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  • NoSQL with RavenDB and ASP.NET MVC - Part 1

    - by shiju
     A while back, I have blogged NoSQL with MongoDB, NoRM and ASP.NET MVC Part 1 and Part 2 on how to use MongoDB with an ASP.NET MVC application. The NoSQL movement is getting big attention and RavenDB is the latest addition to the NoSQL and document database world. RavenDB is an Open Source (with a commercial option) document database for the .NET/Windows platform developed  by Ayende Rahien.  Raven stores schema-less JSON documents, allow you to define indexes using Linq queries and focus on low latency and high performance. RavenDB is .NET focused document database which comes with a fully functional .NET client API  and supports LINQ. RavenDB comes with two components, a server and a client API. RavenDB is a REST based system, so you can write your own HTTP cleint API. As a .NET developer, RavenDB is becoming my favorite document database. Unlike other document databases, RavenDB is supports transactions using System.Transactions. Also it's supports both embedded and server mode of database. You can access RavenDB site at http://ravendb.netA demo App with ASP.NET MVCLet's create a simple demo app with RavenDB and ASP.NET MVC. To work with RavenDB, do the following steps. Go to http://ravendb.net/download and download the latest build.Unzip the downloaded file.Go to the /Server directory and run the RavenDB.exe. This will start the RavenDB server listening on localhost:8080You can change the port of RavenDB  by modifying the "Raven/Port" appSetting value in the RavenDB.exe.config file.When running the RavenDB, it will automatically create a database in the /Data directory. You can change the directory name data by modifying "Raven/DataDirt" appSetting value in the RavenDB.exe.config file.RavenDB provides a browser based admin tool. When the Raven server is running, You can be access the browser based admin tool and view and edit documents and index using your browser admin tool. The web admin tool available at http://localhost:8080The below is the some screen shots of web admin tool     Working with ASP.NET MVC  To working with RavenDB in our demo ASP.NET MVC application, do the following steps Step 1 - Add reference to Raven Cleint API In our ASP.NET MVC application, Add a reference to the Raven.Client.Lightweight.dll from the Client directory. Step 2 - Create DocumentStoreThe document store would be created once per application. Let's create a DocumentStore on application start-up in the Global.asax.cs. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); The above code will create a Raven DB document store and will be listening the server locahost at port 8080    Step 3 - Create DocumentSession on BeginRequest   Let's create a DocumentSession on BeginRequest event in the Global.asax.cs. We are using the document session for every unit of work. In our demo app, every HTTP request would be a single Unit of Work (UoW). BeginRequest += (sender, args) =>   HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); Step 4 - Destroy the DocumentSession on EndRequest  EndRequest += (o, eventArgs) => {     var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable;     if (disposable != null)         disposable.Dispose(); };  At the end of HTTP request, we are destroying the DocumentSession  object.The below  code block shown all the code in the Global.asax.cs  private const string RavenSessionKey = "RavenMVC.Session"; private static DocumentStore documentStore;   protected void Application_Start() { //Create a DocumentStore in Application_Start //DocumentStore should be created once per application and stored as a singleton. documentStore = new DocumentStore { Url = "http://localhost:8080/" }; documentStore.Initialise(); AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); //DI using Unity 2.0 ConfigureUnity(); }   public MvcApplication() { //Create a DocumentSession on BeginRequest   //create a document session for every unit of work BeginRequest += (sender, args) =>     HttpContext.Current.Items[RavenSessionKey] = documentStore.OpenSession(); //Destroy the DocumentSession on EndRequest EndRequest += (o, eventArgs) => { var disposable = HttpContext.Current.Items[RavenSessionKey] as IDisposable; if (disposable != null) disposable.Dispose(); }; }   //Getting the current DocumentSession public static IDocumentSession CurrentSession {   get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } }  We have setup all necessary code in the Global.asax.cs for working with RavenDB. For our demo app, Let’s write a domain class  public class Category {       public string Id { get; set; }       [Required(ErrorMessage = "Name Required")]     [StringLength(25, ErrorMessage = "Must be less than 25 characters")]     public string Name { get; set;}     public string Description { get; set; }   } We have created simple domain entity Category. Let's create repository class for performing CRUD operations against our domain entity Category.  public interface ICategoryRepository {     Category Load(string id);     IEnumerable<Category> GetCategories();     void Save(Category category);     void Delete(string id);       }    public class CategoryRepository : ICategoryRepository {     private IDocumentSession session;     public CategoryRepository()     {             session = MvcApplication.CurrentSession;     }     //Load category based on Id     public Category Load(string id)     {         return session.Load<Category>(id);     }     //Get all categories     public IEnumerable<Category> GetCategories()     {         var categories= session.LuceneQuery<Category>()                 .WaitForNonStaleResults()             .ToArray();         return categories;       }     //Insert/Update category     public void Save(Category category)     {         if (string.IsNullOrEmpty(category.Id))         {             //insert new record             session.Store(category);         }         else         {             //edit record             var categoryToEdit = Load(category.Id);             categoryToEdit.Name = category.Name;             categoryToEdit.Description = category.Description;         }         //save the document session         session.SaveChanges();     }     //delete a category     public void Delete(string id)     {         var category = Load(id);         session.Delete<Category>(category);         session.SaveChanges();     }        } For every CRUD operations, we are taking the current document session object from HttpContext object. session = MvcApplication.CurrentSession; We are calling the static method CurrentSession from the Global.asax.cs public static IDocumentSession CurrentSession {     get { return (IDocumentSession)HttpContext.Current.Items[RavenSessionKey]; } }  Retrieve Entities  The Load method get the single Category object based on the Id. RavenDB is working based on the REST principles and the Id would be like categories/1. The Id would be created by automatically when a new object is inserted to the document store. The REST uri categories/1 represents a single category object with Id representation of 1.   public Category Load(string id) {    return session.Load<Category>(id); } The GetCategories method returns all the categories calling the session.LuceneQuery method. RavenDB is using a lucen query syntax for querying. I will explain more details about querying and indexing in my future posts.   public IEnumerable<Category> GetCategories() {     var categories= session.LuceneQuery<Category>()             .WaitForNonStaleResults()         .ToArray();     return categories;   } Insert/Update entityFor insert/Update a Category entity, we have created Save method in repository class. If  the Id property of Category is null, we call Store method of Documentsession for insert a new record. For editing a existing record, we load the Category object and assign the values to the loaded Category object. The session.SaveChanges() will save the changes to document store.  //Insert/Update category public void Save(Category category) {     if (string.IsNullOrEmpty(category.Id))     {         //insert new record         session.Store(category);     }     else     {         //edit record         var categoryToEdit = Load(category.Id);         categoryToEdit.Name = category.Name;         categoryToEdit.Description = category.Description;     }     //save the document session     session.SaveChanges(); }  Delete Entity  In the Delete method, we call the document session's delete method and call the SaveChanges method to reflect changes in the document store.  public void Delete(string id) {     var category = Load(id);     session.Delete<Category>(category);     session.SaveChanges(); }  Let’s create ASP.NET MVC controller and controller actions for handling CRUD operations for the domain class Category  public class CategoryController : Controller { private ICategoryRepository categoyRepository; //DI enabled constructor public CategoryController(ICategoryRepository categoyRepository) {     this.categoyRepository = categoyRepository; } public ActionResult Index() {         var categories = categoyRepository.GetCategories();     if (categories == null)         return RedirectToAction("Create");     return View(categories); }   [HttpGet] public ActionResult Edit(string id) {     var category = categoyRepository.Load(id);         return View("Save",category); } // GET: /Category/Create [HttpGet] public ActionResult Create() {     var category = new Category();     return View("Save", category); } [HttpPost] public ActionResult Save(Category category) {     if (!ModelState.IsValid)     {         return View("Save", category);     }           categoyRepository.Save(category);         return RedirectToAction("Index");     }        [HttpPost] public ActionResult Delete(string id) {     categoyRepository.Delete(id);     var categories = categoyRepository.GetCategories();     return PartialView("CategoryList", categories);      }        }  RavenDB is an awesome document database and I hope that it will be the winner in .NET space of document database world.  The source code of demo application available at http://ravenmvc.codeplex.com/

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  • Metro: Declarative Data Binding

