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  • Top things web developers should know about the Visual Studio 2013 release

    - by Jon Galloway
    ASP.NET and Web Tools for Visual Studio 2013 Release NotesASP.NET and Web Tools for Visual Studio 2013 Release NotesSummary for lazy readers: Visual Studio 2013 is now available for download on the Visual Studio site and on MSDN subscriber downloads) Visual Studio 2013 installs side by side with Visual Studio 2012 and supports round-tripping between Visual Studio versions, so you can try it out without committing to a switch Visual Studio 2013 ships with the new version of ASP.NET, which includes ASP.NET MVC 5, ASP.NET Web API 2, Razor 3, Entity Framework 6 and SignalR 2.0 The new releases ASP.NET focuses on One ASP.NET, so core features and web tools work the same across the platform (e.g. adding ASP.NET MVC controllers to a Web Forms application) New core features include new templates based on Bootstrap, a new scaffolding system, and a new identity system Visual Studio 2013 is an incredible editor for web files, including HTML, CSS, JavaScript, Markdown, LESS, Coffeescript, Handlebars, Angular, Ember, Knockdown, etc. Top links: Visual Studio 2013 content on the ASP.NET site are in the standard new releases area: http://www.asp.net/vnext ASP.NET and Web Tools for Visual Studio 2013 Release Notes Short intro videos on the new Visual Studio web editor features from Scott Hanselman and Mads Kristensen Announcing release of ASP.NET and Web Tools for Visual Studio 2013 post on the official .NET Web Development and Tools Blog Scott Guthrie's post: Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework Okay, for those of you who are still with me, let's dig in a bit. Quick web dev notes on downloading and installing Visual Studio 2013 I found Visual Studio 2013 to be a pretty fast install. According to Brian Harry's release post, installing over pre-release versions of Visual Studio is supported.  I've installed the release version over pre-release versions, and it worked fine. If you're only going to be doing web development, you can speed up the install if you just select Web Developer tools. Of course, as a good Microsoft employee, I'll mention that you might also want to install some of those other features, like the Store apps for Windows 8 and the Windows Phone 8.0 SDK, but they do download and install a lot of other stuff (e.g. the Windows Phone SDK sets up Hyper-V and downloads several GB's of VM's). So if you're planning just to do web development for now, you can pick just the Web Developer Tools and install the other stuff later. If you've got a fast internet connection, I recommend using the web installer instead of downloading the ISO. The ISO includes all the features, whereas the web installer just downloads what you're installing. Visual Studio 2013 development settings and color theme When you start up Visual Studio, it'll prompt you to pick some defaults. These are totally up to you -whatever suits your development style - and you can change them later. As I said, these are completely up to you. I recommend either the Web Development or Web Development (Code Only) settings. The only real difference is that Code Only hides the toolbars, and you can switch between them using Tools / Import and Export Settings / Reset. Web Development settings Web Development (code only) settings Usually I've just gone with Web Development (code only) in the past because I just want to focus on the code, although the Standard toolbar does make it easier to switch default web browsers. More on that later. Color theme Sigh. Okay, everyone's got their favorite colors. I alternate between Light and Dark depending on my mood, and I personally like how the low contrast on the window chrome in those themes puts the emphasis on my code rather than the tabs and toolbars. I know some people got pretty worked up over that, though, and wanted the blue theme back. I personally don't like it - it reminds me of ancient versions of Visual Studio that I don't want to think about anymore. So here's the thing: if you install Visual Studio Ultimate, it defaults to Blue. The other versions default to Light. If you use Blue, I won't criticize you - out loud, that is. You can change themes really easily - either Tools / Options / Environment / General, or the smart way: ctrl+q for quick launch, then type Theme and hit enter. Signing in During the first run, you'll be prompted to sign in. You don't have to - you can click the "Not now, maybe later" link at the bottom of that dialog. I recommend signing in, though. It's not hooked in with licensing or tracking the kind of code you write to sell you components. It is doing good things, like  syncing your Visual Studio settings between computers. More about that here. So, you don't have to, but I sure do. Overview of shiny new things in ASP.NET land There are a lot of good new things in ASP.NET. I'll list some of my favorite here, but you can read more on the ASP.NET site. One ASP.NET You've heard us talk about this for a while. The idea is that options are good, but choice can be a burden. When you start a new ASP.NET project, why should you have to make a tough decision - with long-term consequences - about how your application will work? If you want to use ASP.NET Web Forms, but have the option of adding in ASP.NET MVC later, why should that be hard? It's all ASP.NET, right? Ideally, you'd just decide that you want to use ASP.NET to build sites and services, and you could use the appropriate tools (the green blocks below) as you needed them. So, here it is. When you create a new ASP.NET application, you just create an ASP.NET application. Next, you can pick from some templates to get you started... but these are different. They're not "painful decision" templates, they're just some starting pieces. And, most importantly, you can mix and match. I can pick a "mostly" Web Forms template, but include MVC and Web API folders and core references. If you've tried to mix and match in the past, you're probably aware that it was possible, but not pleasant. ASP.NET MVC project files contained special project type GUIDs, so you'd only get controller scaffolding support in a Web Forms project if you manually edited the csproj file. Features in one stack didn't work in others. Project templates were painful choices. That's