gzip collection data, documentation, consumer library, multitask, logging destroyed connections. Takeaways: DoS mitigation is easier with a complete picture Bouncer designed to make it easier to detect and defend DoS—not a complete cure Security Response in the Age of Mass Customized Attacks Peleus Uhley and Karthik Raman Peleus Uhley and Karthik Raman, Adobe ASSET, blogs.adobe.com/asset/ Peleus and Karthik talked about response to mass-customized exploits. Attackers behave much like a business. "Mass customization" refers to concept discussed in the book Future Perfect by Stan Davis of Harvard Business School. Mass customization is differentiating a product for an individual customer, but at a mass production price. For example, the same individual with a debit card receives basically the same customized ATM experience around the world. Or designing your own PC from commodity parts. Exploit kits are another example of mass customization. The kits support multiple browsers and plugins, allows new modules. Exploit kits are cheap and customizable. Organized gangs use exploit kits. A group at Berkeley looked at 77,000 malicious websites (Grier et al., "Manufacturing Compromise: The Emergence of Exploit-as-a-Service", 2012). They found 10,000 distinct binaries among them, but derived from only a dozen or so exploit kits. Characteristics of Mass Malware: potent, resilient, relatively low cost Technical characteristics: multiple OS, multipe payloads, multiple scenarios, multiple languages, obfuscation Response time for 0-day exploits has gone down from ~40 days 5 years ago to about ~10 days now. So the drive with malware is towards mass customized exploits, to avoid detection There's plenty of evicence that exploit development has Project Manager bureaucracy. They infer from the malware edicts to: support all versions of reader support all versions of windows support all versions of flash support all browsers write large complex, difficult to main code (8750 lines of JavaScript for example Exploits have "loose coupling" of multipe versions of software (adobe), OS, and browser. This allows specific attacks against specific versions of multiple pieces of software. Also allows exploits of more obscure software/OS/browsers and obscure versions. Gave examples of exploits that exploited 2, 3, 6, or 14 separate bugs. However, these complete exploits are more likely to be buggy or fragile in themselves and easier to defeat. Future research includes normalizing malware and Javascript. Conclusion: The coming trend is that mass-malware with mass zero-day attacks will result in mass customization of attacks. x86 Rewriting: Defeating RoP and other Shinanighans Richard Wartell Richard Wartell The attack vector we are addressing here is: First some malware causes a buffer overflow. The malware has no program access, but input access and buffer overflow code onto stack Later the stack became non-executable. The workaround malware used was to write a bogus return address to the stack jumping to malware Later came ASLR (Address Space Layout Randomization) to randomize memory layout and make addresses non-deterministic. The workaround malware used was to jump t existing code segments in the program that can be used in bad ways "RoP" is Return-oriented Programming attacks. RoP attacks use your own code and write return address on stack to (existing) expoitable code found in program ("gadgets"). Pinkie Pie was paid $60K last year for a RoP attack. One solution is using anti-RoP compilers that compile source code with NO return instructions. ASLR does not randomize address space, just "gadgets". IPR/ILR ("Instruction Location Randomization") randomizes each instruction with a virtual machine. Richard's goal was to randomize a binary with no source code access. He created "STIR" (Self-Transofrming Instruction Relocation). STIR disassembles binary and operates on "basic blocks" of code. The STIR disassembler is conservative in what to disassemble. Each basic block is moved to a random location in memory. Next, STIR writes new code sections with copies of "basic blocks" of code in randomized locations. The old code is copied and rewritten with jumps to new code. the original code sections in the file is marked non-executible. STIR has better entropy than ASLR in location of code. Makes brute force attacks much harder. STIR runs on MS Windows (PEM) and Linux (ELF). It eliminated 99.96% or more "gadgets" (i.e., moved the address). Overhead usually 5-10% on MS Windows, about 1.5-4% on Linux (but some code actually runs faster!). The unique thing about STIR is it requires no source access and the modified binary fully works! Current work is to rewrite code to enforce security policies. For example, don't create a *.{exe,msi,bat} file. Or don't connect to the network after reading from the disk. Clowntown Express: interesting bugs and running a bug bounty program Collin Greene Collin Greene, Facebook Collin talked about Facebook's bug bounty program. Background at FB: FB has good security frameworks, such as security teams, external audits, and cc'ing on diffs. But there's lots of "deep, dark, forgotten" parts of legacy FB code. Collin gave several examples of bountied bugs. Some bounty submissions were on software purchased from a third-party (but bounty claimers don't know and don't care). We use security questions, as does everyone else, but they are basically insecure (often easily discoverable). Collin didn't expect many bugs from the bounty program, but they ended getting 20+ good bugs in first 24 hours and good submissions continue to come in. Bug bounties bring people in with different perspectives, and are paid only for success. Bug bounty is a better use of a fixed amount of time and money versus just code review or static code analysis. The Bounty program started July 2011 and paid out $1.5 million to date. 14% of the submissions have been high priority problems that needed to be fixed immediately. The best bugs come from a small % of submitters (as with everything else)—the top paid submitters are paid 6 figures a year. Spammers like to backstab competitors. The youngest sumitter was 13. Some submitters have been hired. Bug bounties also allows to see bugs that were missed by tools or reviews, allowing improvement in the process. Bug bounties might not work for traditional software companies where the product has release cycle or is not on Internet. Active Fingerprinting of Encrypted VPNs Anna Shubina Anna Shubina, Dartmouth Institute for Security, Technology, and Society (I missed the start of her talk because another track went overtime. But I have the DVD of the talk, so I'll expand later) IPsec leaves fingerprints. Using netcat, one can easily visually distinguish various crypto chaining modes just from packet timing on a chart (example, DES-CBC versus AES-CBC) One can tell a lot about VPNs just from ping roundtrips (such as what router is used) Delayed packets are not informative about a network, especially if far away from the network More needed to explore about how TCP works in real life with respect to timing Making Attacks Go Backwards Fuzzynop FuzzyNop, Mandiant This talk is not about threat attribution (finding who), product solutions, politics, or sales pitches. But who are making these malware threats? It's not a single person or group—they have diverse skill levels. There's a lot of fat-fingered fumblers out there. Always look for low-hanging fruit first: "hiding" malware in the temp, recycle, or root directories creation of unnamed scheduled tasks obvious names of files and syscalls ("ClearEventLog") uncleared event logs. Clearing event log in itself, and time of clearing, is a red flag and good first clue to look for on a suspect system Reverse engineering is hard. Disassembler use takes practice and skill. A popular tool is IDA Pro, but it takes multiple interactive iterations to get a clean disassembly. Key loggers are used a lot in targeted attacks. They are typically custom code or built in a backdoor. A big tip-off is that non-printable characters need to be printed out (such as "[Ctrl]" "[RightShift]") or time stamp printf strings. Look for these in files. Presence is not proof they are used. Absence is not proof they are not used. Java exploits. Can parse jar file with idxparser.py and decomile Java file. Java typially used to target tech companies. Backdoors are the main persistence mechanism (provided externally) for malware. Also malware typically needs command and control. Application of Artificial Intelligence in Ad-Hoc Static Code Analysis John Ashaman John Ashaman, Security Innovation Initially John tried to analyze open source files with open source static analysis tools, but these showed thousands of false positives. Also tried using grep, but tis fails to find anything even mildly complex. So next John decided to write his own tool. His approach was to first generate a call graph then analyze the graph. However, the problem is that making a call graph is really hard. For example, one problem is "evil" coding techniques, such as passing function pointer. First the tool generated an Abstract Syntax Tree (AST) with the nodes created from method declarations and edges created from method use. Then the tool generated a control flow graph with the goal to find a path through the AST (a maze) from source to sink. The algorithm is to look at adjacent nodes to see if any are "scary" (a vulnerability), using heuristics for search order. The tool, called "Scat" (Static Code Analysis Tool), currently looks for C# vulnerabilities and some simple PHP. Later, he plans to add more PHP, then JSP and Java. For more information see his posts in Security Innovation blog and NRefactory on GitHub. Mask Your Checksums—The Gorry Details Eric (XlogicX) Davisson Eric (XlogicX) Davisson Sometimes in emailing or posting TCP/IP packets to analyze problems, you may want to mask the IP address. But to do this correctly, you need to mask the checksum too, or you'll leak information about the IP. Problem reports found in stackoverflow.com, sans.org, and pastebin.org are usually not masked, but a few companies do care. If only the IP is masked, the IP may be guessed from checksum (that is, it leaks data). Other parts of packet may leak more data about the IP. TCP and IP checksums both refer to the same data, so can get more bits of information out of using both checksums than just using one checksum. Also, one can usually determine the OS from the TTL field and ports in a packet header. If we get hundreds of possible results (16x each masked nibble that is unknown), one can do other things to narrow the results, such as look at packet contents for domain or geo information. With hundreds of results, can import as CSV format into a spreadsheet. Can corelate with geo data and see where each possibility is located. Eric then demoed a real email report with a masked IP packet attached. Was able to find the exact IP address, given the geo and university of the sender. Point is if you're going to mask a packet, do it right. Eric wouldn't usually bother, but do it correctly if at all, to not create a false impression of security. Adventures with weird machines thirty years after "Reflections on Trusting Trust" Sergey Bratus Sergey Bratus, Dartmouth College (and Julian Bangert and Rebecca Shapiro, not present) "Reflections on Trusting Trust" refers to Ken Thompson's classic 1984 paper. "You can't trust code that you did not totally create yourself." There's invisible links in the chain-of-trust, such as "well-installed microcode bugs" or in the compiler, and other planted bugs. Thompson showed how a compiler can introduce and propagate bugs in unmodified source. But suppose if there's no bugs and you trust the author, can you trust the code? Hell No! There's too many factors—it's Babylonian in nature. Why not? Well, Input is not well-defined/recognized (code's assumptions about "checked" input will be violated (bug/vunerabiliy). For example, HTML is recursive, but Regex checking is not recursive. Input well-formed but so complex there's no telling what it does For example, ELF file parsing is complex and has multiple ways of parsing. Input is seen differently by different pieces of program or toolchain Any Input is a program input executes on input handlers (drives state changes & transitions) only a well-defined execution model can be trusted (regex/DFA, PDA, CFG) Input handler either is a "recognizer" for the inputs as a well-defined language (see langsec.org) or it's a "virtual machine" for inputs to drive into pwn-age ELF ABI (UNIX/Linux executible file format) case study. Problems can arise from these steps (without planting bugs): compiler linker loader ld.so/rtld relocator DWARF (debugger info) exceptions The problem is you can't really automatically analyze code (it's the "halting problem" and undecidable). Only solution is to freeze code and sign it. But you can't freeze everything! Can't freeze ASLR or loading—must have tables and metadata. Any sufficiently complex input data is the same as VM byte code Example, ELF relocation entries + dynamic symbols == a Turing Complete Machine (TM). @bxsays created a Turing machine in Linux from relocation data (not code) in an ELF file. For more information, see Rebecca "bx" Shapiro's presentation from last year's Toorcon, "Programming Weird Machines with ELF Metadata" @bxsays did same thing with Mach-O bytecode Or a DWARF exception handling data .eh_frame + glibc == Turning Machine X86 MMU (IDT, GDT, TSS): used address translation to create a Turning Machine. Page handler reads and writes (on page fault) memory. Uses a page table, which can be used as Turning Machine byte code. Example on Github using this TM that will fly a glider across the screen Next Sergey talked about "Parser Differentials". That having one input format, but two parsers, will create confusion and opportunity for exploitation. For example, CSRs are parsed during creation by cert requestor and again by another parser at the CA. Another example is ELF—several parsers in OS tool chain, which are all different. Can have two different Program Headers (PHDRs) because ld.so parses multiple PHDRs. The second PHDR can completely transform the executable. This is described in paper in the first issue of International Journal of PoC. Conclusions trusting computers not only about bugs! Bugs are part of a problem, but no by far all of it complex data formats means bugs no "chain of trust" in Babylon! (that is, with parser differentials) we need to squeeze complexity out of data until data stops being "code equivalent" Further information See and langsec.org. USENIX WOOT 2013 (Workshop on Offensive Technologies) for "weird machines" papers and videos.

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CodePlex Daily Summary for Saturday, March 10, 2012