    - by Stephen.Walther
    The goal of this blog post is to describe how declarative data binding works in the WinJS library. In particular, you learn how to use both the data-win-bind and data-win-bindsource attributes. You also learn how to use calculated properties and converters to format the value of a property automatically when performing data binding. By taking advantage of WinJS data binding, you can use the Model-View-ViewModel (MVVM) pattern when building Metro style applications with JavaScript. By using the MVVM pattern, you can prevent your JavaScript code from spinning into chaos. The MVVM pattern provides you with a standard pattern for organizing your JavaScript code which results in a more maintainable application. Using Declarative Bindings You can use the data-win-bind attribute with any HTML element in a page. The data-win-bind attribute enables you to bind (associate) an attribute of an HTML element to the value of a property. Imagine, for example, that you want to create a product details page. You want to show a product object in a page. In that case, you can create the following HTML page to display the product details: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Product Details</h1> <div class="field"> Product Name: <span data-win-bind="innerText:name"></span> </div> <div class="field"> Product Price: <span data-win-bind="innerText:price"></span> </div> <div class="field"> Product Picture: <br /> <img data-win-bind="src:photo;alt:name" /> </div> </body> </html> The HTML page above contains three data-win-bind attributes – one attribute for each product property displayed. You use the data-win-bind attribute to set properties of the HTML element associated with the data-win-attribute. The data-win-bind attribute takes a semicolon delimited list of element property names and data source property names: data-win-bind=”elementPropertyName:datasourcePropertyName; elementPropertyName:datasourcePropertyName;…” In the HTML page above, the first two data-win-bind attributes are used to set the values of the innerText property of the SPAN elements. The last data-win-bind attribute is used to set the values of the IMG element’s src and alt attributes. By the way, using data-win-bind attributes is perfectly valid HTML5. The HTML5 standard enables you to add custom attributes to an HTML document just as long as the custom attributes start with the prefix data-. So you can add custom attributes to an HTML5 document with names like data-stephen, data-funky, or data-rover-dog-is-hungry and your document will validate. The product object displayed in the page above with the data-win-bind attributes is created in the default.js file: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var product = { name: "Tesla", price: 80000, photo: "/images/TeslaPhoto.png" }; WinJS.Binding.processAll(null, product); } }; app.start(); })(); In the code above, a product object is created with a name, price, and photo property. The WinJS.Binding.processAll() method is called to perform the actual binding (Don’t confuse WinJS.Binding.processAll() and WinJS.UI.processAll() – these are different methods). The first parameter passed to the processAll() method represents the root element for the binding. In other words, binding happens on this element and its child elements. If you provide the value null, then binding happens on the entire body of the document (document.body). The second parameter represents the data context. This is the object that has the properties which are displayed with the data-win-bind attributes. In the code above, the product object is passed as the data context parameter. Another word for data context is view model.  Creating Complex View Models In the previous section, we used the data-win-bind attribute to display the properties of a simple object: a single product. However, you can use binding with more complex view models including view models which represent multiple objects. For example, the view model in the following default.js file represents both a customer and a product object. Furthermore, the customer object has a nested address object: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var viewModel = { customer: { firstName: "Fred", lastName: "Flintstone", address: { street: "1 Rocky Way", city: "Bedrock", country: "USA" } }, product: { name: "Bowling Ball", price: 34.55 } }; WinJS.Binding.processAll(null, viewModel); } }; app.start(); })(); The following page displays the customer (including the customer address) and the product. Notice that you can use dot notation to refer to child objects in a view model such as customer.address.street. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Customer Details</h1> <div class="field"> First Name: <span data-win-bind="innerText:customer.firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:customer.lastName"></span> </div> <div class="field"> Address: <address> <span data-win-bind="innerText:customer.address.street"></span> <br /> <span data-win-bind="innerText:customer.address.city"></span> <br /> <span data-win-bind="innerText:customer.address.country"></span> </address> </div> <h1>Product</h1> <div class="field"> Name: <span data-win-bind="innerText:product.name"></span> </div> <div class="field"> Price: <span data-win-bind="innerText:product.price"></span> </div> </body> </html> A view model can be as complicated as you need and you can bind the view model to a view (an HTML document) by using declarative bindings. Creating Calculated Properties You might want to modify a property before displaying the property. For example, you might want to format the product price property before displaying the property. You don’t want to display the raw product price “80000”. Instead, you want to display the formatted price “$80,000”. You also might need to combine multiple properties. For example, you might need to display the customer full name by combining the values of the customer first and last name properties. In these situations, it is tempting to call a function when performing binding. For example, you could create a function named fullName() which concatenates the customer first and last name. Unfortunately, the WinJS library does not support the following syntax: <span data-win-bind=”innerText:fullName()”></span> Instead, in these situations, you should create a new property in your view model that has a getter. For example, the customer object in the following default.js file includes a property named fullName which combines the values of the firstName and lastName properties: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var customer = { firstName: "Fred", lastName: "Flintstone", get fullName() { return this.firstName + " " + this.lastName; } }; WinJS.Binding.processAll(null, customer); } }; app.start(); })(); The customer object has a firstName, lastName, and fullName property. Notice that the fullName property is defined with a getter function. When you read the fullName property, the values of the firstName and lastName properties are concatenated and returned. The following HTML page displays the fullName property in an H1 element. You can use the fullName property in a data-win-bind attribute in exactly the same way as any other property. <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1 data-win-bind="innerText:fullName"></h1> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> </body> </html> Creating a Converter In the previous section, you learned how to format the value of a property by creating a property with a getter. This approach makes sense when the formatting logic is specific to a particular view model. If, on the other hand, you need to perform the same type of formatting for multiple view models then it makes more sense to create a converter function. A converter function is a function which you can apply whenever you are using the data-win-bind attribute. Imagine, for example, that you want to create a general function for displaying dates. You always want to display dates using a short format such as 12/25/1988. The following JavaScript file – named converters.js – contains a shortDate() converter: (function (WinJS) { var shortDate = WinJS.Binding.converter(function (date) { return date.getMonth() + 1 + "/" + date.getDate() + "/" + date.getFullYear(); }); // Export shortDate WinJS.Namespace.define("MyApp.Converters", { shortDate: shortDate }); })(WinJS); The file above uses the Module Pattern, a pattern which is used through the WinJS library. To learn more about the Module Pattern, see my blog entry on namespaces and modules: http://stephenwalther.com/blog/archive/2012/02/22/windows-web-applications-namespaces-and-modules.aspx The file contains the definition for a converter function named shortDate(). This function converts a JavaScript date object into a short date string such as 12/1/1988. The converter function is created with the help of the WinJS.Binding.converter() method. This method takes a normal function and converts it into a converter function. Finally, the shortDate() converter is added to the MyApp.Converters namespace. You can call the shortDate() function by calling MyApp.Converters.shortDate(). The default.js file contains the customer object that we want to bind. Notice that the customer object has a firstName, lastName, and birthday property. We will use our new shortDate() converter when displaying the customer birthday property: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { var customer = { firstName: "Fred", lastName: "Flintstone", birthday: new Date("12/1/1988") }; WinJS.Binding.processAll(null, customer); } }; app.start(); })(); We actually use our shortDate converter in the HTML document. The following HTML document displays all of the customer properties: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> <script type="text/javascript" src="js/converters.js"></script> </head> <body> <h1>Customer Details</h1> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> <div class="field"> Birthday: <span data-win-bind="innerText:birthday MyApp.Converters.shortDate"></span> </div> </body> </html> Notice the data-win-bind attribute used to display the birthday property. It looks like this: <span data-win-bind="innerText:birthday MyApp.Converters.shortDate"></span> The shortDate converter is applied to the birthday property when the birthday property is bound to the SPAN element’s innerText property. Using data-win-bindsource Normally, you pass the view model (the data context) which you want to use with the data-win-bind attributes in a page by passing the view model to the WinJS.Binding.processAll() method like this: WinJS.Binding.processAll(null, viewModel); As an alternative, you can specify the view model declaratively in your markup by using the data-win-datasource attribute. For example, the following default.js script exposes a view model with the fully-qualified name of MyWinWebApp.viewModel: (function () { "use strict"; var app = WinJS.Application; app.onactivated = function (eventObject) { if (eventObject.detail.kind === Windows.ApplicationModel.Activation.ActivationKind.launch) { // Create view model var viewModel = { customer: { firstName: "Fred", lastName: "Flintstone" }, product: { name: "Bowling Ball", price: 12.99 } }; // Export view model to be seen by universe WinJS.Namespace.define("MyWinWebApp", { viewModel: viewModel }); // Process data-win-bind attributes WinJS.Binding.processAll(); } }; app.start(); })(); In the code above, a view model which represents a customer and a product is exposed as MyWinWebApp.viewModel. The following HTML page illustrates how you can use the data-win-bindsource attribute to bind to this view model: <!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Application1</title> <!-- WinJS references --> <link href="//Microsoft.WinJS.0.6/css/ui-dark.css" rel="stylesheet"> <script src="//Microsoft.WinJS.0.6/js/base.js"></script> <script src="//Microsoft.WinJS.0.6/js/ui.js"></script> <!-- Application1 references --> <link href="/css/default.css" rel="stylesheet"> <script src="/js/default.js"></script> </head> <body> <h1>Customer Details</h1> <div data-win-bindsource="MyWinWebApp.viewModel.customer"> <div class="field"> First Name: <span data-win-bind="innerText:firstName"></span> </div> <div class="field"> Last Name: <span data-win-bind="innerText:lastName"></span> </div> </div> <h1>Product</h1> <div data-win-bindsource="MyWinWebApp.viewModel.product"> <div class="field"> Name: <span data-win-bind="innerText:name"></span> </div> <div class="field"> Price: <span data-win-bind="innerText:price"></span> </div> </div> </body> </html> The data-win-bindsource attribute is used twice in the page above: it is used with the DIV element which contains the customer details and it is used with the DIV element which contains the product details. If an element has a data-win-bindsource attribute then all of the child elements of that element are affected. The data-win-bind attributes of all of the child elements are bound to the data source represented by the data-win-bindsource attribute. Summary The focus of this blog entry was data binding using the WinJS library. You learned how to use the data-win-bind attribute to bind the properties of an HTML element to a view model. We also discussed several advanced features of data binding. We examined how to create calculated properties by including a property with a getter in your view model. We also discussed how you can create a converter function to format the value of a view model property when binding the property. Finally, you learned how to use the data-win-bindsource attribute to specify a view model declaratively.

