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  • restoring with mysqldump, but where is the data?

    - by Ole Media
    Ok, so I'm in need to restore a table and I do: mysqldump --opt database table_name < table_name.sql I hit enter and Done! Well, not really, when I go to see if there is anything on the table it show 0 records. I have look into the table_name.sql and I see two records. What am I doing wrong?

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  • ASP.NET MVC Validation Complete

    - by Ricardo Peres
    OK, so let’s talk about validation. Most people are probably familiar with the out of the box validation attributes that MVC knows about, from the System.ComponentModel.DataAnnotations namespace, such as EnumDataTypeAttribute, RequiredAttribute, StringLengthAttribute, RangeAttribute, RegularExpressionAttribute and CompareAttribute from the System.Web.Mvc namespace. All of these validators inherit from ValidationAttribute and perform server as well as client-side validation. In order to use them, you must include the JavaScript files MicrosoftMvcValidation.js, jquery.validate.js or jquery.validate.unobtrusive.js, depending on whether you want to use Microsoft’s own library or jQuery. No significant difference exists, but jQuery is more extensible. You can also create your own attribute by inheriting from ValidationAttribute, but, if you want to have client-side behavior, you must also implement IClientValidatable (all of the out of the box validation attributes implement it) and supply your own JavaScript validation function that mimics its server-side counterpart. Of course, you must reference the JavaScript file where the declaration function is. Let’s see an example, validating even numbers. First, the validation attribute: 1: [Serializable] 2: [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)] 3: public class IsEvenAttribute : ValidationAttribute, IClientValidatable 4: { 5: protected override ValidationResult IsValid(Object value, ValidationContext validationContext) 6: { 7: Int32 v = Convert.ToInt32(value); 8:  9: if (v % 2 == 0) 10: { 11: return (ValidationResult.Success); 12: } 13: else 14: { 15: return (new ValidationResult("Value is not even")); 16: } 17: } 18:  19: #region IClientValidatable Members 20:  21: public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) 22: { 23: yield return (new ModelClientValidationRule() { ValidationType = "iseven", ErrorMessage = "Value is not even" }); 24: } 25:  26: #endregion 27: } The iseven validation function is declared like this in JavaScript, using jQuery validation: 1: jQuery.validator.addMethod('iseven', function (value, element, params) 2: { 3: return (true); 4: return ((parseInt(value) % 2) == 0); 5: }); 6:  7: jQuery.validator.unobtrusive.adapters.add('iseven', [], function (options) 8: { 9: options.rules['iseven'] = options.params; 10: options.messages['iseven'] = options.message; 11: }); Do keep in mind that this is a simple example, for example, we are not using parameters, which may be required for some more advanced scenarios. As a side note, if you implement a custom validator that also requires a JavaScript function, you’ll probably want them together. One way to achieve this is by including the JavaScript file as an embedded resource on the same assembly where the custom attribute is declared. You do this by having its Build Action set as Embedded Resource inside Visual Studio: Then you have to declare an attribute at assembly level, perhaps in the AssemblyInfo.cs file: 1: [assembly: WebResource("SomeNamespace.IsEven.js", "text/javascript")] In your views, if you want to include a JavaScript file from an embedded resource you can use this code: 1: public static class UrlExtensions 2: { 3: private static readonly MethodInfo getResourceUrlMethod = typeof(AssemblyResourceLoader).GetMethod("GetWebResourceUrlInternal", BindingFlags.NonPublic | BindingFlags.Static); 4:  5: public static IHtmlString Resource<TType>(this UrlHelper url, String resourceName) 6: { 7: return (Resource(url, typeof(TType).Assembly.FullName, resourceName)); 8: } 9:  10: public static IHtmlString Resource(this UrlHelper url, String assemblyName, String resourceName) 11: { 12: String resourceUrl = getResourceUrlMethod.Invoke(null, new Object[] { Assembly.Load(assemblyName), resourceName, false, false, null }).ToString(); 13: return (new HtmlString(resourceUrl)); 14: } 15: } And on the view: 1: <script src="<%: this.Url.Resource("SomeAssembly", "SomeNamespace.IsEven.js") %>" type="text/javascript"></script> Then there’s the CustomValidationAttribute. It allows externalizing your validation logic to another class, so you have to tell which type and method to use. The method can be static as well as instance, if it is instance, the class cannot be abstract and must have a public parameterless constructor. It can be applied to a property as well as a class. It does not, however, support client-side validation. Let’s see an example declaration: 1: [CustomValidation(typeof(ProductValidator), "OnValidateName")] 2: public String Name 3: { 4: get; 5: set; 6: } The validation method needs this signature: 1: public static ValidationResult OnValidateName(String name) 2: { 3: if ((String.IsNullOrWhiteSpace(name) == false) && (name.Length <= 50)) 4: { 5: return (ValidationResult.Success); 6: } 7: else 8: { 9: return (new ValidationResult(String.Format("The name has an invalid value: {0}", name), new String[] { "Name" })); 10: } 11: } Note that it can be either static or instance and it must return a ValidationResult-derived class. ValidationResult.Success is null, so any non-null value is considered a validation error. The single method argument must match the property type to which the attribute is attached to or the class, in case it is applied to a class: 1: [CustomValidation(typeof(ProductValidator), "OnValidateProduct")] 2: public class Product 3: { 4: } The signature must thus be: 1: public static ValidationResult OnValidateProduct(Product product) 2: { 3: } Continuing with attribute-based validation, another possibility is RemoteAttribute. This allows specifying a controller and an action method just for performing the validation of a property or set of properties. This works in a client-side AJAX way and it can be very useful. Let’s see an example, starting with the attribute declaration and proceeding to the action method implementation: 1: [Remote("Validate", "Validation")] 2: public String Username 3: { 4: get; 5: set; 6: } The controller action method must contain an argument that can be bound to the property: 1: public ActionResult Validate(String username) 2: { 3: return (this.Json(true, JsonRequestBehavior.AllowGet)); 4: } If in your result JSON object you include a string instead of the true value, it will consider it as an error, and the validation will fail. This string will be displayed as the error message, if you have included it in your view. You can also use the remote validation approach for validating your entire entity, by including all of its properties as included fields in the attribute and having an action method that receives an entity instead of a single property: 1: [Remote("Validate", "Validation", AdditionalFields = "Price")] 2: public String Name 3: { 4: get; 5: set; 6: } 7:  8: public Decimal Price 9: { 10: get; 11: set; 12: } The action method will then be: 1: public ActionResult Validate(Product product) 2: { 3: return (this.Json("Product is not valid", JsonRequestBehavior.AllowGet)); 4: } Only the property to which the attribute is applied and the additional properties referenced by the AdditionalFields will be populated in the entity instance received by the validation method. The same rule previously stated applies, if you return anything other than true, it will be used as the validation error message for the entity. The remote validation is triggered automatically, but you can also call it explicitly. In the next example, I am causing the full entity validation, see the call to serialize(): 1: function validate() 2: { 3: var form = $('form'); 4: var data = form.serialize(); 5: var url = '<%: this.Url.Action("Validation", "Validate") %>'; 6:  7: var result = $.ajax 8: ( 9: { 10: type: 'POST', 11: url: url, 12: data: data, 13: async: false 14: } 15: ).responseText; 16:  17: if (result) 18: { 19: //error 20: } 21: } Finally, by implementing IValidatableObject, you can implement your validation logic on the object itself, that is, you make it self-validatable. This will only work server-side, that is, the ModelState.IsValid property will be set to false on the controller’s action method if the validation in unsuccessful. Let’s see how to implement it: 1: public class Product : IValidatableObject 2: { 3: public String Name 4: { 5: get; 6: set; 7: } 8:  9: public Decimal Price 10: { 11: get; 12: set; 13: } 14:  15: #region IValidatableObject Members 16: 17: public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) 18: { 19: if ((String.IsNullOrWhiteSpace(this.Name) == true) || (this.Name.Length > 50)) 20: { 21: yield return (new ValidationResult(String.Format("The name has an invalid value: {0}", this.Name), new String[] { "Name" })); 22: } 23: 24: if ((this.Price <= 0) || (this.Price > 100)) 25: { 26: yield return (new ValidationResult(String.Format("The price has an invalid value: {0}", this.Price), new String[] { "Price" })); 27: } 28: } 29: 30: #endregion 31: } The errors returned will be matched against the model properties through the MemberNames property of the ValidationResult class and will be displayed in their proper labels, if present on the view. On the controller action method you can check for model validity by looking at ModelState.IsValid and you can get actual error messages and related properties by examining all of the entries in the ModelState dictionary: 1: Dictionary<String, String> errors = new Dictionary<String, String>(); 2:  3: foreach (KeyValuePair<String, ModelState> keyValue in this.ModelState) 4: { 5: String key = keyValue.Key; 6: ModelState modelState = keyValue.Value; 7:  8: foreach (ModelError error in modelState.Errors) 9: { 10: errors[key] = error.ErrorMessage; 11: } 12: } And these are the ways to perform date validation in ASP.NET MVC. Don’t forget to use them!