CodePlex Daily Summary for Saturday, March 10, 2012Popular ReleasesPlayer Framework by Microsoft: Player Framework for Windows 8 Metro (BETA): Player Framework for HTML/JavaScript and XAML/C# Metro Style Applications.WPF Application Framework (WAF): WAF for .NET 4.5 (Experimental): Version: 2.5.0.440 (Experimental): This is an experimental release! It can be used to investigate the new .NET Framework 4.5 features. The ideas shown in this release might come in a future release (after 2.5) of the WPF Application Framework (WAF). More information can be found in this dicussion post. Requirements .NET Framework 4.5 (The package contains a solution file for Visual Studio 11) The unit test projects require Visual Studio 11 Professional Changelog All: Upgrade all proje...SSH.NET Library: 2012.3.9: There are still few outstanding issues I wanted to include in this release but since its been a while and there are few new features already I decided to create a new release now. New Features Add SOCKS4, SOCKS5 and HTTP Proxy support when connecting to remote server. For silverlight only IP address can be used for server address when using proxy. Add dynamic port forwarding support using ForwardedPortDynamic class. Add new ShellStream class to work with SSH Shell. Add supports for mu...Test Case Import Utilities for Visual Studio 2010 and Visual Studio 11 Beta: V1.2 RTM: This release (V1.2 RTM) includes: Support for connecting to Hosted Team Foundation Server Preview. Support for connecting to Team Foundation Server 11 Beta. Fix to issue with read-only attribute being set for LinksMapping-ReportFile which may have led to problems when saving the report file. Fix to issue with “related links” not being set properly in certain conditions. Fix to ensure that tool works fine when the Excel file contained rich text data. Note: Data is still imported in pl...Audio Pitch & Shift: Audio Pitch And Shift 3.5.0: Modules (mod, xm, it, etc..) supportcallisto: callisto 2.0.19: BUG FIX: Autorun.load() function in scripting now has sandboxed path (Thanks Mikey!) BUG FIX: UserObject.Name property now allows full 20 byte string replacements. FEATURE REQUEST: File.* script functions now allow file extensions.EntitiesToDTOs - Entity Framework DTO Generator: EntitiesToDTOs.v2.1: Changelog Fixed template file access issue on Win7. Fix on configuration load when target project was not found and "Use project default namespace" was checked. Minor fix on loading latest configuration at startup. Minor fix in VisualStudioHelper class. DTO's properties accessors are now in one line. Improvements in PropertyHelper to get a cleaner and more performant code. Added Website project type as a not supported project type. Using Error List pane from VS IDE to show Enti...DotNetNuke® Community Edition CMS: 06.01.04: Major Highlights Fixed issue with loading the splash page skin in the login, privacy and terms of use pages Fixed issue when searching for words with special characters in them Fixed redirection issue when the user does not have permissions to access a resource Fixed issue when clearing the cache using the ClearHostCache() function Fixed issue when displaying the site structure in the link to page feature Fixed issue when inline editing the title of modules Fixed issue with ...Mayhem: Mayhem Developer Preview: This is the developer preview of Mayhem. Enjoy!Team Foundation Server Process Template Customization Guidance: v1 - For Visual Studio 11: Welcome to the BETA release of the Team Foundation Server Process Template Customization preview. As this is a BETA release and the quality bar for the final Release has not been achieved, we value your candid feedback and recommend that you do not use or deploy these BETA artifacts in a production environment. Quality-Bar Details Documentation has been reviewed by Visual Studio ALM Rangers Documentation has not been through an independent technical review Documentation has not been rev...Magelia WebStore Open-source Ecommerce software: Magelia WebStore 1.2: Medium trust compliant lot of small change for medium trust compliance full refactoring of user management refactoring of Client Refactoring of user management Magelia.WebStore.Client no longer reference Magelia.WebStore.Services.Contract Refactoring page category multi parent category added copy category feature added Refactoring page catalog copy catalog feature added variant management improvement ability to define a default variant for a variable product ability to ord...PDFsharp - A .NET library for processing PDF: PDFsharp and MigraDoc Foundation 1.32: PDFsharp and MigraDoc Foundation 1.32 is a stable version that fixes a few bugs that were found with version 1.31. Version 1.32 includes solutions for Visual Studio 2010 only (but it should be possible to add the project files to existing solutions for VS 2005 or VS 2008). Users of VS 2005 or VS 2008 can still download version 1.31 with the solutions for those versions that allow them to easily try the samples that are included. While it may create smaller PDF files than version 1.30 because...Terminals: Version 2.0 - Release: Changes since version 1.9a:New art works New usability in Organize favorites window Improved usability of imports/exports and scans Large number of fixes Improvements in single instance mode Comparing November beta 4, this corrects: New application icons Doesn't show Logon error codes Fixed command line arguments exception for single instance mode Fixed detaching of tabs improved usability in detached window Fixed option settings for Capture manager Fixed system tray noti...MFCMAPI: March 2012 Release: Build: 15.0.0.1032 Full release notes at SGriffin's blog. If you just want to run the MFCMAPI or MrMAPI, get the executables. If you want to debug them, get the symbol files and the source. The 64 bit builds will only work on a machine with Outlook 2010 64 bit installed. All other machines should use the 32 bit builds, regardless of the operating system. Facebook BadgeTortoiseHg: TortoiseHg 2.3.1: bugfix releaseSimple Injector: Simple Injector v1.4.1: This release adds two small improvements to the SimpleInjector.Extensions.dll. No changes have been made to the core library. New features and improvements in this release for the SimpleInjector.Extensions.dll The RegisterManyForOpenGeneric extension methods now accept non-generic decorator, as long as they implement the given open generic service type. GetTypesToRegister methods added to the OpenGenericBatchRegistrationExtensions class which allows to customize the behavior. Note that the...CommonLibrary: Code: CodeVidCoder: 1.3.1: Updated HandBrake core to 0.9.6 release (svn 4472). Removed erroneous "None" container choice. Change some logic and help text to stop assuming you have to pick the VIDEO_TS folder for a DVD scan. This should make previewing DVD titles on the Queue Multiple Titles window possible when you've picked the root DVD directory.Google Books Downloader for Windows: Google Books Downloader: Google Books Downloader 1.8ExtAspNet: ExtAspNet v3.1.0: ExtAspNet - ?? ExtJS ??? ASP.NET 2.0 ???，????? AJAX ?????????? ExtAspNet ????? ExtJS ??? ASP.NET 2.0 ???，????? AJAX ??????????。 ExtAspNet ??????? JavaScript，?? CSS，?? UpdatePanel，?? ViewState，?? WebServices ???????。 ??????: IE 7.0, Firefox 3.6, Chrome 3.0, Opera 10.5, Safari 3.0+ ????：Apache License 2.0 (Apache) ??：http://extasp.net/ ??：http://bbs.extasp.net/ ??：http://extaspnet.codeplex.com/ ??：http://sanshi.cnblogs.com/ ????： +2012-03-04 v3.1.0 -??Hidden???????（〓?〓）。 -?PageManager??...New ProjectsAres Backup: Ares Backup is a Backup software which can save bytediffs and provides several storage plugins.BackItUp: Backup-Tool für Visual Studio Projektebinbin domain: binbin domain Blexus Service Plattform: Some cool stuff about Wcf Services. - can communicate files - can communicate xaml objects (generate dynamically Gui) CardPlay - a Solitaire Framework for .Net: CardPlay is a C# framework for developing Solitaire card games. The solution includes a sample WPF client along with over 100 games.Cloud Files Upload: Windows application to script cloud file uploads.Code First API Library, Scaffolding & Guidance for Coded UI Tests: Code first Coded UI Tests for web apps. Library, Scaffolding and Guidance.CPEBook by FMUG & TPAY: CPEBook by MUG & TPAY Projet dot NET CPEBookDot Net Application String Resources Viewer: Dot Net Application String Resources ViewerFilter for SharePoint Web Settings Page: This solution show a simple way to integrate a filter box by using jquery, a global farm feature and a simple delegate control for AdditionalPageHead.Google Books Downloader for Windows: Save Google books in PDF, JPEG or PNG format.GUIToolkit: C++ Windowless GUI，DirectUIHarvest Sports: Harvest SportsInfoPath Analyzer: InfoPath Analyzer makes InfoPath form development and troubleshooting much easier. You're easy to find the relationship between controls and data fields, search data fields or controls by name, edit InfoPath inner html directly.Kinectsignlanguage project: This project will help kinect be used for sign language to speech so that sign language people can be understood while talking to important people. LotteryVote: ????manager123: Trying out CodePlexMcRegister: McRegister is an asp.net mvc 3 razor website that enables you to register users on your minecraft server it works in conjunction with a minecraft mod called EasyAuth.MetroTipi: HelloTipi Sous l'interface Metro de Windows 8Microsoft AppFactory: AppFactory is a powerful data-driven build system for Windows Phone (and soon Windows 8) projects. Its purpose is to help developers start with template projects and turn them into suites of applications.MiniStock: MiniStock is an experimental reference architecture for scalable cloud-based architectures. Implemented in .net.online book shopping: online book shoppingScopa: Carousel Team Scopa per WP7 XNA testtom03092012tfs01: testtom03092012tfs01UsingLib: A library of automatically removed utilities: 1.Changing cursor to hourglass in Windows Forms 2.Logging It's developed in C#WHMCS Library: WHMCS is an all-in-one client management, billing & support solution for online businesses. Handling everything from signup to termination, WHMCS is a powerful business automation tool that puts you firmly in control. The WHMCS Library is a .NET wrapper for the WHMCS API. Written entirely in C# but really easy to port over to VB.NET. Coming from a VB.NET background we tried hard to make sure porting would be simple for VB.NET community members. ZoneEditService: Windows service to update ZoneEdit for dynamic dns.

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The broken Promise of the Mobile Web

- by Rick Strahl

High end mobile devices have been with us now for almost 7 years and they have utterly transformed the way we access information. Mobile phones and smartphones that have access to the Internet and host smart applications are in the hands of a large percentage of the population of the world. In many places even very remote, cell phones and even smart phones are a common sight. I’ll never forget when I was in India in 2011 I was up in the Southern Indian mountains riding an elephant out of a tiny local village, with an elephant herder in front riding atop of the elephant in front of us. He was dressed in traditional garb with the loin wrap and head cloth/turban as did quite a few of the locals in this small out of the way and not so touristy village. So we’re slowly trundling along in the forest and he’s lazily using his stick to guide the elephant and… 10 minutes in he pulls out his cell phone from his sash and starts texting. In the middle of texting a huge pig jumps out from the side of the trail and he takes a picture running across our path in the jungle! So yeah, mobile technology is very pervasive and it’s reached into even very buried and unexpected parts of this world. Apps are still King Apps currently rule the roost when it comes to mobile devices and the applications that run on them. If there’s something that you need on your mobile device your first step usually is to look for an app, not use your browser. But native app development remains a pain in the butt, with the requirement to have to support 2 or 3 completely separate platforms. There are solutions that try to bridge that gap. Xamarin is on a tear at the moment, providing their cross-device toolkit to build applications using C#. While Xamarin tools are impressive – and also *very* expensive – they only address part of the development madness that is app development. There are still specific device integration isssues, dealing with the different developer programs, security and certificate setups and all that other noise that surrounds app development. There’s also PhoneGap/Cordova which provides a hybrid solution that involves creating local HTML/CSS/JavaScript based applications, and then packaging them to run in a specialized App container that can run on most mobile device platforms using a WebView interface. This allows for using of HTML technology, but it also still requires all the set up, configuration of APIs, security keys and certification and submission and deployment process just like native applications – you actually lose many of the benefits that Web based apps bring. The big selling point of Cordova is that you get to use HTML have the ability to build your UI once for all platforms and run across all of them – but the rest of the app process remains in place. Apps can be a big pain to create and manage especially when we are talking about specialized or vertical business applications that aren’t geared at the mainstream market and that don’t fit the ‘store’ model. If you’re building a small intra department application you don’t want to deal with multiple device platforms and certification etc. for various public or corporate app stores. That model is simply not a good fit both from the development and deployment perspective. Even for commercial, big ticket apps, HTML as a UI platform offers many advantages over native, from write-once run-anywhere, to remote maintenance, single point of management and failure to having full control over the application as opposed to have the app store overloads censor you. In a lot of ways Web based HTML/CSS/JavaScript applications have so much potential for building better solutions based on existing Web technologies for the very same reasons a lot of content years ago moved off the desktop to the Web. To me the Web as a mobile platform makes perfect sense, but the reality of today’s Mobile Web unfortunately looks a little different… Where’s the Love for the Mobile Web? Yet here we are in the middle of 2014, nearly 7 years after the first iPhone was released and brought the promise of rich interactive information at your fingertips, and yet we still don’t really have a solid mobile Web platform. I know what you’re thinking: “But we have lots of HTML/JavaScript/CSS features that allows us to build nice mobile interfaces”. I agree to a point – it’s actually quite possible to build nice looking, rich and capable Web UI today. We have media queries to deal with varied display sizes, CSS transforms for smooth animations and transitions, tons of CSS improvements in CSS 3 that facilitate rich layout, a host of APIs geared towards mobile device features and lately even a number of JavaScript framework choices that facilitate development of multi-screen apps in a consistent manner. Personally I’ve been working a lot with AngularJs and heavily modified Bootstrap themes to build mobile first UIs and that’s been working very well to provide highly usable and attractive UI for typical mobile business applications. From the pure UI perspective things actually look very good. Not just about the UI But it’s not just about the UI - it’s also about integration with the mobile device. When it comes to putting all those pieces together into what amounts to a consolidated platform to build mobile Web applications, I think we still have a ways to go… there are a lot of missing pieces to make it all work together and integrate with the device more smoothly, and more importantly to make it work uniformly across the majority of devices. I think there are a number of reasons for this. Slow Standards Adoption HTML standards implementations and ratification has been dreadfully slow, and browser vendors all seem to pick and choose different pieces of the technology they implement. The end result is that we have a capable UI platform that’s missing some of the infrastructure pieces to make it whole on mobile devices. There’s lots of potential but what is lacking that final 10% to build truly compelling mobile applications that can compete favorably with native applications. Some of it is the fragmentation of browsers and the slow evolution of the mobile specific HTML APIs. A host of mobile standards exist but many of the standards are in the early review stage and they have been there stuck for long periods of time and seem to move at a glacial pace. Browser vendors seem even slower to implement them, and for good reason – non-ratified standards mean that implementations may change and vendor implementations tend to be experimental and likely have to be changed later. Neither Vendors or developers are not keen on changing standards. This is the typical chicken and egg scenario, but without some forward momentum from some party we end up stuck in the mud. It seems that either the standards bodies or the vendors need to carry the torch forward and that doesn’t seem to be happening quickly enough. Mobile Device Integration just isn’t good enough Current standards are not far reaching enough to address a number of the use case scenarios necessary for many mobile applications. While not every application needs to have access to all mobile device features, almost every mobile application could benefit from some integration with other parts of the mobile device platform. Integration with GPS, phone, media, messaging, notifications, linking and contacts system are benefits that are unique to mobile applications and could be widely used, but are mostly (with the exception of GPS) inaccessible for Web based applications today. Unfortunately trying to do most of this today only with a mobile Web browser is a losing battle. Aside from PhoneGap/Cordova’s app centric model with its own custom API accessing mobile device features and the token exception of the GeoLocation API, most device integration features are not widely supported by the current crop of mobile browsers. For example there’s no usable messaging API that allows access to SMS or contacts from HTML. Even obvious components like the Media Capture API are only implemented partially by mobile devices. There are alternatives and workarounds for some of these interfaces by using browser specific code, but that’s might ugly and something that I thought we were trying to leave behind with newer browser standards. But it’s not quite working out that way. It’s utterly perplexing to me that mobile standards like Media Capture and Streams, Media Gallery Access, Responsive Images, Messaging API, Contacts Manager API have only minimal or no traction at all today. Keep in mind we’ve had mobile browsers for nearly 7 years now, and yet we still have to think about how to get access to an image from the image gallery or the camera on some devices? Heck Windows Phone IE Mobile just gained the ability to upload images recently in the Windows 8.1 Update – that’s feature that HTML has had for 20 years! These are simple concepts and common problems that should have been solved a long time ago. It’s extremely frustrating to see build 90% of a mobile Web app with relative ease and then hit a brick wall for the remaining 10%, which often can be show stoppers. The remaining 10% have to do with platform integration, browser differences and working around the limitations that browsers and ‘pinned’ applications impose on HTML applications. The maddening part is that these limitations seem arbitrary as they could easily work on all mobile platforms. For example, SMS has a URL Moniker interface that sort of works on Android, works badly with iOS (only works if the address is already in the contact list) and not at all on Windows Phone. There’s no reason this shouldn’t work universally using the same interface – after all all phones have supported SMS since before the year 2000! But, it doesn’t have to be this way Change can happen very quickly. Take the GeoLocation API for example. Geolocation has taken off at the very beginning of the mobile device era and today it works well, provides the necessary security (a big concern for many mobile APIs), and is supported by just about all major mobile and even desktop browsers today. It handles security concerns via prompts to avoid unwanted access which is a model that would work for most other device APIs in a similar fashion. One time approval and occasional re-approval if code changes or caches expire. Simple and only slightly intrusive. It all works well, even though GeoLocation actually has some physical limitations, such as representing the current location when no GPS device is present. Yet this is a solved problem, where other APIs that are conceptually much simpler to implement have failed to gain any traction at all. Technically none of these APIs should be a problem to implement, but it appears that the momentum is just not there. Inadequate Web Application Linking and Activation Another important piece of the puzzle missing is the integration of HTML based Web applications. Today HTML based applications are not first class citizens on mobile operating systems. When talking about HTML based content there’s a big difference between content and applications. Content is great for search engine discovery and plain browser usage. Content is usually accessed intermittently and permanent linking is not so critical for this type of content. But applications have different needs. Applications need to be started up quickly and must be easily switchable to support a multi-tasking user workflow. Therefore, it’s pretty crucial that mobile Web apps are integrated into the underlying mobile OS and work with the standard task management features. Unfortunately this integration is not as smooth as it should be. It starts with actually trying to find mobile Web applications, to ‘installing’ them onto a phone in an easily accessible manner in a prominent position. The experience of discovering a Mobile Web ‘App’ and making it sticky is by no means as easy or satisfying. Today the way you’d go about this is: Open the browser Search for a Web Site in the browser with your search engine of choice Hope that you find the right site Hope that you actually find a site that works for your mobile device Click on the link and run the app in a fully chrome’d browser instance (read tiny surface area) Pin the app to the home screen (with all the limitations outline above) Hope you pointed at the right URL when you pinned Even for you and me as developers, there are a few steps in there that are painful and annoying, but think about the average user. First figuring out how to search for a specific site or URL? And then pinning the app and hopefully from the right location? You’ve probably lost more than half of your audience at that point. This experience sucks. For developers too this process is painful since app developers can’t control the shortcut creation directly. This problem often gets solved by crazy coding schemes, with annoying pop-ups that try to get people to create shortcuts via fancy animations that are both annoying and add overhead to each and every application that implements this sort of thing differently. And that’s not the end of it - getting the link onto the home screen with an application icon varies quite a bit between browsers. Apple’s non-standard meta tags are prominent and they work with iOS and Android (only more recent versions), but not on Windows Phone. Windows Phone instead requires you to create an actual screen or rather a partial screen be captured for a shortcut in the tile manager. Who had that brilliant idea I wonder? Surprisingly Chrome on recent Android versions seems to actually get it right – icons use pngs, pinning is easy and pinned applications properly behave like standalone apps and retain the browser’s active page state and content. Each of the platforms has a different way to specify icons (WP doesn’t allow you to use an icon image at all), and the most widely used interface in use today is a bunch of Apple specific meta tags that other browsers choose to support. The question is: Why is there no standard implementation for installing shortcuts across mobile platforms using an official format rather than a proprietary one? Then there’s iOS and the crazy way it treats home screen linked URLs using a crazy hybrid format that is neither as capable as a Web app running in Safari nor a WebView hosted application. Moving off the Web ‘app’ link when switching to another app actually causes the browser and preview it to ‘blank out’ the Web application in the Task View (see screenshot on the right). Then, when the ‘app’ is reactivated it ends up completely restarting the browser with the original link. This is crazy behavior that you can’t easily work around. In some situations you might be able to store the application state and restore it using LocalStorage, but for many scenarios that involve complex data sources (like say Google Maps) that’s not a possibility. The only reason for this screwed up behavior I can think of is that it is deliberate to make Web apps a pain in the butt to use and forcing users trough the App Store/PhoneGap/Cordova route. App linking and management is a very basic problem – something that we essentially have solved in every desktop browser – yet on mobile devices where it arguably matters a lot more to have easy access to web content we have to jump through hoops to have even a remotely decent linking/activation experience across browsers. Where’s the Money? It’s not surprising that device home screen integration and Mobile Web support in general is in such dismal shape – the mobile OS vendors benefit financially from App store sales and have little to gain from Web based applications that bypass the App store and the cash cow that it presents. On top of that, platform specific vendor lock-in of both end users and developers who have invested in hardware, apps and consumables is something that mobile platform vendors actually aspire to. Web based interfaces that are cross-platform are the anti-thesis of that and so again it’s no surprise that the mobile Web is on a struggling path. But – that may be changing. More and more we’re seeing operations shifting to services that are subscription based or otherwise collect money for usage, and that may drive more progress into the Web direction in the end . Nothing like the almighty dollar to drive innovation forward. Do we need a Mobile Web App Store? As much as I dislike moderated experiences in today’s massive App Stores, they do at least provide one single place to look for apps for your device. I think we could really use some sort of registry, that could provide something akin to an app store for mobile Web apps, to make it easier to actually find mobile applications. This could take the form of a specialized search engine, or maybe a more formal store/registry like structure. Something like apt-get/chocolatey for Web apps. It could be curated and provide at least some feedback and reviews that might help with the integrity of applications. Coupled to that could be a native application on each platform that would allow searching and browsing of the registry and then also handle installation in the form of providing the home screen linking, plus maybe an initial security configuration that determines what features are allowed access to for the app. I’m not holding my breath. In order for this sort of thing to take off and gain widespread appeal, a lot of coordination would be required. And in order to get enough traction it would have to come from a well known entity – a mobile Web app store from a no name source is unlikely to gain high enough usage numbers to make a difference. In a way this would eliminate some of the freedom of the Web, but of course this would also be an optional search path in addition to the standard open Web search mechanisms to find and access content today. Security Security is a big deal, and one of the perceived reasons why so many IT professionals appear to be willing to go back to the walled garden of deployed apps is that Apps are perceived as safe due to the official review and curation of the App stores. Curated stores are supposed to protect you from malware, illegal and misleading content. It doesn’t always work out that way and all the major vendors have had issues with security and the review process at some time or another. Security is critical, but I also think that Web applications in general pose less of a security threat than native applications, by nature of the sandboxed browser and JavaScript environments. Web applications run externally completely and in the HTML and JavaScript sandboxes, with only a very few controlled APIs allowing access to device specific features. And as discussed earlier – security for any device interaction can be granted the same for mobile applications through a Web browser, as they can for native applications either via explicit policies loaded from the Web, or via prompting as GeoLocation does today. Security is important, but it’s certainly solvable problem for Web applications even those that need to access device hardware. Security shouldn’t be a reason for Web apps to be an equal player in mobile applications. Apps are winning, but haven’t we been here before? So now we’re finding ourselves back in an era of installed app, rather than Web based and managed apps. Only it’s even worse today than with Desktop applications, in that the apps are going through a gatekeeper that charges a toll and censors what you can and can’t do in your apps. Frankly it’s a mystery to me why anybody would buy into this model and why it’s lasted this long when we’ve already been through this process. It’s crazy… It’s really a shame that this regression is happening. We have the technology to make mobile Web apps much more prominent, but yet we’re basically held back by what seems little more than bureaucracy, partisan bickering and self interest of the major parties involved. Back in the day of the desktop it was Internet Explorer’s 98+% market shareholding back the Web from improvements for many years – now it’s the combined mobile OS market in control of the mobile browsers. If mobile Web apps were allowed to be treated the same as native apps with simple ways to install and run them consistently and persistently, that would go a long way to making mobile applications much more usable and seriously viable alternatives to native apps. But as it is mobile apps have a severe disadvantage in placement and operation. There are a few bright spots in all of this. Mozilla’s FireFoxOs is embracing the Web for it’s mobile OS by essentially building every app out of HTML and JavaScript based content. It supports both packaged and certified package modes (that can be put into the app store), and Open Web apps that are loaded and run completely off the Web and can also cache locally for offline operation using a manifest. Open Web apps are treated as full class citizens in FireFoxOS and run using the same mechanism as installed apps. Unfortunately FireFoxOs is getting a slow start with minimal device support and specifically targeting the low end market. We can hope that this approach will change and catch on with other vendors, but that’s also an uphill battle given the conflict of interest with platform lock in that it represents. Recent versions of Android also seem to be working reasonably well with mobile application integration onto the desktop and activation out of the box. Although it still uses the Apple meta tags to find icons and behavior settings, everything at least works as you would expect – icons to the desktop on pinning, WebView based full screen activation, and reliable application persistence as the browser/app is treated like a real application. Hopefully iOS will at some point provide this same level of rudimentary Web app support. What’s also interesting to me is that Microsoft hasn’t picked up on the obvious need for a solid Web App platform. Being a distant third in the mobile OS war, Microsoft certainly has nothing to lose and everything to gain by using fresh ideas and expanding into areas that the other major vendors are neglecting. But instead Microsoft is trying to beat the market leaders at their own game, fighting on their adversary’s terms instead of taking a new tack. Providing a kick ass mobile Web platform that takes the lead on some of the proposed mobile APIs would be something positive that Microsoft could do to improve its miserable position in the mobile device market. Where are we at with Mobile Web? It sure sounds like I’m really down on the Mobile Web, right? I’ve built a number of mobile apps in the last year and while overall result and response has been very positive to what we were able to accomplish in terms of UI, getting that final 10% that required device integration dialed was an absolute nightmare on every single one of them. Big compromises had to be made and some features were left out or had to be modified for some devices. In two cases we opted to go the Cordova route in order to get the integration we needed, along with the extra pain involved in that process. Unless you’re not integrating with device features and you don’t care deeply about a smooth integration with the mobile desktop, mobile Web development is fraught with frustration. So, yes I’m frustrated! But it’s not for lack of wanting the mobile Web to succeed. I am still a firm believer that we will eventually arrive a much more functional mobile Web platform that allows access to the most common device features in a sensible way. It wouldn't be difficult for device platform vendors to make Web based applications first class citizens on mobile devices. But unfortunately it looks like it will still be some time before this happens. So, what’s your experience building mobile Web apps? Are you finding similar issues? Just giving up on raw Web applications and building PhoneGap apps instead? Completely skipping the Web and going native? Leave a comment for discussion. Resources Rick Strahl on DotNet Rocks talking about Mobile Web© Rick Strahl, West Wind Technologies, 2005-2014Posted in HTML5 Mobile Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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Messing with the Team

