static routes - Page 107

How to detect invalid route and trigger function in Backbone.Controller

- by tomodian

Is there any method to detect invalid (or undefined) route and trigger 404 page in Backbone.Controller? I've defined routes in my Controller like this, but it didn't work. class MyController extends Backbone.Controller routes: "method_a": "methodA" "method_b": "methodB" "*undefined": "show404Error" # when access to /#method_a methodA: -> console.log "this page exists" # when access to /#method_b methodB: -> console.log "this also exists" # when access to /#some_invalid_hash_fragment_for_malicious_attack show404Error: -> console.log "sorry, this page does not exist"

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

- by Varun Chatterji

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

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C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

- by James Michael Hare

Once again we consider some of the lesser known classes and keywords of C#. In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>. Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>. Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework. And out of this framework emerged the System.Collections namespace, and it was good. It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections. The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever! With generics the C# language finally got an equivalent of the very powerful C++ templates. As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections. The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on. The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well. So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them. The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required. Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11: 12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20: 21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner. Looking at today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes. With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe. This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations. Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5: 6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9: 10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17: 18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock. With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level). So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently! For example, what if you have a Dictionary that has frequent reads but in-frequent updates? Do you want to lock down the entire Dictionary for every access? This would be overkill and would prevent concurrent reads. In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell). This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in. The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null. Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to. Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic. For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty! This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models. I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts. Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration). Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container. If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations. This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2: 3: // adding to stack is much the same as before 4: stack.Push("First"); 5: 6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek(). This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed. Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items. Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6: 7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10: 11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call. That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call. This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2: 3: // adding to stack is much the same as before 4: stack.Push("First"); 5: 6: var results = stack.GetEnumerator(); 7: 8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10: 11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct. You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all. In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class. The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays. Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart. Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count. This results overall in a O(1) complexity which is quite good. It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2: 3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue. There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue(). Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results. Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2: 3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: 6: var iterator = queue.GetEnumerator(); 7: 8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10: 11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious. Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation. This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5: 6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12: 13: results.Enqueue(result); 14: }); 15: 16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here. Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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Dynamic Filtering

- by Ricardo Peres

Continuing my previous posts on dynamic LINQ, now it's time for dynamic filtering. For now, I'll focus on string matching. There are three standard operators for string matching, which both NHibernate, Entity Framework and LINQ to SQL recognize: Equals Contains StartsWith EndsWith So, if we want to apply filtering by one of these operators on a string property, we can use this code: public enum MatchType { StartsWith = 0, EndsWith = 1, Contains = 2, Equals = 3 } public static List Filter(IEnumerable enumerable, String propertyName, String filter, MatchType matchType) { return (Filter(enumerable, typeof(T), propertyName, filter, matchType) as List); } public static IList Filter(IEnumerable enumerable, Type elementType, String propertyName, String filter, MatchType matchType) { MethodInfo asQueryableMethod = typeof(Queryable).GetMethods(BindingFlags.Static | BindingFlags.Public).Where(m = (m.Name == "AsQueryable") && (m.ContainsGenericParameters == false)).Single(); IQueryable query = (enumerable is IQueryable) ? (enumerable as IQueryable) : asQueryableMethod.Invoke(null, new Object [] { enumerable }) as IQueryable; MethodInfo whereMethod = typeof(Queryable).GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = m.Name == "Where").ToArray() [ 0 ].MakeGenericMethod(elementType); MethodInfo matchMethod = typeof(String).GetMethod ( (matchType == MatchType.StartsWith) ? "StartsWith" : (matchType == MatchType.EndsWith) ? "EndsWith" : (matchType == MatchType.Contains) ? "Contains" : "Equals", new Type [] { typeof(String) } ); PropertyInfo displayProperty = elementType.GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance); MemberExpression member = Expression.MakeMemberAccess(Expression.Parameter(elementType, "n"), displayProperty); MethodCallExpression call = Expression.Call(member, matchMethod, Expression.Constant(filter)); LambdaExpression where = Expression.Lambda(call, member.Expression as ParameterExpression); query = whereMethod.Invoke(null, new Object [] { query, where }) as IQueryable; MethodInfo toListMethod = typeof(Enumerable).GetMethod("ToList", BindingFlags.Static | BindingFlags.Public).MakeGenericMethod(elementType); IList list = toListMethod.Invoke(null, new Object [] { query }) as IList; return (list); } var list = new [] { new { A = "aa" }, new { A = "aabb" }, new { A = "ccaa" }, new { A = "ddaadd" } }; var contains = Filter(list, "A", "aa", MatchType.Contains); var endsWith = Filter(list, "A", "aa", MatchType.EndsWith); var startsWith = Filter(list, "A", "aa", MatchType.StartsWith); var equals = Filter(list, "A", "aa", MatchType.Equals); Perhaps I'll write some more posts on this subject in the near future. SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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Helper method to Replace/Remove characters that do not match the Regular Expression

- by Michael Freidgeim

I have a few fields, that use regEx for validation. In case if provided field has unaccepted characters, I don't want to reject the whole field, as most of validators do, but just remove invalid characters. I am expecting to keep only Character Classes for allowed characters and created a helper method to strip unaccepted characters. The allowed pattern should be in Regex format, expect them wrapped in square brackets. function will insert a tilde after opening squere bracket , according to http://stackoverflow.com/questions/4460290/replace-chars-if-not-match. [^ ] at the start of a character class negates it - it matches characters not in the class.I anticipate that it could work not for all RegEx describing valid characters sets,but it works for relatively simple sets, that we are using. /// <summary> /// Replaces not expected characters. /// </summary> /// <param name="text"> The text.</param> /// <param name="allowedPattern"> The allowed pattern in Regex format, expect them wrapped in brackets</param> /// <param name="replacement"> The replacement.</param> /// <returns></returns> /// // http://stackoverflow.com/questions/4460290/replace-chars-if-not-match. //http://stackoverflow.com/questions/6154426/replace-remove-characters-that-do-not-match-the-regular-expression-net //[^ ] at the start of a character class negates it - it matches characters not in the class. //Replace/Remove characters that do not match the Regular Expression static public string ReplaceNotExpectedCharacters( this string text, string allowedPattern,string replacement ) { allowedPattern = allowedPattern.StripBrackets( "[", "]" ); //[^ ] at the start of a character class negates it - it matches characters not in the class. var result = Regex .Replace(text, @"[^" + allowedPattern + "]", replacement); return result; }static public string RemoveNonAlphanumericCharacters( this string text) { var result = text.ReplaceNotExpectedCharacters(NonAlphaNumericCharacters, "" ); return result; } public const string NonAlphaNumericCharacters = "[a-zA-Z0-9]";There are a couple of functions from my StringHelper class http://geekswithblogs.net/mnf/archive/2006/07/13/84942.aspx , that are used here. // /// <summary> /// 'StripBrackets checks that starts from sStart and ends with sEnd (case sensitive). /// 'If yes, than removes sStart and sEnd. /// 'Otherwise returns full string unchanges /// 'See also MidBetween /// </summary> /// <param name="str"></param> /// <param name="sStart"></param> /// <param name="sEnd"></param> /// <returns></returns> public static string StripBrackets( this string str, string sStart, string sEnd) { if (CheckBrackets(str, sStart, sEnd)) { str = str.Substring(sStart.Length, (str.Length - sStart.Length) - sEnd.Length); } return str; } public static bool CheckBrackets( string str, string sStart, string sEnd) { bool flag1 = (str != null ) && (str.StartsWith(sStart) && str.EndsWith(sEnd)); return flag1; } public static string WrapBrackets( string str, string sStartBracket, string sEndBracket) { StringBuilder builder1 = new StringBuilder(sStartBracket); builder1.Append(str); builder1.Append(sEndBracket); return builder1.ToString(); }v

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why client can not receive message from server (java) [migrated]

- by user1745931

I have just started learning java. I modified the client side code for a server/client communication program, by creating two threads for the client side, main thread for receiving user's input, and inputThread for receiving server's response. I am sure that server has sent the response to client, however, no response message is obtain at client. Here is my code. Can anyone help me to figure it out? Thanks package clientnio; import java.net.*; import java.nio.*; import java.io.*; import java.nio.channels.*; import java.util.Scanner; public class ClientNIO { public static int bufferLen = 50; public static SocketChannel client; public static ByteBuffer writeBuffer; public static ByteBuffer readBuffer; public static void main(String[] args) { writeBuffer = ByteBuffer.allocate(bufferLen); readBuffer = ByteBuffer.allocate(bufferLen); try { SocketAddress address = new InetSocketAddress("localhost",5505); System.out.println("Local address: "+ address); client=SocketChannel.open(address); client.configureBlocking(false); //readBuffer.flip(); new inputThread(readBuffer); /* String a="asdasdasdasddffasfas"; writeBuffer.put(a.getBytes()); writeBuffer.clear(); int d=client.write(writeBuffer); writeBuffer.flip(); */ while (true) { InputStream inStream = System.in; Scanner scan = new Scanner(inStream); if (scan.hasNext()==true) { String inputLine = scan.nextLine(); writeBuffer.put(inputLine.getBytes()); //writeBuffer.clear(); System.out.println(writeBuffer.remaining()); client.write(writeBuffer); System.out.println("Sending data: "+new String(writeBuffer.array())); writeBuffer.flip(); Thread.sleep(300); } } } catch(Exception e) { System.out.println(e); } } } class inputThread extends Thread { private ByteBuffer readBuffer; public inputThread(ByteBuffer readBuffer1) { System.out.println("Receiving thread starts."); this.readBuffer = readBuffer1; start(); } @Override public void run() { try { while (true) { readBuffer.flip(); int i=ClientNIO.client.read(readBuffer); if(i>0) { byte[] b=readBuffer.array(); System.out.println("Receiving data: "+new String(b)); //client.close(); //System.out.println("Connection closed."); //break; } Thread.sleep(100); } } catch (Exception e) { System.out.println(e); } } }