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  • MVC Automatic Menu

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

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  • Adding an Admin user to an ASP.NET MVC 4 application using a single drop-in file

    - by Jon Galloway
    I'm working on an ASP.NET MVC 4 tutorial and wanted to set it up so just dropping a file in App_Start would create a user named "Owner" and assign them to the "Administrator" role (more explanation at the end if you're interested). There are reasons why this wouldn't fit into most application scenarios: It's not efficient, as it checks for (and creates, if necessary) the user every time the app starts up The username, password, and role name are hardcoded in the app (although they could be pulled from config) Automatically creating an administrative account in code (without user interaction) could lead to obvious security issues if the user isn't informed However, with some modifications it might be more broadly useful - e.g. creating a test user with limited privileges, ensuring a required account isn't accidentally deleted, or - as in my case - setting up an account for demonstration or tutorial purposes. Challenge #1: Running on startup without requiring the user to install or configure anything I wanted to see if this could be done just by having the user drop a file into the App_Start folder and go. No copying code into Global.asax.cs, no installing addition NuGet packages, etc. That may not be the best approach - perhaps a NuGet package with a dependency on WebActivator would be better - but I wanted to see if this was possible and see if it offered the best experience. Fortunately ASP.NET 4 and later provide a PreApplicationStartMethod attribute which allows you to register a method which will run when the application starts up. You drop this attribute in your application and give it two parameters: a method name and the type that contains it. I created a static class named PreApplicationTasks with a static method named, then dropped this attribute in it: [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] That's it. One small gotcha: the namespace can be a problem with assembly attributes. I decided my class didn't need a namespace. Challenge #2: Only one PreApplicationStartMethod per assembly In .NET 4, the PreApplicationStartMethod is marked as AllMultiple=false, so you can only have one PreApplicationStartMethod per assembly. This was fixed in .NET 4.5, as noted by Jon Skeet, so you can have as many PreApplicationStartMethods as you want (allowing you to keep your users waiting for the application to start indefinitely!). The WebActivator NuGet package solves the multiple instance problem if you're in .NET 4 - it registers as a PreApplicationStartMethod, then calls any methods you've indicated using [assembly: WebActivator.PreApplicationStartMethod(type, method)]. David Ebbo blogged about that here:  Light up your NuGets with startup code and WebActivator. In my scenario (bootstrapping a beginner level tutorial) I decided not to worry about this and stick with PreApplicationStartMethod. Challenge #3: PreApplicationStartMethod kicks in before configuration has been read This is by design, as Phil explains. It allows you to make changes that need to happen very early in the pipeline, well before Application_Start. That's fine in some cases, but it caused me problems when trying to add users, since the Membership Provider configuration hadn't yet been read - I got an exception stating that "Default Membership Provider could not be found." The solution here is to run code that requires configuration in a PostApplicationStart method. But how to do that? Challenge #4: Getting PostApplicationStartMethod without requiring WebActivator The WebActivator NuGet package, among other things, provides a PostApplicationStartMethod attribute. That's generally how I'd recommend running code that needs to happen after Application_Start: [assembly: WebActivator.PostApplicationStartMethod(typeof(TestLibrary.MyStartupCode), "CallMeAfterAppStart")] This works well, but I wanted to see if this would be possible without WebActivator. Hmm. Well, wait a minute - WebActivator works in .NET 4, so clearly it's registering and calling PostApplicationStartup tasks somehow. Off to the source code! Sure enough, there's even a handy comment in ActivationManager.cs which shows where PostApplicationStartup tasks are being registered: public static void Run() { if (!_hasInited) { RunPreStartMethods(); // Register our module to handle any Post Start methods. But outside of ASP.NET, just run them now if (HostingEnvironment.IsHosted) { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(StartMethodCallingModule)); } else { RunPostStartMethods(); } _hasInited = true; } } Excellent. Hey, that DynamicModuleUtility seems familiar... Sure enough, K. Scott Allen mentioned it on his blog last year. This is really slick - a PreApplicationStartMethod can register a new HttpModule in code. Modules are run right after application startup, so that's a perfect time to do any startup stuff that requires configuration to be read. As K. Scott says, it's this easy: using System; using System.Web; using Microsoft.Web.Infrastructure.DynamicModuleHelper; [assembly:PreApplicationStartMethod(typeof(MyAppStart), "Start")] public class CoolModule : IHttpModule { // implementation not important // imagine something cool here } public static class MyAppStart { public static void Start() { DynamicModuleUtility.RegisterModule(typeof(CoolModule)); } } Challenge #5: Cooperating with SimpleMembership The ASP.NET MVC Internet template includes SimpleMembership. SimpleMembership is a big improvement over traditional ASP.NET Membership. For one thing, rather than forcing a database schema, it can work with your database schema. In the MVC 4 Internet template case, it uses Entity Framework Code First to define the user model. SimpleMembership bootstrap includes a call to InitializeDatabaseConnection, and I want to play nice with that. There's a new [InitializeSimpleMembership] attribute on the AccountController, which calls \Filters\InitializeSimpleMembershipAttribute.cs::OnActionExecuting(). That comment in that method that says "Ensure ASP.NET Simple Membership is initialized only once per app start" which sounds like good advice. I figured the best thing would be to call that directly: new Mvc4SampleApplication.Filters.InitializeSimpleMembershipAttribute().OnActionExecuting(null); I'm not 100% happy with this - in fact, it's my least favorite part of this solution. There are two problems - first, directly calling a method on a filter, while legal, seems odd. Worse, though, the Filter lives in the application's namespace, which means that this code no longer works well as a generic drop-in. The simplest workaround would be to duplicate the relevant SimpleMembership initialization code into my startup code, but I'd rather not. I'm interested in your suggestions here. Challenge #6: Module Init methods are called more than once When debugging, I noticed (and remembered) that the Init method may be called more than once per page request - it's run once per instance in the app pool, and an individual page request can cause multiple resource requests to the server. While SimpleMembership does have internal checks to prevent duplicate user or role entries, I'd rather not cause or handle those exceptions. So here's the standard single-use lock in the Module's init method: void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { //Do stuff } initialized = true; } } Putting it all together With all of that out of the way, here's the code I came up with: using Mvc4SampleApplication.Filters; using System.Web; using System.Web.Security; using WebMatrix.WebData; [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] public static class PreApplicationTasks { public static void Initializer() { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility .RegisterModule(typeof(UserInitializationModule)); } } public class UserInitializationModule : IHttpModule { private static bool initialized; private static object lockObject = new object(); private const string _username = "Owner"; private const string _password = "p@ssword123"; private const string _role = "Administrator"; void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { new InitializeSimpleMembershipAttribute().OnActionExecuting(null); if (!WebSecurity.UserExists(_username)) WebSecurity.CreateUserAndAccount(_username, _password); if (!Roles.RoleExists(_role)) Roles.CreateRole(_role); if (!Roles.IsUserInRole(_username, _role)) Roles.AddUserToRole(_username, _role); } initialized = true; } } void IHttpModule.Dispose() { } } The Verdict: Is this a good thing? Maybe. I think you'll agree that the journey was undoubtedly worthwhile, as it took us through some of the finer points of hooking into application startup, integrating with membership, and understanding why the WebActivator NuGet package is so useful Will I use this in the tutorial? I'm leaning towards no - I think a NuGet package with a dependency on WebActivator might work better: It's a little more clear what's going on Installing a NuGet package might be a little less error prone than copying a file A novice user could uninstall the package when complete It's a good introduction to NuGet, which is a good thing for beginners to see This code either requires either duplicating a little code from that filter or modifying the file to use the namespace Honestly I'm undecided at this point, but I'm glad that I can weigh the options. If you're interested: Why are you doing this? I'm updating the MVC Music Store tutorial to ASP.NET MVC 4, taking advantage of a lot of new ASP.NET MVC 4 features and trying to simplify areas that are giving people trouble. One change that addresses both needs us using the new OAuth support for membership as much as possible - it's a great new feature from an application perspective, and we get a fair amount of beginners struggling with setting up membership on a variety of database and development setups, which is a distraction from the focus of the tutorial - learning ASP.NET MVC. Side note: Thanks to some great help from Rick Anderson, we had a draft of the tutorial that was looking pretty good earlier this summer, but there were enough changes in ASP.NET MVC 4 all the way up to RTM that there's still some work to be done. It's high priority and should be out very soon. The one issue I ran into with OAuth is that we still need an Administrative user who can edit the store's inventory. I thought about a number of solutions for that - making the first user to register the admin, or the first user to use the username "Administrator" is assigned to the Administrator role - but they both ended up requiring extra code; also, I worried that people would use that code without understanding it or thinking about whether it was a good fit.

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  • A Simple Approach For Presenting With Code Samples