no longer the case. Hooray! I just did a demo in a presentation last week where I created a new Web Forms + MVC + Web API site, built a model, scaffolded MVC and Web API controllers with EF Code First, add data in the MVC view, viewed it in Web API, then added a GridView to the Web Forms Default.aspx page and bound it to the Model. In about 5 minutes. Sure, it's a simple example, but it's great to be able to share code and features across the whole ASP.NET family. Authentication In the past, authentication was built into the templates. So, for instance, there was an ASP.NET MVC 4 Intranet Project template which created a new ASP.NET MVC 4 application that was preconfigured for Windows Authentication. All of that authentication stuff was built into each template, so they varied between the stacks, and you couldn't reuse them. You didn't see a lot of changes to the authentication options, since they required big changes to a bunch of project templates. Now, the new project dialog includes a common authentication experience. When you hit the Change Authentication button, you get some common options that work the same way regardless of the template or reference settings you've made. These options work on all ASP.NET frameworks, and all hosting environments (IIS, IIS Express, or OWIN for self-host) The default is Individual User Accounts: This is the standard "create a local account, using username / password or OAuth" thing; however, it's all built on the new Identity system. More on that in a second. The one setting that has some configuration to it is Organizational Accounts, which lets you configure authentication using Active Directory, Windows Azure Active Directory, or Office 365. Identity There's a new identity system. We've taken the best parts of the previous ASP.NET Membership and Simple Identity systems, rolled in a lot of feedback and made big enhancements to support important developer concerns like unit testing and extensiblity. I've written long posts about ASP.NET identity, and I'll do it again. Soon. This is not that post. The short version is that I think we've finally got just the right Identity system. Some of my favorite features: There are simple, sensible defaults that work well - you can File / New / Run / Register / Login, and everything works. It supports standard username / password as well as external authentication (OAuth, etc.). It's easy to customize without having to re-implement an entire provider. It's built using pluggable pieces, rather than one large monolithic system. It's built using interfaces like IUser and IRole that allow for unit testing, dependency injection, etc. You can easily add user profile data (e.g. URL, twitter handle, birthday). You just add properties to your ApplicationUser model and they'll automatically be persisted. Complete control over how the identity data is persisted. By default, everything works with Entity Framework Code First, but it's built to support changes from small (modify the schema) to big (use another ORM, store your data in a document database or in the cloud or in XML or in the EXIF data of your desktop background or whatever). It's configured via OWIN. More on OWIN and Katana later, but the fact that it's built using OWIN means it's portable. You can find out more in the Authentication and Identity section of the ASP.NET site (and lots more content will be going up there soon). New Bootstrap based project templates The new project templates are built using Bootstrap 3. Bootstrap (formerly Twitter Bootstrap) is a front-end framework that brings a lot of nice benefits: It's responsive, so your projects will automatically scale to device width using CSS media queries. For example, menus are full size on a desktop browser, but on narrower screens you automatically get a mobile-friendly menu. The built-in Bootstrap styles make your standard page elements (headers, footers, buttons, form inputs, tables etc.) look nice and modern. Bootstrap is themeable, so you can reskin your whole site by dropping in a new Bootstrap theme. Since Bootstrap is pretty popular across the web development community, this gives you a large and rapidly growing variety of templates (free and paid) to choose from. Bootstrap also includes a lot of very useful things: components (like progress bars and badges), useful glyphicons, and some jQuery plugins for tooltips, dropdowns, carousels, etc.). Here's a look at how the responsive part works. When the page is full screen, the menu and header are optimized for a wide screen display: When I shrink the page down (this is all based on page width, not useragent sniffing) the menu turns into a nice mobile-friendly dropdown: For a quick example, I grabbed a new free theme off bootswatch.com. For simple themes, you just need to download the boostrap.css file and replace the /content/bootstrap.css file in your project. Now when I refresh the page, I've got a new theme: Scaffolding The big change in scaffolding is that it's one system that works across ASP.NET. You can create a new Empty Web project or Web Forms project and you'll get the Scaffold context menus. For release, we've got MVC 5 and Web API 2 controllers. We had a preview of Web Forms scaffolding in the preview releases, but they weren't fully baked for RTM. Look for them in a future update, expected pretty soon. This scaffolding system wasn't just changed to work across the ASP.NET frameworks, it's also built to enable future extensibility. That's not in this release, but should also hopefully be out soon. Project Readme page This is a small thing, but I really like it. When you create a new project, you get a Project_Readme.html page that's added to the root of your project and opens in the Visual Studio built-in browser. I love it. A long time ago, when you created a new project we just dumped it on you and left you scratching your head about what to do next. Not ideal. Then we started adding a bunch of Getting Started information to the new project templates. That told you what to do next, but you had to delete all of that stuff out of your website. It doesn't belong there. Not ideal. This is a simple HTML file that's not integrated into your project code at all. You can delete it if you want. But, it shows a lot of helpful links that are current for the project you just created. In the future, if we add new wacky project types, they