- by Robert May

Good Product Owners will help the team be the best that they can be. Bad product owners will mess with the team and won’t care about the team. If you’re a product owner, seek to do good and avoid bad behavior at all costs. Remember, this is for YOUR benefit and you have much power given to you. Use that power wisely. Scope Creep The product owner has several tools at his disposal to inject scope into an iteration. First, the product owner can use defects to inject scope. To do this, they’ll tell the team what functionality that they want to see in a feature. Then, after the feature is developed, the Product Owner will decide that they don’t really like how the functionality behaves. To change it, rather than creating a new story, they’ll add a defect. The functionality is correct, as designed, but the Product Owner doesn’t like it. By creating the defect, the Product Owner destroys the trust that the team has of the product owner. They may not be able to count the story, because the Product Owner changed the story in the iteration, and the team then ends up looking like they have low velocity for something over which they have no control. This is bad. One way to deal with this is to add “Product Owner Time” to the iteration. This will slow the velocity, but then the ScrumMaster can tell stake holders that this time is strictly in place to deal with bad behavior of the Product Owner. Another mechanism often used to inject Scope is the concept of directed development. Outside of planning, stand-ups, or any other meeting, the Product Owner will take a developer aside and ask them to complete a task for them. This is bad! The team should be allocating all of their time to development. If the Product Owner asks for a favor, then time that would normally be used for development will be used for a pet project of the Product Owner and the team will not get credit for this work. Selfish product owners do this, and I typically see people who were “managers” do this behavior. Authoritarian command and control development environments also see this happen. The best thing that can happen is for the team member to report the issue to the ScrumMaster and the ScrumMaster to get very aggressive with management and the Product Owner to try and stop the behavior. This may result in the ScrumMaster being fired, but if the behavior continues, Scrum is doomed. This problem is especially bad in cases where the team member’s direct supervisor is the Product Owner. I don’t recommend that the Product Owner or ScrumMaster have a direct report relationship with team members, since team members need the ability to say no. To work around this issue, team members need to say no. If that fails, team members need to add extra time to the iteration to deal with the scope creep injection and accept the lower velocity. As discussed above, another mechanism for injecting scope is by changing acceptance tests after the work is complete. This is similar to adding defects to change scope and is bad. To get around, add time for Product Owner uncertainty to the iteration and make sure that stakeholders are aware of the need to add this time because of the Product Owner. Refusing to Prioritize Refusing to prioritize causes chaos for the team. From the team’s perspective, things that are not important will be worked on while things that the team knows are vital will be ignored. A poor Product Owner will often pick the stories for the iteration on a whim. This leads to the team working on many different aspects of the product and results in a lower velocity, since each iteration the team must switch context to the new area of development. The team will also experience confusion about priorities. In one iteration, Feature X was the highest priority and had to be done. Then, the following iteration, even though parts of Feature X still need to be completed, no stories to address them will be in the iteration. However, three iterations later, Feature X will again become high priority. This will cause the team to not trust the Product Owner, and eventually, they’ll stop caring about the features they implement. They won’t know what is important, so to insulate themselves from the ever changing chaos, they’ll become apathetic to all features. Team members are some of the most creative people in a company. By losing their engagement, the company is going to have a substandard product because the passion for the product won’t be in the team. Other signs that the Product Owner refuses to prioritize is that no one outside of the product owner will be consulted on priorities. Additionally, the product, release, and iteration backlogs will be weak or non-existent. Dealing with this issue is not easy. This really isn’t something the team can fix, short of taking over the role of Product Owner themselves. An appeal to the stake holders might work, but only if the Product Owner isn’t a “manager” themselves. The ScrumMaster needs to protect the team and do what they can to either get the Product Owner to prioritize or have the Product Owner replaced. Managing the Team A Product Owner that is also the “boss” of team members is a Scrum team that is waiting to fail. If your boss tells you to do something, failing to do that something can cause you to be fired. The team needs the ability to tell the Product Owner NO. If the product owner introduces scope creep, the team has a responsibility to tell the Product Owner no. If the Product Owner tries to get the team to commit to more than they can accomplish in an iteration, the team needs the ability to tell the Product Owner no. If the Product Owner is your boss and determines your pay increases, you’re probably not going to ever tell them no, and Scrum will likely fail. The team can’t do much in this situation. Another aspect of “managing the team” that often happens is the Product Owner tries to tell the team how to develop the stories that are in the iteration. This is one reason why I recommend that Product Owners are NOT technical people. That way, the team can come up with the tasks that are needed to accomplish the stories and the Product Owner won’t know better. If the Product Owner is technical, the ScrumMaster will need to take great care to protect the team from the ScrumMaster changing how the team thinks they need to implement the stories. Product Owners can also try to manage the team by their body language. If the team says a task is going to take 6 hours to complete, and the Product Owner disagrees, they will use some kind of sour body language to indicate this disagreement. In weak teams, this may cause the team to revise their estimate down, which will result in them taking longer than estimated and may result in them missing the iteration. The ScrumMaster will need to make sure that the Product Owner doesn’t send such messages and that the team ignores them and estimates what they REALLY think it will take to complete the tasks. Forcing the team to deal with such items in the retrospective can be helpful. Absenteeism The team is completely dependent upon the Product Owner to develop features for the customer. The Product Owner IS the voice of the customer and without them, the team will lack direction. Being the Product Owner is a full time job! If the Product Owner cannot dedicate daily time with the team, a different product owner should be found. The Product Owner needs to attend every stand-up, planning meeting, showcase, and retrospective that the team has. The team also must be able to have instant communication with the product owner. They must not be required to schedule meetings to speak with their product owner. The team must be the highest priority task that the Product Owner has. The best way to work around an absent Product Owner is to appoint a new Product Owner in the team. This person will be responsible for making the decisions that the Product Owner should be making and to act as the liaison to the absent Product Owner. If the delegate Product Owner doesn’t have authority to make decisions for the team, Scrum will fail. If the Product Owner is absent, the ScrumMaster should seek to have that Product Owner replaced by someone who has the time and ability to be a real Product Owner. Making it Personal Too often Product Owners will become convinced that their ideas are the ones that matter and that anyone who disagrees is making a personal attack on them. Remember that Product Owners will inherently be at odds with many people, simply because they have the need to prioritize. Others will frequently question prioritization because they only see part of the picture that Product Owners face. Product Owners must have a thick skin and think egos. If they don’t, they tend to make things personal, which causes them to become emotional and causes them to take actions that can destroy the trust that team members have in the Product Owner. If a Product Owner is making things person, the best thing that team members can do is reassure them that its not personal, but be firm about doing what is best for the Company and for the users. The ScrumMaster should also spend significant time coaching the Product Owner on how to not react emotionally and how to accept criticism without becoming defensive. Conclusion I’m sure there are other ways that a Product Owner can mess with the team, but these are the most common that I’ve seen. I would encourage all Product Owners to seek to be a good Product Owner. If you find yourself behaving in any of the bad product owner ways, change your behavior today! Your team will thank you. Remember, being Product Owner is very difficult! Product Owner is one of the most difficult roles in Scrum. However, it can also be one of the most rewarding roles in Scrum, since Product Owners literally see their ideas brought to life on the computer screen. Product Owners need to be very patient, even in the face of criticism and need to be willing to make tough decisions on priority, but then not become offended when others disagree with those decisions. Companies should spend the time needed to find the right product owners for their teams. Doing so will only help the company to write better software. Technorati Tags: Scrum,Product Owner

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Windows Azure AppFabric: ServiceBus Queue WPF Sample