    - by Jesse Taber
    Originally posted on: http://geekswithblogs.net/GruffCode/archive/2013/07/31/a-simple-approach-for-presenting-with-code-samples.aspxI’ve been getting ready for a presentation and have been struggling a bit with the best way to show and execute code samples. I don’t present often (hardly ever), but when I do I like the presentation to have a lot of succinct and executable code snippets to help illustrate the points that I’m making. Depending on what the presentation is about, I might just want to build an entire sample application that I would run during the presentation. In other cases, however, building a full-blown application might not really be the best way to present the code. The presentation I’m working on now is for an open source utility library for dealing with dates and times. I could have probably cooked up a sample app for accepting date and time input and then contrived ways in which it could put the library through its paces, but I had trouble coming up with one app that would illustrate all of the various features of the library that I wanted to highlight. I finally decided that what I really needed was an approach that met the following criteria: Simple: I didn’t want the user interface or overall architecture of a sample application to serve as a distraction from the demonstration of the syntax of the library that the presentation is about. I want to be able to present small bits of code that are focused on accomplishing a single task. Several of these examples will look similar, and that’s OK. I want each sample to “stand on its own” and not rely much on external classes or methods (other than the library that is being presented, of course). “Debuggable” (not really a word, I know): I want to be able to easily run the sample with the debugger attached in Visual Studio should I want to step through any bits of code and show what certain values might be at run time. As far as I know this rules out something like LinqPad, though using LinqPad to present code samples like this is actually a very interesting idea that I might explore another time. Flexible and Selectable: I’m going to have lots of code samples to show, and I want to be able to just package them all up into a single project or module and have an easy way to just run the sample that I want on-demand. Since I’m presenting on a .NET framework library, one of the simplest ways in which I could execute some code samples would be to just create a Console application and use Console.WriteLine to output the pertinent info at run time. This gives me a “no frills” harness from which to run my code samples, and I just hit ‘F5’ to run it with the debugger. This satisfies numbers 1 and 2 from my list of criteria above, but item 3 is a little harder. By default, just running a console application is going to execute the ‘main’ method, and then terminate the program after all code is executed. If I want to have several different code samples and run them one at a time, it would be cumbersome to keep swapping the code I want in and out of the ‘main’ method of the console application. What I really want is an easy way to keep the console app running throughout the whole presentation and just have it run the samples I want when I want. I could setup a simple Windows Forms or WPF desktop application with buttons for the different samples, but then I’m getting away from my first criteria of keeping things as simple as possible. Infinite Loops To The Rescue I found a way to have a simple console application satisfy all three of my requirements above, and it involves using an infinite loop and some Console.ReadLine calls that will give the user an opportunity to break out and exit the program. (All programs that need to run until they are closed explicitly (or crash!) likely use similar constructs behind the scenes. Create a new Windows Forms project, look in the ‘Program.cs’ that gets generated, and then check out the docs for the Application.Run method that it calls.). Here’s how the main method might look: 1: static void Main(string[] args) 2: { 3: do 4: { 5: Console.Write("Enter command or 'exit' to quit: > "); 6: var command = Console.ReadLine(); 7: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 8: { 9: Console.WriteLine("Quitting."); 10: break; 11: } 12: 13: } while (true); 14: } The idea here is the app prompts me for the command I want to run, or I can type in ‘exit’ to break out of the loop and let the application close. The only trick now is to create a set of commands that map to each of the code samples that I’m going to want to run. Each sample is already encapsulated in a single public method in a separate class, so I could just write a big switch statement or create a hashtable/dictionary that maps command text to an Action that will invoke the proper method, but why re-invent the wheel? CLAP For Your Own Presentation I’ve blogged about the CLAP library before, and it turns out that it’s a great fit for satisfying criteria #3 from my list above. CLAP lets you decorate methods in a class with an attribute and then easily invoke those methods from within a console application. CLAP was designed to take the arguments passed into the console app from the command line and parse them to determine which method to run and what arguments to pass to that method, but there’s no reason you can’t re-purpose it to accept command input from within the infinite loop defined above and invoke the corresponding method. Here’s how you might define a couple of different methods to contain two different code samples that you want to run during your presentation: 1: public static class CodeSamples 2: { 3: [Verb(Aliases="one")] 4: public static void SampleOne() 5: { 6: Console.WriteLine("This is sample 1"); 7: } 8:   9: [Verb(Aliases="two")] 10: public static void SampleTwo() 11: { 12: Console.WriteLine("This is sample 2"); 13: } 14: } A couple of things to note about the sample above: I’m using static methods. You don’t actually need to use static methods with CLAP, but the syntax ends up being a bit simpler and static methods happen to lend themselves well to the “one self-contained method per code sample” approach that I want to use. The methods are decorated with a ‘Verb’ attribute. This tells CLAP that they are eligible targets for commands. The “Aliases” argument lets me give them short and easy-to-remember aliases that can be used to invoke them. By default, CLAP just uses the full method name as the command name, but with aliases you can simply the usage a bit. I’m not using any parameters. CLAP’s main feature is its ability to parse out arguments from a command line invocation of a console application and automatically pass them in as parameters to the target methods. My code samples don’t need parameters ,and honestly having them would complicate giving the presentation, so this is a good thing. You could use this same approach to invoke methods with parameters, but you’d have a couple of things to figure out. When you invoke a .NET application from the command line, Windows will parse the arguments and pass them in as a string array (called ‘args’ in the boilerplate console project Program.cs). The parsing that gets done here is smart enough to deal with things like treating strings in double quotes as one argument, and you’d have to re-create that within your infinite loop if you wanted to use parameters. I plan on either submitting a pull request to CLAP to add this capability or maybe just making a small utility class/extension method to do it and posting that here in the future. So I now have a simple class with static methods to contain my code samples, and an infinite loop in my ‘main’ method that can accept text commands. Wiring this all up together is pretty easy: 1: static void Main(string[] args) 2: { 3: do 4: { 5: try 6: { 7: Console.Write("Enter command or 'exit' to quit: > "); 8: var command = Console.ReadLine(); 9: if ((command ?? string.Empty).Equals("exit", StringComparison.OrdinalIgnoreCase)) 10: { 11: Console.WriteLine("Quitting."); 12: break; 13: } 14:   15: Parser.Run<CodeSamples>(new[] { command }); 16: Console.WriteLine("---------------------------------------------------------"); 17: } 18: catch (Exception ex) 19: { 20: Console.Error.WriteLine("Error: " + ex.Message); 21: } 22:   23: } while (true); 24: } Note that I’m now passing the ‘CodeSamples’ class into the CLAP ‘Parser.Run’ as a type argument. This tells CLAP to inspect that class for methods that might be able to handle the commands passed in. I’m also throwing in a little “----“ style line separator and some basic error handling (because I happen to know that some of the samples are going to throw exceptions for demonstration purposes) and I’m good to go. Now during my presentation I can just have the console application running the whole time with the debugger attached and just type in the alias of the code sample method that I want to run when I want to run it.