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Getting a SecurityToken from a RequestSecurityTokenResponse in WIF

- by Shawn Cicoria

When you’re working with WIF and WSTrustChannelFactory when you call the Issue operation, you can also request that a RequestSecurityTokenResponse as an out parameter. However, what can you do with that object? Well, you could keep it around and use it for subsequent calls with the extension method CreateChannelWithIssuedToken – or can you? public static T CreateChannelWithIssuedToken<T>(this ChannelFactory<T> factory, SecurityToken issuedToken); As you can see from the method signature it takes a SecurityToken – but that’s not present on the RequestSecurityTokenResponse class. However, you can through a little magic get a GenericXmlSecurityToken by means of the following set of extension methods below – just call rstr.GetSecurityTokenFromResponse() – and you’ll get a GenericXmlSecurityToken as a return. public static class TokenHelper { /// <summary> /// Takes a RequestSecurityTokenResponse, pulls out the GenericXmlSecurityToken usable for further WS-Trust calls /// </summary> /// <param name="rstr"></param> /// <returns></returns> public static GenericXmlSecurityToken GetSecurityTokenFromResponse(this RequestSecurityTokenResponse rstr) { var lifeTime = rstr.Lifetime; var appliesTo = rstr.AppliesTo.Uri; var tokenXml = rstr.GetSerializedTokenFromResponse(); var token = GetTokenFromSerializedToken(tokenXml, appliesTo, lifeTime); return token; } /// <summary> /// Provides a token as an XML string. /// </summary> /// <param name="rstr"></param> /// <returns></returns> public static string GetSerializedTokenFromResponse(this RequestSecurityTokenResponse rstr) { var serializedRst = new WSFederationSerializer().GetResponseAsString(rstr, new WSTrustSerializationContext()); return serializedRst; } /// <summary> /// Turns the XML representation of the token back into a GenericXmlSecurityToken. /// </summary> /// <param name="tokenAsXmlString"></param> /// <param name="appliesTo"></param> /// <param name="lifetime"></param> /// <returns></returns> public static GenericXmlSecurityToken GetTokenFromSerializedToken(this string tokenAsXmlString, Uri appliesTo, Lifetime lifetime) { RequestSecurityTokenResponse rstr2 = new WSFederationSerializer().CreateResponse( new SignInResponseMessage(appliesTo, tokenAsXmlString), new WSTrustSerializationContext()); return new GenericXmlSecurityToken( rstr2.RequestedSecurityToken.SecurityTokenXml, new BinarySecretSecurityToken( rstr2.RequestedProofToken.ProtectedKey.GetKeyBytes()), lifetime.Created.HasValue ? lifetime.Created.Value : DateTime.MinValue, lifetime.Expires.HasValue ? lifetime.Expires.Value : DateTime.MaxValue, rstr2.RequestedAttachedReference, rstr2.RequestedUnattachedReference, null); } }

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NSString drawAtPoint Crash on the iPhone (NSString drawAtPoint)

- by Kyle

Hey. I have a very simple text output to buffer system which will crash randomly. It will be fine for DAYS, then sometimes it'll crash a few times in a few minutes. The callstack is almost exactly the same for other guys who use higher level controls: http://discussions.apple.com/thread.jspa?messageID=7949746 http://stackoverflow.com/questions/1978997/iphone-app-crashed-assertion-failed-function-evictglyphentryfromstrike-file It crashes at the line (below as well in drawTextToBuffer()): [nsString drawAtPoint:CGPointMake(0, 0) withFont:clFont]; I have the same call of "evict_glyph_entry_from_cache" with the abort calls immediately following it. Apparently it happens to other people. I can say that my NSString* is perfectly fine at the time of the crash. I can read the text from the debugger just fine. static CGColorSpaceRef curColorSpace; static CGContextRef myContext; static float w, h; static int iFontSize; static NSString* sFontName; static UIFont* clFont; static int iLineHeight; unsigned long* txb; /* 256x256x4 Buffer */ void selectFont(int iSize, NSString* sFont) { iFontSize = iSize; clFont = [UIFont fontWithName:sFont size:iFontSize]; iLineHeight = (int)(ceil([clFont capHeight])); } void initText() { w = 256; h = 256; txb = (unsigned long*)malloc_(w * h * 4); curColorSpace = CGColorSpaceCreateDeviceRGB(); myContext = CGBitmapContextCreate(txb, w, h, 8, w * 4, curColorSpace, kCGImageAlphaPremultipliedLast); selectFont(12, @"Helvetica"); } void drawTextToBuffer(NSString* nsString) { CGContextSaveGState(myContext); CGContextSetRGBFillColor(myContext, 1, 1, 1, 1); UIGraphicsPushContext(myContext); /* This line will crash. It crashes even with constant Strings.. At the time of the crash, the pointer to nsString is perfectly fine. The data looks fine! */ [nsString drawAtPoint:CGPointMake(0, 0) withFont:clFont]; UIGraphicsPopContext(); CGContextRestoreGState(myContext); } It will happen with other non-unicode supporting methods as well such as CGContextShowTextAtPoint(); the callstack is similar with that as well. Is this any kind of known issue with the iPhone? Or, perhaps, can something outside of this cause be causing an exception in this particular call (drawAtPoint)?

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C# - WebBrowser control seems to cache screenshots

- by Justin

Hey, I'm using the WebBrowser control in an ASP.NET MVC 2 app (don't judge, I'm doing it in an admin section only to be used by me), here's the code: public static class Screenshot { private static string _url; private static int _width; private static byte[] _bytes; public static byte[] Get(string url) { // This method gets a screenshot of the webpage // rendered at its full size (height and width) return Get(url, 50); } public static byte[] Get(string url, int width) { //set properties. _url = url; _width = width; //start screen scraper. var webBrowseThread = new Thread(new ThreadStart(TakeScreenshot)); webBrowseThread.SetApartmentState(ApartmentState.STA); webBrowseThread.Start(); //check every second if it got the screenshot yet. //i know, the thread sleep is terrible, but it's the secure section, don't judge... int numChecks = 20; for (int k = 0; k < numChecks; k++) { Thread.Sleep(1000); if (_bytes != null) { return _bytes; } } return null; } private static void TakeScreenshot() { try { //load the webpage into a WebBrowser control. using (WebBrowser wb = new WebBrowser()) { wb.ScrollBarsEnabled = false; wb.ScriptErrorsSuppressed = true; wb.Navigate(_url); while (wb.ReadyState != WebBrowserReadyState.Complete) { Application.DoEvents(); } //set the size of the WebBrowser control. //take Screenshot of the web pages full width. wb.Width = wb.Document.Body.ScrollRectangle.Width; //take Screenshot of the web pages full height. wb.Height = wb.Document.Body.ScrollRectangle.Height; //get a Bitmap representation of the webpage as it's rendered in the WebBrowser control. var bitmap = new Bitmap(wb.Width, wb.Height); wb.DrawToBitmap(bitmap, new Rectangle(0, 0, wb.Width, wb.Height)); //resize. var height = _width * (bitmap.Height / bitmap.Width); var thumbnail = bitmap.GetThumbnailImage(_width, height, null, IntPtr.Zero); //convert to byte array. var ms = new MemoryStream(); thumbnail.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); _bytes = ms.ToArray(); } } catch(Exception exc) {//TODO: why did screenshot fail? string message = exc.Message; } } This works fine for the first screenshot that I take, however if I try to take subsequent screenshots of different URL's, it saves screenshots of the first url for the new url, or sometimes it'll save the screenshot from 3 or 4 url's ago. I'm creating a new instance of WebBrowser for each screenshot and am disposing of it properly with the "using" block, any idea why it's behaving this way? Thanks, Justin