- by xamlnotes

The latest version of the AppFabric ServiceBus now has support for queues and topics. Today I will show you a bit about using queues and also talk about some of the best practices in using them. If you are just getting started, you can check out this site for more info on Windows Azure. One of the 1st things I thought if when Azure was announced back when was how we handle fault tolerance. Web sites hosted in Azure are no much of an issue unless they are using SQL Azure and then you must account for potential fault or latency issues. Today I want to talk a bit about ServiceBus and how to handle fault tolerance. And theres stuff like connecting to the servicebus and so on you have to take care of. To demonstrate some of the things you can do, let me walk through this sample WPF app that I am posting for you to download. To start off, the application is going to need things like the servicenamespace, issuer details and so forth to make everything work. To facilitate this I created settings in the wpf app for all of these items. Then I mapped a static class to them and set the values when the program loads like so: StaticElements.ServiceNamespace = Convert.ToString(Properties.Settings.Default["ServiceNamespace"]); StaticElements.IssuerName = Convert.ToString(Properties.Settings.Default["IssuerName"]); StaticElements.IssuerKey = Convert.ToString(Properties.Settings.Default["IssuerKey"]); StaticElements.QueueName = Convert.ToString(Properties.Settings.Default["QueueName"]); Now I can get to each of these elements plus some other common values or instances directly from the StaticElements class. Now, lets look at the application. The application looks like this when it starts: The blue graphic represents the queue we are going to use. The next figure shows the form after items were added and the queue stats were updated . You can see how the queue has grown: To add an item to the queue, click the Add Order button which displays the following dialog: After you fill in the form and press OK, the order is published to the ServiceBus queue and the form closes. The application also allows you to read the queued items by clicking the Process Orders button. As you can see below, the form shows the queued items in a list and the queue has disappeared as its now empty. In real practice we normally would use a Windows Service or some other automated process to subscribe to the queue and pull items from it. I created a class named ServiceBusQueueHelper that has the core queue features we need. There are three public methods: * GetOrCreateQueue – Gets an instance of the queue description if the queue exists. if not, it creates the queue and returns a description instance. * SendMessageToQueue = This method takes an order instance and sends it to the queue. The call to the queue is wrapped in the ExecuteAction method from the Transient Fault Tolerance Framework and handles all the retry logic for the queue send process. * GetOrderFromQueue – Grabs an order from the queue and returns a typed order from the queue. It also marks the message complete so the queue can remove it. Now lets turn to the WPF window code (MainWindow.xaml.cs). The constructor contains the 4 lines shown about to setup the static variables and to perform other initialization tasks. The next few lines setup certain features we need for the ServiceBus: TokenProvider credentials = TokenProvider.CreateSharedSecretTokenProvider(StaticElements.IssuerName, StaticElements.IssuerKey); Uri serviceUri = ServiceBusEnvironment.CreateServiceUri("sb", StaticElements.ServiceNamespace, string.Empty); StaticElements.CurrentNamespaceManager = new NamespaceManager(serviceUri, credentials); StaticElements.CurrentMessagingFactory = MessagingFactory.Create(serviceUri, credentials); The next two lines update the queue name label and also set the timer to 20 seconds. QueueNameLabel.Content = StaticElements.QueueName; _timer.Interval = TimeSpan.FromSeconds(20); Next I call the UpdateQueueStats to initialize the UI for the queue: UpdateQueueStats(); _timer.Tick += new EventHandler(delegate(object s, EventArgs a) { UpdateQueueStats(); }); _timer.Start(); } The UpdateQueueStats method shown below. You can see that it uses the GetOrCreateQueue method mentioned earlier to grab the queue description, then it can get the MessageCount property. private void UpdateQueueStats() { _queueDescription = _serviceBusQueueHelper.GetOrCreateQueue(); QueueCountLabel.Content = "(" + _queueDescription.MessageCount + ")"; long count = _queueDescription.MessageCount; long queueWidth = count * 20; QueueRectangle.Width = queueWidth; QueueTickCount += 1; TickCountlabel.Content = QueueTickCount.ToString(); } The ReadQueueItemsButton_Click event handler calls the GetOrderFromQueue method and adds the order to the listbox. If you look at the SendQueueMessageController, you can see the SendMessage method that sends an order to the queue. Its pretty simple as it just creates a new CustomerOrderEntity instance,fills it and then passes it to the SendMessageToQueue. As you can see, all of our interaction with the queue is done through the helper class (ServiceBusQueueHelper). Now lets dig into the helper class. First, before you create anything like this, download the Transient Fault Handling Framework. Microsoft provides this free and they also provide the C# source. Theres a great article that shows how to use this framework with ServiceBus. I included the entire ServiceBusQueueHelper class in List 1. Notice the using statements for TransientFaultHandling: using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; The SendMessageToQueue in Listing 1 shows how to use the async send features of ServiceBus with them wrapped in the Transient Fault Handling Framework. It is not much different than plain old ServiceBus calls but it sure makes it easy to have the fault tolerance added almost for free. The GetOrderFromQueue uses the standard synchronous methods to access the queue. The best practices article walks through using the async approach for a receive operation also. Notice that this method makes a call to Receive to get the message then makes a call to GetBody to get a new strongly typed instance of CustomerOrderEntity to return. Listing 1 using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.AzureCAT.Samples.TransientFaultHandling; using Microsoft.AzureCAT.Samples.TransientFaultHandling.ServiceBus; using Microsoft.ServiceBus; using Microsoft.ServiceBus.Messaging; using System.Xml.Serialization; using System.Diagnostics; namespace WPFServicebusPublishSubscribeSample { class ServiceBusQueueHelper { RetryPolicy currentPolicy = new RetryPolicy<ServiceBusTransientErrorDetectionStrategy>(RetryPolicy.DefaultClientRetryCount); QueueClient currentQueueClient; public QueueDescription GetOrCreateQueue() { QueueDescription queue = null; bool createNew = false; try { // First, let's see if a queue with the specified name already exists. queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); }); createNew = (queue == null); } catch (MessagingEntityNotFoundException) { // Looks like the queue does not exist. We should create a new one. createNew = true; } // If a queue with the specified name doesn't exist, it will be auto-created. if (createNew) { try { var newqueue = new QueueDescription(StaticElements.QueueName); queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.CreateQueue(newqueue); }); } catch (MessagingEntityAlreadyExistsException) { // A queue under the same name was already created by someone else, // perhaps by another instance. Let's just use it. queue = currentPolicy.ExecuteAction<QueueDescription>(() => { return StaticElements.CurrentNamespaceManager.GetQueue(StaticElements.QueueName); }); } } currentQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName); return queue; } public void SendMessageToQueue(CustomerOrderEntity Order) { BrokeredMessage msg = null; GetOrCreateQueue(); // Use a retry policy to execute the Send action in an asynchronous and reliable fashion. currentPolicy.ExecuteAction ( (cb) => { // A new BrokeredMessage instance must be created each time we send it. Reusing the original BrokeredMessage instance may not // work as the state of its BodyStream cannot be guaranteed to be readable from the beginning. msg = new BrokeredMessage(Order); // Send the event asynchronously. currentQueueClient.BeginSend(msg, cb, null); }, (ar) => { try { // Complete the asynchronous operation. // This may throw an exception that will be handled internally by the retry policy. currentQueueClient.EndSend(ar); } finally { // Ensure that any resources allocated by a BrokeredMessage instance are released. if (msg != null) { msg.Dispose(); msg = null; } } }, (ex) => { // Always dispose the BrokeredMessage instance even if the send // operation has completed unsuccessfully. if (msg != null) { msg.Dispose(); msg = null; } // Always log exceptions. Trace.TraceError(ex.Message); } ); } public CustomerOrderEntity GetOrderFromQueue() { CustomerOrderEntity Order = new CustomerOrderEntity(); QueueClient myQueueClient = StaticElements.CurrentMessagingFactory.CreateQueueClient(StaticElements.QueueName, ReceiveMode.PeekLock); BrokeredMessage message; ServiceBusQueueHelper serviceBusQueueHelper = new ServiceBusQueueHelper(); QueueDescription queueDescription; queueDescription = serviceBusQueueHelper.GetOrCreateQueue(); if (queueDescription.MessageCount > 0) { message = myQueueClient.Receive(TimeSpan.FromSeconds(90)); if (message != null) { try { Order = message.GetBody<CustomerOrderEntity>(); message.Complete(); } catch (Exception ex) { throw ex; } } else { throw new Exception("Did not receive the messages"); } } return Order; } } } I will post a link to the download demo in a separate post soon.

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MVC Automatic Menu

- by Nuri Halperin

An ex-colleague of mine used to call his SQL script generator "Super-Scriptmatic 2000". It impressed our then boss little, but was fun to say and use. We called every batch job and script "something 2000" from that day on. I'm tempted to call this one Menu-Matic 2000, except it's waaaay past 2000. Oh well. The problem: I'm developing a bunch of stuff in MVC. There's no PM to generate mounds of requirements and there's no Ux Architect to create wireframe. During development, things change. Specifically, actions get renamed, moved from controller x to y etc. Well, as the site grows, it becomes a major pain to keep a static menu up to date, because the links change. The HtmlHelper doesn't live up to it's name and provides little help. How do I keep this growing list of pesky little forgotten actions reigned in? The general plan is: Decorate every action you want as a menu item with a custom attribute Reflect out all menu items into a structure at load time Render the menu using as CSS friendly <ul><li> HTML. The MvcMenuItemAttribute decorates an action, designating it to be included as a menu item: [AttributeUsage(AttributeTargets.Method, AllowMultiple = true)] public class MvcMenuItemAttribute : Attribute { public string MenuText { get; set; } public int Order { get; set; } public string ParentLink { get; set; } internal string Controller { get; set; } internal string Action { get; set; } #region ctor public MvcMenuItemAttribute(string menuText) : this(menuText, 0) { } public MvcMenuItemAttribute(string menuText, int order) { MenuText = menuText; Order = order; } internal string Link { get { return string.Format("/{0}/{1}", Controller, this.Action); } } internal MvcMenuItemAttribute ParentItem { get; set; } #endregion } The MenuText allows overriding the text displayed on the menu. The Order allows the items to be ordered. The ParentLink allows you to make this item a child of another menu item. An example action could then be decorated thusly: [MvcMenuItem("Tracks", Order = 20, ParentLink = "/Session/Index")] . All pretty straightforward methinks. The challenge with menu hierarchy becomes fairly apparent when you try to render a menu and highlight the "current" item or render a breadcrumb control. Both encounter an ambiguity if you allow a data source to have more than one menu item with the same URL link. The issue is that there is no great way to tell which link a person click. Using referring URL will fail if a user bookmarked the page. Using some extra query string to disambiguate duplicate URLs essentially changes the links, and also ads a chance of collision with other query parameters. Besides, that smells. The stock ASP.Net sitemap provider simply disallows duplicate URLS. I decided not to, and simply pick the first one encountered as the "current". Although it doesn't solve the issue completely – one might say they wanted the second of the 2 links to be "current"- it allows one to include a link twice (home->deals and products->deals etc), and the logic of deciding "current" is easy enough to explain to the customer. Now that we got that out of the way, let's build the menu data structure: public static List<MvcMenuItemAttribute> ListMenuItems(Assembly assembly) { var result = new List<MvcMenuItemAttribute>(); foreach (var type in assembly.GetTypes()) { if (!type.IsSubclassOf(typeof(Controller))) { continue; } foreach (var method in type.GetMethods()) { var items = method.GetCustomAttributes(typeof(MvcMenuItemAttribute), false) as MvcMenuItemAttribute[]; if (items == null) { continue; } foreach (var item in items) { if (String.IsNullOrEmpty(item.Controller)) { item.Controller = type.Name.Substring(0, type.Name.Length - "Controller".Length); } if (String.IsNullOrEmpty(item.Action)) { item.Action = method.Name; } result.Add(item); } } } return result.OrderBy(i => i.Order).ToList(); } Using reflection, the ListMenuItems method takes an assembly (you will hand it your MVC web assembly) and generates a list of menu items. It digs up all the types, and for each one that is an MVC Controller, digs up the methods. Methods decorated with the MvcMenuItemAttribute get plucked and added to the output list. Again, pretty simple. To make the structure hierarchical, a LINQ expression matches up all the items to their parent: public static void RegisterMenuItems(List<MvcMenuItemAttribute> items) { _MenuItems = items; _MenuItems.ForEach(i => i.ParentItem = items.FirstOrDefault(p => String.Equals(p.Link, i.ParentLink, StringComparison.InvariantCultureIgnoreCase))); } The _MenuItems is simply an internal list to keep things around for later rendering. Finally, to package the menu building for easy consumption: public static void RegisterMenuItems(Type mvcApplicationType) { RegisterMenuItems(ListMenuItems(Assembly.GetAssembly(mvcApplicationType))); } To bring this puppy home, a call in Global.asax.cs Application_Start() registers the menu. Notice the ugliness of reflection is tucked away from the innocent developer. All they have to do is call the RegisterMenuItems() and pass in the type of the application. When you use the new project template, global.asax declares a class public class MvcApplication : HttpApplication and that is why the Register call passes in that type. protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); MvcMenu.RegisterMenuItems(typeof(MvcApplication)); } What else is left to do? Oh, right, render! public static void ShowMenu(this TextWriter output) { var writer = new HtmlTextWriter(output); renderHierarchy(writer, _MenuItems, null); } public static void ShowBreadCrumb(this TextWriter output, Uri currentUri) { var writer = new HtmlTextWriter(output); string currentLink = "/" + currentUri.GetComponents(UriComponents.Path, UriFormat.Unescaped); var menuItem = _MenuItems.FirstOrDefault(m => m.Link.Equals(currentLink, StringComparison.CurrentCultureIgnoreCase)); if (menuItem != null) { renderBreadCrumb(writer, _MenuItems, menuItem); } } private static void renderBreadCrumb(HtmlTextWriter writer, List<MvcMenuItemAttribute> menuItems, MvcMenuItemAttribute current) { if (current == null) { return; } var parent = current.ParentItem; renderBreadCrumb(writer, menuItems, parent); writer.Write(current.MenuText); writer.Write(" / "); } static void renderHierarchy(HtmlTextWriter writer, List<MvcMenuItemAttribute> hierarchy, MvcMenuItemAttribute root) { if (!hierarchy.Any(i => i.ParentItem == root)) return; writer.RenderBeginTag(HtmlTextWriterTag.Ul); foreach (var current in hierarchy.Where(element => element.ParentItem == root).OrderBy(i => i.Order)) { if (ItemFilter == null || ItemFilter(current)) { writer.RenderBeginTag(HtmlTextWriterTag.Li); writer.AddAttribute(HtmlTextWriterAttribute.Href, current.Link); writer.AddAttribute(HtmlTextWriterAttribute.Alt, current.MenuText); writer.RenderBeginTag(HtmlTextWriterTag.A); writer.WriteEncodedText(current.MenuText); writer.RenderEndTag(); // link renderHierarchy(writer, hierarchy, current); writer.RenderEndTag(); // li } } writer.RenderEndTag(); // ul } The ShowMenu method renders the menu out to the provided TextWriter. In previous posts I've discussed my partiality to using well debugged, time test HtmlTextWriter to render HTML rather than writing out angled brackets by hand. In addition, writing out using the actual writer on the actual stream rather than generating string and byte intermediaries (yes, StringBuilder being no exception) disturbs me. To carry out the rendering of an hierarchical menu, the recursive renderHierarchy() is used. You may notice that an ItemFilter is called before rendering each item. I figured that at some point one might want to exclude certain items from the menu based on security role or context or something. That delegate is the hook for such future feature. To carry out rendering of a breadcrumb recursion is used again, this time simply to unwind the parent hierarchy from the leaf node, then rendering on the return from the recursion rather than as we go along deeper. I guess I was stuck in LISP that day.. recursion is fun though. Now all that is left is some usage! Open your Site.Master or wherever you'd like to place a menu or breadcrumb, and plant one of these calls: <% MvcMenu.ShowBreadCrumb(this.Writer, Request.Url); %> to show a breadcrumb trail (notice lack of "=" after <% and the semicolon). <% MvcMenu.ShowMenu(Writer); %> to show the menu. As mentioned before, the HTML output is nested <UL> <LI> tags, which should make it easy to style using abundant CSS to produce anything from static horizontal or vertical to dynamic drop-downs. This has been quite a fun little implementation and I was pleased that the code size remained low. The main crux was figuring out how to pass parent information from the attribute to the hierarchy builder because attributes have restricted parameter types. Once I settled on that implementation, the rest falls into place quite easily.

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First toe in the water with Object Databases : DB4O

- by REA_ANDREW

I have been wanting to have a play with Object Databases for a while now, and today I have done just that. One of the obvious choices I had to make was which one to use. My criteria for choosing one today was simple, I wanted one which I could literally wack in and start using, which means I wanted one which either had a .NET API or was designed/ported to .NET. My decision was between two being: db4o MongoDb I went for db4o for the single reason that it looked like I could get it running and integrated the quickest. I am making a Blogging application and front end as a project with which I can test and learn with these object databases. Another requirement which I thought I would mention is that I also want to be able to use the said database in a shared hosting environment where I cannot install, run and maintain a server instance of said object database. I can do exactly this with db4o. I have not tried to do this with MongoDb at time of writing. There are quite a few in the industry now and you read an interesting post about different ones and how they are used with some of the heavy weights in the industry here : http://blog.marcua.net/post/442594842/notes-from-nosql-live-boston-2010 In the example which I am building I am using StructureMap as my IOC. To inject the object for db4o I went with a Singleton instance scope as I am using a single file and I need this to be available to any thread on in the process as opposed to using the server implementation where I could open and close client connections with the server handling each one respectively. Again I want to point out that I have chosen to stick with the non server implementation of db4o as I wanted to use this in a shared hosting environment where I cannot have such servers installed and run. public static class Bootstrapper { public static void ConfigureStructureMap() { ObjectFactory.Initialize(x => x.AddRegistry(new MyApplicationRegistry())); } } public class MyApplicationRegistry : Registry { public const string DB4O_FILENAME = "blog123"; public string DbPath { get { return Path.Combine(Path.GetDirectoryName(Assembly.GetAssembly(typeof(IBlogRepository)).Location), DB4O_FILENAME); } } public MyApplicationRegistry() { For<IObjectContainer>().Singleton().Use( () => Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(), DbPath)); Scan(assemblyScanner => { assemblyScanner.TheCallingAssembly(); assemblyScanner.WithDefaultConventions(); }); } } So my code above is the structure map plumbing which I use for the application. I am doing this simply as a quick scratch pad to play around with different things so I am simply segregating logical layers with folder structure as opposed to different assemblies. It will be easy if I want to do this with any segment but for the purposes of example I have literally just wacked everything in the one assembly. You can see an example file structure I have on the right. I am planning on testing out a few implementations of the object databases out there so I can program to an interface of IBlogRepository One of the things which I was unsure about was how it performed under a multi threaded environment which it will undoubtedly be used 9 times out of 10, and for the reason that I am using the db context as a singleton, I assumed that the library was of course thread safe but I did not know as I have not read any where in the documentation, again this is probably me not reading things correctly. In short though I threw together a simple test where I simply iterate to a limit each time kicking a common task off with a thread from a thread pool. This task simply created and added an random Post and added it to the storage. The execution of the threads I put inside the Setup of the Test and then simply ensure the number of posts committed to the database is equal to the number of iterations I made; here is the code I used to do the multi thread jobs: [TestInitialize] public void Setup() { var sw = new System.Diagnostics.Stopwatch(); sw.Start(); var resetEvent = new ManualResetEvent(false); ThreadPool.SetMaxThreads(20, 20); for (var i = 0; i < MAX_ITERATIONS; i++) { ThreadPool.QueueUserWorkItem(delegate(object state) { var eventToReset = (ManualResetEvent)state; var post = new Post { Author = MockUser, Content = "Mock Content", Title = "Title" }; Repository.Put(post); var counter = Interlocked.Decrement(ref _threadCounter); if (counter == 0) eventToReset.Set(); }, resetEvent); } WaitHandle.WaitAll(new[] { resetEvent }); sw.Stop(); Console.WriteLine("{0:00}.{1:00} seconds", sw.Elapsed.Seconds, sw.Elapsed.Milliseconds); } I was not doing this to test out the speed performance of db4o but while I was doing this I could not help but put in a StopWatch and see out of sheer interest how fast it would take to insert a number of Posts. I tested it out in this case with 10000 inserts of a small, simple POCO and it resulted in an average of: 899.36 object inserts / second. Again this is just simple crude test which came out of my curiosity at how it performed under many threads when using the non server implementation of db4o. The spec summary of the computer I used is as follows: With regards to the actual Repository implementation itself, it really is quite straight forward and I have to say I am very surprised at how easy it was to integrate and get up and running. One thing I have noticed in the exposure I have had so far is that the Query returns IList<T> as opposed to IQueryable<T> but again I have not looked into this in depth and this could be there already and if not they have provided everything one needs to make there own repository. An example of a couple of methods from by db4o implementation of the BlogRepository is below: public class BlogRepository : IBlogRepository { private readonly IObjectContainer _db; public BlogRepository(IObjectContainer db) { _db = db; } public void Put(DomainObject obj) { _db.Store(obj); } public void Delete(DomainObject obj) { _db.Delete(obj); } public Post GetByKey(object key) { return _db.Query<Post>(post => post.Key == key).FirstOrDefault(); } … Anyways I hope to get a few more implementations going of the object databases and literally just get familiarized with them and the concept of no sql databases. Cheers for now, Andrew

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Refactor This (Ugly Code)!