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  • SQL SERVER – Fix Error: Microsoft OLE DB Provider for SQL Server error ’80040e07' or Microsoft SQL Native Client error ’80040e07'

    - by pinaldave
    I quite often receive questions where users are looking for solution to following error: Microsoft OLE DB Provider for SQL Server error ’80040e07′ Syntax error converting datetime from character string. OR Microsoft SQL Native Client error ’80040e07′ Syntax error converting datetime from character string. If you have ever faced above error – I have a very simple solution for you. The solution is being very check date which is inserted in the datetime column. This error often comes up when application or user is attempting to enter an incorrect date into the datetime field. Here is one of the examples – one of the reader was using classing ASP Application with OLE DB provider for SQL Server. When he tried to insert following script he faced above mentioned error. INSERT INTO TestTable (ID, MyDate) VALUES (1, '01-Septeber-2013') The reason for the error was simple as he had misspelled September word. Upon correction of the word, he was able to successfully insert the value and error was not there. Incorrect values or the typo’s are not the only reason for this error. There can be issues with cast or convert as well. If you try to attempt following code using SQL Native Client or in your application you will also get similar errors. SELECT CONVERT (datetime, '01-Septeber-2013', 112) The reason here is very simple, any conversion attempt or any other kind of operation on incorrect date/time string can lead to the above error. If you not using embeded dynamic code in your application language but using attempting similar operation on incorrect datetime string you will get following error. Msg 241, Level 16, State 1, Line 2 Conversion failed when converting date and/or time from character string. Remember: Check your values of the string when you are attempting to convert them to string – either there can be incorrect values or they may be incorrectly formatted. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL DateTime, SQL Error Messages, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Type Casting variables in PHP: Is there a practical example?

    - by Stephen
    PHP, as most of us know, has weak typing. For those who don't, PHP.net says: PHP does not require (or support) explicit type definition in variable declaration; a variable's type is determined by the context in which the variable is used. Love it or hate it, PHP re-casts variables on-the-fly. So, the following code is valid: $var = "10"; $value = 10 + $var; var_dump($value); // int(20) PHP also alows you to explicitly cast a variable, like so: $var = "10"; $value = 10 + $var; $value = (string)$value; var_dump($value); // string(2) "20" That's all cool... but, for the life of me, I cannot conceive of a practical reason for doing this. I don't have a problem with strong typing in languages that support it, like Java. That's fine, and I completely understand it. Also, I'm aware of—and fully understand the usefulness of—type hinting in function parameters. The problem I have with type casting is explained by the above quote. If PHP can swap types at-will, it can do so even after you force cast a type; and it can do so on-the-fly when you need a certain type in an operation. That makes the following valid: $var = "10"; $value = (int)$var; $value = $value . ' TaDa!'; var_dump($value); // string(8) "10 TaDa!" So what's the point? Can anyone show me a practical application or example of type casting—one that would fail if type casting were not involved? I ask this here instead of SO because I figure practicality is too subjective. Edit in response to Chris' comment Take this theoretical example of a world where user-defined type casting makes sense in PHP: You force cast variable $foo as int -- (int)$foo. You attempt to store a string value in the variable $foo. PHP throws an exception!! <--- That would make sense. Suddenly the reason for user defined type casting exists! The fact that PHP will switch things around as needed makes the point of user defined type casting vague. For example, the following two code samples are equivalent: // example 1 $foo = 0; $foo = (string)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo; // example 2 $foo = 0; $foo = (int)$foo; $foo = '# of Reasons for the programmer to type cast $foo as a string: ' . $foo;

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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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  • Physics/Graphics Components

    - by Brett Powell
    I have spent the last 48 hours reading up on Object Component systems, and feel I am ready enough to start implementing it. I got the base Object and Component classes created, but now that I need to start creating the actual components I am a bit confused. When I think of them in terms of HealthComponent or something that would basically just be a property, it makes perfect sense. When it is something more general as a Physics/Graphics component, I get a bit confused. My Object class looks like this so far (If you notice any changes I should make please let me know, still new to this)... typedef unsigned int ID; class GameObject { public: GameObject(ID id, Ogre::String name = ""); ~GameObject(); ID &getID(); Ogre::String &getName(); virtual void update() = 0; // Component Functions void addComponent(Component *component); void removeComponent(Ogre::String familyName); template<typename T> T* getComponent(Ogre::String familyName) { return dynamic_cast<T*>(m_components[familyName]); } protected: // Properties ID m_ID; Ogre::String m_Name; float m_flVelocity; Ogre::Vector3 m_vecPosition; // Components std::map<std::string,Component*> m_components; std::map<std::string,Component*>::iterator m_componentItr; }; Now the problem I am running into is what would the general population put into Components such as Physics/Graphics? For Ogre (my rendering engine) the visible Objects will consist of multiple Ogre::SceneNode (possibly multiple) to attach it to the scene, Ogre::Entity (possibly multiple) to show the visible meshes, and so on. Would it be best to just add multiple GraphicComponent's to the Object and let each GraphicComponent handle one SceneNode/Entity or is the idea to have one of each Component needed? For Physics I am even more confused. I suppose maybe creating a RigidBody and keeping track of mass/interia/etc. would make sense. But I am having trouble thinking of how to actually putting specifics into a Component. Once I get a couple of these "Required" components done, I think it will make a lot more sense. As of right now though I am still a bit stumped.

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  • A Generic Boolean Value Converter

    - by codingbloke
    On fairly regular intervals a question on Stackoverflow like this one:  Silverlight Bind to inverse of boolean property value appears.  The same answers also regularly appear.  They all involve an implementation of IValueConverter and basically include the same boilerplate code. The required output type sometimes varies, other examples that have passed by are Boolean to Brush and Boolean to String conversions.  Yet the code remains pretty much the same.  There is therefore a good case to create a generic Boolean to value converter to contain this common code and then just specialise it for use in Xaml. Here is the basic converter:- BoolToValueConverter using System; using System.Windows.Data; namespace SilverlightApplication1 {     public class BoolToValueConverter<T> : IValueConverter     {         public T FalseValue { get; set; }         public T TrueValue { get; set; }         public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             if (value == null)                 return FalseValue;             else                 return (bool)value ? TrueValue : FalseValue;         }         public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             return value.Equals(TrueValue);         }     } } With this generic converter in place it easy to create a set of converters for various types.  For example here are all the converters mentioned so far:- Value Converters using System; using System.Windows; using System.Windows.Media; namespace SilverlightApplication1 {     public class BoolToStringConverter : BoolToValueConverter<String> { }     public class BoolToBrushConverter : BoolToValueConverter<Brush> { }     public class BoolToVisibilityConverter : BoolToValueConverter<Visibility> { }     public class BoolToObjectConverter : BoolToValueConverter<Object> { } } With the specialised converters created they can be specified in a Resources property on a user control like this:- <local:BoolToBrushConverter x:Key="Highlighter" FalseValue="Transparent" TrueValue="Yellow" /> <local:BoolToStringConverter x:Key="CYesNo" FalseValue="No" TrueValue="Yes" /> <local:BoolToVisibilityConverter x:Key="InverseVisibility" TrueValue="Collapsed" FalseValue="Visible" />

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  • Action delegate in C#

    - by Jalpesh P. Vadgama
    In last few posts about I have written lots of things about delegates and this post is also part of that series. In this post we are going to learn about Action delegates in C#.  Following is a list of post related to delegates. Delegates in C#. Multicast Delegates in C#. Func Delegates in C#. Action Delegates in c#: As per MSDN action delegates used to pass a method as parameter without explicitly declaring custom delegates. Action Delegates are used to encapsulate method that does not have return value. C# 4.0 Action delegates have following different variants like following. It can take up to 16 parameters. Action – It will be no parameter and does not return any value. Action(T) Action(T1,T2) Action(T1,T2,T3) Action(T1,T2,T3,T4) Action(T1,T2,T3,T4,T5) Action(T1,T2,T3,T4,T5,T6) Action(T1,T2,T3,T4,T5,T6,T7) Action(T1,T2,T3,T4,T5,T6,T7,T8) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15) Action(T1,T2,T3,T4,T5,T6,T7,T8,T9,T10,T11,T12,T13,T14,T15,T16) So for this Action delegate you can have up to 16 parameters for Action.  Sound interesting!!… Enough theory now. It’s time to implement real code. Following is a code for that. using System; using System.Collections.Generic; namespace DelegateExample { class Program { static void Main(string[] args) { Action<String> Print = p => Console.WriteLine(p); Action<String,String> PrintAnother = (p1,p2)=> Console.WriteLine(string.Format("{0} {1}",p1,p2)); Print("Hello"); PrintAnother("Hello","World"); } } } In the above code you can see that I have created two Action delegate Print and PrintAnother. Print have one string parameter and its printing that. While PrintAnother have two string parameter and printing both the strings via Console.Writeline. Now it’s time to run example and following is the output as expected. That’s it. Hope you liked it. Stay tuned for more updates!!