can create readme docs with specific information on how to do appropriately wacky things. Side note: I really like that they used the internal browser in Visual Studio to show this content rather than popping open an HTML page in the default browser. I hate that. It's annoying. If you're doing that, I hope you'll stop. What if some unnamed person has 40 or 90 tabs saved in their browser session? When you pop open your "Thanks for installing my Visual Studio extension!" page, all eleventy billion tabs start up and I wish I'd never installed your thing. Be like these guys and pop stuff Visual Studio specific HTML docs in the Visual Studio browser. ASP.NET MVC 5 The biggest change with ASP.NET MVC 5 is that it's no longer a separate project type. It integrates well with the rest of ASP.NET. In addition to that and the other common features we've already looked at (Bootstrap templates, Identity, authentication), here's what's new for ASP.NET MVC. Attribute routing ASP.NET MVC now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your routes by annotating your actions and controllers. This supports some pretty complex, customized routing scenarios, and it allows you to keep your route information right with your controller actions if you'd like. Here's a controller that includes an action whose method name is Hiding, but I've used AttributeRouting to configure it to /spaghetti/with-nesting/where-is-waldo public class SampleController : Controller { [Route("spaghetti/with-nesting/where-is-waldo")] public string Hiding() { return "You found me!"; } } I enable that in my RouteConfig.cs, and I can use that in conjunction with my other MVC routes like this: public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapMvcAttributeRoutes(); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); } } You can read more about Attribute Routing in ASP.NET MVC 5 here. Filter enhancements There are two new additions to filters: Authentication Filters and Filter Overrides. Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests. Override filters let you change which filters apply to a given action method or controller. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers. ASP.NET Web API 2 ASP.NET Web API 2 includes a lot of new features. Attribute Routing ASP.NET Web API supports the same attribute routing system that's in ASP.NET MVC 5. You can read more about the Attribute Routing features in Web API in this article. OAuth 2.0 ASP.NET Web API picks up OAuth 2.0 support, using security middleware running on OWIN (discussed below). This is great for features like authenticated Single Page Applications. OData Improvements ASP.NET Web API now has full OData support. That required adding in some of the most powerful operators: $select, $expand, $batch and $value. You can read more about OData operator support in this article by Mike Wasson. Lots more There's a huge list of other features, including CORS (cross-origin request sharing), IHttpActionResult, IHttpRequestContext, and more. I think the best overview is in the release notes. OWIN and Katana I've written about OWIN and Katana recently. I'm a big fan. OWIN is the Open Web Interfaces for .NET. It's a spec, like HTML or HTTP, so you can't install OWIN. The benefit of OWIN is that it's a community specification, so anyone who implements it can plug into the ASP.NET stack, either as middleware or as a host. Katana is the Microsoft implementation of OWIN. It leverages OWIN to wire up things like authentication, handlers, modules, IIS hosting, etc., so ASP.NET can host OWIN components and Katana components can run in someone else's OWIN implementation. Howard Dierking just wrote a cool article in MSDN magazine describing Katana in depth: Getting Started with the Katana Project. He had an interesting example showing an OWIN based pipeline which leveraged SignalR, ASP.NET Web API and NancyFx components in the same stack. If this kind of thing makes sense to you, that's great. If it doesn't, don't worry, but keep an eye on it. You're going to see some cool things happen as a result of ASP.NET becoming more and more pluggable. Visual Studio Web Tools Okay, this stuff's just crazy. Visual Studio has been adding some nice web dev features over the past few years, but they've really cranked it up for this release. Visual Studio is by far my favorite code editor for all web files: CSS, HTML, JavaScript, and lots of popular libraries. Stop thinking of Visual Studio as a big editor that you only use to write back-end code. Stop editing HTML and CSS in Notepad (or Sublime, Notepad++, etc.). Visual Studio starts up in under 2 seconds on a modern computer with an SSD. Misspelling HTML attributes or your CSS classes or jQuery or Angular syntax is stupid. It doesn't make you a better developer, it makes you a silly person who wastes time. Browser Link Browser Link is a real-time, two-way connection between Visual Studio and all connected browsers. It's only attached when you're running locally, in debug, but it applies to any and all connected browser, including emulators. You may have seen demos that showed the browsers refreshing based on changes in the editor, and I'll agree that's pretty cool. But it's really just the start. It's a two-way connection, and it's built for extensiblity. That means you can write extensions that push information from your running application (in IE, Chrome, a mobile emulator, etc.) back to Visual Studio. Mads and team have showed off some demonstrations where they enabled edit mode in the browser which updated the source HTML back on the browser. It's also possible to look at how the rendered HTML performs, check for compatibility issues, watch for unused CSS classes, the sky's the limit. New HTML editor The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Here's a 3 minute tour from Mads Kristensen. The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Lots more Visual Studio web dev features That's just a sampling - there's a ton of great features for JavaScript editing, CSS editing, publishing, and Page Inspector (which shows real-time rendering of your page inside Visual Studio). Here are some more short videos showing those features. Lots, lots more Okay, that's just a summary, and it's still quite a bit. Head on over to http://asp.net/vnext for more information, and download Visual Studio 2013 now to get started!