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design of orm tool

- by ifree

Hello , I want to design a orm tool for my daily work, but I'm always worry about the mapping of foreign key. Here's part of my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Data; namespace OrmTool { [AttributeUsage(AttributeTargets.Property)] public class ColumnAttribute:Attribute { public string Name { get; set; } public SqlDbType DataType { get; set; } public bool IsPk { get; set; } } [AttributeUsage(AttributeTargets.Class,AllowMultiple=false,Inherited=false)] public class TableAttribute:Attribute { public string TableName { get; set; } public string Description { get; set; } } [AttributeUsage(AttributeTargets.Property)] public class ReferencesAttribute : ColumnAttribut { public Type Host { get; set; } public string HostPkName{get;set;} } } I want to use Attribute to get the metadata of Entity ,then mapping them,but i think it's really hard to get it done; public class DbUtility { private static readonly string CONNSTR = ConfigurationManager.ConnectionStrings["connstr"].ConnectionString; private static readonly Type TableType = typeof(TableAttribute); private static readonly Type ColumnType = typeof(ColumnAttribute); private static readonly Type ReferenceType = typeof(ReferencesAttribute); private static IList<TEntity> EntityListGenerator<TEntity>(string tableName,PropertyInfo[] props,params SqlParameter[] paras) { return null; } private static IList<TEntity> ResultList() { return null; } private static SqlCommand PrepareCommand(string sql,SqlConnection conn,params SqlParameter[] paras) { SqlCommand cmd = new SqlCommand(); cmd.CommandText = sql; cmd.Connection = conn; if (paras != null) cmd.Parameters.AddRange(paras); conn.Open(); return cmd; } } I don't know how to do the next step, if every Entity has it's own foreign key,how do I get the return result ? If the Entity like this: [Table(Name="ArtBook")] public class ArtBook{ [column(Name="id",IsPk=true,DataType=SqlDbType.Int)] public int Id{get;set;} [References(Name="ISBNId",DataType=SqlDataType.Int,Host=typeof(ISBN),HostPkName="Id")] public ISBN BookISBN{get;set;} public .....more properties. } public class ISBN{ public int Id{get;set;} public bool IsNative{get;set;} } If I read all ArtBooks from database and when I get a ReferencesAttribute how do I set the value of BookISBN?

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Capture Highlighted Text from any window using C#

- by dineshrekula

How to read the highlighted/Selected Text from any window using c#. i tried 2 approaches. Send "^c" whenever user selects some thing. But in this case my clipboard is flooded with lots of unnecessary data. Sometime it copied passwords also. so i switched my approach to 2nd method, send message method. see this sample code [DllImport("user32.dll")] static extern int GetFocus(); [DllImport("user32.dll")] static extern bool AttachThreadInput(uint idAttach, uint idAttachTo, bool fAttach); [DllImport("kernel32.dll")] static extern uint GetCurrentThreadId(); [DllImport("user32.dll")] static extern uint GetWindowThreadProcessId(int hWnd, int ProcessId); [DllImport("user32.dll") ] static extern int GetForegroundWindow(); [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)] static extern int SendMessage(int hWnd, int Msg, int wParam, StringBuilder lParam); // second overload of SendMessage [DllImport("user32.dll")] private static extern int SendMessage(IntPtr hWnd, uint Msg, out int wParam, out int lParam); const int WM_SETTEXT = 12; const int WM_GETTEXT = 13; private string PerformCopy() { try { //Wait 5 seconds to give us a chance to give focus to some edit window, //notepad for example System.Threading.Thread.Sleep(5000); StringBuilder builder = new StringBuilder(500); int foregroundWindowHandle = GetForegroundWindow(); uint remoteThreadId = GetWindowThreadProcessId(foregroundWindowHandle, 0); uint currentThreadId = GetCurrentThreadId(); //AttachTrheadInput is needed so we can get the handle of a focused window in another app AttachThreadInput(remoteThreadId, currentThreadId, true); //Get the handle of a focused window int focused = GetFocus(); //Now detach since we got the focused handle AttachThreadInput(remoteThreadId, currentThreadId, false); //Get the text from the active window into the stringbuilder SendMessage(focused, WM_GETTEXT, builder.Capacity, builder); return builder.ToString(); } catch (System.Exception oException) { throw oException; } } this code working fine in Notepad. But if i try to capture from another applications like Mozilla firefox, or Visual Studio IDE, it's not returning the text. Can anybody please help me, where i am doing wrong? First of all, i have chosen the right approach?

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How to pass ctor args in Activator.CreateInstance?

- by thames

I need a performance enhanced Activator.CreateInstance() and came across this article by Miron Abramson that uses a factory to create the instance in IL and then cache it. (I've included code below from Miron Abramson's site in case it somehow disappears). I'm new to IL Emit code and anything beyond Activator.CreateInstance() for instantiating a class and any help would be much appreciative. My problem is that I need to create an instance of an object that takes a ctor with a parameter. I see there is a way to pass in the Type of the parameter, but is there a way to pass in the value of the ctor parameter as well? If possible, I would like to use a method similar to CreateObjectFactory<T>(params object[] constructorParams) as some objects I want to instantiate may have more than 1 ctor param. // Source: http://mironabramson.com/blog/post/2008/08/Fast-version-of-the-ActivatorCreateInstance-method-using-IL.aspx public static class FastObjectFactory { private static readonly Hashtable creatorCache = Hashtable.Synchronized(new Hashtable()); private readonly static Type coType = typeof(CreateObject); public delegate object CreateObject(); /// /// Create an object that will used as a 'factory' to the specified type T /// public static CreateObject CreateObjectFactory() where T : class { Type t = typeof(T); FastObjectFactory.CreateObject c = creatorCache[t] as FastObjectFactory.CreateObject; if (c == null) { lock (creatorCache.SyncRoot) { c = creatorCache[t] as FastObjectFactory.CreateObject; if (c != null) { return c; } DynamicMethod dynMethod = new DynamicMethod("DM$OBJ_FACTORY_" + t.Name, typeof(object), null, t); ILGenerator ilGen = dynMethod.GetILGenerator(); ilGen.Emit(OpCodes.Newobj, t.GetConstructor(Type.EmptyTypes)); ilGen.Emit(OpCodes.Ret); c = (CreateObject)dynMethod.CreateDelegate(coType); creatorCache.Add(t, c); } } return c; } } Update to Miron's code from commentor on his post 2010-01-11 public static class FastObjectFactory2<T> where T : class, new() { public static Func<T> CreateObject { get; private set; } static FastObjectFactory2() { Type objType = typeof(T); var dynMethod = new DynamicMethod("DM$OBJ_FACTORY_" + objType.Name, objType, null, objType); ILGenerator ilGen = dynMethod.GetILGenerator(); ilGen.Emit(OpCodes.Newobj, objType.GetConstructor(Type.EmptyTypes)); ilGen.Emit(OpCodes.Ret); CreateObject = (Func<T>) dynMethod.CreateDelegate(typeof(Func<T>)); } }

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Steganography Experiment - Trouble hiding message bits in DCT coefficients