- by Alois Kraus

Ayende has put on his blog some ugly code to refactor. First and foremost it is nearly impossible to reason about other peoples code without knowing the driving forces behind the current code. It is certainly possible to make it much cleaner when potential sources of errors cannot happen in the first place due to good design. I can see what the intention of the code is but I do not know about every brittle detail if I am allowed to reorder things here and there to simplify things. So I decided to make it much simpler by identifying the different responsibilities of the methods and encapsulate it in different classes. The code we need to refactor seems to deal with a handler after a message has been sent to a message queue. The handler does complete the current transaction if there is any and does handle any errors happening there. If during the the completion of the transaction errors occur the transaction is at least disposed. We can enter the handler already in a faulty state where we try to deliver the complete event in any case and signal a failure event and try to resend the message again to the queue if it was not inside a transaction. All is decorated with many try/catch blocks, duplicated code and some state variables to route the program flow. It is hard to understand and difficult to reason about. In other words: This code is a mess and could be written by me if I was under pressure. Here comes to code we want to refactor: private void HandleMessageCompletion( Message message, TransactionScope tx, OpenedQueue messageQueue, Exception exception, Action<CurrentMessageInformation, Exception> messageCompleted, Action<CurrentMessageInformation> beforeTransactionCommit) { var txDisposed = false; if (exception == null) { try { if (tx != null) { if (beforeTransactionCommit != null) beforeTransactionCommit(currentMessageInformation); tx.Complete(); tx.Dispose(); txDisposed = true; } try { if (messageCompleted != null) messageCompleted(currentMessageInformation, exception); } catch (Exception e) { Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e); } return; } catch (Exception e) { Trace.TraceWarning("Failed to complete transaction, moving to error mode"+ e); exception = e; } } try { if (txDisposed == false && tx != null) { Trace.TraceWarning("Disposing transaction in error mode"); tx.Dispose(); } } catch (Exception e) { Trace.TraceWarning("Failed to dispose of transaction in error mode."+ e); } if (message == null) return; try { if (messageCompleted != null) messageCompleted(currentMessageInformation, exception); } catch (Exception e) { Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e); } try { var copy = MessageProcessingFailure; if (copy != null) copy(currentMessageInformation, exception); } catch (Exception moduleException) { Trace.TraceError("Module failed to process message failure: " + exception.Message+ moduleException); } if (messageQueue.IsTransactional == false)// put the item back in the queue { messageQueue.Send(message); } } You can see quite some processing and handling going on there. Yes this looks like real world code one did put together to make things work and he does not trust his callbacks. I guess these are event handlers which are optional and the delegates were extracted from an event to call them back later when necessary. Lets see what the author of this code did intend: private void HandleMessageCompletion( TransactionHandler transactionHandler, MessageCompletionHandler handler, CurrentMessageInformation messageInfo, ErrorCollector errors ) { // commit current pending transaction transactionHandler.CallHandlerAndCommit(messageInfo, errors); // We have an error for a null message do not send completion event if (messageInfo.CurrentMessage == null) return; // Send completion event in any case regardless of errors handler.OnMessageCompleted(messageInfo, errors); // put message back if queue is not transactional transactionHandler.ResendMessageOnError(messageInfo.CurrentMessage, errors); } I did not bother to write the intention here again since the code should be pretty self explaining by now. I have used comments to explain the still nontrivial procedure step by step revealing the real intention about all this complex program flow. The original complexity of the problem domain does not go away but by applying the techniques of SRP (Single Responsibility Principle) and some functional style but we can abstract the necessary complexity away in useful abstractions which make it much easier to reason about it. Since most of the method seems to deal with errors I thought it was a good idea to encapsulate the error state of our current message in an ErrorCollector object which stores all exceptions in a list along with a description what the error all was about in the exception itself. We can log it later or not depending on the log level or whatever. It is really just a simple list that encapsulates the current error state. class ErrorCollector { List<Exception> _Errors = new List<Exception>(); public void Add(Exception ex, string description) { ex.Data["Description"] = description; _Errors.Add(ex); } public Exception Last { get { return _Errors.LastOrDefault(); } } public bool HasError { get { return _Errors.Count > 0; } } } Since the error state is global we have two choices to store a reference in the other helper objects (TransactionHandler and MessageCompletionHandler)or pass it to the method calls when necessary. I did chose the latter one because a second argument does not hurt and makes it easier to reason about the overall state while the helper objects remain stateless and immutable which makes the helper objects much easier to understand and as a bonus thread safe as well. This does not mean that the stored member variables are stateless or thread safe as well but at least our helper classes are it. Most of the complexity is located the transaction handling I consider as a separate responsibility that I delegate to the TransactionHandler which does nothing if there is no transaction or Call the Before Commit Handler Commit Transaction Dispose Transaction if commit did throw In fact it has a second responsibility to resend the message if the transaction did fail. I did see a good fit there since it deals with transaction failures. class TransactionHandler { TransactionScope _Tx; Action<CurrentMessageInformation> _BeforeCommit; OpenedQueue _MessageQueue; public TransactionHandler(TransactionScope tx, Action<CurrentMessageInformation> beforeCommit, OpenedQueue messageQueue) { _Tx = tx; _BeforeCommit = beforeCommit; _MessageQueue = messageQueue; } public void CallHandlerAndCommit(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { if (_Tx != null && !errors.HasError) { try { if (_BeforeCommit != null) { _BeforeCommit(currentMessageInfo); } _Tx.Complete(); _Tx.Dispose(); } catch (Exception ex) { errors.Add(ex, "Failed to complete transaction, moving to error mode"); Trace.TraceWarning("Disposing transaction in error mode"); try { _Tx.Dispose(); } catch (Exception ex2) { errors.Add(ex2, "Failed to dispose of transaction in error mode."); } } } } public void ResendMessageOnError(Message message, ErrorCollector errors) { if (errors.HasError && !_MessageQueue.IsTransactional) { _MessageQueue.Send(message); } } } If we need to change the handling in the future we have a much easier time to reason about our application flow than before. After we did complete our transaction and called our callback we can call the completion handler which is the main purpose of the HandleMessageCompletion method after all. The responsiblity o the MessageCompletionHandler is to call the completion callback and the failure callback when some error has occurred. class MessageCompletionHandler { Action<CurrentMessageInformation, Exception> _MessageCompletedHandler; Action<CurrentMessageInformation, Exception> _MessageProcessingFailure; public MessageCompletionHandler(Action<CurrentMessageInformation, Exception> messageCompletedHandler, Action<CurrentMessageInformation, Exception> messageProcessingFailure) { _MessageCompletedHandler = messageCompletedHandler; _MessageProcessingFailure = messageProcessingFailure; } public void OnMessageCompleted(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { try { if (_MessageCompletedHandler != null) { _MessageCompletedHandler(currentMessageInfo, errors.Last); } } catch (Exception ex) { errors.Add(ex, "An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"); } if (errors.HasError) { SignalFailedMessage(currentMessageInfo, errors); } } void SignalFailedMessage(CurrentMessageInformation currentMessageInfo, ErrorCollector errors) { try { if (_MessageProcessingFailure != null) _MessageProcessingFailure(currentMessageInfo, errors.Last); } catch (Exception moduleException) { errors.Add(moduleException, "Module failed to process message failure"); } } } If for some reason I did screw up the logic and we need to call the completion handler from our Transaction handler we can simple add to the CallHandlerAndCommit method a third argument to the MessageCompletionHandler and we are fine again. If the logic becomes even more complex and we need to ensure that the completed event is triggered only once we have now one place the completion handler to capture the state. During this refactoring I simple put things together that belong together and came up with useful abstractions. If you look at the original argument list of the HandleMessageCompletion method I have put many things together: Original Arguments New Arguments Encapsulate Message message CurrentMessageInformation messageInfo Message message TransactionScope tx Action<CurrentMessageInformation> beforeTransactionCommit OpenedQueue messageQueue TransactionHandler transactionHandler TransactionScope tx OpenedQueue messageQueue Action<CurrentMessageInformation> beforeTransactionCommit Exception exception, ErrorCollector errors Action<CurrentMessageInformation, Exception> messageCompleted MessageCompletionHandler handler Action<CurrentMessageInformation, Exception> messageCompleted Action<CurrentMessageInformation, Exception> messageProcessingFailure The reason is simple: Put the things that have relationships together and you will find nearly automatically useful abstractions. I hope this makes sense to you. If you see a way to make it even more simple you can show Ayende your improved version as well.

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Evil DRY

- by StefanSteinegger

DRY (Don't Repeat Yourself) is a basic software design and coding principle. But there is just no silver bullet. While DRY should increase maintainability by avoiding common design mistakes, it could lead to huge maintenance problems when misunderstood. The root of the problem is most probably that many developers believe that DRY means that any piece of code that is written more then once should be made reusable. But the principle is stated as "Every piece of knowledge must have a single, unambiguous, authoritative representation within a system." So the important thing here is "knowledge". Nobody ever said "every piece of code". I try to give some examples of misusing the DRY principle. Code Repetitions by Coincidence There is code that is repeated by pure coincidence. It is not the same code because it is based on the same piece of knowledge, it is just the same by coincidence. It's hard to give an example of such a case. Just think about some lines of code the developer thinks "I already wrote something similar". Then he takes the original code, puts it into a public method, even worse into a base class where none had been there before, puts some weird arguments and some if or switch statements into it to support all special cases and calls this "increasing maintainability based on the DRY principle". The resulting "reusable method" is usually something the developer not even can give a meaningful name, because its contents isn't anything specific, it is just a bunch of code. For the same reason, nobody will really understand this piece of code. Typically this method only makes sense to call after some other method had been called. All the symptoms of really bad design is evident. Fact is, writing this kind of "reusable methods" is worse then copy pasting! Believe me. What will happen when you change this weird piece of code? You can't say what'll happen, because you can't understand what the code is actually doing. So better don't touch it anymore. Maintainability just died. Of course this problem is with any badly designed code. But because the developer tried to make this method as reusable as possible, large parts of the system get dependent on it. Completely independent parts get tightly coupled by this common piece of code. Changing on the single common place will have effects anywhere in the system, a typical symptom of too tight coupling. Without trying to dogmatically (and wrongly) apply the DRY principle, you just had a system with a weak design. Now you get a system which just can't be maintained anymore. So what can you do against it? When making code reusable, always identify the generally reusable parts of it. Find the reason why the code is repeated, find the common "piece of knowledge". If you have to search too far, it's probably not really there. Explain it to a colleague, if you can't explain or the explanation is to complicated, it's probably not worth to reuse. If you identify the piece of knowledge, don't forget to carefully find the place where it should be implemented. Reusing code is never worth giving up a clean design. Methods always need to do something specific. If you can't give it a simple and explanatory name, you did probably something weird. If you can't find the common piece of knowledge, try to make the code simpler. For instance, if you have some complicated string or collection operations within this code, write some general-purpose operations into a helper class. If your code gets simple enough, its not so bad if it can't be reused. If you are not able to find anything simple and reasonable, copy paste it. Put a comment into the code to reference the other copies. You may find a solution later. Requirements Repetitions by Coincidence Let's assume that you need to implement complex tax calculations for many countries. It's possible that some countries have very similar tax rules. These rules are still completely independent from each other, since every country can change it of its own. (Assumed that this similarity is actually by coincidence and not by political membership. There might be basic rules applying to all European countries. etc.) Let's assume that there are similarities between an Asian country and an African country. Moving the common part to a central place will cause problems. What happens if one of the countries changes its rules? Or - more likely - what happens if users of one country complain about an error in the calculation? If there is shared code, it is very risky to change it, even for a bugfix. It is hard to find requirements to be repeated by coincidence. Then there is not much you can do against the repetition of the code. What you really should consider is to make coding of the rules as simple as possible. So this independent knowledge "Tax Rules in Timbuktu" or wherever should be as pure as possible, without much overhead and stuff that does not belong to it. So you can write every independent requirement short and clean. DRYing try-catch and using Blocks This is a technical issue. Blocks like try-catch or using (e.g. in C#) are very hard to DRY. Imagine a complex exception handling, including several catch blocks. When the contents of the try block as well as the contents of the individual catch block are trivial, but the whole structure is repeated on many places in the code, there is almost no reasonable way to DRY it. try { // trivial code here using (Thingy thing = new thingy) { //trivial, but always different line of code } } catch(FooException foo) { // trivial foo handling } catch (BarException bar) { // trivial bar handling } catch { // trivial common handling } finally { // trivial finally block } The key here is that every block is trivial, so there is nothing to just move into a separate method. The only part that differs from case to case is the line of code in the body of the using block (or any other block). The situation is especially interesting if the many occurrences of this structure are completely independent: they appear in classes with no common base class, they don't aggregate each other and so on. Let's assume that this is a common pattern in service methods within the whole system. Examples of Evil DRYing in this situation: Put a if or switch statement into the method to choose the line of code to execute. There are several reasons why this is not a good idea: The close coupling of the formerly independent implementation is the strongest. Also the readability of the code and the use of a parameter to control the logic. Put everything into a method which takes a delegate as argument to call. The caller just passes his "specific line of code" to this method. The code will be very unreadable. The same maintainability problems apply as for any "Code Repetition by Coincidence" situations. Enforce a base class to all the classes where this pattern appears and use the template method pattern. It's the same readability and maintainability problem as above, but additionally complex and tightly coupled because of the base class. I would call this "Inheritance by Coincidence" which will not lead to great software design. What can you do against it: Ideally, the individual line of code is a call to a class or interface, which could be made individual by inheritance. If this would be the case, it wouldn't be a problem at all. I assume that it is no such a trivial case. Consider to refactor the error concept to make error handling easier. The last but not worst option is to keep the replications. Some pattern of code must be maintained in consistency, there is nothing we can do against it. And no reason to make it unreadable. Conclusion The DRY-principle is an important and basic principle every software developer should master. The key is to identify the "pieces of knowledge". There is code which can't be reused easily because of technical reasons. This requires quite a bit flexibility and creativity to make code simple and maintainable. It's not the problem of the principle, it is the problem of blindly applying a principle without understanding the problem it should solve. The result is mostly much worse then ignoring the principle.