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  • Sorting and Filtering By Model-Based LOV Display Value

    - by Steven Davelaar
    If you use a model-based LOV and you use display type "choice", then ADF nicely displays the display value, even if the table is read-only. In the screen shot below, you see the RegionName attribute displayed instead of the RegionId. This is accomplished by the model-based LOV, I did not modify the Countries view object to include a join with Regions.  Also note the sort icon, the table is sorted by RegionId. This sorting typically results in a bug reported by your test team. Europe really shouldn't come before America when sorting ascending, right? To fix this, we could of course change the Countries view object query and add a join with the Regions table to include the RegionName attribute. If the table is updateable, we still need the choice list, so we need to move the model-based LOV from the RegionId attribute to the RegionName attribute and hide the RegionId attribute in the table. But that is a lot of work for such a simple requirement, in particular if we have lots of model-based choice lists in our view object. Fortunately, there is an easier way to do this, with some generic code in your view object base class that fixes this at once for all model-based choice lists that we have defined in our application. The trick is to override the method getSortCriteria() in the base view object class. By default, this method returns null because the sorting is done in the database through a SQL Order By clause. However, if the getSortCriteria method does return a sort criteria the framework will perform in memory sorting which is what we need to achieve sorting by region name. So, inside this method we need to evaluate the Order By clause, and if the order by column matches an attribute that has a model-based LOV choicelist defined with a display attribute that is different from the value attribute, we need to return a sort criterria. Here is the complete code of this method: public SortCriteria[] getSortCriteria() {   String orderBy = getOrderByClause();          if (orderBy!=null )   {     boolean descending = false;     if (orderBy.endsWith(" DESC"))      {       descending = true;       orderBy = orderBy.substring(0,orderBy.length()-5);     }     // extract column name, is part after the dot     int dotpos = orderBy.lastIndexOf(".");     String columnName = orderBy.substring(dotpos+1);     // loop over attributes and find matching attribute     AttributeDef orderByAttrDef = null;     for (AttributeDef attrDef : getAttributeDefs())     {       if (columnName.equals(attrDef.getColumnName()))       {         orderByAttrDef = attrDef;         break;       }     }     if (orderByAttrDef!=null && "choice".equals(orderByAttrDef.getProperty("CONTROLTYPE"))          && orderByAttrDef.getListBindingDef()!=null)     {       String orderbyAttr = orderByAttrDef.getName();       String[] displayAttrs = orderByAttrDef.getListBindingDef().getListDisplayAttrNames();       String[] listAttrs = orderByAttrDef.getListBindingDef().getListAttrNames();       // if first list display attributes is not the same as first list attribute, than the value       // displayed is different from the value copied back to the order by attribute, in which case we need to       // use our custom comparator       if (displayAttrs!=null && listAttrs!=null && displayAttrs.length>0 && !displayAttrs[0].equals(listAttrs[0]))       {                  SortCriteriaImpl sc1 = new SortCriteriaImpl(orderbyAttr, descending);         SortCriteria[] sc = new SortCriteriaImpl[]{sc1};         return sc;                           }     }     }   return super.getSortCriteria(); } If this method returns a sort criteria, then the framework will call the sort method on the view object. The sort method uses a Comparator object to determine the sequence in which the rows should be returned. This comparator is retrieved by calling the getRowComparator method on the view object. So, to ensure sorting by our display value, we need to override this method to return our custom comparator: public Comparator getRowComparator() {   return new LovDisplayAttributeRowComparator(getSortCriteria()); } The custom comparator class extends the default RowComparator class and overrides the method compareRows and looks up the choice display value to compare the two rows. The complete code of this class is included in the sample application.  With this code in place, clicking on the Region sort icon nicely sorts the countries by RegionName, as you can see below. When using the Query-By-Example table filter at the top of the table, you typically want to use the same choice list to filter the rows. One way to do that is documented in ADF code corner sample 16 - How To Customize the ADF Faces Table Filter.The solution in this sample is perfectly fine to use. This sample requires you to define a separate iterator binding and associated tree binding to populate the choice list in the table filter area using the af:iterator tag. You might be able to reuse the same LOV view object instance in this iterator binding that is used as view accessor for the model-bassed LOV. However, I have seen quite a few customers who have a generic LOV view object (mapped to one "refcodes" table) with the bind variable values set in the LOV view accessor. In such a scenario, some duplicate work is needed to get a dedicated view object instance with the correct bind variables that can be used in the iterator binding. Looking for ways to maximize reuse, wouldn't it be nice if we could just reuse our model-based LOV to populate this filter choice list? Well we can. Here are the basic steps: 1. Create an attribute list binding in the page definition that we can use to retrieve the list of SelectItems needed to populate the choice list <list StaticList="false" Uses="LOV_RegionId"               IterBinding="CountriesView1Iterator" id="RegionId"/>  We need this "current row" list binding because the implicit list binding used by the item in the table is not accessible outside a table row, we cannot use the expression #{row.bindings.RegionId} in the table filter facet. 2. Create a Map-style managed bean with the get method retrieving the list binding as key, and returning the list of SelectItems. To return this list, we take the list of selectItems contained by the list binding and replace the index number that is normally used as key value with the actual attribute value that is set by the choice list. Here is the code of the get method:  public Object get(Object key) {   if (key instanceof FacesCtrlListBinding)   {     // we need to cast to internal class FacesCtrlListBinding rather than JUCtrlListBinding to     // be able to call getItems method. To prevent this import, we could evaluate an EL expression     // to get the list of items     FacesCtrlListBinding lb = (FacesCtrlListBinding) key;     if (cachedFilterLists.containsKey(lb.getName()))     {       return cachedFilterLists.get(lb.getName());     }     List<SelectItem> items = (List<SelectItem>)lb.getItems();     if (items==null || items.size()==0)     {       return items;     }     List<SelectItem> newItems = new ArrayList<SelectItem>();     JUCtrlValueDef def = ((JUCtrlValueDef)lb.getDef());     String valueAttr = def.getFirstAttrName();     // the items list has an index number as value, we need to replace this with the actual     // value of the attribute that is copied back by the choice list     for (int i = 0; i < items.size(); i++)     {       SelectItem si = (SelectItem) items.get(i);       Object value = lb.getValueFromList(i);       if (value instanceof Row)       {         Row row = (Row) value;         si.setValue(row.getAttribute(valueAttr));                 }       else       {         // this is the "empty" row, set value to empty string so all rows will be returned         // as user no longer wants to filter on this attribute         si.setValue("");       }       newItems.add(si);     }     cachedFilterLists.put(lb.getName(), newItems);     return newItems;   }   return null; } Note that we added caching to speed up performance, and to handle the situation where table filters or search criteria are set such that no rows are retrieved in the table. When there are no rows, there is no current row and the getItems method on the list binding will return no items.  An alternative approach to create the list of SelectItems would be to retrieve the iterator binding from the list binding and loop over the rows in the iterator binding rowset. Then we wouldn't need the import of the ADF internal oracle.adfinternal.view.faces.model.binding.FacesCtrlListBinding class, but then we need to figure out the display attributes from the list binding definition, and possible separate them with a dash if multiple display attributes are defined in the LOV. Doable but less reuse and more work. 3. Inside the filter facet for the column create an af:selectOneChoice with the value property of the f:selectItems tag referencing the get method of the managed bean:  <f:facet name="filter">   <af:selectOneChoice id="soc0" autoSubmit="true"                       value="#{vs.filterCriteria.RegionId}">     <!-- attention: the RegionId list binding must be created manually in the page definition! -->                       <f:selectItems id="si0"                    value="#{viewScope.TableFilterChoiceList[bindings.RegionId]}"/>   </af:selectOneChoice> </f:facet> Note that the managed bean is defined in viewScope for the caching to take effect. Here is a screen shot of the tabe filter in action: You can download the sample application here. 