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  • JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue

    - by John-Brown.Evans
    JMS Step 2 - Using the QueueSend.java Sample Program to Send a Message to a JMS Queue .c21_2{vertical-align:top;width:487.3pt;border-style:solid;border-color:#000000;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c15_2{vertical-align:top;width:487.3pt;border-style:solid;border-color:#ffffff;border-width:1pt;padding:5pt 5pt 5pt 5pt} .c0_2{padding-left:0pt;direction:ltr;margin-left:36pt} .c20_2{list-style-type:circle;margin:0;padding:0} .c10_2{list-style-type:disc;margin:0;padding:0} .c6_2{background-color:#ffffff} .c17_2{padding-left:0pt;margin-left:72pt} .c3_2{line-height:1.0;direction:ltr} .c1_2{font-size:10pt;font-family:"Courier New"} .c16_2{color:#1155cc;text-decoration:underline} .c13_2{color:inherit;text-decoration:inherit} .c7_2{background-color:#ffff00} .c9_2{border-collapse:collapse} .c2_2{font-family:"Courier New"} .c18_2{font-size:18pt} .c5_2{font-weight:bold} .c19_2{color:#ff0000} .c12_2{background-color:#f3f3f3;border-style:solid;border-color:#000000;border-width:1pt;} .c14_2{font-size:24pt} .c8_2{direction:ltr;background-color:#ffffff} .c11_2{font-style:italic} .c4_2{height:11pt} .title{padding-top:24pt;line-height:1.15;text-align:left;color:#000000;font-size:36pt;font-family:"Arial";font-weight:bold;padding-bottom:6pt}.subtitle{padding-top:18pt;line-height:1.15;text-align:left;color:#666666;font-style:italic;font-size:24pt;font-family:"Georgia";padding-bottom:4pt} li{color:#000000;font-size:10pt;font-family:"Arial"} p{color:#000000;font-size:10pt;margin:0;font-family:"Arial"} h1{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:24pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h2{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:18pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h3{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:14pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h4{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:12pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h5{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:11pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} h6{padding-top:0pt;line-height:1.15;text-align:left;color:#888;font-size:10pt;font-family:"Arial";font-weight:normal;padding-bottom:0pt} This post is the second in a series of JMS articles which demonstrate how to use JMS queues in a SOA context. In the previous post JMS Step 1 - How to Create a Simple JMS Queue in Weblogic Server 11g I showed you how to create a JMS queue and its dependent objects in WebLogic Server. In this article, we will use a sample program to write a message to that queue. Please review the previous post if you have not created those objects yet, as they will be required later in this example. The previous post also includes useful background information and links to the Oracle documentation for addional research. The following post in this series will show how to read the message from the queue again. 1. Source code The following java code will be used to write a message to the JMS queue. It is based on a sample program provided with the WebLogic Server installation. The sample is not installed by default, but needs to be installed manually using the WebLogic Server Custom Installation option, together with many, other useful samples. You can either copy-paste the following code into your editor, or install all the samples. The knowledge base article in My Oracle Support: How To Install WebLogic Server and JMS Samples in WLS 10.3.x (Doc ID 1499719.1) describes how to install the samples. QueueSend.java package examples.jms.queue; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.util.Hashtable; import javax.jms.*; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; /** This example shows how to establish a connection * and send messages to the JMS queue. The classes in this * package operate on the same JMS queue. Run the classes together to * witness messages being sent and received, and to browse the queue * for messages. The class is used to send messages to the queue. * * @author Copyright (c) 1999-2005 by BEA Systems, Inc. All Rights Reserved. */ public class QueueSend { // Defines the JNDI context factory. public final static String JNDI_FACTORY="weblogic.jndi.WLInitialContextFactory"; // Defines the JMS context factory. public final static String JMS_FACTORY="jms/TestConnectionFactory"; // Defines the queue. public final static String QUEUE="jms/TestJMSQueue"; private QueueConnectionFactory qconFactory; private QueueConnection qcon; private QueueSession qsession; private QueueSender qsender; private Queue queue; private TextMessage msg; /** * Creates all the necessary objects for sending * messages to a JMS queue. * * @param ctx JNDI initial context * @param queueName name of queue * @exception NamingException if operation cannot be performed * @exception JMSException if JMS fails to initialize due to internal error */ public void init(Context ctx, String queueName) throws NamingException, JMSException { qconFactory = (QueueConnectionFactory) ctx.lookup(JMS_FACTORY); qcon = qconFactory.createQueueConnection(); qsession = qcon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE); queue = (Queue) ctx.lookup(queueName); qsender = qsession.createSender(queue); msg = qsession.createTextMessage(); qcon.start(); } /** * Sends a message to a JMS queue. * * @param message message to be sent * @exception JMSException if JMS fails to send message due to internal error */ public void send(String message) throws JMSException { msg.setText(message); qsender.send(msg); } /** * Closes JMS objects. * @exception JMSException if JMS fails to close objects due to internal error */ public void close() throws JMSException { qsender.close(); qsession.close(); qcon.close(); } /** main() method. * * @param args WebLogic Server URL * @exception Exception if operation fails */ public static void main(String[] args) throws Exception { if (args.length != 1) { System.out.println("Usage: java examples.jms.queue.QueueSend WebLogicURL"); return; } InitialContext ic = getInitialContext(args[0]); QueueSend qs = new QueueSend(); qs.init(ic, QUEUE); readAndSend(qs); qs.close(); } private static void readAndSend(QueueSend qs) throws IOException, JMSException { BufferedReader msgStream = new BufferedReader(new InputStreamReader(System.in)); String line=null; boolean quitNow = false; do { System.out.print("Enter message (\"quit\" to quit): \n"); line = msgStream.readLine(); if (line != null && line.trim().length() != 0) { qs.send(line); System.out.println("JMS Message Sent: "+line+"\n"); quitNow = line.equalsIgnoreCase("quit"); } } while (! quitNow); } private static InitialContext getInitialContext(String url) throws NamingException { Hashtable env = new Hashtable(); env.put(Context.INITIAL_CONTEXT_FACTORY, JNDI_FACTORY); env.put(Context.PROVIDER_URL, url); return new InitialContext(env); } } 2. How to Use This Class 2.1 From the file system on UNIX/Linux Log in to a machine with a WebLogic installation and create a directory to contain the source and code matching the package name, e.g. $HOME/examples/jms/queue. Copy the above QueueSend.java file to this directory. Set the CLASSPATH and environment to match the WebLogic server environment. Go to $MIDDLEWARE_HOME/user_projects/domains/base_domain/bin  and execute . ./setDomainEnv.sh Collect the following information required to run the script: The JNDI name of a JMS queue to use In the Weblogic server console > Services > Messaging > JMS Modules > (Module name, e.g. TestJMSModule) > (JMS queue name, e.g. TestJMSQueue)Select the queue and note its JNDI name, e.g. jms/TestJMSQueue The JNDI name of a connection factory to connect to the queue Follow the same path as above to get the connection factory for the above queue, e.g. TestConnectionFactory and its JNDI namee.g. jms/TestConnectionFactory The URL and port of the WebLogic server running the above queue Check the JMS server for the above queue and the managed server it is targeted to, for example soa_server1. Now find the port this managed server is listening on, by looking at its entry under Environment > Servers in the WLS console, e.g. 8001 The URL for the server to be given to the QueueSend program in this example will therefore be t3://host.domain:8001 e.g. t3://jbevans-lx.de.oracle.com:8001 Edit QueueSend.java and enter the above queue name and connection factory respectively under ...public final static String  JMS_FACTORY=" jms/TestConnectionFactory "; ... public final static String QUEUE=" jms/TestJMSQueue "; ... Compile QueueSend.java using javac QueueSend.java Go to the source’s top-level directory and execute it using java examples.jms.queue.QueueSend t3://jbevans-lx.de.oracle.com:8001 This will prompt for a text input or “quit” to end. In the WLS console, go to the queue and select Monitoring to confirm that a new message was written to the queue. 2.2 From JDeveloper Create a new application in JDeveloper, called, for example JMSTests. When prompted for a project name, enter QueueSend and select Java as the technology Default Package = examples.jms.queue (but you can enter anything here as you will overwrite it in the code later). Leave the other values at their defaults. Press Finish Create a new Java class called QueueSend and use the default values This will create a file called QueueSend.java. Open QueueSend.java, if it is not already open and replace all its contents with the QueueSend java code listed above Some lines might have warnings due to unfound objects. These are due to missing libraries in the JDeveloper project. Add the following libraries to the JDeveloper project: right-click the QueueSend  project in the navigation menu and select Libraries and Classpath , then Add JAR/Directory  Go to the folder containing the JDeveloper installation and find/choose the file javax.jms_1.1.1.jar , e.g. at D:\oracle\jdev11116\modules\javax.jms_1.1.1.jar Do the same for the weblogic.jar file located, for example in D:\oracle\jdev11116\wlserver_10.3\server\lib\weblogic.jar Now you should be able to compile the project, for example by selecting the Make or Rebuild icons   If you try to execute the project, you will get a usage message, as it requires a parameter pointing to the WLS installation containing the JMS queue, for example t3://jbevans-lx.de.oracle.com:8001 . You can automatically pass this parameter to the program from JDeveloper by editing the project’s Run/Debug/Profile. Select the project properties, select Run/Debug/Profile and edit the Default run configuration and add the connection parameter to the Program Arguments field If you execute it again, you will see that it has passed the parameter to the start command If you get a ClassNotFoundException for the class weblogic.jndi.WLInitialContextFactory , then check that the weblogic.jar file was correctly added to the project in one of the earlier steps above. Set the values of JMS_FACTORY and QUEUE the same way as described above in the description of how to use this from a Linux file system, i.e. ...public final static String  JMS_FACTORY=" jms/TestConnectionFactory "; ... public final static String QUEUE=" jms/TestJMSQueue "; ... You need to make one more change to the project. If you execute it now, it will prompt for the payload for the JMS message, but you won’t be able to enter it by default in JDeveloper. You need to enable program input for the project first. Select the project’s properties, then Tool Settings, then check the Allow Program Input checkbox at the bottom and Save. Now when you execute the project, you will get a text entry field at the bottom into which you can enter the payload. You can enter multiple messages until you enter “quit”, which will cause the program to stop. The following screen shot shows the TestJMSQueue’s Monitoring page, after a message was sent to the queue: This concludes the sample. In the following post I will show you how to read the message from the queue again.