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  • Google Chrome proxy settings?

    - by becko
    When I try to set Google Chrome's proxy settings (on chrome://linux-proxy-config/), I get the following message: When running Google Chrome under a supported desktop environment, the system proxy settings will be used. However, either your system is not supported or there was a problem launching your system configuration. But you can still configure via the command line. Please see man google-chrome-stable for more information on flags and environment variables. I need to set proxy settings to use Chrome, but I don't want to be setting them in the command line every time I use Chrome. Is there a way to set these settings permanently? Also, is there an option in Chrome so that it doesn't use proxy for specific domains (analogous to the No proxy for setting in Firefox)?

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  • Entity Framework Code-First, OData & Windows Phone Client

    - by Jon Galloway
    Entity Framework Code-First is the coolest thing since sliced bread, Windows  Phone is the hottest thing since Tickle-Me-Elmo and OData is just too great to ignore. As part of the Full Stack project, we wanted to put them together, which turns out to be pretty easy… once you know how.   EF Code-First CTP5 is available now and there should be very few breaking changes in the release edition, which is due early in 2011.  Note: EF Code-First evolved rapidly and many of the existing documents and blog posts which were written with earlier versions, may now be obsolete or at least misleading.   Code-First? With traditional Entity Framework you start with a database and from that you generate “entities” – classes that bridge between the relational database and your object oriented program. With Code-First (Magic-Unicorn) (see Hanselman’s write up and this later write up by Scott Guthrie) the Entity Framework looks at classes you created and says “if I had created these classes, the database would have to have looked like this…” and creates the database for you! By deriving your entity collections from DbSet and exposing them via a class that derives from DbContext, you "turn on" database backing for your POCO with a minimum of code and no hidden designer or configuration files. POCO == Plain Old CLR Objects Your entity objects can be used throughout your applications - in web applications, console applications, Silverlight and Windows Phone applications, etc. In our case, we'll want to read and update data from a Windows Phone client application, so we'll expose the entities through a DataService and hook the Windows Phone client application to that data via proxies.  Piece of Pie.  Easy as cake. The Demo Architecture To see this at work, we’ll create an ASP.NET/MVC application which will act as the host for our Data Service.  We’ll create an incredibly simple data layer using EF Code-First on top of SQLCE4 and we’ll expose the data in a WCF Data Service using the oData protocol.  Our Windows Phone 7 client will instantiate  the data context via a URI and load the data asynchronously. Setting up the Server project with MVC 3, EF Code First, and SQL CE 4 Create a new application of type ASP.NET MVC 3 and name it DeadSimpleServer.  We need to add the latest SQLCE4 and Entity Framework Code First CTP's to our project. Fortunately, NuGet makes that really easy. Open the Package Manager Console (View / Other Windows / Package Manager Console) and type in "Install-Package EFCodeFirst.SqlServerCompact" at the PM> command prompt. Since NuGet handles dependencies for you, you'll see that it installs everything you need to use Entity Framework Code First in your project. PM> install-package EFCodeFirst.SqlServerCompact 'SQLCE (= 4.0.8435.1)' not installed. Attempting to retrieve dependency from source... Done 'EFCodeFirst (= 0.8)' not installed. Attempting to retrieve dependency from source... Done 'WebActivator (= 1.0.0.0)' not installed. Attempting to retrieve dependency from source... Done You are downloading SQLCE from Microsoft, the license agreement to which is available at http://173.203.67.148/licenses/SQLCE/EULA_ENU.rtf. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'SQLCE 4.0.8435.1' You are downloading EFCodeFirst from Microsoft, the license agreement to which is available at http://go.microsoft.com/fwlink/?LinkID=206497. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'EFCodeFirst 0.8' Successfully installed 'WebActivator 1.0.0.0' You are downloading EFCodeFirst.SqlServerCompact from Microsoft, the license agreement to which is available at http://173.203.67.148/licenses/SQLCE/EULA_ENU.rtf. Check the package for additional dependencies, which may come with their own license agreement(s). Your use of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device. Successfully installed 'EFCodeFirst.SqlServerCompact 0.8' Successfully added 'SQLCE 4.0.8435.1' to EfCodeFirst-CTP5 Successfully added 'EFCodeFirst 0.8' to EfCodeFirst-CTP5 Successfully added 'WebActivator 1.0.0.0' to EfCodeFirst-CTP5 Successfully added 'EFCodeFirst.SqlServerCompact 0.8' to EfCodeFirst-CTP5 Note: We're using SQLCE 4 with Entity Framework here because they work really well together from a development scenario, but you can of course use Entity Framework Code First with other databases supported by Entity framework. Creating The Model using EF Code First Now we can create our model class. Right-click the Models folder and select Add/Class. Name the Class Person.cs and add the following code: using System.Data.Entity; namespace DeadSimpleServer.Models { public class Person { public int ID { get; set; } public string Name { get; set; } } public class PersonContext : DbContext { public DbSet<Person> People { get; set; } } } Notice that the entity class Person has no special interfaces or base class. There's nothing special needed to make it work - it's just a POCO. The context we'll use to access the entities in the application is called PersonContext, but you could name it anything you wanted. The important thing is that it inherits DbContext and contains one or more DbSet which holds our entity collections. Adding Seed Data We need some testing data to expose from our service. The simplest way to get that into our database is to modify the CreateCeDatabaseIfNotExists class in AppStart_SQLCEEntityFramework.cs by adding some seed data to the Seed method: protected virtual void Seed( TContext context ) { var personContext = context as PersonContext; personContext.People.Add( new Person { ID = 1, Name = "George Washington" } ); personContext.People.Add( new Person { ID = 2, Name = "John Adams" } ); personContext.People.Add( new Person { ID = 3, Name = "Thomas Jefferson" } ); personContext.SaveChanges(); } The CreateCeDatabaseIfNotExists class name is pretty self-explanatory - when our DbContext is accessed and the database isn't found, a new one will be created and populated with the data in the Seed method. There's one more step to make that work - we need to uncomment a line in the Start method at the top of of the AppStart_SQLCEEntityFramework class and set the context name, as shown here, public static class AppStart_SQLCEEntityFramework { public static void Start() { DbDatabase.DefaultConnectionFactory = new SqlCeConnectionFactory("System.Data.SqlServerCe.4.0"); // Sets the default database initialization code for working with Sql Server Compact databases // Uncomment this line and replace CONTEXT_NAME with the name of your DbContext if you are // using your DbContext to create and manage your database DbDatabase.SetInitializer(new CreateCeDatabaseIfNotExists<PersonContext>()); } } Now our database and entity framework are set up, so we can expose data via WCF Data Services. Note: This is a bare-bones implementation with no administration screens. If you'd like to see how those are added, check out The Full Stack screencast series. Creating the oData Service using WCF Data Services Add a new WCF Data Service to the project (right-click the project / Add New Item / Web / WCF Data Service). We’ll be exposing all the data as read/write.  