- by JohnHankinson

I have an application requiring me to be able to embed loss-less data into an image. As such I've been experimenting with steganography, specifically via modification of DCT coefficients as the method I select, apart from being loss-less must also be relatively resilient against format conversion, scaling/DSP etc. From the research I've done thus far this method seems to be the best candidate. I've seen a number of papers on the subject which all seem to neglect specific details (some neglect to mention modification of 0 coefficients, or modification of AC coefficient etc). After combining the findings and making a few modifications of my own which include: 1) Using a more quantized version of the DCT matrix to ensure we only modify coefficients that would still be present should the image be JPEG'ed further or processed (I'm using this in place of simply following a zig-zag pattern). 2) I'm modifying bit 4 instead of the LSB and then based on what the original bit value was adjusting the lower bits to minimize the difference. 3) I'm only modifying the blue channel as it should be the least visible. This process must modify the actual image and not the DCT values stored in file (like jsteg) as there is no guarantee the file will be a JPEG, it may also be opened and re-saved at a later stage in a different format. For added robustness I've included the message multiple times and use the bits that occur most often, I had considered using a QR code as the message data or simply applying the reed-solomon error correction, but for this simple application and given that the "message" in question is usually going to be between 10-32 bytes I have plenty of room to repeat it which should provide sufficient redundancy to recover the true bits. No matter what I do I don't seem to be able to recover the bits at the decode stage. I've tried including / excluding various checks (even if it degrades image quality for the time being). I've tried using fixed point vs. double arithmetic, moving the bit to encode, I suspect that the message bits are being lost during the IDCT back to image. Any thoughts or suggestions on how to get this working would be hugely appreciated. (PS I am aware that the actual DCT/IDCT could be optimized from it's naive On4 operation using row column algorithm, or an FDCT like AAN, but for now it just needs to work :) ) Reference Papers: http://www.lokminglui.com/dct.pdf http://arxiv.org/ftp/arxiv/papers/1006/1006.1186.pdf Code for the Encode/Decode process in C# below: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Drawing.Imaging; using System.Drawing; namespace ImageKey { public class Encoder { public const int HIDE_BIT_POS = 3; // use bit position 4 (1 << 3). public const int HIDE_COUNT = 16; // Number of times to repeat the message to avoid error. // JPEG Standard Quantization Matrix. // (to get higher quality multiply by (100-quality)/50 .. // for lower than 50 multiply by 50/quality. Then round to integers and clip to ensure only positive integers. public static double[] Q = {16,11,10,16,24,40,51,61, 12,12,14,19,26,58,60,55, 14,13,16,24,40,57,69,56, 14,17,22,29,51,87,80,62, 18,22,37,56,68,109,103,77, 24,35,55,64,81,104,113,92, 49,64,78,87,103,121,120,101, 72,92,95,98,112,100,103,99}; // Maximum qauality quantization matrix (if all 1's doesn't modify coefficients at all). public static double[] Q2 = {1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1, 1,1,1,1,1,1,1,1}; public static Bitmap Encode(Bitmap b, string key) { Bitmap response = new Bitmap(b.Width, b.Height, PixelFormat.Format32bppArgb); uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Start be transferring the unmodified image portions. // As we'll be using slightly less width/height for the encoding process we'll need the edges to be populated. for (int y = 0; y < b.Height; y++) for (int x = 0; x < b.Width; x++) { if( (x >= imgWidth && x < b.Width) || (y>=imgHeight && y < b.Height)) response.SetPixel(x, y, b.GetPixel(x, y)); } // Setup the counters and byte data for the message to encode. StringBuilder sb = new StringBuilder(); for(int i=0;i<HIDE_COUNT;i++) sb.Append(key); byte[] codeBytes = System.Text.Encoding.ASCII.GetBytes(sb.ToString()); int bitofs = 0; // Current bit position we've encoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to encode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] redData = GetRedChannelData(b, x, y); int[] greenData = GetGreenChannelData(b, x, y); int[] blueData = GetBlueChannelData(b, x, y); int[] newRedData; int[] newGreenData; int[] newBlueData; if (bitofs < totalBits) { double[] redDCT = DCT(ref redData); double[] greenDCT = DCT(ref greenData); double[] blueDCT = DCT(ref blueData); int[] redDCTI = Quantize(ref redDCT, ref Q2); int[] greenDCTI = Quantize(ref greenDCT, ref Q2); int[] blueDCTI = Quantize(ref blueDCT, ref Q2); int[] blueDCTC = Quantize(ref blueDCT, ref Q); HideBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); double[] redDCT2 = DeQuantize(ref redDCTI, ref Q2); double[] greenDCT2 = DeQuantize(ref greenDCTI, ref Q2); double[] blueDCT2 = DeQuantize(ref blueDCTI, ref Q2); newRedData = IDCT(ref redDCT2); newGreenData = IDCT(ref greenDCT2); newBlueData = IDCT(ref blueDCT2); } else { newRedData = redData; newGreenData = greenData; newBlueData = blueData; } MapToRGBRange(ref newRedData); MapToRGBRange(ref newGreenData); MapToRGBRange(ref newBlueData); for(int dy=0;dy<8;dy++) { for(int dx=0;dx<8;dx++) { int col = (0xff<<24) + (newRedData[dx+(dy*8)]<<16) + (newGreenData[dx+(dy*8)]<<8) + (newBlueData[dx+(dy*8)]); response.SetPixel(x+dx,y+dy,Color.FromArgb(col)); } } } } if (bitofs < totalBits) throw new Exception("Failed to encode data - insufficient cover image coefficients"); return (response); } public static void HideBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { int tempValue = 0; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ( (u != 0 || v != 0) && CMatrix[v+(u*8)] != 0 && DCTMatrix[v+(u*8)] != 0) { if (bitofs < totalBits) { tempValue = DCTMatrix[v + (u * 8)]; int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); byte value = (byte)((codeBytes[bytePos] & mask) >> bitPos); // 0 or 1. if (value == 0) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a != 0) DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS) - 1; DCTMatrix[v + (u * 8)] &= ~(1 << HIDE_BIT_POS); } else if (value == 1) { int a = DCTMatrix[v + (u * 8)] & (1 << HIDE_BIT_POS); if (a == 0) DCTMatrix[v + (u * 8)] &= ~((1 << HIDE_BIT_POS) - 1); DCTMatrix[v + (u * 8)] |= (1 << HIDE_BIT_POS); } if (DCTMatrix[v + (u * 8)] != 0) bitofs++; else DCTMatrix[v + (u * 8)] = tempValue; } } } } } public static void MapToRGBRange(ref int[] data) { for(int i=0;i<data.Length;i++) { data[i] += 128; if(data[i] < 0) data[i] = 0; else if(data[i] > 255) data[i] = 255; } } public static int[] GetRedChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x,y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 16) & 0xff) - 128; } } return (data); } public static int[] GetGreenChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 8) & 0xff) - 128; } } return (data); } public static int[] GetBlueChannelData(Bitmap b, int sx, int sy) { int[] data = new int[8 * 8]; for (int y = sy; y < (sy + 8); y++) { for (int x = sx; x < (sx + 8); x++) { uint col = (uint)b.GetPixel(x, y).ToArgb(); data[(x - sx) + ((y - sy) * 8)] = (int)((col >> 0) & 0xff) - 128; } } return (data); } public static int[] Quantize(ref double[] DCTMatrix, ref double[] Q) { int[] DCTMatrixOut = new int[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (int)Math.Round(DCTMatrix[v + (u * 8)] / Q[v + (u * 8)]); } } return(DCTMatrixOut); } public static double[] DeQuantize(ref int[] DCTMatrix, ref double[] Q) { double[] DCTMatrixOut = new double[8*8]; for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { DCTMatrixOut[v + (u * 8)] = (double)DCTMatrix[v + (u * 8)] * Q[v + (u * 8)]; } } return(DCTMatrixOut); } public static double[] DCT(ref int[] data) { double[] DCTMatrix = new double[8 * 8]; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double sum = 0.0; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double s = data[x + (y * 8)]; double dctVal = Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += s * dctVal; } } DCTMatrix[u + (v * 8)] = (0.25 * cu * cv * sum); } } return (DCTMatrix); } public static int[] IDCT(ref double[] DCTMatrix) { int[] Matrix = new int[8 * 8]; for (int y = 0; y < 8; y++) { for (int x = 0; x < 8; x++) { double sum = 0; for (int v = 0; v < 8; v++) { for (int u = 0; u < 8; u++) { double cu = 1; if (u == 0) cu = (1.0 / Math.Sqrt(2.0)); double cv = 1; if (v == 0) cv = (1.0 / Math.Sqrt(2.0)); double idctVal = (cu * cv) / 4.0 * Math.Cos((2 * y + 1) * v * Math.PI / 16) * Math.Cos((2 * x + 1) * u * Math.PI / 16); sum += (DCTMatrix[u + (v * 8)] * idctVal); } } Matrix[x + (y * 8)] = (int)Math.Round(sum); } } return (Matrix); } } public class Decoder { public static string Decode(Bitmap b, int expectedLength) { expectedLength *= Encoder.HIDE_COUNT; uint imgWidth = ((uint)b.Width) & ~((uint)7); // Maximum usable X resolution (divisible by 8). uint imgHeight = ((uint)b.Height) & ~((uint)7); // Maximum usable Y resolution (divisible by 8). // Setup the counters and byte data for the message to decode. byte[] codeBytes = new byte[expectedLength]; byte[] outBytes = new byte[expectedLength / Encoder.HIDE_COUNT]; int bitofs = 0; // Current bit position we've decoded too. int totalBits = (codeBytes.Length * 8); // Total number of bits to decode. for (int y = 0; y < imgHeight; y += 8) { for (int x = 0; x < imgWidth; x += 8) { int[] blueData = ImageKey.Encoder.GetBlueChannelData(b, x, y); double[] blueDCT = ImageKey.Encoder.DCT(ref blueData); int[] blueDCTI = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q2); int[] blueDCTC = ImageKey.Encoder.Quantize(ref blueDCT, ref Encoder.Q); if (bitofs < totalBits) GetBits(ref blueDCTI, ref blueDCTC, ref bitofs, ref totalBits, ref codeBytes); } } bitofs = 0; for (int i = 0; i < (expectedLength / Encoder.HIDE_COUNT) * 8; i++) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); List<int> values = new List<int>(); int zeroCount = 0; int oneCount = 0; for (int j = 0; j < Encoder.HIDE_COUNT; j++) { int val = (codeBytes[bytePos + ((expectedLength / Encoder.HIDE_COUNT) * j)] & mask) >> bitPos; values.Add(val); if (val == 0) zeroCount++; else oneCount++; } if (oneCount >= zeroCount) outBytes[bytePos] |= mask; bitofs++; values.Clear(); } return (System.Text.Encoding.ASCII.GetString(outBytes)); } public static void GetBits(ref int[] DCTMatrix, ref int[] CMatrix, ref int bitofs, ref int totalBits, ref byte[] codeBytes) { for (int u = 0; u < 8; u++) { for (int v = 0; v < 8; v++) { if ((u != 0 || v != 0) && CMatrix[v + (u * 8)] != 0 && DCTMatrix[v + (u * 8)] != 0) { if (bitofs < totalBits) { int bytePos = (bitofs) >> 3; int bitPos = (bitofs) % 8; byte mask = (byte)(1 << bitPos); int value = DCTMatrix[v + (u * 8)] & (1 << Encoder.HIDE_BIT_POS); if (value != 0) codeBytes[bytePos] |= mask; bitofs++; } } } } } } } UPDATE: By switching to using a QR Code as the source message and swapping a pair of coefficients in each block instead of bit manipulation I've been able to get the message to survive the transform. However to get the message to come through without corruption I have to adjust both coefficients as well as swap them. For example swapping (3,4) and (4,3) in the DCT matrix and then respectively adding 8 and subtracting 8 as an arbitrary constant seems to work. This survives a re-JPEG'ing of 96 but any form of scaling/cropping destroys the message again. I was hoping that by operating on mid to low frequency values that the message would be preserved even under some light image manipulation.