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  • Vertex buffer acting strange? [on hold]

    - by Ryan Capote
    I'm having a strange problem, and I don't know what could be causing it. My current code is identical to how I've done this before. I'm trying to render a rectangle using VBO and orthographic projection.   My results:     What I expect: 3x3 rectangle in the top left corner   #include <stdio.h> #include <GL\glew.h> #include <GLFW\glfw3.h> #include "lodepng.h"   static const int FALSE = 0; static const int TRUE = 1;   static const char* VERT_SHADER =     "#version 330\n"       "layout(location=0) in vec4 VertexPosition; "     "layout(location=1) in vec2 UV;"     "uniform mat4 uProjectionMatrix;"     /*"out vec2 TexCoords;"*/       "void main(void) {"     "    gl_Position = uProjectionMatrix*VertexPosition;"     /*"    TexCoords = UV;"*/     "}";   static const char* FRAG_SHADER =     "#version 330\n"       /*"uniform sampler2D uDiffuseTexture;"     "uniform vec4 uColor;"     "in vec2 TexCoords;"*/     "out vec4 FragColor;"       "void main(void) {"    /* "    vec4 texel = texture2D(uDiffuseTexture, TexCoords);"     "    if(texel.a <= 0) {"     "         discard;"     "    }"     "    FragColor = texel;"*/     "    FragColor = vec4(1.f);"     "}";   static int g_running; static GLFWwindow *gl_window; static float gl_projectionMatrix[16];   /*     Structures */ typedef struct _Vertex {     float x, y, z, w;     float u, v; } Vertex;   typedef struct _Position {     float x, y; } Position;   typedef struct _Bitmap {     unsigned char *pixels;     unsigned int width, height; } Bitmap;   typedef struct _Texture {     GLuint id;     unsigned int width, height; } Texture;   typedef struct _VertexBuffer {     GLuint bufferObj, vertexArray; } VertexBuffer;   typedef struct _ShaderProgram {     GLuint vertexShader, fragmentShader, program; } ShaderProgram;   /*   http://en.wikipedia.org/wiki/Orthographic_projection */ void createOrthoProjection(float *projection, float width, float height, float far, float near)  {       const float left = 0;     const float right = width;     const float top = 0;     const float bottom = height;          projection[0] = 2.f / (right - left);     projection[1] = 0.f;     projection[2] = 0.f;     projection[3] = -(right+left) / (right-left);     projection[4] = 0.f;     projection[5] = 2.f / (top - bottom);     projection[6] = 0.f;     projection[7] = -(top + bottom) / (top - bottom);     projection[8] = 0.f;     projection[9] = 0.f;     projection[10] = -2.f / (far-near);     projection[11] = (far+near)/(far-near);     projection[12] = 0.f;     projection[13] = 0.f;     projection[14] = 0.f;     projection[15] = 1.f; }   /*     Textures */ void loadBitmap(const char *filename, Bitmap *bitmap, int *success) {     int error = lodepng_decode32_file(&bitmap->pixels, &bitmap->width, &bitmap->height, filename);       if (error != 0) {         printf("Failed to load bitmap. ");         printf(lodepng_error_text(error));         success = FALSE;         return;     } }   void destroyBitmap(Bitmap *bitmap) {     free(bitmap->pixels); }   void createTexture(Texture *texture, const Bitmap *bitmap) {     texture->id = 0;     glGenTextures(1, &texture->id);     glBindTexture(GL_TEXTURE_2D, texture);       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);       glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bitmap->width, bitmap->height, 0,              GL_RGBA, GL_UNSIGNED_BYTE, bitmap->pixels);       glBindTexture(GL_TEXTURE_2D, 0); }   void destroyTexture(Texture *texture) {     glDeleteTextures(1, &texture->id);     texture->id = 0; }   /*     Vertex Buffer */ void createVertexBuffer(VertexBuffer *vertexBuffer, Vertex *vertices) {     glGenBuffers(1, &vertexBuffer->bufferObj);     glGenVertexArrays(1, &vertexBuffer->vertexArray);     glBindVertexArray(vertexBuffer->vertexArray);       glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->bufferObj);     glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * 6, (const GLvoid*)vertices, GL_STATIC_DRAW);       const unsigned int uvOffset = sizeof(float) * 4;       glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, sizeof(Vertex), 0);     glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (GLvoid*)uvOffset);       glEnableVertexAttribArray(0);     glEnableVertexAttribArray(1);       glBindBuffer(GL_ARRAY_BUFFER, 0);     glBindVertexArray(0); }   void destroyVertexBuffer(VertexBuffer *vertexBuffer) {     glDeleteBuffers(1, &vertexBuffer->bufferObj);     glDeleteVertexArrays(1, &vertexBuffer->vertexArray); }   void bindVertexBuffer(VertexBuffer *vertexBuffer) {     glBindVertexArray(vertexBuffer->vertexArray);     glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer->bufferObj); }   void drawVertexBufferMode(GLenum mode) {     