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  • Simulating smooth movement along a line after calculating a collision containing a restitution of zero in 2D

    - by Casey
    [for tl;dr see after listing] //...Code to determine shapes types involved in collision here... //...Rectangle-Line collision detected. if(_rbTest->GetCollisionShape()->Intersects(*_ground->GetCollisionShape())) { //Convert incoming shape to a line. a2de::Line l(*dynamic_cast<a2de::Line*>(_ground->GetCollisionShape())); //Get line's normal. a2de::Vector2D normal_vector(l.GetSlope().GetY(), -l.GetSlope().GetX()); a2de::Vector2D::Normalize(normal_vector); //Accumulate forces involved. a2de::Vector2D intermediate_forces; a2de::Vector2D normal_force = normal_vector * _rbTest->GetMass() * _world->GetGravityHandler()->GetGravityValue(); intermediate_forces += normal_force; //Calculate final velocity: See [1] double Ma = _rbTest->GetMass(); a2de::Vector2D Ua = _rbTest->GetVelocity(); double Mb = _ground->GetMass(); a2de::Vector2D Ub = _ground->GetVelocity(); double mCr = Mb * _ground->GetRestitution(); a2de::Vector2D collision_velocity( ((Ma * Ua) + (Mb * Ub) + ((mCr * Ub) - (mCr * Ua))) / (Ma + Mb)); //Calculate reflection vector: See [2] a2de::Vector2D reflect_velocity( -collision_velocity + 2 * (a2de::Vector2D::DotProduct(collision_velocity, normal_vector)) * normal_vector ); //Affect velocity to account for restitution of colliding bodies. reflect_velocity *= (_ground->GetRestitution() * _rbTest->GetRestitution()); _rbTest->SetVelocity(reflect_velocity); //THE ULTIMATE ISSUE STEMS FROM THE FOLLOWING LINE: //Move object away from collision one pixel to prevent constant collision. _rbTest->SetPosition(_rbTest->GetPosition() + normal_vector); _rbTest->ApplyImpulse(intermediate_forces); } Sources: (1) Wikipedia: Coefficient of Restitution: Speeds after impact (2) Wikipedia: Specular Reflection: Direction of reflection First, I have a system in place to account for friction (that is, a coefficient of friction) but is not used right now (in addition, it is zero, which should not affect the math anyway). I'll deal with that after I get this working. Anyway, when the restitution of either object involved in the collision is zero the object stops as required, but if movement along the same direction (again, irrespective of the friction value that isn't used) as the line is attempted the object moves as if slogging through knee deep snow. If I remove the line of code in question and the object is not push away one pixel the object barely moves at all. All because the object collides, is stopped, is pushed up, collides, is stopped...etc. OR collides, is stopped, collides, is stopped, etc... TL;DR How do I only account for a collision ONCE for restitution purposes (BONUS: but CONTINUALLY for frictional purposes, to be implemented later)

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  • Java - Draw Cards and Eliminate Cards Problem

    - by Jen
    I am having a problem in this question. I want a system inside a game wherein the player draws 2 cards randomly, and the enemy draws 2 cards randomly. Then, what the program does is to print out to the console the cards the player draw and the enemy's. The cards should not conflict and must not be the same. Then lastly, the program prints out the card that was not drawn by both the player and the enemy. Here's how I did it but it was lengthy and full of errors: import java.util.Random; public class Draw { public static Random random = new Random(); public static String cards[] = {"Hall", "Kitchen", "Billiard", "Study", "Pool"}; public static int playercounter; public static int enemycounter; public static String playercardA = null; public static String playercardB = null; public static String enemycardA = null; public static String enemycardB = null; public String lastcard = null; public static void playercardAdraw() { playercounter = random.nextInt(5); playercardA = cards[playercounter]; } public static void playercardBdraw() { playercounter=random.nextInt(5); playercardB= cards[playercounter]; if (playercardB==playercardA || playercardB == enemycardA || playercardB == enemycardB) { return; } } public static void enemycardAdraw () { enemycounter = random.nextInt(5); enemycardA=cards[enemycounter]; if (enemycardA == playercardA || enemycardA == playercardB) { return; } } public static void enemycardBdraw () { enemycounter = random.nextInt(5); enemycardB=cards[enemycounter]; if (enemycardB == playercardA || enemycardB == playercardB || enemycardB == enemycardA) { return; } } public static void main (String args []) { System.out.println("Starting to draw..."); System.out.println("Player's Turn: "); playercardAdraw(); System.out.println("Player's first card: " + playercardA); playercardBdraw(); System.out.println("Player's second card: " + playercardB); System.out.println("Enemy's Turn: "); enemycardAdraw(); System.out.println("Enemy's first card: " + enemycardA); enemycardBdraw(); System.out.println("Enemy's Second card: " + enemycardB); } }

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  • Draw Cards and Eliminate Cards Problem

    - by Jen
    I am having a problem in this question. I want a system inside a game wherein the player draws 2 cards randomly, and the enemy draws 2 cards randomly. Then, what the program does is to print out to the console the cards the player draw and the enemy's. The cards should not conflict and must not be the same. Then lastly, the program prints out the card that was not drawn by both the player and the enemy. Here's how I did it but it was lengthy and full of errors: import java.util.Random; public class Draw { public static Random random = new Random(); public static String cards[] = {"Hall", "Kitchen", "Billiard", "Study", "Pool"}; public static int playercounter; public static int enemycounter; public static String playercardA = null; public static String playercardB = null; public static String enemycardA = null; public static String enemycardB = null; public String lastcard = null; public static void playercardAdraw() { playercounter = random.nextInt(5); playercardA = cards[playercounter]; } public static void playercardBdraw() { playercounter=random.nextInt(5); playercardB= cards[playercounter]; if (playercardB==playercardA || playercardB == enemycardA || playercardB == enemycardB) { return; } } public static void enemycardAdraw () { enemycounter = random.nextInt(5); enemycardA=cards[enemycounter]; if (enemycardA == playercardA || enemycardA == playercardB) { return; } } public static void enemycardBdraw () { enemycounter = random.nextInt(5); enemycardB=cards[enemycounter]; if (enemycardB == playercardA || enemycardB == playercardB || enemycardB == enemycardA) { return; } } public static void main (String args []) { System.out.println("Starting to draw..."); System.out.println("Player's Turn: "); playercardAdraw(); System.out.println("Player's first card: " + playercardA); playercardBdraw(); System.out.println("Player's second card: " + playercardB); System.out.println("Enemy's Turn: "); enemycardAdraw(); System.out.println("Enemy's first card: " + enemycardA); enemycardBdraw(); System.out.println("Enemy's Second card: " + enemycardB); } }

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  • Combobox binding with different types

    - by George Evjen
    Binding to comboboxes in Silverlight has been an adventure the past couple of days. In our framework at ArchitectNow we use LookupGroups and LookupValues. In our database we would have a LookupGroup of NBA Teams for example. The group would be called NBATeams, we get the LookupGroupID and then get the values from the LookupValues table. So we would end up with a list of all 30+ teams. Our lookup values entity has a display text(string), value(string), IsActive and some other fields. With our applications we load all this information into the system when the user is logging in or right after they login. So in cache we have a list of groups and values that we can get at whenever we want to. We get this information in our framework simply by creating an observable collection of type LookupValue. To get a list of these values into our property all we have to do is. var NBATeams = AppContext.Current.LookupSerivce.GetLookupValues(“NBATeams”); Our combobox then is bound like this. (We use telerik components in most if not all our projects) <telerik:RadComboBox ItemsSource="{Binding NBATeams}”></telerik:RadComboBox> This should give you a list in your combobox. We also set up another property in our ViewModel that is a just single object of NBATeams  - “SelectedNBATeam” Our selectedItem in our combobox would look like, we would set this to a two way binding since we are sending data back. SelectedItem={Binding SelectedNBATeam, mode=TwoWay}” This is all pretty straight forward and we use this pattern throughout all our applications. What do you do though when you have a combobox in a ItemsControl or ListBox? Here we have a list of NBA Teams that are a string that are being brought back from the database. We cant have the selected item be our LookupValue because the data is a string and its being bound in an ItemsControl. In the example above we would just have the combobox in a form. Here though we have it in a ItemsControl, where there is no selected item from the initial ItemsSource. In order to get the selected item to be displayed in the combobox you have to convert the LookupValue to a string. Then instead of using SelectedItem in the combobox use SelectedValue. To convert the LookupValue we do this. Create an observable collection of strings public ObservableCollection<string> NBATeams { get; set;} Then convert your lookups to strings var NBATeams = new ObservableCollection<string>(AppContext.Current.LookupService.GetLookupValues(“NBATeams”).Select(x => x.DisplayText)); This will give us a list of strings and our selected value should be bound to the NBATeams property in our ItemsSource in our ItemsControl. SelectedValue={Binding NBATeam, mode=TwoWay}”

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  • Fuji camera "mounts" but folder not in Dolphin After Kubuntu 13.10 upgrade