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What Regex can strip e.g. "note:" and "firstName: " from the left of a string?

- by Edward Tanguay

I need to strip the "label" off the front of strings, e.g. note: this is a note needs to return: note and this is a note I've produced the following code example but am having trouble with the regexes. What code do I need in the two ???????? areas below so that I get the desired results shown in the comments? using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Text.RegularExpressions; namespace TestRegex8822 { class Program { static void Main(string[] args) { List<string> lines = new List<string>(); lines.Add("note: this is a note"); lines.Add("test: just a test"); lines.Add("test:\t\t\tjust a test"); lines.Add("firstName: Jim"); //"firstName" IS a label because it does NOT contain a space lines.Add("She said this to him: follow me."); //this is NOT a label since there is a space before the colon lines.Add("description: this is the first description"); lines.Add("description:this is the second description"); //no space after colon lines.Add("this is a line with no label"); foreach (var line in lines) { Console.WriteLine(StringHelpers.GetLabelFromLine(line)); Console.WriteLine(StringHelpers.StripLabelFromLine(line)); Console.WriteLine("--"); //note //this is a note //-- //test //just a test //-- //test //just a test //-- //firstName //Jim //-- // //She said this to him: follow me. //-- //description //this is the first description //-- //description //this is the first description //-- // //this is a line with no label //-- } Console.ReadLine(); } } public static class StringHelpers { public static string GetLabelFromLine(this string line) { string label = line.GetMatch(@"^?:(\s)"); //??????????????? if (!label.IsNullOrEmpty()) return label; else return ""; } public static string StripLabelFromLine(this string line) { return ...//??????????????? } public static bool IsNullOrEmpty(this string line) { return String.IsNullOrEmpty(line); } } public static class RegexHelpers { public static string GetMatch(this string text, string regex) { Match match = Regex.Match(text, regex); if (match.Success) { string theMatch = match.Groups[0].Value; return theMatch; } else { return null; } } } }

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Why does C# exit when calling the Ada elaboration routine using debug?

- by erict

I have a DLL created in Ada using GPS. I am dynamically loading it and calling it successfully both from Ada and from C++. But when I try to call it from C#, the program exits on the call to Elaboration init. What am I missing? The exact same DLL is perfectly happy getting called from C++ and Ada. Edit: If I start the program without Debugging, it also works with C#. But if I run it with the Debugger, then it exits on the call to ElaborationInit. There are no indications in any of the Windows event logs. If the Ada DLL is Pure, and I skip the elaboration init call, the actual function DLL is called correctly, so it has something to do with the elaboration. using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace CallingDLLfromCS { class Program { [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern IntPtr LoadLibrary(string dllToLoad); [DllImport("kernel32.dll", CharSet = CharSet.Ansi, SetLastError = true)] public static extern IntPtr GetProcAddress(IntPtr hModule, string procedureName); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] public static extern bool FreeLibrary(IntPtr hModule); [UnmanagedFunctionPointer(CallingConvention.StdCall)] delegate int AdaCallable2_dlgt(int val); static AdaCallable2_dlgt fnAdaCallable2 = null; [UnmanagedFunctionPointer(CallingConvention.StdCall)] delegate void ElaborationInit_dlgt(); static ElaborationInit_dlgt ElaborationInit = null; [UnmanagedFunctionPointer(CallingConvention.StdCall)] delegate void AdaFinal_dlgt(); static AdaFinal_dlgt AdaFinal = null; static void Main(string[] args) { int result; bool fail = false; // assume the best IntPtr pDll2 = LoadLibrary("libDllBuiltFromAda.dll"); if (pDll2 != IntPtr.Zero) { // Note the @4 is because 4 bytes are passed. This can be further reduced by the use of a DEF file in the DLL generation. IntPtr pAddressOfFunctionToCall = GetProcAddress(pDll2, "AdaCallable@4"); if (pAddressOfFunctionToCall != IntPtr.Zero) { fnAdaCallable2 = (AdaCallable2_dlgt)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(AdaCallable2_dlgt)); } else fail = true; pAddressOfFunctionToCall = GetProcAddress(pDll2, "DllBuiltFromAdainit"); if (pAddressOfFunctionToCall != IntPtr.Zero) { ElaborationInit = (ElaborationInit_dlgt)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(ElaborationInit_dlgt)); } else fail = true; pAddressOfFunctionToCall = GetProcAddress(pDll2, "DllBuiltFromAdafinal"); if (pAddressOfFunctionToCall != IntPtr.Zero) AdaFinal = (AdaFinal_dlgt)Marshal.GetDelegateForFunctionPointer(pAddressOfFunctionToCall, typeof(AdaFinal_dlgt)); else fail = true; if (!fail) { ElaborationInit.Invoke(); // ^^^^^^^^^^^^^^^^^^^^^^^^^ FAILS HERE result = fnAdaCallable2(50); Console.WriteLine("Return value is " + result.ToString()); AdaFinal(); } FreeLibrary(pDll2); } } } }

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Why is my namespace not recognized in Visual Studio / xaml

- by msfanboy

Hello, these are my 2 classes a Attachable Property SelectedItems: code is from here: http://stackoverflow.com/questions/1297643/sync-selecteditems-in-a-muliselect-listbox-with-a-collection-in-viewmodel The namespace TBM.Helper is for sure proper as it works for other classes too. The namespace reference is also in the xaml file: xmlns:Helper="clr_namespace:TBM.Helper" But <ListBox Helper:SelectedItems.Items="{Binding SelectedItems}" ... does not work because = The property 'SelectedItems.Items' does not exist in XML namespace 'clr_namespace:TBM.Helper'. The attachable property 'Items' was not found in type 'SelectedItems What do I have to change ? using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Windows.Controls; using System.Collections; using System.Windows; namespace TBM.Helper { public static class SelectedItems : DependencyObject { private static readonly DependencyProperty SelectedItemsBehaviorProperty = DependencyProperty.RegisterAttached( "SelectedItemsBehavior", typeof(SelectedItemsBehavior), typeof(ListBox), null); public static readonly DependencyProperty ItemsProperty = DependencyProperty.RegisterAttached( "Items", typeof(IList), typeof(SelectedItems), new PropertyMetadata(null, ItemsPropertyChanged)); public static void SetItems(ListBox listBox, IList list) { listBox.SetValue(ItemsProperty, list); } public static IList GetItems(ListBox listBox) { return listBox.GetValue(ItemsProperty) as IList; } private static void ItemsPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var target = d as ListBox; if (target != null) { GetOrCreateBehavior(target, e.NewValue as IList); } } private static SelectedItemsBehavior GetOrCreateBehavior(ListBox target, IList list) { var behavior = target.GetValue(SelectedItemsBehaviorProperty) as SelectedItemsBehavior; if (behavior == null) { behavior = new SelectedItemsBehavior(target, list); target.SetValue(SelectedItemsBehaviorProperty, behavior); } return behavior; } } } using System.Windows; using System.Windows.Controls; using System.Collections; namespace TBM.Helper { public class SelectedItemsBehavior { private readonly ListBox _listBox; private readonly IList _boundList; public SelectedItemsBehavior(ListBox listBox, IList boundList) { _boundList = boundList; _listBox = listBox; SetSelectedItems(); _listBox.SelectionChanged += OnSelectionChanged; _listBox.DataContextChanged += OnDataContextChanged; } private void SetSelectedItems() { _listBox.SelectedItems.Clear(); foreach (object item in _boundList) { // References in _boundList might not be the same as in _listBox.Items int i = _listBox.Items.IndexOf(item); if (i >= 0) _listBox.SelectedItems.Add(_listBox.Items[i]); } } private void OnDataContextChanged(object sender, DependencyPropertyChangedEventArgs e) { SetSelectedItems(); } private void OnSelectionChanged(object sender, SelectionChangedEventArgs e) { _boundList.Clear(); foreach (var item in _listBox.SelectedItems) _boundList.Add(item); } } }

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java web application best practices

- by Bruce

Hi all I'm trying to figure out the optimum way to develop and release a fairly simple web application, and I'm running into several problems. I'll outline the decisions I've made, because somewhere I've clearly gone off the rails.. Hugely grateful for any help! I have what I think is a fairly simple web application. It contains a couple of jsps that reference a couple of java beans, and the usual static html, js, css and images. Decision 1) I wanted to have a clear and clean release procedure, such that I could develop on my local machine and then release reliably to a production machine. I therefore made the decision to package the application into a war file (including all the static resources), to minimize the separate bits and pieces I would need to release. So far so good? Decision 2) I wanted things on my local machine to be as similar as possible to the production environment. So in my html, for example, I may have a reference to a static file such as http://static.foo.com/file . To keep this code working seamlessly on dev and prod, I decided to put static.foo.com in my /etc/hosts when developing locally, so that all the urls work correctly without changing anything. Decision 3) I decided to use eclipse and maven to give me a best practice environment for administering and building my project. So I have a nice tight set up now, except that: Every time I want to change anything in development, like one line in an html file, I have to rebuild the entire project and then wait for tomcat to load the war before I can see if it's what I wanted. So my questions are: 1) Is there a way to connect up eclipse and tomcat so that I don't have to rebuild the war each time? ie tomcat is looking straight at my actual workspace to serve up the static files? 2)I think I'm maybe making things harder by using /etc/hosts to reflect production urls - is there a better way that doesn't involve manually changing over urls (relative urls are fine of course, but where you have many subdomains, say one for static files and one for dynamic, you have to write out the full path, surely?) 3) Is this really best practice?? How do people set things up so that they balance the requirement for an automated, all-encompassing build process on the one hand, and the speed and flexibility to be able to develop javascript and html and css quickly, as quickly as if one just pointed apache at the directory and developed live? What do people find works? Many thanks!