glDrawArrays(mode, 0, 6); }   void drawVertexBuffer() {     drawVertexBufferMode(GL_TRIANGLES); }   void unbindVertexBuffer() {     glBindVertexArray(0);     glBindBuffer(GL_ARRAY_BUFFER, 0); }   /*     Shaders */ void compileShader(ShaderProgram *shaderProgram, const char *vertexSrc, const char *fragSrc) {     GLenum err;     shaderProgram->vertexShader = glCreateShader(GL_VERTEX_SHADER);     shaderProgram->fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);       if (shaderProgram->vertexShader == 0) {         printf("Failed to create vertex shader.");         return;     }       if (shaderProgram->fragmentShader == 0) {         printf("Failed to create fragment shader.");         return;     }       glShaderSource(shaderProgram->vertexShader, 1, &vertexSrc, NULL);     glCompileShader(shaderProgram->vertexShader);     glGetShaderiv(shaderProgram->vertexShader, GL_COMPILE_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to compile vertex shader.");         return;     }       glShaderSource(shaderProgram->fragmentShader, 1, &fragSrc, NULL);     glCompileShader(shaderProgram->fragmentShader);     glGetShaderiv(shaderProgram->fragmentShader, GL_COMPILE_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to compile fragment shader.");         return;     }       shaderProgram->program = glCreateProgram();     glAttachShader(shaderProgram->program, shaderProgram->vertexShader);     glAttachShader(shaderProgram->program, shaderProgram->fragmentShader);     glLinkProgram(shaderProgram->program);          glGetProgramiv(shaderProgram->program, GL_LINK_STATUS, &err);       if (err != GL_TRUE) {         printf("Failed to link shader.");         return;     } }   void destroyShader(ShaderProgram *shaderProgram) {     glDetachShader(shaderProgram->program, shaderProgram->vertexShader);     glDetachShader(shaderProgram->program, shaderProgram->fragmentShader);       glDeleteShader(shaderProgram->vertexShader);     glDeleteShader(shaderProgram->fragmentShader);       glDeleteProgram(shaderProgram->program); }   GLuint getUniformLocation(const char *name, ShaderProgram *program) {     GLuint result = 0;     result = glGetUniformLocation(program->program, name);       return result; }   void setUniformMatrix(float *matrix, const char *name, ShaderProgram *program) {     GLuint loc = getUniformLocation(name, program);       if (loc == -1) {         printf("Failed to get uniform location in setUniformMatrix.\n");         return;     }       glUniformMatrix4fv(loc, 1, GL_FALSE, matrix); }   /*     General functions */ static int isRunning() {     return g_running && !glfwWindowShouldClose(gl_window); }   static void initializeGLFW(GLFWwindow **window, int width, int height, int *success) {     if (!glfwInit()) {         printf("Failed it inialize GLFW.");         *success = FALSE;        return;     }          glfwWindowHint(GLFW_RESIZABLE, 0);     *window = glfwCreateWindow(width, height, "Alignments", NULL, NULL);          if (!*window) {         printf("Failed to create window.");         glfwTerminate();         *success = FALSE;         return;     }          glfwMakeContextCurrent(*window);       GLenum glewErr = glewInit();     if (glewErr != GLEW_OK) {         printf("Failed to initialize GLEW.");         printf(glewGetErrorString(glewErr));         *success = FALSE;         return;     }       glClearColor(0.f, 0.f, 0.f, 1.f);     glViewport(0, 0, width, height);     *success = TRUE; }   int main(int argc, char **argv) {          int err = FALSE;     initializeGLFW(&gl_window, 480, 320, &err);     glDisable(GL_DEPTH_TEST);     if (err == FALSE) {         return 1;     }          createOrthoProjection(gl_projectionMatrix, 480.f, 320.f, 0.f, 1.f);          g_running = TRUE;          ShaderProgram shader;     compileShader(&shader, VERT_SHADER, FRAG_SHADER);     glUseProgram(shader.program);     setUniformMatrix(&gl_projectionMatrix, "uProjectionMatrix", &shader);       Vertex rectangle[6];     VertexBuffer vbo;     rectangle[0] = (Vertex){0.f, 0.f, 0.f, 1.f, 0.f, 0.f}; // Top left     rectangle[1] = (Vertex){3.f, 0.f, 0.f, 1.f, 1.f, 0.f}; // Top right     rectangle[2] = (Vertex){0.f, 3.f, 0.f, 1.f, 0.f, 1.f}; // Bottom left     rectangle[3] = (Vertex){3.f, 0.f, 0.f, 1.f, 1.f, 0.f}; // Top left     rectangle[4] = (Vertex){0.f, 3.f, 0.f, 1.f, 0.f, 1.f}; // Bottom left     rectangle[5] = (Vertex){3.f, 3.f, 0.f, 1.f, 1.f, 1.f}; // Bottom right       createVertexBuffer(&vbo, &rectangle);            bindVertexBuffer(&vbo);          while (isRunning()) {         glClear(GL_COLOR_BUFFER_BIT);         glfwPollEvents();                    drawVertexBuffer();                    glfwSwapBuffers(gl_window);     }          unbindVertexBuffer(&vbo);       glUseProgram(0);     destroyShader(&shader);     destroyVertexBuffer(&vbo);     glfwTerminate();     return 0; }