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A WPF Image Button

- by psheriff

Instead of a normal button with words, sometimes you want a button that is just graphical. Yes, you can put an Image control in the Content of a normal Button control, but you still have the button outline, and trying to change the style can be rather difficult. Instead I like creating a user control that simulates a button, but just accepts an image. Figure 1 shows an example of three of these custom user controls to represent minimize, maximize and close buttons for a borderless window. Notice the highlighted image button has a gray rectangle around it. You will learn how to highlight using the VisualStateManager in this blog post.Figure 1: Creating a custom user control for things like image buttons gives you complete control over the look and feel.I would suggest you read my previous blog post on creating a custom Button user control as that is a good primer for what I am going to expand upon in this blog post. You can find this blog post at http://weblogs.asp.net/psheriff/archive/2012/08/10/create-your-own-wpf-button-user-controls.aspx.The User ControlThe XAML for this image button user control contains just a few controls, plus a Visual State Manager. The basic outline of the user control is shown below:<Border Grid.Row="0" Name="borMain" Style="{StaticResource pdsaButtonImageBorderStyle}" MouseEnter="borMain_MouseEnter" MouseLeave="borMain_MouseLeave" MouseLeftButtonDown="borMain_MouseLeftButtonDown"> <VisualStateManager.VisualStateGroups> ... MORE XAML HERE ... </VisualStateManager.VisualStateGroups> <Image Style="{StaticResource pdsaButtonImageImageStyle}" Visibility="{Binding Path=Visibility}" Source="{Binding Path=ImageUri}" ToolTip="{Binding Path=ToolTip}" /></Border>There is a Border control named borMain and a single Image control in this user control. That is all that is needed to display the buttons shown in Figure 1. The definition for this user control is in a DLL named PDSA.WPF. The Style definitions for both the Border and the Image controls are contained in a resource dictionary names PDSAButtonStyles.xaml. Using a resource dictionary allows you to create a few different resource dictionaries, each with a different theme for the buttons.The Visual State ManagerTo display the highlight around the button as your mouse moves over the control, you will need to add a Visual State Manager group. Two different states are needed; MouseEnter and MouseLeave. In the MouseEnter you create a ColorAnimation to modify the BorderBrush color of the Border control. You specify the color to animate as “DarkGray”. You set the duration to less than a second. The TargetName of this storyboard is the name of the Border control “borMain” and since we are specifying a single color, you need to set the TargetProperty to “BorderBrush.Color”. You do not need any storyboard for the MouseLeave state. Leaving this VisualState empty tells the Visual State Manager to put everything back the way it was before the MouseEnter event.<VisualStateManager.VisualStateGroups> <VisualStateGroup Name="MouseStates"> <VisualState Name="MouseEnter"> <Storyboard> <ColorAnimation To="DarkGray" Duration="0:0:00.1" Storyboard.TargetName="borMain" Storyboard.TargetProperty="BorderBrush.Color" /> </Storyboard> </VisualState> <VisualState Name="MouseLeave" /> </VisualStateGroup></VisualStateManager.VisualStateGroups>Writing the Mouse EventsTo trigger the Visual State Manager to run its storyboard in response to the specified event, you need to respond to the MouseEnter event on the Border control. In the code behind for this event call the GoToElementState() method of the VisualStateManager class exposed by the user control. To this method you will pass in the target element (“borMain”) and the state (“MouseEnter”). The VisualStateManager will then run the storyboard contained within the defined state in the XAML.private void borMain_MouseEnter(object sender, MouseEventArgs e){ VisualStateManager.GoToElementState(borMain, "MouseEnter", true);}You also need to respond to the MouseLeave event. In this event you call the VisualStateManager as well, but specify “MouseLeave” as the state to go to.private void borMain_MouseLeave(object sender, MouseEventArgs e){ VisualStateManager.GoToElementState(borMain, "MouseLeave", true);}The Resource DictionaryBelow is the definition of the PDSAButtonStyles.xaml resource dictionary file contained in the PDSA.WPF DLL. This dictionary can be used as the default look and feel for any image button control you add to a window. <ResourceDictionary ... >     <Style TargetType="Border" x:Key="pdsaButtonImageBorderStyle"> <Setter Property="Margin" Value="4" /> <Setter Property="Padding" Value="2" /> <Setter Property="BorderBrush" Value="Transparent" /> <Setter Property="BorderThickness" Value="1" /> <Setter Property="VerticalAlignment" Value="Top" /> <Setter Property="HorizontalAlignment" Value="Left" /> <Setter Property="Background" Value="Transparent" /> </Style>  <Style TargetType="Image" x:Key="pdsaButtonImageImageStyle"> <Setter Property="Width" Value="40" /> <Setter Property="Margin" Value="6" /> <Setter Property="VerticalAlignment" Value="Top" /> <Setter Property="HorizontalAlignment" Value="Left" /> </Style></ResourceDictionary>Using the Button ControlOnce you make a reference to the PDSA.WPF DLL from your WPF application you will see the “PDSAucButtonImage” control appear in your Toolbox. Drag and drop the button onto a Window or User Control in your application. I have not referenced the PDSAButtonStyles.xaml file within the control itself so you do need to add a reference to this resource dictionary somewhere in your application such as in the App.xaml.<Application.Resources> <ResourceDictionary> <ResourceDictionary.MergedDictionaries> <ResourceDictionary Source="/PDSA.WPF;component/PDSAButtonStyles.xaml" /> </ResourceDictionary.MergedDictionaries> </ResourceDictionary></Application.Resources>This will give your buttons a default look and feel unless you override that dictionary on a specific Window or User Control or on an individual button. After you have given a global style to your application and you drag your image button onto a window, the following will appear in your XAML window.<my:PDSAucButtonImage ... />There will be some other attributes set on the above XAML, but you simply need to set the x:Name, the ToolTip and ImageUri properties. You will also want to respond to the Click event procedure in order to associate an action with clicking on this button. In the sample code you download for this blog post you will find the declaration of the Minimize button to be the following:<my:PDSAucButtonImage x:Name="btnMinimize" Click="btnMinimize_Click" ToolTip="Minimize Application" ImageUri="/PDSA.WPF;component/Images/Minus.png" />The ImageUri property is a dependency property in the PDSAucButtonImage user control. The x:Name and the ToolTip we get for free. You have to create the Click event procedure yourself. This is also created in the PDSAucButtonImage user control as follows:private void borMain_MouseLeftButtonDown(object sender, MouseButtonEventArgs e){ RaiseClick(e);}public delegate void ClickEventHandler(object sender, RoutedEventArgs e);public event ClickEventHandler Click;protected void RaiseClick(RoutedEventArgs e){ if (null != Click) Click(this, e);}Since a Border control does not have a Click event you will create one by using the MouseLeftButtonDown on the border to fire an event you create called “Click”.SummaryCreating your own image button control can be done in a variety of ways. In this blog post I showed you how to create a custom user control and simulate a button using a Border and Image control. With just a little bit of code to respond to the MouseLeftButtonDown event on the border you can raise your own Click event. Dependency properties, such as ImageUri, allow you to set attributes on your custom user control. Feel free to expand on this button by adding additional dependency properties, change the resource dictionary, and even the animation to make this button look and act like you want.NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A WPF Image Button” from the drop down list.

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Dynamically loading Assemblies to reduce Runtime Depencies

- by Rick Strahl

I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change. So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. That being said though - I serialized 10,000 objects in 80ms vs. 45ms so this isn't hardly slouchy. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?On occasion dynamic loading makes sense. But there's a price to be paid in added code complexity and a performance hit. But for some operations that are not pivotal to a component or application and only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful tool. Hopefully some of you find this information useful…© Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET C# Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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CodePlex Daily Summary for Saturday, May 24, 2014

CodePlex Daily Summary for Saturday, May 24, 2014Popular ReleasesSimCityPak: SimCityPak 0.3.1.0: Main New Features: Fixed Importing of Instance Names (get rid of the Dutch translations) Added advanced editor for Decal Dictionaries Added possibility to import .PNG to generate new decals Added advanced editor for Path display entriesTiny Deduplicator: Tiny Deduplicator 1.0.1.0: Increased version number to 1.0.1.0 Moved all options to a separate 'Options' dialog window. Allows the user to specify a selection strategy which will help when dealing with large numbers of duplicate files. Available options are "None," "Keep First," and "Keep Last"C64 Studio: 3.5: Add: BASIC renumber function Add: !PET pseudo op Add: elseif for !if, } else { pseudo op Add: !TRACE pseudo op Add: Watches are saved/restored with a solution Add: Ctrl-A works now in export assembly controls Add: Preliminary graphic import dialog (not fully functional yet) Add: range and block selection in sprite/charset editor (Shift-Click = range, Alt-Click = block) Fix: Expression evaluator could miscalculate when both division and multiplication were in an expression without parenthesisSEToolbox: SEToolbox 01.031.009 Release 1: Added mirroring of ConveyorTubeCurved. Updated Ship cube rotation to rotate ship back to original location (cubes are reoriented but ship appears no different to outsider), and to rotate Grouped items. Repair now fixes the loss of Grouped controls due to changes in Space Engineers 01.030. Added export asteroids. Rejoin ships will merge grouping and conveyor systems (even though broken ships currently only maintain the Grouping on one part of the ship). Installation of this version wi...Player Framework by Microsoft: Player Framework for Windows and WP v2.0: Support for new Universal and Windows Phone 8.1 projects for both Xaml and JavaScript projects. See a detailed list of improvements, breaking changes and a general overview of version 2 ADDITIONAL DOWNLOADSSmooth Streaming Client SDK for Windows 8 Applications Smooth Streaming Client SDK for Windows 8.1 Applications Smooth Streaming Client SDK for Windows Phone 8.1 Applications Microsoft PlayReady Client SDK for Windows 8 Applications Microsoft PlayReady Client SDK for Windows 8.1 Applicat...TerraMap (Terraria World Map Viewer): TerraMap 1.0.6: Added support for the new Terraria v1.2.4 update. New items, walls, and tiles Added the ability to select multiple highlighted block types. Added a dynamic, interactive highlight opacity slider, making it easier to find highlighted tiles with dark colors (and fixed blurriness from 1.0.5 alpha). Added ability to find Enchanted Swords (in the stone) and Water Bolt books Fixed Issue 35206: Hightlight/Find doesn't work for Demon Altars Fixed finding Demon Hearts/Shadow Orbs Fixed inst...DotNet.Highcharts: DotNet.Highcharts 4.0 with Examples: DotNet.Highcharts 4.0 Tested and adapted to the latest version of Highcharts 4.0.1 Added new chart type: Heatmap Added new type PointPlacement which represents enumeration or number for the padding of the X axis. Changed target framework from .NET Framework 4 to .NET Framework 4.5. Closed issues: 974: Add 'overflow' property to PlotOptionsColumnDataLabels class 997: Split container from JS 1006: Series/Categories with numeric names don't render DotNet.Highcharts.Samples Updated s...Compile Mono With Visual Studio: 0.9 Beta 1 Release: exciting 0.9 Beta Release ( 0.9.0.2 )PowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.1.3: Added CompressLogs option to the config file. Each Install / Uninstall creates a timestamped zip file with all MSI and PSAppDeployToolkit logs contained within Added variable expansion to all paths in the configuration file Added documentation for each of the Toolkit internal variables that can be used Changed Install-MSUpdates to continue if any errors are encountered when installing updates Implement /Force parameter on Update-GroupPolicy (ensure that any logoff message is ignored) ...WordMat: WordMat v. 1.07: A quick fix because scientific notation was broken in v. 1.06 read more at http://wordmat.blogspot.com????: 《????》: 《????》（c???）??“????”???????，???????????????C?????????。???????,???????????????????????. ??????????????????????????????????；????????????????????????????。Mini SQL Query: Mini SQL Query (1.0.72.457): Apologies for the previous update! FK issue fixed and also a template data cache issue.Wsus Package Publisher: Release v1.3.1405.17: Add Russian translation (thanks to VSharmanov) Fix a bug that make WPP to crash if the user click on "Connect/Reload" while the Report Tab is loading. Enhance the way WPP store the password for remote computers command.MoreTerra (Terraria World Viewer): More Terra 1.12.9: =========== = Compatibility = =========== Updated to account for new format 1.2.4.1 =========== = Issues = =========== all items have not been added. Some colors for new tiles may be off. I wanted to get this out so people have a usable program.LINQ to Twitter: LINQ to Twitter v3.0.3: Supports .NET 4.5x, Windows Phone 8.x, Windows 8.x, Windows Azure, Xamarin.Android, and Xamarin.iOS. New features include Status/Lookup, Mute APIs, and bug fixes. 100% Twitter API v1.1 coverage, Async, Portable Class Library (PCL).CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.26.0: Added access to the Release Notes during 'Check for Updates...'' Debug panels Added support for generic types members Members are grouped into 'Raw View' and 'Non-Public members' categories Implemented dedicated (array-like) view for Lists and Dictionaries http://download-codeplex.sec.s-msft.com/Download?ProjectName=csscriptnpp&DownloadId=846498ClosedXML - The easy way to OpenXML: ClosedXML 0.70.0: A lot of fixes. See history.TBox - tool to make developer's life easier.: TBox 1.29: Bug fixing. Add LocalizationTool pluginYAXLib: Yet Another XML Serialization Library for the .NET Framework: YAXLib 2.13: Fixed a bug and added unit tests related to serializing path like aliases with one letter (e.g., './B'). Thanks go to CodeProject user B.O.B. for reporting this bug. Added `Bin/*.dll.mdb` to `.gitignore`. Fixed the issue with Indexer properties. Indexers must not be serialized/deserialized. YAXLib will ignore delegate (callback/function pointer) properties, so that the exception upon serializing them is prevented. Significant improve in cycling object reference detection Self Referr...SFDL.NET: SFDL.NET (2.2.9.2): Changelog: Neues Icon Xup.in CnL Plugin BugfixNew ProjectsA minimal UDP based logger: a minimal udp loggerApr-Jul-2014: Educational project for studying .NET and C#CliqSafe - Safe Email - An Add on for Microsoft Outlook & Windows Mobile Devices: CliqSafe - Safe Email - An Add on for Microsoft Outlook & Windows Mobile Devices:CodePlex Testing Project: Project for testing codeplex features.EF6: Project EF6electronixwebform: tesekkürü bir borc bilirizelektronix: tesekkuru bir borc bilirizI-Ching: This class can generate fortune telling phrases with the I-Ching book of changes.J-Processors: Various project to develop microprocessors based on FPGAs and a hardware decription language. Software environment for operation.Kart-Trie: Manage and search associative array with Kart tree.NewBreeze: NewBreeze - Fast and light-weight Qt4 based File ManagerOE Orchard Project: interactive educationPostal: Postal is a collection of open-source aspects for PostSharp.SoundCloud Downloader: SoundCloud Downloader for people who are searching for one!Ternary Search Tree: This class can insert and search text using ternary search trees.?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ?????-?????【??】?????????: ???????????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ???????????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！ ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ?? API C# ??: ??.NET，?? C# ????? API ????，????????? API。?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ??????、??????????????????,???????.??????????,????????。 ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ??????、??????????????????,???????.??????????,????????。

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Dynamically loading Assemblies to reduce Runtime Dependencies