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How can I connect to MSMQ over a workgroup?

- by cyclotis04

I'm writing a simple console client-server app using MSMQ. I'm attempting to run it over the workgroup we have set up. They run just fine when run on the same computer, but I can't get them to connect over the network. I've tried adding Direct=, OS:, and a bunch of combinations of other prefaces, but I'm running out of ideas, and obviously don't know the right way to do it. My queue's don't have GUIDs, which is also slightly confusing. Whenever I attempt to connect to a remote machine, I get an invalid queue name message. What do I have to do to make this work? Server: class Program { static string _queue = @"\Private$\qim"; static MessageQueue _mq; static readonly object _mqLock = new object(); static void Main(string[] args) { _queue = Dns.GetHostName() + _queue; lock (_mqLock) { if (!MessageQueue.Exists(_queue)) _mq = MessageQueue.Create(_queue); else _mq = new MessageQueue(_queue); } Console.Write("Starting server at {0}:\n\n", _mq.Path); _mq.Formatter = new BinaryMessageFormatter(); _mq.BeginReceive(new TimeSpan(0, 1, 0), new object(), OnReceive); while (Console.ReadKey().Key != ConsoleKey.Escape) { } _mq.Close(); } static void OnReceive(IAsyncResult result) { Message msg; lock (_mqLock) { try { msg = _mq.EndReceive(result); Console.Write(msg.Body); } catch (Exception ex) { Console.Write("\n" + ex.Message + "\n"); } } _mq.BeginReceive(new TimeSpan(0, 1, 0), new object(), OnReceive); } } Client: class Program { static MessageQueue _mq; static void Main(string[] args) { string queue; while (_mq == null) { Console.Write("Enter the queue name:\n"); queue = Console.ReadLine(); //queue += @"\Private$\qim"; try { if (MessageQueue.Exists(queue)) _mq = new MessageQueue(queue); } catch (Exception ex) { Console.Write("\n" + ex.Message + "\n"); _mq = null; } } Console.Write("Connected. Begin typing.\n\n"); _mq.Formatter = new BinaryMessageFormatter(); ConsoleKeyInfo key = new ConsoleKeyInfo(); while (key.Key != ConsoleKey.Escape) { key = Console.ReadKey(); _mq.Send(key.KeyChar.ToString()); } } }

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Endianness conversion and g++ warnings

- by SuperBloup

I've got the following C++ code : template <int isBigEndian, typename val> struct EndiannessConv { inline static val fromLittleEndianToHost( val v ) { union { val outVal __attribute__ ((used)); uint8_t bytes[ sizeof( val ) ] __attribute__ ((used)); } ; outVal = v; std::reverse( &bytes[0], &bytes[ sizeof(val) ] ); return outVal; } inline static void convertArray( val v[], uint32_t size ) { // TODO : find a way to map the array for (uint32_t i = 0; i < size; i++) for (uint32_t i = 0; i < size; i++) v[i] = fromLittleEndianToHost( v[i] ); } }; Which work and has been tested (without the used attributes). When compiling I obtain the following errors from g++ (version 4.4.1) || g++ -Wall -Wextra -O3 -o t t.cc || t.cc: In static member function 'static val EndiannessConv<isBigEndian, val>::fromLittleEndianToHost(val)': t.cc|98| warning: 'used' attribute ignored t.cc|99| warning: 'used' attribute ignored || t.cc: In static member function 'static val EndiannessConv<isBigEndian, val>::fromLittleEndianToHost(val) [with int isBigEndian = 1, val = double]': t.cc|148| instantiated from here t.cc|100| warning: unused variable 'outVal' t.cc|100| warning: unused variable 'bytes' I've tried to use the following code : template <int size, typename valType> struct EndianInverser { /* should not compile */ }; template <typename valType> struct EndianInverser<4, valType> { static inline valType reverseEndianness( const valType &val ) { uint32_t castedVal = *reinterpret_cast<const uint32_t*>( &val ); castedVal = (castedVal & 0x000000FF << (3 * 8)) | (castedVal & 0x0000FF00 << (1 * 8)) | (castedVal & 0x00FF0000 >> (1 * 8)) | (castedVal & 0xFF000000 >> (3 * 8)); return *reinterpret_cast<valType*>( &castedVal ); } }; but it break when enabling optimizations due to the type punning. So, why does my used attribute got ignored? Is there a workaround to convert endianness (I rely on the enum to avoid type punning) in templates?

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Getting huge lags when downloading files via Service

- by Copa

I have a Service which receives URLs to download. The Service than downloads these URLs and save them to a file on the SD Card. When I put more than 2 items in the download queue my device is unusable. It nearly freezes. Huge lags and so on. Any idea? Sourcecode: private static boolean downloading = false; private static ArrayList<DownloadItem> downloads = new ArrayList<DownloadItem>(); /** * called once when the service started */ public static void start() { Thread thread = new Thread(new Runnable() { @Override public void run() { while (true) { if (downloads.size() > 0 && !downloading) { downloading = true; DownloadItem item = downloads.get(0); downloadSingleFile(item.getUrl(), item.getFile()); } } } }); thread.start(); } public static void addDownload(DownloadItem item) { downloads.add(item); } private static void downloadSuccessfullFinished() { if (downloads.size() > 0) downloads.get(0).setDownloaded(true); downloadFinished(); } private static void downloadFinished() { // remove the first entry; it has been downloaded if (downloads.size() > 0) downloads.remove(0); downloading = false; } private static void downloadSingleFile(String url, File output) { final int maxBufferSize = 4096; HttpResponse response = null; try { response = new DefaultHttpClient().execute(new HttpGet(url)); if (response != null && response.getStatusLine().getStatusCode() == 200) { // request is ok InputStream is = response.getEntity().getContent(); BufferedInputStream bis = new BufferedInputStream(is); RandomAccessFile raf = new RandomAccessFile(output, "rw"); ByteArrayBuffer baf = new ByteArrayBuffer(maxBufferSize); long current = 0; long i = 0; // read and write 4096 bytes each time while ((current = bis.read()) != -1) { baf.append((byte) current); if (++i == maxBufferSize) { raf.write(baf.toByteArray()); baf = new ByteArrayBuffer(maxBufferSize); i = 0; } } if (i > 0) // write the last bytes to the file raf.write(baf.toByteArray()); baf.clear(); raf.close(); bis.close(); is.close(); // download finished get start next download downloadSuccessfullFinished(); return; } } catch (Exception e) { // not successfully downloaded downloadFinished(); return; } // not successfully downloaded downloadFinished(); return; }

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How to compare DateTime Objects while looping through a list?

- by Taniq

I'm trying to loop through a list (csv) containing two fields; a name and a date. There are various duplicated names and various dates in the list. I'm trying to deduce for each name in the list, where there are multiple instances of the same name, which corresponding date is the latest. I realise, from looking at another answer, that I need to use the DateTime.Compare method which is fine, but my problem is working out which date is later. Once I know this I need to produce a file with unique names and the latest date relating to it. This is my first question which makes me a newbie. EDIT: Initially I thought it would be 'ok' to set the LatestDate object to a date that wouldn't show up in my file, therefore making any later dates in the file the LatestDate. Here's my coding so far: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; namespace flybe_overwriter { class Program { static DateTime currentDate; static DateTime latestDate = new DateTime(1000,1,1); static HashSet<string> uniqueNames = new HashSet<string>(); static string indexpath = @"e:\flybe test\indexing.csv"; static string[] indexlist = File.ReadAllLines(indexpath); static StreamWriter outputfile = new StreamWriter(@"e:\flybe test\match.csv"); static void Main(string[] args) { foreach (string entry in indexlist) { uniqueNames.Add(entry.Split(',')[0]); } HashSet<string>.Enumerator fenum = new HashSet<string>.Enumerator(); fenum = uniqueNames.GetEnumerator(); while (fenum.MoveNext()) { string currentName = fenum.Current; foreach (string line in indexlist) { currentDate = new DateTime(Convert.ToInt32(line.Split(',')[1].Substring(4, 4)), Convert.ToInt32(line.Split(',')[1].Substring(2, 2)), Convert.ToInt32(line.Split(',')[1].Substring(0, 2))); if (currentName == line.Split(',')[0]) { if(DateTime.Compare(latestDate.Date, currentDate.Date) < 1) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is earlier than " + currentDate.ToShortDateString()); } else if (DateTime.Compare(latestDate.Date, currentDate.Date) > 1) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is later than " + currentDate.ToShortDateString()); } else if (DateTime.Compare(latestDate.Date, currentDate.Date) == 0) { // Console.WriteLine(currentName + " " + latestDate.ToShortDateString() + " is the same as " + currentDate.ToShortDateString()); } } } } } } } Any help appreciated. Thanks.