Remember to reconfigure to control and minimize access as appropriate for your own application. Open the code behind for your service. In our case, the service was called PersonTestDataService.svc so the code behind class file is PersonTestDataService.svc.cs. using System.Data.Services; using System.Data.Services.Common; using System.ServiceModel; using DeadSimpleServer.Models; namespace DeadSimpleServer { [ServiceBehavior( IncludeExceptionDetailInFaults = true )] public class PersonTestDataService : DataService<PersonContext> { // This method is called only once to initialize service-wide policies. public static void InitializeService( DataServiceConfiguration config ) { config.SetEntitySetAccessRule( "*", EntitySetRights.All ); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2; config.UseVerboseErrors = true; } } } We're enabling a few additional settings to make it easier to debug if you run into trouble. The ServiceBehavior attribute is set to include exception details in faults, and we're using verbose errors. You can remove both of these when your service is working, as your public production service shouldn't be revealing exception information. You can view the output of the service by running the application and browsing to http://localhost:[portnumber]/PersonTestDataService.svc/: <service xml:base="http://localhost:49786/PersonTestDataService.svc/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:app="http://www.w3.org/2007/app" xmlns="http://www.w3.org/2007/app"> <workspace> <atom:title>Default</atom:title> <collection href="People"> <atom:title>People</atom:title> </collection> </workspace> </service> This indicates that the service exposes one collection, which is accessible by browsing to http://localhost:[portnumber]/PersonTestDataService.svc/People <?xml version="1.0" encoding="iso-8859-1" standalone="yes"?> <feed xml:base=http://localhost:49786/PersonTestDataService.svc/ xmlns:d="http://schemas.microsoft.com/ado/2007/08/dataservices" xmlns:m="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata" xmlns="http://www.w3.org/2005/Atom"> <title type="text">People</title> <id>http://localhost:49786/PersonTestDataService.svc/People</id> <updated>2010-12-29T01:01:50Z</updated> <link rel="self" title="People" href="People" /> <entry> <id>http://localhost:49786/PersonTestDataService.svc/People(1)</id> <title type="text"></title> <updated>2010-12-29T01:01:50Z</updated> <author> <name /> </author> <link rel="edit" title="Person" href="People(1)" /> <category term="DeadSimpleServer.Models.Person" scheme="http://schemas.microsoft.com/ado/2007/08/dataservices/scheme" /> <content type="application/xml"> <m:properties> <d:ID m:type="Edm.Int32">1</d:ID> <d:Name>George Washington</d:Name> </m:properties> </content> </entry> <entry> ... </entry> </feed> Let's recap what we've done so far. But enough with services and XML - let's get this into our Windows Phone client application. Creating the DataServiceContext for the Client Use the latest DataSvcUtil.exe from http://odata.codeplex.com. As of today, that's in this download: http://odata.codeplex.com/releases/view/54698 You need to run it with a few options: /uri - This will point to the service URI. In this case, it's http://localhost:59342/PersonTestDataService.svc  Pick up the port number from your running server (e.g., the server formerly known as Cassini). /out - This is the DataServiceContext class that will be generated. You can name it whatever you'd like. /Version - should be set to 2.0 /DataServiceCollection - Include this flag to generate collections derived from the DataServiceCollection base, which brings in all the ObservableCollection goodness that handles your INotifyPropertyChanged events for you. Here's the console session from when we ran it: <ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding}" SelectionChanged="MainListBox_SelectionChanged"> Next, to keep things simple, change the Binding on the two TextBlocks within the DataTemplate to Name and ID, <ListBox x:Name="MainListBox" Margin="0,0,-12,0" ItemsSource="{Binding}" SelectionChanged="MainListBox_SelectionChanged"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Margin="0,0,0,17" Width="432"> <TextBlock Text="{Binding Name}" TextWrapping="Wrap" Style="{StaticResource PhoneTextExtraLargeStyle}" /> <TextBlock Text="{Binding ID}" TextWrapping="Wrap" Margin="12,-6,12,0" Style="{StaticResource PhoneTextSubtleStyle}" /> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> Getting The Context In the code-behind you’ll first declare a member variable to hold the context from the Entity Framework. This is named using convention over configuration. The db type is Person and the context is of type PersonContext, You initialize it by providing the URI, in this case using the URL obtained from the Cassini web server, PersonContext context = new PersonContext( new Uri( "http://localhost:49786/PersonTestDataService.svc/" ) ); Create a second member variable of type DataServiceCollection<Person> but do not initialize it, DataServiceCollection<Person> people; In the constructor you’ll initialize the DataServiceCollection using the PersonContext, public MainPage() { InitializeComponent(); people = new DataServiceCollection<Person>( context ); Finally, you’ll load the people collection using the LoadAsync method, passing in the fully specified URI for the People collection in the web service, people.LoadAsync( new Uri( "http://localhost:49786/PersonTestDataService.svc/People" ) ); Note that this method runs asynchronously and when it is finished the people  collection is already populated. Thus, since we didn’t need or want to override any of the behavior we don’t implement the LoadCompleted. You can use the LoadCompleted event if you need to do any other UI updates, but you don't need to. The final code is as shown below: using System; using System.Data.Services.Client; using System.Windows; using System.Windows.Controls; using DeadSimpleServer.Models; using Microsoft.Phone.Controls; namespace WindowsPhoneODataTest { public partial class MainPage : PhoneApplicationPage { PersonContext context = new PersonContext( new Uri( "http://localhost:49786/PersonTestDataService.svc/" ) ); DataServiceCollection<Person> people; // Constructor public MainPage() { InitializeComponent(); // Set the data context of the listbox control to the sample data // DataContext = App.ViewModel; people = new DataServiceCollection<Person>( context ); people.LoadAsync( new Uri( "http://localhost:49786/PersonTestDataService.svc/People" ) ); DataContext = people; this.Loaded += new RoutedEventHandler( MainPage_Loaded ); } // Handle selection changed on ListBox private void MainListBox_SelectionChanged( object sender, SelectionChangedEventArgs e ) { // If selected index is -1 (no selection) do nothing if ( MainListBox.SelectedIndex == -1 ) return; // Navigate to the new page NavigationService.Navigate( new Uri( "/DetailsPage.xaml?selectedItem=" + MainListBox.SelectedIndex, UriKind.Relative ) ); // Reset selected index to -1 (no selection) MainListBox.SelectedIndex = -1; } // Load data for the ViewModel Items private void MainPage_Loaded( object sender, RoutedEventArgs e ) { if ( !App.ViewModel.IsDataLoaded ) { App.ViewModel.LoadData(); } } } } With people populated we can set it as the DataContext and run the application; you’ll find that the Name and ID are displayed in the list on the Mainpage. Here's how the pieces in the client fit together: Complete source code available here