    - by user207207
    Fuji camera mount reported in attached devices but not visible in Dolphin After Kubuntu 13.10 upgrade Have reinstalled the driver, and a few other suggestions, for other cameras mounts failing on previous Ubuntu upgrades. I have already spent a couple of hours trying to get my photo's off the camera, very annoying. Worked perfectly in 11.04, 11.10, 12.04, 12.10 and 13.04. dmesg | tail; lsusb; lsb_release -a [ 6181.858786] CPUM: APIC 03 at 00000000fee00000 (mapped at ffffc90009400000) - ver 0x80050010, lint0=0x10700 lint1=0x10400 pc=0x00400 thmr=0x10000 [17261.396236] CPUM: APIC 00 at 00000000fee00000 (mapped at ffffc90000c6a000) - ver 0x80050010, lint0=0x10700 lint1=0x00400 pc=0x00400 thmr=0x10000 [17261.396239] CPUM: APIC 03 at 00000000fee00000 (mapped at ffffc90000c72000) - ver 0x80050010, lint0=0x10700 lint1=0x10400 pc=0x00400 thmr=0x10000 [17261.396241] CPUM: APIC 02 at 00000000fee00000 (mapped at ffffc90000c70000) - ver 0x80050010, lint0=0x10700 lint1=0x10400 pc=0x00400 thmr=0x10000 [17261.396255] CPUM: APIC 01 at 00000000fee00000 (mapped at ffffc90000c6e000) - ver 0x80050010, lint0=0x10700 lint1=0x10400 pc=0x00400 thmr=0x10000 [32456.884907] usb 2-5: new high-speed USB device number 2 using ehci-pci [32457.654046] usb 2-5: New USB device found, idVendor=04cb, idProduct=01e8 [32457.654050] usb 2-5: New USB device strings: Mfr=0, Product=2, SerialNumber=3 [32457.654052] usb 2-5: Product: Digital Camera [32457.654053] usb 2-5: SerialNumber: 4C3230302020091117CAA59WP18548 Bus 002 Device 002: ID 04cb:01e8 Fuji Photo Film Co., Ltd Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 003: ID 2013:024f PCTV Systems nanoStick T2 290e Bus 001 Device 002: ID 046d:082d Logitech, Inc. HD Pro Webcam C920 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub No LSB modules are available. Distributor ID: Ubuntu vissibleDescription: Ubuntu 13.10 Release: 13.10 Codename: saucy sudo apt-get install gvfs-bin gvfs-mount gphoto2://[usb:002,002] Error mounting location: Error initializing camera: -108: No such file or directory ...... I have reported a bug in Dolphin, which has been transferred to Solid. Further information : I ran solid-hardware list details udi = '/org/kde/solid/udev/sys/devices/pci0000:00/0000:00:04.1/usb2/2-5' parent = '/org/kde/solid/udev' (string) vendor = '04cb' (string) product = 'Digital Camera' (string) description = 'Camera' (string) Block.major = 189 (0xbd) (int) Block.minor = 137 (0x89) (int) Block.device = '/dev/bus/usb/002/010' (string) Camera.supportedProtocols = {'ptp'} (string list) Camera.supportedDrivers = {'gphoto'} (string list) I still can't get my photo's off, I can see the folders using the Gimp menu. If anyone has got any ideas, I'm willing to try them.

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  • OAuth with RestSharp in Windows Phone

    - by midoBB
    Nearly every major API provider uses OAuth for the user authentication and while it is easy to understand the concept, using it in a Windows Phone app isn’t pretty straightforward. So for this quick tutorial we will be using RestSharp for WP7 and the API from getglue.com (an entertainment site) to authorize the user. So the first step is to get the OAuth request token and then we redirect our browserControl to the authorization URL private void StartLogin() {   var client = new RestClient("https://api.getglue.com/"); client.Authenticator = OAuth1Authenticator.ForRequestToken("ConsumerKey", "ConsumerSecret"); var request = new RestRequest("oauth/request_token"); client.ExecuteAsync(request, response => { _oAuthToken = GetQueryParameter(response.Content, "oauth_token"); _oAuthTokenSecret = GetQueryParameter(response.Content, "oauth_token_secret"); string authorizeUrl = "http://getglue.com/oauth/authorize" + "?oauth_token=" + _oAuthToken + "&style=mobile"; Dispatcher.BeginInvoke(() => { browserControl.Navigate(new Uri(authorizeUrl)); }); }); } private static string GetQueryParameter(string input, string parameterName) { foreach (string item in input.Split('&')) { var parts = item.Split('='); if (parts[0] == parameterName) { return parts[1]; } } return String.Empty; } Then we listen to the browser’s Navigating Event private void Navigating(Microsoft.Phone.Controls.NavigatingEventArgs e) { if (e.Uri.AbsoluteUri.Contains("oauth_callback")) { var arguments = e.Uri.AbsoluteUri.Split('?'); if (arguments.Length < 1) return; GetAccessToken(arguments[1]); } } private void GetAccessToken(string uri) { var requestToken = GetQueryParameter(uri, "oauth_token"); var client = new RestClient("https://api.getglue.com/"); client.Authenticator = OAuth1Authenticator.ForAccessToken(ConsumerKey, ConsumerSecret, _oAuthToken, _oAuthTokenSecret); var request = new RestRequest("oauth/access_token"); client.ExecuteAsync(request, response => { AccessToken = GetQueryParameter(response.Content, "oauth_token"); AccessTokenSecret = GetQueryParameter(response.Content, "oauth_token_secret"); UserId = GetQueryParameter(response.Content, "glue_userId"); }); } Now to test it we can access the user’s friends list var client = new RestClient("http://api.getglue.com/v2"); client.Authenticator = OAuth1Authenticator.ForProtectedResource(ConsumerKey, ConsumerSecret, GAccessToken, AccessTokenSecret); var request = new RestRequest("/user/friends"); request.AddParameter("userId", UserId,ParameterType.GetOrPost); // request.AddParameter("category", "all",ParameterType.GetOrPost); client.ExecuteAsync(request, response => { TreatFreindsList(); }); And that’s it now we can access all OAuth methods using RestSharp.

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  • Artificial Intelligence ... how to make an object roam freely/avoid other objects, and model consciousness? [on hold]

    - by help bonafide pigeons
    Say a simple free roam battle scene in which a player runs around freely and engages in battle with other enemies/objects, as shown below: The dragon/dinosaur (or whatever that thing I drew appears to be) will, by some measure, try and avoid attacks so it is modeled to appear to have a conscious desire to avoid pain. My question is ... since this is very complex, many possible strategies for solving this, algorithms, etc., what is the basic idea behind how this would be accomplished in any sort? Like, we can assume the enemy in the picture is not just going to aimlessly hop around and avoid, but freely be modeled to behave as if it were really exploring/fighting. For the best example I can give, witness the behavior of the enemies in Final Fantasy 12 in this video: http://www.youtube.com/watch?v=mO0TkmhiQ6w How do the pros, or how would anyone attempt solve/implement this? PS: I have tried several times to give an image the "illusion" that is has a conciousness, but aside from emulating a real animal's consciousness in complete, I fall short and get choppy moving images that follow predictable patterns, error-prone movements, and the worst imaginable scenario of a battle engagement.

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

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

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  • Getting a 'base' Domain from a Domain

    - by Rick Strahl
    Here's a simple one: How do you reliably get the base domain from full domain name or URI? Specifically I've run into this scenario in a few recent applications when creating the Forms Auth Cookie in my ASP.NET applications where I explicitly need to force the domain name to the common base domain. So, www.west-wind.com, store.west-wind.com, west-wind.com, dev.west-wind.com all should return west-wind.com. Here's the code where I need to use this type of logic for issuing an AuthTicket explicitly:private void IssueAuthTicket(UserState userState, bool rememberMe) { FormsAuthenticationTicket ticket = new FormsAuthenticationTicket(1, userState.UserId, DateTime.Now, DateTime.Now.AddDays(10), rememberMe, userState.ToString()); string ticketString = FormsAuthentication.Encrypt(ticket); HttpCookie cookie = new HttpCookie(FormsAuthentication.FormsCookieName, ticketString); cookie.HttpOnly = true; if (rememberMe) cookie.Expires = DateTime.Now.AddDays(10); // write out a domain cookie cookie.Domain = Request.Url.GetBaseDomain(); HttpContext.Response.Cookies.Add(cookie); } Now unfortunately there's no Uri.GetBaseDomain() method unfortunately, as I was surprised to find out. So I ended up creating one:public static class NetworkUtils { /// <summary> /// Retrieves a base domain name from a full domain name. /// For example: www.west-wind.com produces west-wind.com /// </summary> /// <param name="domainName">Dns Domain name as a string</param> /// <returns></returns> public static string GetBaseDomain(string domainName) { var tokens = domainName.Split('.'); // only split 3 segments like www.west-wind.com if (tokens == null || tokens.Length != 3) return domainName; var tok = new List<string>(tokens); var remove = tokens.Length - 2; tok.RemoveRange(0, remove); return tok[0] + "." + tok[1]; ; } /// <summary> /// Returns the base domain from a domain name /// Example: http://www.west-wind.com returns west-wind.com /// </summary> /// <param name="uri"></param> /// <returns></returns> public static string GetBaseDomain(this Uri uri) { if (uri.HostNameType == UriHostNameType.Dns) return GetBaseDomain(uri.DnsSafeHost); return uri.Host; } } I've had a need for this so frequently it warranted a couple of helpers. The second Uri helper is an Extension method to the Uri class, which is what's used the in the first code sample. This is the preferred way to call this since the URI class can differentiate between Dns names and IP Addresses. If you use the first string based version there's a little more guessing going on if a URL is an IP Address. There are a couple of small twists in dealing with 'domain names'. When passing a string only there's a possibility to not actually pass domain name, but end up passing an IP address, so the code explicitly checks for three domain segments (can there be more than 3?). IP4 Addresses have 4 and IP6 have none so they'll fall through. Then there are things like localhost or a NetBios machine name which also come back on URL strings, but also shouldn't be handled. Anyway, small thing but maybe somebody else will find this useful.© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  Networking   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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  • Deploying a SharePoint 2007 theme using Features