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Simplex Noise Help

- by Alex Larsen

Im Making A Minecraft Like Gae In XNA C# And I Need To Generate Land With Caves This Is The Code For Simplex I Have /// <summary> /// 1D simplex noise /// </summary> /// <param name="x"></param> /// <returns></returns> public static float Generate(float x) { int i0 = FastFloor(x); int i1 = i0 + 1; float x0 = x - i0; float x1 = x0 - 1.0f; float n0, n1; float t0 = 1.0f - x0 * x0; t0 *= t0; n0 = t0 * t0 * grad(perm[i0 & 0xff], x0); float t1 = 1.0f - x1 * x1; t1 *= t1; n1 = t1 * t1 * grad(perm[i1 & 0xff], x1); // The maximum value of this noise is 8*(3/4)^4 = 2.53125 // A factor of 0.395 scales to fit exactly within [-1,1] return 0.395f * (n0 + n1); } /// <summary> /// 2D simplex noise /// </summary> /// <param name="x"></param> /// <param name="y"></param> /// <returns></returns> public static float Generate(float x, float y) { const float F2 = 0.366025403f; // F2 = 0.5*(sqrt(3.0)-1.0) const float G2 = 0.211324865f; // G2 = (3.0-Math.sqrt(3.0))/6.0 float n0, n1, n2; // Noise contributions from the three corners // Skew the input space to determine which simplex cell we're in float s = (x + y) * F2; // Hairy factor for 2D float xs = x + s; float ys = y + s; int i = FastFloor(xs); int j = FastFloor(ys); float t = (float)(i + j) * G2; float X0 = i - t; // Unskew the cell origin back to (x,y) space float Y0 = j - t; float x0 = x - X0; // The x,y distances from the cell origin float y0 = y - Y0; // For the 2D case, the simplex shape is an equilateral triangle. // Determine which simplex we are in. int i1, j1; // Offsets for second (middle) corner of simplex in (i,j) coords if (x0 > y0) { i1 = 1; j1 = 0; } // lower triangle, XY order: (0,0)->(1,0)->(1,1) else { i1 = 0; j1 = 1; } // upper triangle, YX order: (0,0)->(0,1)->(1,1) // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where // c = (3-sqrt(3))/6 float x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords float y1 = y0 - j1 + G2; float x2 = x0 - 1.0f + 2.0f * G2; // Offsets for last corner in (x,y) unskewed coords float y2 = y0 - 1.0f + 2.0f * G2; // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds int ii = i % 256; int jj = j % 256; // Calculate the contribution from the three corners float t0 = 0.5f - x0 * x0 - y0 * y0; if (t0 < 0.0f) n0 = 0.0f; else { t0 *= t0; n0 = t0 * t0 * grad(perm[ii + perm[jj]], x0, y0); } float t1 = 0.5f - x1 * x1 - y1 * y1; if (t1 < 0.0f) n1 = 0.0f; else { t1 *= t1; n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1]], x1, y1); } float t2 = 0.5f - x2 * x2 - y2 * y2; if (t2 < 0.0f) n2 = 0.0f; else { t2 *= t2; n2 = t2 * t2 * grad(perm[ii + 1 + perm[jj + 1]], x2, y2); } // Add contributions from each corner to get the final noise value. // The result is scaled to return values in the interval [-1,1]. return 40.0f * (n0 + n1 + n2); // TODO: The scale factor is preliminary! } public static float Generate(float x, float y, float z) { // Simple skewing factors for the 3D case const float F3 = 0.333333333f; const float G3 = 0.166666667f; float n0, n1, n2, n3; // Noise contributions from the four corners // Skew the input space to determine which simplex cell we're in float s = (x + y + z) * F3; // Very nice and simple skew factor for 3D float xs = x + s; float ys = y + s; float zs = z + s; int i = FastFloor(xs); int j = FastFloor(ys); int k = FastFloor(zs); float t = (float)(i + j + k) * G3; float X0 = i - t; // Unskew the cell origin back to (x,y,z) space float Y0 = j - t; float Z0 = k - t; float x0 = x - X0; // The x,y,z distances from the cell origin float y0 = y - Y0; float z0 = z - Z0; // For the 3D case, the simplex shape is a slightly irregular tetrahedron. // Determine which simplex we are in. int i1, j1, k1; // Offsets for second corner of simplex in (i,j,k) coords int i2, j2, k2; // Offsets for third corner of simplex in (i,j,k) coords /* This code would benefit from a backport from the GLSL version! */ if (x0 >= y0) { if (y0 >= z0) { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // X Y Z order else if (x0 >= z0) { i1 = 1; j1 = 0; k1 = 0; i2 = 1; j2 = 0; k2 = 1; } // X Z Y order else { i1 = 0; j1 = 0; k1 = 1; i2 = 1; j2 = 0; k2 = 1; } // Z X Y order } else { // x0<y0 if (y0 < z0) { i1 = 0; j1 = 0; k1 = 1; i2 = 0; j2 = 1; k2 = 1; } // Z Y X order else if (x0 < z0) { i1 = 0; j1 = 1; k1 = 0; i2 = 0; j2 = 1; k2 = 1; } // Y Z X order else { i1 = 0; j1 = 1; k1 = 0; i2 = 1; j2 = 1; k2 = 0; } // Y X Z order } // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z), // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where // c = 1/6. float x1 = x0 - i1 + G3; // Offsets for second corner in (x,y,z) coords float y1 = y0 - j1 + G3; float z1 = z0 - k1 + G3; float x2 = x0 - i2 + 2.0f * G3; // Offsets for third corner in (x,y,z) coords float y2 = y0 - j2 + 2.0f * G3; float z2 = z0 - k2 + 2.0f * G3; float x3 = x0 - 1.0f + 3.0f * G3; // Offsets for last corner in (x,y,z) coords float y3 = y0 - 1.0f + 3.0f * G3; float z3 = z0 - 1.0f + 3.0f * G3; // Wrap the integer indices at 256, to avoid indexing perm[] out of bounds int ii = i % 256; int jj = j % 256; int kk = k % 256; // Calculate the contribution from the four corners float t0 = 0.6f - x0 * x0 - y0 * y0 - z0 * z0; if (t0 < 0.0f) n0 = 0.0f; else { t0 *= t0; n0 = t0 * t0 * grad(perm[ii + perm[jj + perm[kk]]], x0, y0, z0); } float t1 = 0.6f - x1 * x1 - y1 * y1 - z1 * z1; if (t1 < 0.0f) n1 = 0.0f; else { t1 *= t1; n1 = t1 * t1 * grad(perm[ii + i1 + perm[jj + j1 + perm[kk + k1]]], x1, y1, z1); } float t2 = 0.6f - x2 * x2 - y2 * y2 - z2 * z2; if (t2 < 0.0f) n2 = 0.0f; else { t2 *= t2; n2 = t2 * t2 * grad(perm[ii + i2 + perm[jj + j2 + perm[kk + k2]]], x2, y2, z2); } float t3 = 0.6f - x3 * x3 - y3 * y3 - z3 * z3; if (t3 < 0.0f) n3 = 0.0f; else { t3 *= t3; n3 = t3 * t3 * grad(perm[ii + 1 + perm[jj + 1 + perm[kk + 1]]], x3, y3, z3); } // Add contributions from each corner to get the final noise value. // The result is scaled to stay just inside [-1,1] return 32.0f * (n0 + n1 + n2 + n3); // TODO: The scale factor is preliminary! } private static byte[] perm = new byte[512] { 151,160,137,91,90,15, 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180, 151,160,137,91,90,15, 131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, 190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, 88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, 77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, 102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, 135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, 5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, 223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, 129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, 251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, 49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, 138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 }; private static int FastFloor(float x) { return (x > 0) ? ((int)x) : (((int)x) - 1); } private static float grad(int hash, float x) { int h = hash & 15; float grad = 1.0f + (h & 7); // Gradient value 1.0, 2.0, ..., 8.0 if ((h & 8) != 0) grad = -grad; // Set a random sign for the gradient return (grad * x); // Multiply the gradient with the distance } private static float grad(int hash, float x, float y) { int h = hash & 7; // Convert low 3 bits of hash code float u = h < 4 ? x : y; // into 8 simple gradient directions, float v = h < 4 ? y : x; // and compute the dot product with (x,y). return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -2.0f * v : 2.0f * v); } private static float grad(int hash, float x, float y, float z) { int h = hash & 15; // Convert low 4 bits of hash code into 12 simple float u = h < 8 ? x : y; // gradient directions, and compute dot product. float v = h < 4 ? y : h == 12 || h == 14 ? x : z; // Fix repeats at h = 12 to 15 return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v); } private static float grad(int hash, float x, float y, float z, float t) { int h = hash & 31; // Convert low 5 bits of hash code into 32 simple float u = h < 24 ? x : y; // gradient directions, and compute dot product. float v = h < 16 ? y : z; float w = h < 8 ? z : t; return ((h & 1) != 0 ? -u : u) + ((h & 2) != 0 ? -v : v) + ((h & 4) != 0 ? -w : w); } This Is My World Generation Code Block[,] BlocksInMap = new Block[1024, 256]; public bool IsWorldGenerated = false; Random r = new Random(); private void RunThread() { for (int BH = 0; BH <= 256; BH++) { for (int BW = 0; BW <= 1024; BW++) { Block b = new Block(); if (BH >= 192) { } BlocksInMap[BW, BH] = b; } } IsWorldGenerated = true; } public void GenWorld() { new Thread(new ThreadStart(RunThread)).Start(); } And This Is A Example Of How I Set Blocks Block b = new Block(); b.BlockType = = Block.BlockTypes.Air; This Is A Example Of How I Set Models foreach (Block b in MyWorld) { switch(b.BlockType) { case Block.BlockTypes.Dirt: b.Model = DirtModel; break; ect. } } How Would I Use These To Generate To World (The Block Array) And If Possible Thread It More? btw It's 1024 Wide And 256 Tall