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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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  • How to Troubleshoot TFS Build Server Failure?

    - by Tarun Arora
    Ever found your self in this helpless situation where you think you have tried every possible suggestion on the internet to bring the build server back but it just won’t work. Well some times before hunting around for a solution it is important to understand what the problem is, if the error messages in the build logs don’t seem to help you can always enable tracing on the build server to get more information on what could possibly be the root cause of failure. In this blog post today I’ll be showing you how to enable tracing on, - TFS 2010/11 Server - Build Server - Client Enable Tracing on Team Foundation Server 2010/2011 On the Team Foundation Server navigate to C:\Program Files\Microsoft Team Foundation Server 2010\Application Tier\Web Services, right click web.config and from the context menu select edit.          Search for the <appSettings> node in the config file and set the value of the key ‘traceWriter’ to true.          In the <System.diagnostics> tag set the value of switches from 0 to 4 to set the trace level to maximum to write diagnostics level trace information.          Restart the TFS Application pool to force this change to take effect. The application pool restart will impact any one using the TFS server at present. Note - It is recommended that you do not make any changes to the TFS production application server, this can have serious consequences and can even jeopardize the installation of your server.          Download the Debug view tool from http://technet.microsoft.com/en-us/sysinternals/bb896647.aspx and set it to capture “Global Events”. Perform any actions in the Team Explorer on the client machine, you should be able to see a series of trace data in the debug view tool now.         Enable Tracing on Build Controller/Agents Log on to the Build Controller/Agent and Navigate to the directory C:\Program Files\Microsoft Team Foundation Server 2010\Tools         Look for the configuration file ‘TFSBuildServiceHost.exe.config’ if it is not already there create a new text file and rename it to ‘TFSBuildServiceHost.exe.config’         To Enable tracing uncomment the <system.diagnostics> and paste the snippet below if it is not already there. <configuration> <system.diagnostics> <switches> <add name="BuildServiceTraceLevel" value="4"/> </switches> <trace autoflush="true" indentsize="4"> <listeners> <add name="myListener" type="Microsoft.TeamFoundation.TeamFoundationTextWriterTraceListener, Microsoft.TeamFoundation.Common, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" initializeData="c:\logs\TFSBuildServiceHost.exe.log" /> <remove name="Default" /> </listeners> </trace> </system.diagnostics> </configuration> The highlighted path above is where the Log file will be created. If the folder is not already there then create the folder, also, make sure that the account running the build service has access to write to this folder.         Restart the build Controller/Agent service from the administration console (or net stop tfsbuildservicehost & net start tfsbuildservicehost) in order for the new setting to be picked up.         Enable TFS Tracing on the Client Machine On the client machine, shut down Visual Studio, navigate to C:\Program Files\Microsoft Visual Studio 10.0\Common 7\IDE          Search for devenv.exe.config, make a backup copy of the config file and right click the file and from the context menu select edit. If its not already there create this file.          Edit devenv.exe.config by adding the below code snippet before the last </configuration> tag <system.diagnostics> <switches> <add name="TeamFoundationSoapProxy" value="4" /> <add name="VersionControl" value="4" /> </switches> <trace autoflush="true" indentsize="3"> <listeners> <add name="myListener" type="Microsoft.TeamFoundation.TeamFoundationTextWriterTraceListener,Microsoft.TeamFoundation.Common, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" initializeData="c:\tf.log" /> <add name="perfListener" type="Microsoft.TeamFoundation.Client.PerfTraceListener, Microsoft.TeamFoundation.Client, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"/> </listeners> </trace> </system.diagnostics> The highlighted path above is where the Log file will be created. If the folder is not already there then create the folder. Start Visual Studio and after a bit of activity you should be able to see the new log file being created on the folder specified in the config file. Other Resources Below are some Key resource you might like to review. I would highly recommend the documentation, walkthroughs and videos available on MSDN.   Thank you for taking the time out and reading this blog post. If you enjoyed the post, remember to subscribe to http://feeds.feedburner.com/TarunArora. Have you come across an interesting one to one with the build server, please share your experience here. Questions/Feedback/Suggestions, etc please leave a comment. Thank You! Share this post : CodeProject

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  • HTG Explains: What “Everything Is a File” Means on Linux

    - by Chris Hoffman
    One of the defining features of Linux and other UNIX-like operating systems is that “everything is a file.” This is an oversimplification, but understanding what it means will help you understand how Linux works. Many things on Linux appear in your file system, but they aren’t actually files. They’re special files that represent hardware devices, system information, and other things — including a random number generator. These special files may be located in pseudo or virtual file systems such as /dev, which contains special files that represent devices, and /proc, which contains special files that represent system and process information. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • How to remove the “AMD Testing use only” watermark from Ubuntu 12.10

    - by Lucio
    I've installed the latest catalyst driver (beta) following the step in this guide for Ubuntu Quantal Quetzal. My system is 64 bit and my graphic card is an ATI RadeonHD 6670, this g.c. is Officially Supported (Catalyst & Open Source), you can confirm that from this AMD Linux Community thread. I don't have any problem, except the AMD testing use only watermark. I see the following frame in any stage into the OS (logged, unlloged, etc.) except in the terminals. I found different versions of how to remove this image, but this change according to the system, so I want an answer from this popular (trusted) site. How to solve this issue in Ubuntu 12.10 32b? This procedure is different in a 64b system?

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  • SQLAuthority News – Why VoIP Service Providers Should Think About NuoDB’s Geo Distribution

    - by Pinal Dave
    You can always tell when someone’s showing off their cool, cutting edge comms technology. They tend to raise their voice a lot. Back in the day they’d announce their gadget leadership to the rest of the herd by shouting into their cellphone. Usually the message was no more urgent than “Hi, I’m on my cellphone!” Now the same types will loudly name-drop a different technology to the rest of the airport lounge. “I’m leveraging the wifi,” a fellow passenger bellowed, the other day, as we filtered through the departure gate. Nobody needed to know that, but the subtext was “look at me everybody”. You can tell the really advanced mobile user – they tend to whisper. Their handset has a microphone (how cool is that!) and they know how to use it. Sometimes these shouty public broadcasters aren’t even connected anyway because the database for their Voice over IP (VoIP) platform can’t cope. This will happen if they are using a traditional SQL model to try and cope with a phone network which has far flung offices and hundreds of mobile employees. That, like shouting into your phone, is just wrong on so many levels. What VoIP needs now is a single, logical database across multiple servers in different geographies. It needs to be updated in real-time and automatically scaled out during times of peak demand. A VoIP system should scale up to handle increased traffic, but just as importantly is must then go back down in the off peak hours. Try this with a MySQL database. It can’t scale easily enough, so it will keep your developers busy. They’ll have spent many hours trying to knit the different databases together. Traditional relational databases can possibly achieve this, at a price. Mind you, you could extend baked bean cans and string to every point on the network and that would be no less elegant. That’s not really following engineering principles though is it? Having said that, most telcos and VoIP systems use a separate, independent solution for each office location, which they link together – loosely.  The more office locations, the more complex and expensive the solution becomes and so the more you spend on maintenance. Ideally, you’d have a fluid system that can automatically shift its shape as the need arises. That’s the point of software isn’t it – it adapts. Otherwise, we might as well return to the old days. A MySQL system isn’t exactly baked bean cans attached by string, but it’s closer in spirit to the old many teethed mechanical beast that was employed in the first type of automated switchboard. NuoBD’s NewSQL is designed to be a single database that works across multiple servers, which can scale easily, and scale on demand. That’s one system that gives high connectivity but no latency, complexity or maintenance issues. MySQL works in some circumstances, but a period of growth isn’t one of them. So as a company moves forward, the MySQL database can’t keep pace. Data storage and data replication errors creep in. Soon the diaspora of offices becomes a problem. Your telephone system isn’t just distributed, it is literally all over the place. Though voice calls are often a software function, some of the old habits of telephony remain. When you call an engineer out, some of them will listen to what you’re asking for and announce that it cannot be done. This is what happens if you ask, say, database engineers familiar with Oracle or Microsoft to fulfill your wish for a low maintenance system built on a single, fluid, scalable database. No can do, they’d say. In fact, I heard one shouting something similar into his VoIP handset at the airport. “I can’t get on the network, Mac. I’m on MySQL.” You can download NuoDB from here. “NuoDB provides the ability to replicate data globally in real-time, which is not available with any other product offering,” states Weeks.  “That alone is remarkable and it works. I’ve seen it. I’ve used it.  I’ve tested it. The ability to deploy NuoDB removes a tremendous burden from our support and engineering teams.” Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL Tagged: NuoDB