- by Rick Strahl

I've been working on a request to the West Wind Application Configuration library to add JSON support. The config library is a very easy to use code-first approach to configuration: You create a class that holds the configuration data that inherits from a base configuration class, and then assign a persistence provider at runtime that determines where and how the configuration data is store. Currently the library supports .NET Configuration stores (web.config/app.config), XML files, SQL records and string storage.About once a week somebody asks me about JSON support and I've deflected this question for the longest time because frankly I think that JSON as a configuration store doesn't really buy a heck of a lot over XML. Both formats require the user to perform some fixup of the plain configuration data - in XML into XML tags, with JSON using JSON delimiters for properties and property formatting rules. Sure JSON is a little less verbose and maybe a little easier to read if you have hierarchical data, but overall the differences are pretty minor in my opinion. And yet - the requests keep rolling in.Hard Link Issues in a Component LibraryAnother reason I've been hesitant is that I really didn't want to pull in a dependency on an external JSON library - in this case JSON.NET - into the core library. If you're not using JSON.NET elsewhere I don't want a user to have to require a hard dependency on JSON.NET unless they want to use the JSON feature. JSON.NET is also sensitive to versions and doesn't play nice with multiple versions when hard linked. For example, when you have a reference to V4.4 in your project but the host application has a reference to version 4.5 you can run into assembly load problems. NuGet's Update-Package can solve some of this *if* you can recompile, but that's not ideal for a component that's supposed to be just plug and play. This is no criticism of JSON.NET - this really applies to any dependency that might change. So hard linking the DLL can be problematic for a number reasons, but the primary reason is to not force loading of JSON.NET unless you actually need it when you use the JSON configuration features of the library.Enter Dynamic LoadingSo rather than adding an assembly reference to the project, I decided that it would be better to dynamically load the DLL at runtime and then use dynamic typing to access various classes. This allows me to run without a hard assembly reference and allows more flexibility with version number differences now and in the future.But there are also a couple of downsides:No assembly reference means only dynamic access - no compiler type checking or IntellisenseRequirement for the host application to have reference to JSON.NET or else get runtime errorsThe former is minor, but the latter can be problematic. Runtime errors are always painful, but in this case I'm willing to live with this. If you want to use JSON configuration settings JSON.NET needs to be loaded in the project. If this is a Web project, it'll likely be there already.So there are a few things that are needed to make this work:Dynamically create an instance and optionally attempt to load an Assembly (if not loaded)Load types into dynamic variablesUse Reflection for a few tasks like statics/enumsThe dynamic keyword in C# makes the formerly most difficult Reflection part - method calls and property assignments - fairly painless. But as cool as dynamic is it doesn't handle all aspects of Reflection. Specifically it doesn't deal with object activation, truly dynamic (string based) member activation or accessing of non instance members, so there's still a little bit of work left to do with Reflection.Dynamic Object InstantiationThe first step in getting the process rolling is to instantiate the type you need to work with. This might be a two step process - loading the instance from a string value, since we don't have a hard type reference and potentially having to load the assembly. Although the host project might have a reference to JSON.NET, that instance might have not been loaded yet since it hasn't been accessed yet. In ASP.NET this won't be a problem, since ASP.NET preloads all referenced assemblies on AppDomain startup, but in other executable project, assemblies are just in time loaded only when they are accessed.Instantiating a type is a two step process: Finding the type reference and then activating it. Here's the generic code out of my ReflectionUtils library I use for this:/// <summary> /// Creates an instance of a type based on a string. Assumes that the type's /// </summary> /// <param name="typeName">Common name of the type</param> /// <param name="args">Any constructor parameters</param> /// <returns></returns> public static object CreateInstanceFromString(string typeName, params object[] args) { object instance = null; Type type = null; try { type = GetTypeFromName(typeName); if (type == null) return null; instance = Activator.CreateInstance(type, args); } catch { return null; } return instance; } /// <summary> /// Helper routine that looks up a type name and tries to retrieve the /// full type reference in the actively executing assemblies. /// </summary> /// <param name="typeName"></param> /// <returns></returns> public static Type GetTypeFromName(string typeName) { Type type = null; // Let default name binding find it type = Type.GetType(typeName, false); if (type != null) return type; // look through assembly list var assemblies = AppDomain.CurrentDomain.GetAssemblies(); // try to find manually foreach (Assembly asm in assemblies) { type = asm.GetType(typeName, false); if (type != null) break; } return type; } To use this for loading JSON.NET I have a small factory function that instantiates JSON.NET and sets a bunch of configuration settings on the generated object. The startup code also looks for failure and tries loading up the assembly when it fails since that's the main reason the load would fail. Finally it also caches the loaded instance for reuse (according to James the JSON.NET instance is thread safe and quite a bit faster when cached). Here's what the factory function looks like in JsonSerializationUtils:/// <summary> /// Dynamically creates an instance of JSON.NET /// </summary> /// <param name="throwExceptions">If true throws exceptions otherwise returns null</param> /// <returns>Dynamic JsonSerializer instance</returns> public static dynamic CreateJsonNet(bool throwExceptions = true) { if (JsonNet != null) return JsonNet; lock (SyncLock) { if (JsonNet != null) return JsonNet; // Try to create instance dynamic json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); if (json == null) { try { var ass = AppDomain.CurrentDomain.Load("Newtonsoft.Json"); json = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.JsonSerializer"); } catch (Exception ex) { if (throwExceptions) throw; return null; } } if (json == null) return null; json.ReferenceLoopHandling = (dynamic) ReflectionUtils.GetStaticProperty("Newtonsoft.Json.ReferenceLoopHandling", "Ignore"); // Enums as strings in JSON dynamic enumConverter = ReflectionUtils.CreateInstanceFromString("Newtonsoft.Json.Converters.StringEnumConverter"); json.Converters.Add(enumConverter); JsonNet = json; } return JsonNet; }This code's purpose is to return a fully configured JsonSerializer instance. As you can see the code tries to create an instance and when it fails tries to load the assembly, and then re-tries loading.Once the instance is loaded some configuration occurs on it. Specifically I set the ReferenceLoopHandling option to not blow up immediately when circular references are encountered. There are a host of other small config setting that might be useful to set, but the default seem to be good enough in recent versions. Note that I'm setting ReferenceLoopHandling which requires an Enum value to be set. There's no real easy way (short of using the cardinal numeric value) to set a property or pass parameters from static values or enums. This means I still need to use Reflection to make this work. I'm using the same ReflectionUtils class I previously used to handle this for me. The function looks up the type and then uses Type.InvokeMember() to read the static property.Another feature I need is have Enum values serialized as strings rather than numeric values which is the default. To do this I can use the StringEnumConverter to convert enums to strings by adding it to the Converters collection.As you can see there's still a bit of Reflection to be done even in C# 4+ with dynamic, but with a few helpers this process is relatively painless.Doing the actual JSON ConversionFinally I need to actually do my JSON conversions. For the Utility class I need serialization that works for both strings and files so I created four methods that handle these tasks two each for serialization and deserialization for string and file.Here's what the File Serialization looks like:/// <summary> /// Serializes an object instance to a JSON file. /// </summary> /// <param name="value">the value to serialize</param> /// <param name="fileName">Full path to the file to write out with JSON.</param> /// <param name="throwExceptions">Determines whether exceptions are thrown or false is returned</param> /// <param name="formatJsonOutput">if true pretty-formats the JSON with line breaks</param> /// <returns>true or false</returns> public static bool SerializeToFile(object value, string fileName, bool throwExceptions = false, bool formatJsonOutput = false) { dynamic writer = null; FileStream fs = null; try { Type type = value.GetType(); var json = CreateJsonNet(throwExceptions); if (json == null) return false; fs = new FileStream(fileName, FileMode.Create); var sw = new StreamWriter(fs, Encoding.UTF8); writer = Activator.CreateInstance(JsonTextWriterType, sw); if (formatJsonOutput) writer.Formatting = (dynamic)Enum.Parse(FormattingType, "Indented"); writer.QuoteChar = '"'; json.Serialize(writer, value); } catch (Exception ex) { Debug.WriteLine("JsonSerializer Serialize error: " + ex.Message); if (throwExceptions) throw; return false; } finally { if (writer != null) writer.Close(); if (fs != null) fs.Close(); } return true; }You can see more of the dynamic invocation in this code. First I grab the dynamic JsonSerializer instance using the CreateJsonNet() method shown earlier which returns a dynamic. I then create a JsonTextWriter and configure a couple of enum settings on it, and then call Serialize() on the serializer instance with the JsonTextWriter that writes the output to disk. Although this code is dynamic it's still fairly short and readable.For full circle operation here's the DeserializeFromFile() version:/// <summary> /// Deserializes an object from file and returns a reference. /// </summary> /// <param name="fileName">name of the file to serialize to</param> /// <param name="objectType">The Type of the object. Use typeof(yourobject class)</param> /// <param name="binarySerialization">determines whether we use Xml or Binary serialization</param> /// <param name="throwExceptions">determines whether failure will throw rather than return null on failure</param> /// <returns>Instance of the deserialized object or null. Must be cast to your object type</returns> public static object DeserializeFromFile(string fileName, Type objectType, bool throwExceptions = false) { dynamic json = CreateJsonNet(throwExceptions); if (json == null) return null; object result = null; dynamic reader = null; FileStream fs = null; try { fs = new FileStream(fileName, FileMode.Open, FileAccess.Read); var sr = new StreamReader(fs, Encoding.UTF8); reader = Activator.CreateInstance(JsonTextReaderType, sr); result = json.Deserialize(reader, objectType); reader.Close(); } catch (Exception ex) { Debug.WriteLine("JsonNetSerialization Deserialization Error: " + ex.Message); if (throwExceptions) throw; return null; } finally { if (reader != null) reader.Close(); if (fs != null) fs.Close(); } return result; }This code is a little more compact since there are no prettifying options to set. Here JsonTextReader is created dynamically and it receives the output from the Deserialize() operation on the serializer.You can take a look at the full JsonSerializationUtils.cs file on GitHub to see the rest of the operations, but the string operations are very similar - the code is fairly repetitive.These generic serialization utilities isolate the dynamic serialization logic that has to deal with the dynamic nature of JSON.NET, and any code that uses these functions is none the wiser that JSON.NET is dynamically loaded.Using the JsonSerializationUtils WrapperThe final consumer of the SerializationUtils wrapper is an actual ConfigurationProvider, that is responsible for handling reading and writing JSON values to and from files. The provider is simple a small wrapper around the SerializationUtils component and there's very little code to make this work now:The whole provider looks like this:/// <summary> /// Reads and Writes configuration settings in .NET config files and /// sections. Allows reading and writing to default or external files /// and specification of the configuration section that settings are /// applied to. /// </summary> public class JsonFileConfigurationProvider<TAppConfiguration> : ConfigurationProviderBase<TAppConfiguration> where TAppConfiguration: AppConfiguration, new() { /// <summary> /// Optional - the Configuration file where configuration settings are /// stored in. If not specified uses the default Configuration Manager /// and its default store. /// </summary> public string JsonConfigurationFile { get { return _JsonConfigurationFile; } set { _JsonConfigurationFile = value; } } private string _JsonConfigurationFile = string.Empty; public override bool Read(AppConfiguration config) { var newConfig = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfiguration)) as TAppConfiguration; if (newConfig == null) { if(Write(config)) return true; return false; } DecryptFields(newConfig); DataUtils.CopyObjectData(newConfig, config, "Provider,ErrorMessage"); return true; } /// <summary> /// Return /// </summary> /// <typeparam name="TAppConfig"></typeparam> /// <returns></returns> public override TAppConfig Read<TAppConfig>() { var result = JsonSerializationUtils.DeserializeFromFile(JsonConfigurationFile, typeof(TAppConfig)) as TAppConfig; if (result != null) DecryptFields(result); return result; } /// <summary> /// Write configuration to XmlConfigurationFile location /// </summary> /// <param name="config"></param> /// <returns></returns> public override bool Write(AppConfiguration config) { EncryptFields(config); bool result = JsonSerializationUtils.SerializeToFile(config, JsonConfigurationFile,false,true); // Have to decrypt again to make sure the properties are readable afterwards DecryptFields(config); return result; } }This incidentally demonstrates how easy it is to create a new provider for the West Wind Application Configuration component. Simply implementing 3 methods will do in most cases.Note this code doesn't have any dynamic dependencies - all that's abstracted away in the JsonSerializationUtils(). From here on, serializing JSON is just a matter of calling the static methods on the SerializationUtils class.Already, there are several other places in some other tools where I use JSON serialization this is coming in very handy. With a couple of lines of code I was able to add JSON.NET support to an older AJAX library that I use replacing quite a bit of code that was previously in use. And for any other manual JSON operations (in a couple of apps I use JSON Serialization for 'blob' like document storage) this is also going to be handy.Performance?Some of you might be thinking that using dynamic and Reflection can't be good for performance. And you'd be right… In performing some informal testing it looks like the performance of the native code is nearly twice as fast as the dynamic code. Most of the slowness is attributable to type lookups. To test I created a native class that uses an actual reference to JSON.NET and performance was consistently around 85-90% faster with the referenced code. This will change though depending on the size of objects serialized - the larger the object the more processing time is spent inside the actual dynamically activated components and the less difference there will be. Dynamic code is always slower, but how much it really affects your application primarily depends on how frequently the dynamic code is called in relation to the non-dynamic code executing. In most situations where dynamic code is used 'to get the process rolling' as I do here the overhead is small enough to not matter.All that being said though - I serialized 10,000 objects in 80ms vs. 45ms so this is hardly slouchy performance. For the configuration component speed is not that important because both read and write operations typically happen once on first access and then every once in a while. But for other operations - say a serializer trying to handle AJAX requests on a Web Server one would be well served to create a hard dependency.Dynamic Loading - Worth it?Dynamic loading is not something you need to worry about but on occasion dynamic loading makes sense. But there's a price to be paid in added code and a performance hit which depends on how frequently the dynamic code is accessed. But for some operations that are not pivotal to a component or application and are only used under certain circumstances dynamic loading can be beneficial to avoid having to ship extra files adding dependencies and loading down distributions. These days when you create new projects in Visual Studio with 30 assemblies before you even add your own code, trying to keep file counts under control seems like a good idea. It's not the kind of thing you do on a regular basis, but when needed it can be a useful option in your toolset… © Rick Strahl, West Wind Technologies, 2005-2013Posted in .NET C# Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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Implementing a post-notification function to perform custom validation

- by Alejandro Sosa

Introduction Oracle Workflow Notification System can be extended to perform extra validation or processing via PLSQL procedures when the notification is being responded to. These PLSQL procedures are called post-notification functions since they are executed after a notification action such as Approve, Reject, Reassign or Request Information is performed. The standard signature for the post-notification function is procedure <procedure_name> (itemtype in varchar2, itemkey in varchar2, actid in varchar2, funcmode in varchar2, resultout in out nocopy varchar2); Modes The post-notification function provides the parameter 'funcmode' which will have the following values: 'RESPOND', 'VALIDATE, and 'RUN' for a notification is responded to (Approve, Reject, etc) 'FORWARD' for a notification being forwarded to another user 'TRANSFER' for a notification being transferred to another user 'QUESTION' for a request of more information from one user to another 'QUESTION' for a response to a request of more information 'TIMEOUT' for a timed-out notification 'CANCEL' when the notification is being re-executed in a loop. Context Variables Oracle Workflow provides different context information that corresponds to the current notification being acted upon to the post-notification function. WF_ENGINE.context_nid - The notification ID WF_ENGINE.context_new_role - The new role to which the action on the notification is directed WF_ENGINE.context_user_comment - Comments appended to the notification WF_ENGINE.context_user - The user who is responsible for taking the action that updated the notification's state WF_ENGINE.context_recipient_role - The role currently designated as the recipient of the notification. This value may be the same as the value of WF_ENGINE.context_user variable, or it may be a group role of which the context user is a member. WF_ENGINE.context_original_recipient - The role that has ownership of and responsibility for the notification. This value may differ from the value of the WF_ENGINE.context_recipient_role variable if the notification has previously been reassigned. Example Let us assume there is an EBS transaction that can only be approved by a certain people thus any attempt to transfer or delegate such notification should be allowed only to users SPIERSON or CBAKER. The way to implement this functionality would be as follows: Edit the corresponding workflow definition in Workflow Builder and open the notification. In the Function Name enter the name of the procedure where the custom code is handled, for instance, TEST_PACKAGE.Post_Notification In PLSQL create the corresponding package TEST_PACKAGE with a procedure named Post_Notification, as follows: procedure Post_Notification (itemtype in varchar2, itemkey in varchar2, actid in varchar2, funcmode in varchar2, resultout in out nocopy varchar2) is l_count number; begin if funcmode in ('TRANSFER','FORWARD') then select count(1) into l_count from WF_ROLES where WF_ENGINE.context_new_role in ('SPIERSON','CBAKER'); --and/or any other conditions if l_count<1 then WF_CORE.TOKEN('ROLE', WF_ENGINE.context_new_role); WF_CORE.RAISE('WFNTF_TRANSFER_FAIL'); end if; end if; end Post_Notification; Launch the workflow process with the changed notification and attempt to reassign or transfer it. When trying to reassign the notification to user CBROWN the screen would like like below: Check the Workflow API Reference Guide, section Post-Notification Functions, to see all the standard, seeded WF_ENGINE variables available for extending notifications processing.