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How to set up Mod_WSGI for Python on Ubuntu

- by AutomatedTester

Hi, I am trying to setup MOD_WSGI on my Ubuntu box. I have found steps that said I needed to do the following steps I found at http://ubuntuforums.org/showthread.php?t=833766 sudo apt-get install libapache2-mod-wsgi sudo a2enmod mod-wsgi sudo /etc/init.d/apache2 restart sudo gedit /etc/apache2/sites-available/default and update the Directory <Directory /var/www/> Options Indexes FollowSymLinks MultiViews ExecCGI AddHandler cgi-script .cgi AddHandler wsgi-script .wsgi AllowOverride None Order allow,deny allow from all </Directory> sudo /etc/init.d/apache2 restart Created test.wsgi with def application(environ, start_response): status = '200 OK' output = 'Hello World!' response_headers = [('Content-type', 'text/plain'), ('Content-Length', str(len(output)))] start_response(status, response_headers) return [output] Step 2 fails because it says it can't find mod-wsgi even though the apt-get found it. If I carry on with the steps the python app just shows as plain text in a browser. Any ideas what I have done wrong? EDIT: Results for questions asked automatedtester@ubuntu:~$ dpkg -l libapache2-mod-wsgi Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Cfg-files/Unpacked/Failed-cfg/Half-inst/trig-aWait/Trig-pend |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) ||/ Name Version Description +++-======================================-======================================-============================================================================================ ii libapache2-mod-wsgi 2.5-1 Python WSGI adapter module for Apache automatedtester@ubuntu:~$ dpkg -s libapache2-mod-wsgi Package: libapache2-mod-wsgi Status: install ok installed Priority: optional Section: python Installed-Size: 376 Maintainer: Ubuntu MOTU Developers <[email protected]> Architecture: i386 Source: mod-wsgi Version: 2.5-1 Depends: apache2, apache2.2-common, libc6 (>= 2.4), libpython2.6 (>= 2.6), python (>= 2.5), python (<< 2.7) Suggests: apache2-mpm-worker | apache2-mpm-event Conffiles: /etc/apache2/mods-available/wsgi.load 06d2b4d2c95b28720f324bd650b7cbd6 /etc/apache2/mods-available/wsgi.conf 408487581dfe024e8475d2fbf993a15c Description: Python WSGI adapter module for Apache The mod_wsgi adapter is an Apache module that provides a WSGI (Web Server Gateway Interface, a standard interface between web server software and web applications written in Python) compliant interface for hosting Python based web applications within Apache. The adapter provides significantly better performance than using existing WSGI adapters for mod_python or CGI. Original-Maintainer: Debian Python Modules Team <[email protected]> Homepage: http://www.modwsgi.org/ automatedtester@ubuntu:~$ sudo a2enmod libapache2-mod-wsgi ERROR: Module libapache2-mod-wsgi does not exist! automatedtester@ubuntu:~$ sudo a2enmod mod-wsgi ERROR: Module mod-wsgi does not exist! FURTHER EDIT FOR RMYates automatedtester@ubuntu:~$ apache2ctl -t -D DUMP_MODULES apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.1.1 for ServerName Loaded Modules: core_module (static) log_config_module (static) logio_module (static) mpm_worker_module (static) http_module (static) so_module (static) alias_module (shared) auth_basic_module (shared) authn_file_module (shared) authz_default_module (shared) authz_groupfile_module (shared) authz_host_module (shared) authz_user_module (shared) autoindex_module (shared) cgid_module (shared) deflate_module (shared) dir_module (shared) env_module (shared) mime_module (shared) negotiation_module (shared) python_module (shared) setenvif_module (shared) status_module (shared) Syntax OK automatedtester@ubuntu:~$

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Several IPs for my VPS

- by Serafim

I bought vps on santrex.net but can't receive any reply from support. My Problem: I have 5 ip but it pings only 1!!! I can't setup DNS because I need 2 ip minimum . Could you help me to activate other my IPs? root@spnova:~# ifconfig eth0 Link encap:Ethernet HWaddr aa:00:b9:4f:19:01 inet addr:188.72.240.100 Bcast:188.72.240.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:163342 errors:0 dropped:0 overruns:0 frame:0 TX packets:13585 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:32862185 (32.8 MB) TX bytes:15189036 (15.1 MB) eth0:0 Link encap:Ethernet HWaddr aa:00:b9:4f:19:01 inet addr:188.72.240.101 Bcast:188.72.240.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:1 Link encap:Ethernet HWaddr aa:00:b9:4f:19:01 inet addr:188.72.240.102 Bcast:188.72.240.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:2 Link encap:Ethernet HWaddr aa:00:b9:4f:19:01 inet addr:188.72.240.103 Bcast:188.72.240.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 eth0:3 Link encap:Ethernet HWaddr aa:00:b9:4f:19:01 inet addr:188.72.240.104 Bcast:188.72.240.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:11885 errors:0 dropped:0 overruns:0 frame:0 TX packets:11885 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:8124693 (8.1 MB) TX bytes:8124693 (8.1 MB) root@spnova:~# nano /etc/network/interfaces # Auto generated eth0 interfaces auto eth0 lo iface eth0 inet static address 188.72.240.100 netmask 255.255.255.0 up route add -net 188.72.225.0 netmask 255.255.255.0 dev eth0 up route add default gw 188.72.225.1 iface lo inet loopback auto eth0:0 iface eth0:0 inet static address 188.72.240.101 netmask 255.255.255.0 auto eth0:1 iface eth0:1 inet static address 188.72.240.102 netmask 255.255.255.0 auto eth0:2 iface eth0:2 inet static address 188.72.240.103 netmask 255.255.255.0 auto eth0:3 iface eth0:3 inet static address 188.72.240.104 netmask 255.255.255.0

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Sticky connection and HTTPS support for HAProxy

- by Saif

Hi Mates, We have 2 HTTP Load balancer with HAproxy and heartbeat. There are 4 apache nodes in this cluster. It's doing round robin load balancing. The HTTP cluster working fine. We are having problem with our portal because it uses SSO. We need sticky connection support in our HAproxy. Also we need load balancing for HTTPS traffic. Here's our HAproxy conf file. global # to have these messages end up in /var/log/haproxy.log you will # need to: # # 1) configure syslog to accept network log events. This is done # by adding the '-r' option to the SYSLOGD_OPTIONS in # /etc/sysconfig/syslog # # 2) configure local2 events to go to the /var/log/haproxy.log # file. A line like the following can be added to # /etc/sysconfig/syslog # # local2.* /var/log/haproxy.log # log 127.0.0.1 local0 log 127.0.0.1 local1 notice chroot /var/lib/haproxy pidfile /var/run/haproxy.pid maxconn 4000 user haproxy group haproxy daemon # turn on stats unix socket stats socket /var/lib/haproxy/stats #--------------------------------------------------------------------- # common defaults that all the 'listen' and 'backend' sections will # use if not designated in their block #--------------------------------------------------------------------- defaults mode http log global option httplog option dontlognull option http-server-close option forwardfor except 127.0.0.0/8 option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 #--------------------------------------------------------------------- # main frontend which proxys to the backends #--------------------------------------------------------------------- frontend main *:5000 acl url_static path_beg -i /static /images /javascript /stylesheets acl url_static path_end -i .jpg .gif .png .css .js use_backend static if url_static default_backend app #--------------------------------------------------------------------- # static backend for serving up images, stylesheets and such #--------------------------------------------------------------------- backend static balance roundrobin server static 127.0.0.1:4331 check #--------------------------------------------------------------------- # round robin balancing between the various backends #--------------------------------------------------------------------- backend app listen ha-http 10.190.1.28:80 mode http stats enable stats auth admin:xxxxxx balance roundrobin cookie JSESSIONID prefix option httpclose option forwardfor option httpchk HEAD /haproxy.txt HTTP/1.0 server apache1 portal-04:80 cookie A check server apache2 im-01:80 cookie B check server apache3 im-02:80 cookie B check server apache4 im-03:80 cookie B check Please advice. Thanks for your help in advance.

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