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  • A Look Inside JSR 360 - CLDC 8

    - by Roger Brinkley
    If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

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  • Why doesn't my implementation of ElGamal work for long text strings?

    - by angstrom91
    I'm playing with the El Gamal cryptosystem, and my goal is to be able to encipher and decipher long sequences of text. I have come up with a method that works for short sequences, but does not work for long sequences, and I cannot figure out why. El Gamal requires the plaintext to be an integer. I have turned my string into a byte[] using the .getBytes() method for Strings, and then created a BigInteger out of the byte[]. After encryption/decryption, I turn the BigInteger into a byte[] using the .toByteArray() method for BigIntegers, and then create a new String object from the byte[]. This works perfectly when i call ElGamalEncipher with strings up to 129 characters. With 130 or more characters, the output produced from ElGamalDecipher is garbled. Can someone suggest how to solve this issue? Is this an issue with my method of turning the string into a BigInteger? If so, is there a better way to turn my string of text into a BigInteger and back? Below is my encipher/decipher code with a program to demonstrate the problem. import java.math.BigInteger; public class Main { static BigInteger P = new BigInteger("15893293927989454301918026303382412" + "2586402937727056707057089173871237566896685250125642378268385842" + "6917261652781627945428519810052550093673226849059197769795219973" + "9423619267147615314847625134014485225178547696778149706043781174" + "2873134844164791938367765407368476144402513720666965545242487520" + "288928241768306844169"); static BigInteger G = new BigInteger("33234037774370419907086775226926852" + "1714093595439329931523707339920987838600777935381196897157489391" + "8360683761941170467795379762509619438720072694104701372808513985" + "2267495266642743136795903226571831274837537691982486936010899433" + "1742996138863988537349011363534657200181054004755211807985189183" + "22832092343085067869"); static BigInteger R = new BigInteger("72294619754760174015019300613282868" + "7219874058383991405961870844510501809885568825032608592198728334" + "7842806755320938980653857292210955880919036195738252708294945320" + "3969657021169134916999794791553544054426668823852291733234236693" + "4178738081619274342922698767296233937873073756955509269717272907" + "8566607940937442517"); static BigInteger A = new BigInteger("32189274574111378750865973746687106" + "3695160924347574569923113893643975328118502246784387874381928804" + "6865920942258286938666201264395694101012858796521485171319748255" + "4630425677084511454641229993833255506759834486100188932905136959" + "7287419551379203001848457730376230681693887924162381650252270090" + "28296990388507680954"); public static void main(String[] args) { FewChars(); System.out.println(); ManyChars(); } public static void FewChars() { //ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) BigInteger[] cipherText = ElGamal.ElGamalEncipher("This is a string " + "of 129 characters which works just fine . This is a string " + "of 129 characters which works just fine . This is a s", P, G, R); System.out.println("This is a string of 129 characters which works " + "just fine . This is a string of 129 characters which works " + "just fine . This is a s"); //ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) System.out.println("The decrypted text is: " + ElGamal.ElGamalDecipher(cipherText[0], cipherText[1], A, P)); } public static void ManyChars() { //ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) BigInteger[] cipherText = ElGamal.ElGamalEncipher("This is a string " + "of 130 characters which doesn’t work! This is a string of " + "130 characters which doesn’t work! This is a string of ", P, G, R); System.out.println("This is a string of 130 characters which doesn’t " + "work! This is a string of 130 characters which doesn’t work!" + " This is a string of "); //ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) System.out.println("The decrypted text is: " + ElGamal.ElGamalDecipher(cipherText[0], cipherText[1], A, P)); } } import java.math.BigInteger; import java.security.SecureRandom; public class ElGamal { public static BigInteger[] ElGamalEncipher(String plaintext, BigInteger p, BigInteger g, BigInteger r) { // returns a BigInteger[] cipherText // cipherText[0] is c // cipherText[1] is d SecureRandom sr = new SecureRandom(); BigInteger[] cipherText = new BigInteger[2]; BigInteger pText = new BigInteger(plaintext.getBytes()); // 1: select a random integer k such that 1 <= k <= p-2 BigInteger k = new BigInteger(p.bitLength() - 2, sr); // 2: Compute c = g^k(mod p) BigInteger c = g.modPow(k, p); // 3: Compute d= P*r^k = P(g^a)^k(mod p) BigInteger d = pText.multiply(r.modPow(k, p)).mod(p); // C =(c,d) is the ciphertext cipherText[0] = c; cipherText[1] = d; return cipherText; } public static String ElGamalDecipher(BigInteger c, BigInteger d, BigInteger a, BigInteger p) { //returns the plaintext enciphered as (c,d) // 1: use the private key a to compute the least non-negative residue // of an inverse of (c^a)' (mod p) BigInteger z = c.modPow(a, p).modInverse(p); BigInteger P = z.multiply(d).mod(p); byte[] plainTextArray = P.toByteArray(); return new String(plainTextArray); } }

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