    - by Kelly Jones
    I recently had a requirement to update the branding on an existing Windows SharePoint Services (WSS version 3.0) site.  I needed to update the theme, along with the master page.  An additional requirement is that my client likes to have all changes bundled up in SharePoint solutions.  This makes it much easier to move code from dev to test to prod and more importantly, makes it easier to undo code migrations if any issues would arise (I agree with this approach). Updating the theme was easy enough.  I created a new theme, along with a two new features.  The first feature, scoped at the farm level, deploys the theme, adding it to the spthemes.xml file (in the 12 hive –> \Template\layouts\1033 folder).  Here’s the method that I call from the feature activated event: private static void AddThemeToSpThemes(string id, string name, string description, string thumbnail, string preview, SPFeatureReceiverProperties properties) { XmlDocument spThemes = new XmlDocument(); //use GetGenericSetupPath to find the 12 hive folder string spThemesPath = SPUtility.GetGenericSetupPath(@"TEMPLATE\LAYOUTS\1033\spThemes.xml"); //load the spthemes file into our xmldocument, since it is just xml spThemes.Load(spThemesPath); XmlNode root = spThemes.DocumentElement; //search the themes file to see if our theme is already added bool found = false; foreach (XmlNode node in root.ChildNodes) { foreach (XmlNode prop in node.ChildNodes) { if (prop.Name.Equals("TemplateID")) { if (prop.InnerText.Equals(id)) { found = true; break; } } } if (found) { break; } } if (!found) //theme not found, so add it { //This is what we need to add: // <Templates> // <TemplateID>ThemeName</TemplateID> // <DisplayName>Theme Display Name</DisplayName> // <Description>My theme description</Description> // <Thumbnail>images/mythemethumb.gif</Thumbnail> // <Preview>images/mythemepreview.gif</Preview> // </Templates> StringBuilder sb = new StringBuilder(); sb.Append("<Templates><TemplateID>"); sb.Append(id); sb.Append("</TemplateID><DisplayName>"); sb.Append(name); sb.Append("</DisplayName><Description>"); sb.Append(description); sb.Append("</Description><Thumbnail>"); sb.Append(thumbnail); sb.Append("</Thumbnail><Preview>"); sb.Append(preview); sb.Append("</Preview></Templates>"); root.CreateNavigator().AppendChild(sb.ToString()); spThemes.Save(spThemesPath); } } Just as important, is the code that removes the theme when the feature is deactivated: private static void RemoveThemeFromSpThemes(string id) { XmlDocument spThemes = new XmlDocument(); string spThemesPath = HostingEnvironment.MapPath("/_layouts/") + @"1033\spThemes.xml"; spThemes.Load(spThemesPath); XmlNode root = spThemes.DocumentElement; foreach (XmlNode node in root.ChildNodes) { foreach (XmlNode prop in node.ChildNodes) { if (prop.Name.Equals("TemplateID")) { if (prop.InnerText.Equals(id)) { root.RemoveChild(node); spThemes.Save(spThemesPath); break; } } } } } So, that takes care of deploying the theme.  In order to apply the theme to the web, my activate feature method looks like this: public override void FeatureDeactivating(SPFeatureReceiverProperties properties) { using (SPWeb curweb = (SPWeb)properties.Feature.Parent) { curweb.ApplyTheme("myThemeName"); curweb.Update(); } } Deactivating is just as simple: public override void FeatureDeactivating(SPFeatureReceiverProperties properties) { using (SPWeb curweb = (SPWeb)properties.Feature.Parent) { curweb.ApplyTheme("none"); curweb.Update(); } } Ok, that’s the code necessary to deploy, apply, un-apply, and retract the theme.  Also, the solution (WSP file) contains the actual theme files. SO, next is the master page, which I’ll cover in my next blog post.

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  • Building applications with WCF - Intro

    - by skjagini
    I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database     BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had  to derive from EF specific base classes. In EF 4 it  is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks.  Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System;   namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } }   In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity;   namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } }   Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information.   using System; using System.Data.Entity.ModelConfiguration;   namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); }   private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id);   //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } }   Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context.   We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository   using System; using System.Data.Entity; using System.Linq; using BankDAL.Model;   namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers;   public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; }   public IQueryable<Customer> Query() { return _customers; }   public void Add(Customer customer) { _customers.Add(customer); } } }   From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods.   Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model;   namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts;   public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; }   public IQueryable<CheckingAccount> Query() { return _checkingAccounts; }   public void Add(CheckingAccount account) { _checkingAccounts.Add(account); }   public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); }   } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details.   using System; using System.ServiceModel; using BankDAL.Model;   namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth);   [OperationContract] Customer GetCustomer(int id);   } }   ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account.   using System.ServiceModel;   namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId);   [OperationContract] void DepositAmount(int customerId,decimal amount);   [OperationContract] void WithdrawAmount(int customerId, decimal amount);   } }   Services   Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services.   .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract;   namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth };   using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; }   public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); }   } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract;   namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault();   if (account != null) return account.Balance;   return null; } }   public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault();   if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); }   account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted");   bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } }   BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .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; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients.   using System;   namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); }   private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); }   private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open();   if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient    The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files.   <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/>   </client> </system.serviceModel> The client uses a façade to connect to the services   using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract;   namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); }   public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); }   public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); }   } }   With that in place, lets get our unit tests going   using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract;   namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); }   private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); }     [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); }   [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id));   // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id));   // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id));   // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); }   [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss");   var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id;   ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId));   try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); }   Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } }   We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account.  Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling.  Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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  • Secret Agent Man

    - by Bil Simser
    Just a quick one this morning as we all get started in the week. Something that comes into play (sometimes in a big way) is the user agent string your browser gives off. So for example using the User-Agent field in the request header, you can determine what browser the user is running and act accordingly.Internet Explorer 9 modified the UA string slightly so just in case you're looking for it here are the user agent strings for IE9 (in various modes):Internet Explorer 9 Mode: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)Internet Explorer 8 Mode: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)Internet Explorer 7 Mode: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)Internet Explorer 9 (Compatibility Mode): Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; MS-RTC LM 8; InfoPath.3; .NET4.0C; .NET4.0E; Zune 4.7)A couple of things to note here:This was from a 64-bit Windows 7 client so that might account for the WOW64 in the agent string (I don't have a 32-bit client to test from)Various applications and platforms add to the UA string just like they do in previous IE releases. So for example you can see I have various .NET versions installed as well as Zune. You can take advantage of this by querying the UA string for compatibilities and present options accordingly to the end user.As applications will continue to add and modify this string you'll want to query the string for parts not the entire string. For example if you want to detect if you're coming from IE running  on a Windows Phone 7 just look for "iemobile" in the user agent stringHappy hacking!

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  • Thoughts on C# Extension Methods

    - by Damon
    I'm not a huge fan of extension methods.  When they first came out, I remember seeing a method on an object that was fairly useful, but when I went to use it another piece of code that method wasn't available.  Turns out it was an extension method and I hadn't included the appropriate assembly and imports statement in my code to use it.  I remember being a bit confused at first about how the heck that could happen (hey, extension methods were new, cut me some slack) and it took a bit of time to track down exactly what it was that I needed to include to get that method back.  I just imagined a new developer trying to figure out why a method was missing and fruitlessly searching on MSDN for a method that didn't exist and it just didn't sit well with me. I am of the opinion that if you have an object, then you shouldn't have to include additional assemblies to get additional instance level methods out of that object.  That opinion applies to namespaces as well - I do not like it when the contents of a namespace are split out into multiple assemblies.  I prefer to have static utility classes instead of extension methods to keep things nicely packaged into a cohesive unit.  It also makes it abundantly clear where utility methods are used in code.  I will concede, however, that it can make code a bit more verbose and lengthy.  There is always a trade-off. Some people harp on extension methods because it breaks the tenants of object oriented development and allows you to add methods to sealed classes.  Whatever.  Extension methods are just utility methods that you can tack onto an object after the fact.  Extension methods do not give you any more access to an object than the developer of that object allows, so I say that those who cry OO foul on extension methods really don't have much of an argument on which to stand.  In fact, I have to concede that my dislike of them is really more about style than anything of great substance. One interesting thing that I found regarding extension methods is that you can call them on null objects. Take a look at this extension method: namespace ExtensionMethods {   public static class StringUtility   {     public static int WordCount(this string str)     {       if(str == null) return 0;       return str.Split(new char[] { ' ', '.', '?' },         StringSplitOptions.RemoveEmptyEntries).Length;     }   }   } Notice that the extension method checks to see if the incoming string parameter is null.  I was worried that the runtime would perform a check on the object instance to make sure it was not null before calling an extension method, but that is apparently not the case.  So, if you call the following code it runs just fine. string s = null; int words = s.WordCount(); I am a big fan of things working, but this seems to go against everything I've come to know about instance level methods.  However, an extension method is really a static method masquerading as an instance-level method, so I suppose it would be far more frustrating if it failed since there is really no reason it shouldn't succeed. Although I'm not a fan of extension methods, I will say that if you ever find yourself at an impasse with a die-hard fan of either the utility class or extension method approach, then there is a common ground.  Extension methods are defined in static classes, and you call them from those static classes as well as directly from the objects they extend.  So if you build your utility classes using extension methods, then you can have it your way and they can have it theirs. 