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CodePlex Daily Summary for Friday, May 23, 2014

CodePlex Daily Summary for Friday, May 23, 2014Popular Releasesbabelua: 1.5.5: V1.5.5 - 2014.5.23New feature: support lua5.1 keywords auto completion; debug message would write to output window now; editor outline combobox’s members now will sorting by the first letter; Stability improvement: fix a bug that when search in a file which not exists in current setting folder , result of switch relative path function would not correct; Some other bug fix;DotNet.Highcharts: DotNet.Highcharts 4.0 with Examples: DotNet.Highcharts 4.0 Tested and adapted to the latest version of Highcharts 4.0.1 Added new chart type: Heatmap Added new type PointPlacement which represents enumeration or number for the padding of the X axis. Changed target framework from .NET Framework 4 to .NET Framework 4.5. Closed issues: 974: Add 'overflow' property to PlotOptionsColumnDataLabels class 997: Split container from JS 1006: Series/Categories with numeric names don't render DotNet.Highcharts.Samples Updated s...String.Format Diagnostic (Roslyn): Diagnostic Format String (v1,3): In this release the tool is now capable of reporting multiple issues contained within the text of a formatstring. v1.3 Extends these capability to include if the formatstring argument is a String Constant. Validation Rules Supported Are the Argument Index supplied within range, of those supplied? Is the Argument Index less than the limit of 1000000 (This is defined inside of the .net framework's implementation) Is the Alignment with less than the limit of 1000 000 (This is define insid...Aspose for Apache POI: Missing Features of Apache POI SL - v 1.1: Release contain the Missing Features in Apache POI SL SDK in Comparison with Aspose.Slides for dealing with Microsoft Power Point. What's New ?Following Examples: Managing Slide Transitions Manage Smart Art Adding Media Player Adding Audio Frame to Slide Feedback and Suggestions Many more examples are yet to come here. Keep visiting us. Raise your queries and suggest more examples via Aspose Forums or via this social coding site.OSGi.NET: Asp.net MVC 4.0 integration v2.2: + Support AreaRegistrationPowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.1.3: Added CompressLogs option to the config file. Each Install / Uninstall creates a timestamped zip file with all MSI and PSAppDeployToolkit logs contained within Added variable expansion to all paths in the configuration file Added documentation for each of the Toolkit internal variables that can be used Changed Install-MSUpdates to continue if any errors are encountered when installing updates Implement /Force parameter on Update-GroupPolicy (ensure that any logoff message is ignored) ...WordMat: WordMat v. 1.07: A quick fix because scientific notation was broken in v. 1.06 read more at http://wordmat.blogspot.comConEmu - Windows console with tabs: ConEmu 140522 [Alpha]: ConEmu - developer build x86 and x64 versions. Written in C++, no additional packages required. Run "ConEmu.exe" or "ConEmu64.exe". Some useful information you may found: http://superuser.com/questions/tagged/conemu http://code.google.com/p/conemu-maximus5/wiki/ConEmuFAQ http://code.google.com/p/conemu-maximus5/wiki/TableOfContents If you want to use ConEmu in portable mode, just create empty "ConEmu.xml" file near to "ConEmu.exe" WebExtras: v1.4.0-Beta-1: Enh: Adding support for jQuery UI framework Enh: Adding support for jqPlot charting library Dropping dependency on MoreLinq library Note: Html.LabelForV2(...) extension method has now been deprecated. You should use Html.RequiredFieldLabelFor(...) extension method instead. This extension method will be removed in future versions.????: 《????》: 《????》（c???）??“????”???????，???????????????C?????????。???????,???????????????????????. ??????????????????????????????????；????????????????????????????。Mini SQL Query: Mini SQL Query (1.0.72.457): Apologies for the previous update! FK issue fixed and also a template data cache issue.Wsus Package Publisher: Release v1.3.1405.17: Add Russian translation (thanks to VSharmanov) Fix a bug that make WPP to crash if the user click on "Connect/Reload" while the Report Tab is loading. Enhance the way WPP store the password for remote computers command.MoreTerra (Terraria World Viewer): More Terra 1.12.9: =========== = Compatibility = =========== Updated to account for new format 1.2.4.1 =========== = Issues = =========== all items have not been added. Some colors for new tiles may be off. I wanted to get this out so people have a usable program.LINQ to Twitter: LINQ to Twitter v3.0.3: Supports .NET 4.5x, Windows Phone 8.x, Windows 8.x, Windows Azure, Xamarin.Android, and Xamarin.iOS. New features include Status/Lookup, Mute APIs, and bug fixes. 100% Twitter API v1.1 coverage, Async, Portable Class Library (PCL).CS-Script for Notepad++ (C# intellisense and code execution): Release v1.0.26.0: Added access to the Release Notes during 'Check for Updates...'' Debug panels Added support for generic types members Members are grouped into 'Raw View' and 'Non-Public members' categories Implemented dedicated (array-like) view for Lists and Dictionaries http://download-codeplex.sec.s-msft.com/Download?ProjectName=csscriptnpp&DownloadId=846498ClosedXML - The easy way to OpenXML: ClosedXML 0.70.0: A lot of fixes. See history.TBox - tool to make developer's life easier.: TBox 1.29: Bug fixing. Add LocalizationTool pluginYAXLib: Yet Another XML Serialization Library for the .NET Framework: YAXLib 2.13: Fixed a bug and added unit tests related to serializing path like aliases with one letter (e.g., './B'). Thanks go to CodeProject user B.O.B. for reporting this bug. Added `Bin/*.dll.mdb` to `.gitignore`. Fixed the issue with Indexer properties. Indexers must not be serialized/deserialized. YAXLib will ignore delegate (callback/function pointer) properties, so that the exception upon serializing them is prevented. Significant improve in cycling object reference detection Self Referr...SFDL.NET: SFDL.NET (2.2.9.2): Changelog: Neues Icon Xup.in CnL Plugin BugfixSEToolbox: SEToolbox 01.030.008 Release 1: Fixed cube editor failing to apply color to cubes. Added to cube editor, replace cube dialog, and Build Percent dialog. Corrected for hidden asteroid ore, allowing rare ore to show when importing an asteroid, or converting a 3d model to an asteroid (still appears to be limitations on rare ore in small asteroids). Allowed ore selection to Asteroid file import. (Can copy/import and convert existing asteroid to another ore). Added progress bars to common long running operations. Fixed ...New ProjectsBlueCurve Search: BlueCurve is a small experimental search engine, implemented on top of Lucene. The goal is to test ways to create a powerfull search engine system framework.C64 Studio: C64 Studio is a .NET based IDE. The program supports project based C64 assembly and/or Basic V2 and is geared towards game development.ExpressToAbroad: ExpressToAbroadFarragoJS: A set of simple JavaScript functions: FarragoJS is a set of simple JavaScript functions offering features ranging from useful to totally pointless! But hey, there's a use for everything, right?fischetest: nothingIsDrone: Simple windows client for Parrot ar Drone. ??????? ?????? ??? Parrot ar Drone ??? Windows. Jewelry: this is project about auto generate codeMRBrowserLibrary: webbrowser control libraryQuan Ly Phong Tro DevExpress and LinQ: Quan Ly Phong Tro DevExpress + LinQUseless Games: JavaScript games written for practicing this wonderful language.?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ??????、??????????????????,???????.??????????,????????。 ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ??????-??????【??】??????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ?????-?????【??】?????????: ???????????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！ ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ??????????????????,???,??????????、???????????????????。??????,????、????，??????！ ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ???????????????????????,????,????“???、???、???”?????,?????,?????????????????。??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ??????、??????????????????,???????.??????????,????????。 ?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】?????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ???????????????,??????,??????,??????、??????,??????、??，????，??????！ ??????-??????【??】??????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ???????????????:??????!?????!???:????、????、????、????。??,??????????!??????. ??????-??????【??】??????????: ????????,???????????,??????????,????:??,????,???????? ??????????,????????。??????！ ?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【???????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ??????????????,????????????,????????,???,???????????,????,????。?????,??????. ?????-?????【??】?????????: ??????????????????,???,??????????、???????????????????。??????,????、????，??????！ ?????-?????【??】?????????: ???????????????????????,???????????,??????,??????????????...????????。??????！ ?????-?????【??】?????????: ????????????,????,?????、???、?????,???????,?????,???????????100%。??????！ ?????-?????【??】?????????: ?????1992?,????????????????。??????????????????????。????????????,????，????????！ ?????-?????【??】?????????: ??????、??????????????????,???????.??????????,????????。 ?????-?????【??】?????????: ???????2005?,????????????????????,??????????,??????。?????,???????????????????，??????！ ?????-?????【??】?????????: ?????????????????????,??????,???????????,????????????????,????????.??????. ?????-?????【??】?????????: ??????????????????,???,??????????、???????????????????。??????,????、????，??????！

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The Return Of FILE And LINE In .NET 4.5

- by Alois Kraus

Good things are hard to kill. One of the most useful predefined compiler macros in C/C++ were __FILE__ and __LINE__ which do expand to the compilation units file name and line number where this value is encountered by the compiler. After 4.5 versions of .NET we are on par with C/C++ again. It is of course not a simple compiler expandable macro it is an attribute but it does serve exactly the same purpose. Now we do get CallerLineNumberAttribute == __LINE__ CallerFilePathAttribute == __FILE__ CallerMemberNameAttribute == __FUNCTION__ (MSVC Extension) The most important one is CallerMemberNameAttribute which is very useful to implement the INotifyPropertyChanged interface without the need to hard code the name of the property anymore. Now you can simply decorate your change method with the new CallerMemberName attribute and you get the property name as string directly inserted by the C# compiler at compile time. public string UserName { get { return _userName; } set { _userName=value; RaisePropertyChanged(); // no more RaisePropertyChanged(“UserName”)! } } protected void RaisePropertyChanged([CallerMemberName] string member = "") { var copy = PropertyChanged; if(copy != null) { copy(new PropertyChangedEventArgs(this, member)); } } Nice and handy. This was obviously the prime reason to implement this feature in the C# 5.0 compiler. You can repurpose this feature for tracing to get your hands on the method name of your caller along other stuff very fast now. All infos are added during compile time which is much faster than other approaches like walking the stack. The example on MSDN shows the usage of this attribute with an example public static void TraceMessage(string message, [CallerMemberName] string memberName = "", [CallerFilePath] string sourceFilePath = "", [CallerLineNumber] int sourceLineNumber = 0) { Console.WriteLine("Hi {0} {1} {2}({3})", message, memberName, sourceFilePath, sourceLineNumber); } When I do think of tracing I do usually want to have a API which allows me to Trace method enter and leave Trace messages with a severity like Info, Warning, Error When I do print a trace message it is very useful to print out method and type name as well. So your API must either be able to pass the method and type name as strings or extract it automatically via walking back one Stackframe and fetch the infos from there. The first glaring deficiency is that there is no CallerTypeAttribute yet because the C# compiler team was not satisfied with its performance. A usable Trace Api might therefore look like enum TraceTypes { None = 0, EnterLeave = 1 << 0, Info = 1 << 1, Warn = 1 << 2, Error = 1 << 3 } class Tracer : IDisposable { string Type; string Method; public Tracer(string type, string method) { Type = type; Method = method; if (IsEnabled(TraceTypes.EnterLeave,Type, Method)) { } } private bool IsEnabled(TraceTypes traceTypes, string Type, string Method) { // Do checking here if tracing is enabled return false; } public void Info(string fmt, params object[] args) { } public void Warn(string fmt, params object[] args) { } public void Error(string fmt, params object[] args) { } public static void Info(string type, string method, string fmt, params object[] args) { } public static void Warn(string type, string method, string fmt, params object[] args) { } public static void Error(string type, string method, string fmt, params object[] args) { } public void Dispose() { // trace method leave } } This minimal trace API is very fast but hard to maintain since you need to pass in the type and method name as hard coded strings which can change from time to time. But now we have at least CallerMemberName to rid of the explicit method parameter right? Not really. Since any acceptable usable trace Api should have a method signature like Tracexxx(… string fmt, params [] object args) we not able to add additional optional parameters after the args array. If we would put it before the format string we would need to make it optional as well which would mean the compiler would need to figure out what our trace message and arguments are (not likely) or we would need to specify everything explicitly just like before . There are ways around this by providing a myriad of overloads which in the end are routed to the very same method but that is ugly. I am not sure if nobody inside MS agrees that the above API is reasonable to have or (more likely) that the whole talk about you can use this feature for diagnostic purposes was not a core feature at all but a simple byproduct of making the life of INotifyPropertyChanged implementers easier. A way around this would be to allow for variable argument arrays after the params keyword another set of optional arguments which are always filled by the compiler but I do not know if this is an easy one. The thing I am missing much more is the not provided CallerType attribute. But not in the way you would think of. In the API above I did add some filtering based on method and type to stay as fast as possible for types where tracing is not enabled at all. It should be no more expensive than an additional method call and a bool variable check if tracing for this type is enabled at all. The data is tightly bound to the calling type and method and should therefore become part of the static type instance. Since extending the CLR type system for tracing is not something I do expect to happen I have come up with an alternative approach which allows me basically to attach run time data to any existing type object in super fast way. The key to success is the usage of generics. class Tracer<T> : IDisposable { string Method; public Tracer(string method) { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public void Dispose() { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public static void Info(string fmt, params object[] args) { } /// <summary> /// Every type gets its own instance with a fresh set of variables to describe the /// current filter status. /// </summary> /// <typeparam name="T"></typeparam> internal class TraceData<UsingType> { internal static TraceData<UsingType> Instance = new TraceData<UsingType>(); public bool IsInitialized = false; // flag if we need to reinit the trace data in case of reconfigured trace settings at runtime public TraceTypes Enabled = TraceTypes.None; // Enabled trace levels for this type } } We do not need to pass the type as string or Type object to the trace Api. Instead we define a generic Api that accepts the using type as generic parameter. Then we can create a TraceData static instance which is due to the nature of generics a fresh instance for every new type parameter. My tests on my home machine have shown that this approach is as fast as a simple bool flag check. If you have an application with many types using tracing you do not want to bring the app down by simply enabling tracing for one special rarely used type. The trace filter performance for the types which are not enabled must be therefore the fasted code path. This approach has the nice side effect that if you store the TraceData instances in one global list you can reconfigure tracing at runtime safely by simply setting the IsInitialized flag to false. A similar effect can be achieved with a global static Dictionary<Type,TraceData> object but big hash tables have random memory access semantics which is bad for cache locality and you always need to pay for the lookup which involves hash code generation, equality check and an indexed array access. The generic version is wicked fast and allows you to add more features to your tracing Api with minimal perf overhead. But it is cumbersome to write the generic type argument always explicitly and worse if you do refactor code and move parts of it to other classes it might be that you cannot configure tracing correctly. I would like therefore to decorate my type with an attribute [CallerType] class Tracer<T> : IDisposable to tell the compiler to fill in the generic type argument automatically. class Program { static void Main(string[] args) { using (var t = new Tracer()) // equivalent to new Tracer<Program>() { That would be really useful and super fast since you do not need to pass any type object around but you do have full type infos at hand. This change would be breaking if another non generic type exists in the same namespace where now the generic counterpart would be preferred. But this is an acceptable risk in my opinion since you can today already get conflicts if two generic types of the same name are defined in different namespaces. This would be only a variation of this issue. When you do think about this further you can add more features like to trace the exception in your Dispose method if the method is left with an exception with that little trick I did write some time ago. You can think of tracing as a super fast and configurable switch to write data to an output destination or to execute alternative actions. With such an infrastructure you can e.g. Reconfigure tracing at run time. Take a memory dump when a specific method is left with a specific exception. Throw an exception when a specific trace statement is hit (useful for testing error conditions). Execute a passed delegate which e.g. dumps additional state when enabled. Write data to an in memory ring buffer and dump it when specific events do occur (e.g. method is left with an exception, triggered from outside). Write data to an output device. …. This stuff is really useful to have when your code is in production on a mission critical server and you need to find the root cause of sporadic crashes of your application. It could be a buggy graphics card driver which throws access violations into your application (ok with .NET 4 not anymore except if you enable a compatibility flag) where you would like to have a minidump or you have reached after two weeks of operation a state where you need a full memory dump at a specific point in time in the middle of an transaction. At my older machine I do get with this super fast approach 50 million traces/s when tracing is disabled. When I do know that tracing is enabled for this type I can walk the stack by using StackFrameHelper.GetStackFramesInternal to check further if a specific action or output device is configured for this method which is about 2-3 times faster than the regular StackTrace class. Even with one String.Format I am down to 3 million traces/s so performance is not so important anymore since I do want to do something now. The CallerMemberName feature of the C# 5 compiler is nice but I would have preferred to get direct access to the MethodHandle and not to the stringified version of it. But I really would like to see a CallerType attribute implemented to fill in the generic type argument of the call site to augment the static CLR type data with run time data.

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