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  • Partition Wise Joins

    - by jean-pierre.dijcks
    Some say they are the holy grail of parallel computing and PWJ is the basis for a shared nothing system and the only join method that is available on a shared nothing system (yes this is oversimplified!). The magic in Oracle is of course that is one of many ways to join data. And yes, this is the old flexibility vs. simplicity discussion all over, so I won't go there... the point is that what you must do in a shared nothing system, you can do in Oracle with the same speed and methods. The Theory A partition wise join is a join between (for simplicity) two tables that are partitioned on the same column with the same partitioning scheme. In shared nothing this is effectively hard partitioning locating data on a specific node / storage combo. In Oracle is is logical partitioning. If you now join the two tables on that partitioned column you can break up the join in smaller joins exactly along the partitions in the data. Since they are partitioned (grouped) into the same buckets, all values required to do the join live in the equivalent bucket on either sides. No need to talk to anyone else, no need to redistribute data to anyone else... in short, the optimal join method for parallel processing of two large data sets. PWJ's in Oracle Since we do not hard partition the data across nodes in Oracle we use the Partitioning option to the database to create the buckets, then set the Degree of Parallelism (or run Auto DOP - see here) and get our PWJs. The main questions always asked are: How many partitions should I create? What should my DOP be? In a shared nothing system the answer is of course, as many partitions as there are nodes which will be your DOP. In Oracle we do want you to look at the workload and concurrency, and once you know that to understand the following rules of thumb. Within Oracle we have more ways of joining of data, so it is important to understand some of the PWJ ideas and what it means if you have an uneven distribution across processes. Assume we have a simple scenario where we partition the data on a hash key resulting in 4 hash partitions (H1 -H4). We have 2 parallel processes that have been tasked with reading these partitions (P1 - P2). The work is evenly divided assuming the partitions are the same size and we can scan this in time t1 as shown below. Now assume that we have changed the system and have a 5th partition but still have our 2 workers P1 and P2. The time it takes is actually 50% more assuming the 5th partition has the same size as the original H1 - H4 partitions. In other words to scan these 5 partitions, the time t2 it takes is not 1/5th more expensive, it is a lot more expensive and some other join plans may now start to look exciting to the optimizer. Just to post the disclaimer, it is not as simple as I state it here, but you get the idea on how much more expensive this plan may now look... Based on this little example there are a few rules of thumb to follow to get the partition wise joins. First, choose a DOP that is a factor of two (2). So always choose something like 2, 4, 8, 16, 32 and so on... Second, choose a number of partitions that is larger or equal to 2* DOP. Third, make sure the number of partitions is divisible through 2 without orphans. This is also known as an even number... Fourth, choose a stable partition count strategy, which is typically hash, which can be a sub partitioning strategy rather than the main strategy (range - hash is a popular one). Fifth, make sure you do this on the join key between the two large tables you want to join (and this should be the obvious one...). Translating this into an example: DOP = 8 (determined based on concurrency or by using Auto DOP with a cap due to concurrency) says that the number of partitions >= 16. Number of hash (sub) partitions = 32, which gives each process four partitions to work on. This number is somewhat arbitrary and depends on your data and system. In this case my main reasoning is that if you get more room on the box you can easily move the DOP for the query to 16 without repartitioning... and of course it makes for no leftovers on the table... And yes, we recommend up-to-date statistics. And before you start complaining, do read this post on a cool way to do stats in 11.

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  • Acer 7551g - hibernation and suspending don't work

    - by gonzunio
    Issue is quite the same like here, I've tried everything I found and nothing happens. If I use uswsusp, suspending works good, but graphics doesn't wake up, when I want to hibernate system, it tells me "Looking for splash system... none s2disk:snapshotting system" and nothing happens. I'm using ATI drivers, i've tried to disable kms, unload usb3 and network drivers, still nothing. Please help me, I don't want to come back to Windows after my 2-year-relationship with Linux. I can share all files I have with you, just help me.

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  • some files just wont install- linux-image-3.5.0-42-generic

    - by jatin
    It gives the following details of the package operation failing after using the sofware updater on 12.10: installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... (Reading database ... (Reading database ... 217566 files and directories currently installed.) Preparing to replace linux-image-3.5.0-36-generic 3.5.0-36.57~precise1 (using .../linux-image-3.5.0-36-generic_3.5.0-36.57_amd64.deb) ... locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Done. Unpacking replacement linux-image-3.5.0-36-generic ... dpkg: error processing /var/cache/apt/archives/linux-image-3.5.0-36-generic_3.5.0-36.57_amd64.deb (--unpack): unable to make backup link of `./boot/System.map-3.5.0-36-generic' before installing new version: Operation not permitted No apport report written because MaxReports is reached already dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.5.0-36-generic /boot/vmlinuz-3.5.0-36-generic run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.5.0-36-generic /boot/vmlinuz-3.5.0-36-generic Preparing to replace linux-image-3.5.0-42-generic 3.5.0-42.65~precise1 (using .../linux-image-3.5.0-42-generic_3.5.0-42.65_amd64.deb) ... locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Done. Unpacking replacement linux-image-3.5.0-42-generic ... dpkg: error processing /var/cache/apt/archives/linux-image-3.5.0-42-generic_3.5.0-42.65_amd64.deb (--unpack): unable to make backup link of `./boot/System.map-3.5.0-42-generic' before installing new version: Operation not permitted No apport report written because MaxReports is reached already Examining /etc/kernel/postrm.d . run-parts: executing /etc/kernel/postrm.d/initramfs-tools 3.5.0-42-generic /boot/vmlinuz-3.5.0-42-generic dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) run-parts: executing /etc/kernel/postrm.d/zz-update-grub 3.5.0-42-generic /boot/vmlinuz-3.5.0-42-generic Preparing to replace memtest86+ 4.20-1.1ubuntu1 (using .../memtest86+_4.20-1.1ubuntu2.1_amd64.deb) ... Unpacking replacement memtest86+ ... dpkg: error processing /var/cache/apt/archives/memtest86+_4.20-1.1ubuntu2.1_amd64.deb (--unpack): unable to make backup link of `./boot/memtest86+.bin' before installing new version: Operation not permitted No apport report written because MaxReports is reached already locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Errors were encountered while processing: /var/cache/apt/archives/linux-image-3.5.0-36-generic_3.5.0-36.57_amd64.deb /var/cache/apt/archives/linux-image-3.5.0-42-generic_3.5.0-42.65_amd64.deb /var/cache/apt/archives/memtest86+_4.20-1.1ubuntu2.1_amd64.deb Error in function: Output of df -h: Filesystem Size Used Avail Use% Mounted on /dev/sda6 38G 6.5G 30G 19% / udev 3.5G 4.0K 3.5G 1% /dev tmpfs 1.5G 924K 1.5G 1% /run none 5.0M 4.0K 5.0M 1% /run/lock none 3.6G 296K 3.6G 1% /run/shm none 100M 64K 100M 1% /run/user /dev/sda1 197M 87M 111M 44% /boot /dev/sda5 243G 971M 230G 1% /home