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  • Subterranean IL: Compiling C# exception handlers

    - by Simon Cooper
    An exception handler in C# combines the IL catch and finally exception handling clauses into a single try statement: try { Console.WriteLine("Try block") // ... } catch (IOException) { Console.WriteLine("IOException catch") // ... } catch (Exception e) { Console.WriteLine("Exception catch") // ... } finally { Console.WriteLine("Finally block") // ... } How does this get compiled into IL? Initial implementation If you remember from my earlier post, finally clauses must be specified with their own .try clause. So, for the initial implementation, we take the try/catch/finally, and simply split it up into two .try clauses (I have to use label syntax for this): StartTry: ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndTry: StartIOECatch: ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndIOECatch: StartECatch: ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End EndECatch: StartFinally: ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally EndFinally: End: // ... .try StartTry to EndTry catch [mscorlib]System.IO.IOException handler StartIOECatch to EndIOECatch catch [mscorlib]System.Exception handler StartECatch to EndECatch .try StartTry to EndTry finally handler StartFinally to EndFinally However, the resulting program isn't verifiable, and doesn't run: [IL]: Error: Shared try has finally or fault handler. Nested try blocks What's with the verification error? Well, it's a condition of IL verification that all exception handling regions (try, catch, filter, finally, fault) of a single .try clause have to be completely contained within any outer exception region, and they can't overlap with any other exception handling clause. In other words, IL exception handling clauses must to be representable in the scoped syntax, and in this example, we're overlapping catch and finally clauses. Not only is this example not verifiable, it isn't semantically correct. The finally handler is specified round the .try. What happens if you were able to run this code, and an exception was thrown? Program execution enters top of try block, and exception is thrown within it CLR searches for an exception handler, finds catch Because control flow is leaving .try, finally block is run The catch block is run leave.s End inside the catch handler branches to End label. We're actually running the finally before the catch! What we do about it What we actually need to do is put the catch clauses inside the finally clause, as this will ensure the finally gets executed at the correct time (this time using scoped syntax): .try { .try { ldstr "Try block" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.IO.IOException { ldstr "IOException catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } catch [mscorlib]System.Exception { ldstr "Exception catch" call void [mscorlib]System.Console::WriteLine(string) // ... leave.s End } } finally { ldstr "Finally block" call void [mscorlib]System.Console::WriteLine(string) // ... endfinally } End: ret Returning from methods There is a further semantic mismatch that the C# compiler has to deal with; in C#, you are allowed to return from within an exception handling block: public int HandleMethod() { try { // ... return 0; } catch (Exception) { // ... return -1; } } However, you can't ret inside an exception handling block in IL. So the C# compiler does a leave.s to a ret outside the exception handling area, loading/storing any return value to a local variable along the way (as leave.s clears the stack): .method public instance int32 HandleMethod() { .locals init ( int32 retVal ) .try { // ... ldc.i4.0 stloc.0 leave.s End } catch [mscorlib]System.Exception { // ... ldc.i4.m1 stloc.0 leave.s End } End: ldloc.0 ret } Conclusion As you can see, the C# compiler has quite a few hoops to jump through to translate C# code into semantically-correct IL, and hides the numerous conditions on IL exception handling blocks from the C# programmer. Next up: catch-all blocks, and how the runtime deals with non-Exception exceptions.

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  • Best depth sorting method for a Top Down 2D game using a 3D physics engine

    - by Alic44
    I've spent many days googling this and still have issues with my game engine I'd like to ask about, which I haven't seen addressed before. I think the problem is that my game is an unusual combination of a completely 2D graphical approach using XNA's SpriteBatch, and a completely 3D engine (the amazing BEPU physics engine) with rotation mostly disabled. In essence, my question is similar to this one (the part about "faux 3D"), but the difference is that in my game, the player as well as every other creature is represented by 3D objects, and they can all jump, pick up other objects, and throw them around. What this means is that sorting by one value, such as a Z position (how far north/south a character is on the screen) won't work, because as soon as a smaller creature jumps on top of a larger creature, or a box, and walks backwards, the moment its z value is less than that other creature, it will appear to be behind the object it is actually standing on. I actually originally solved this problem by splitting every object in the game into physics boxes which MUST have a Y height equal to their Z depth. I then based the depth sorting value on the object's y position (how high it is off the ground) PLUS its z position (how far north or south it is on the screen). The problem with this approach is that it requires all moving objects in the game to be split graphically into chunks which match up with a physical box which has its y dimension equal to its z dimension. Which is stupid. So, I got inspired last night to rewrite with a fresh approach. My new method is a little more complex, but I think a little more sane: every object which needs to be sorted by depth in the game exposes the interface IDepthDrawable and is added to a list owned by the DepthDrawer object. IDepthDrawable contains: public interface IDepthDrawable { Rectangle Bounds { get; } //possibly change this to a class if struct copying of the xna Rectangle type becomes an issue DepthDrawShape DepthShape { get; } void Draw(SpriteBatch spriteBatch); } The Bounds Rectangle of each IDepthDrawable object represents the 2D Axis-Aligned Bounding Box it will take up when drawn to the screen. Anything that doesn't intersect the screen will be culled at this stage and the remaining on-screen IDepthDrawables will be Bounds tested for intersections with each other. This is where I get a little less sure of what I'm doing. Each group of collisions will be added to a list or other collection, and each list will sort itself based on its DepthShape property, which will have access to the object-to-be-drawn's physics information. For starting out, lets assume everything in the game is an axis aligned 3D Box shape. Boxes are pretty easy to sort. Something like: if (depthShape1.Back > depthShape2.Front) //if depthShape1 is in front of depthShape2. //depthShape1 goes on top. else if (depthShape1.Bottom > depthShape2.Top) //if depthShape1 is above depthShape2. //depthShape1 goes on top. //if neither of these are true, depthShape2 must be in front or above. So, by sorting draw order by several different factors from the physics engine, I believe I can get a really correct draw order. My question is, is this a good way of going about this, or is there some tried and true, tested way which is completely different and has somehow completely eluded me on the internets? And, if this does seem like a good way to remake my draw order sorting, what's the right sorting algorithm for reordering the Bounds Rectangle collision lists, and how do you deal with a Bounds Rectangle colliding with two different object which don't collide with eachother. I know these are solved problems, but I've only been programming for a year so any specific input here will be greatly appreciated. Thanks for reading this far, ye who made it -- sorry it was so long!

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  • Opening a new Windows from ASP.NET code behind

    - by TATWORTH
    At http://weblogs.asp.net/infinitiesloop/archive/2007/09/25/response-redirect-into-a-new-window-with-extension-methods.aspx there is an excellent post on how to open a new windows from code behind. The purists may not like it but it helped solve a problem for a client's client. Here is an update for VS2010 users: using System; using System.Web; using System.Web.UI; /// <summary> /// Response Helper for opening popup windo from code behind. /// </summary> public static class ResponseHelper {   /// <summary>   /// Redirect to popup window   /// </summary>   /// <param name="response">The response.</param>   /// <param name="url">URL to open to</param>   /// <param name="target">Target of window _self or _blank</param>   /// <param name="windowFeatures">Features such as window bar</param>   /// <remarks>   ///     <list type="bullet">   ///         <item>   /// From http://weblogs.asp.net/infinitiesloop/archive/2007/09/25/response-redirect-into-a-new-window-with-extension-methods.aspx   /// </item>   /// <item>   /// Note: If you use it outside the context of a Page request, you can't redirect to a new window. The reason is the need to call the ResolveClientUrl method on Page, which I can't do if there is no Page. I could have just built my own version of that method, but it's more involved than you might think to do it right. So if you need to use this from an HttpHandler other than a Page, you are on your own.   /// </item>   ///         <item>   /// Beware of popup blockers.   /// </item>   /// <item>   /// Note: Obviously when you are redirecting to a new window, the current window will still be hanging around. Normally redirects abort the current request -- no further processing occurs. But for these redirects, processing continues, since we still have to serve the response for the current window (which also happens to contain the script to open the new window, so it is important that it completes).   /// </item>   /// <item>   /// Sample call Response.Redirect("popup.aspx", "_blank", "menubar=0,width=100,height=100");   /// </item>   ///     </list>   /// </remarks>   public static void Redirect(this HttpResponse response, string url, string target, string windowFeatures)   {     if ((String.IsNullOrEmpty(target) || target.Equals("_self", StringComparison.OrdinalIgnoreCase)) && String.IsNullOrEmpty(windowFeatures))     {       response.Redirect(url);     }     else     {       Page page = (Page)HttpContext.Current.Handler;       if (page == null)       {         throw new InvalidOperationException("Cannot redirect to new window outside Page context.");       }       url = page.ResolveClientUrl(url);       string script;       if (!String.IsNullOrEmpty(windowFeatures))       {         script = @"window.open(""{0}"", ""{1}"", ""{2}"");";       }       else       {         script = @"window.open(""{0}"", ""{1}"");";       }       script = String.Format(script, url, target, windowFeatures);       ScriptManager.RegisterStartupScript(page, typeof(Page), "Redirect", script, true);     }   } }

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