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  • ORA-4030 Troubleshooting

    - by [email protected]
    QUICKLINK: Note 399497.1 FAQ ORA-4030 Note 1088087.1 : ORA-4030 Diagnostic Tools [Video]   Have you observed an ORA-0430 error reported in your alert log? ORA-4030 errors are raised when memory or resources are requested from the Operating System and the Operating System is unable to provide the memory or resources.   The arguments included with the ORA-4030 are often important to narrowing down the problem. For more specifics on the ORA-4030 error and scenarios that lead to this problem, see Note 399497.1 FAQ ORA-4030.   Looking for the best way to diagnose? There are several available diagnostic tools (error tracing, 11g Diagnosibility, OCM, Process Memory Guides, RDA, OSW, diagnostic scripts) that collectively can prove powerful for identifying the cause of the ORA-4030.    Error Tracing   The ORA-4030 error usually occurs on the client workstation and for this reason, a trace file and alert log entry may not have been generated on the server side.  It may be necessary to add additional tracing events to get initial diagnostics on the problem. To setup tracing to trap the ORA-4030, on the server use the following in SQLPlus: alter system set events '4030 trace name heapdump level 536870917;name errorstack level 3';Once the error reoccurs with the event set, you can turn off  tracing using the following command in SQLPlus:alter system set events '4030 trace name context off; name context off';NOTE:   See more diagnostics information to collect in Note 399497.1  11g DiagnosibilityStarting with Oracle Database 11g Release 1, the Diagnosability infrastructure was introduced which places traces and core files into a location controlled by the DIAGNOSTIC_DEST initialization parameter when an incident, such as an ORA-4030 occurs.  For earlier versions, the trace file will be written to either USER_DUMP_DEST (if the error was caught in a user process) or BACKGROUND_DUMP_DEST (if the error was caught in a background process like PMON or SMON). The trace file may contain vital information about what led to the error condition.    Note 443529.1 11g Quick Steps to Package and Send Critical Error Diagnostic Informationto Support[Video]  Oracle Configuration Manager (OCM) Oracle Configuration Manager (OCM) works with My Oracle Support to enable proactive support capability that helps you organize, collect and manage your Oracle configurations. Oracle Configuration Manager Quick Start Guide Note 548815.1: My Oracle Support Configuration Management FAQ Note 250434.1: BULLETIN: Learn More About My Oracle Support Configuration Manager    General Process Memory Guides   An ORA-4030 indicates a limit has been reached with respect to the Oracle process private memory allocation.    Each Operating System will handle memory allocations with Oracle slightly differently. Solaris     Note 163763.1Linux       Note 341782.1IBM AIX   Notes 166491.1 and 123754.1HP           Note 166490.1Windows Note 225349.1, Note 373602.1, Note 231159.1, Note 269495.1, Note 762031.1Generic    Note 169706.1   RDAThe RDA report will show more detailed information about the database and Server Configuration. Note 414966.1 RDA Documentation Index Download RDA -- refer to Note 314422.1 Remote Diagnostic Agent (RDA) 4 - Getting Started OS Watcher (OSW)This tool is designed to gather Operating System side statistics to compare with the findings from the database.  This is a key tool in cases where memory usage is higher than expected on the server while not experiencing ORA-4030 errors currently. Reference more details on setup and usage in Note 301137.1 OS Watcher User Guide Diagnostic Scripts   Refer to Note 1088087.1 : ORA-4030 Diagnostic Tools [Video] Common Causes/Solutions The ORA-4030 can occur for a variety of reasons.  Some common causes are:   * OS Memory limit reached such as physical memory and/or swap/virtual paging.   For instance, IBM AIX can experience ORA-4030 issues related to swap scenarios.  See Note 740603.1 10.2.0.4 not using large pages on AIX for more on that problem. Also reference Note 188149.1 for pointers on 10g and stack size issues.* OS limits reached (kernel or user shell limits) that limit overall, user level or process level memory * OS limit on PGA memory size due to SGA attach address           Reference: Note 1028623.6 SOLARIS How to Relocate the SGA* Oracle internal limit on functionality like PL/SQL varrays or bulk collections. ORA-4030 errors will include arguments like "pl/sql vc2" "pmucalm coll" "pmuccst: adt/re".  See Coding Pointers for pointers on application design to get around these issues* Application design causing limits to be reached* Bug - space leaks, heap leaks   ***For reference to the content in this blog, refer to Note.1088267.1 Master Note for Diagnosing ORA-4030

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  • SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28

    - by pinaldave
    CXPACKET has to be most popular one of all wait stats. I have commonly seen this wait stat as one of the top 5 wait stats in most of the systems with more than one CPU. Books On-Line: Occurs when trying to synchronize the query processor exchange iterator. You may consider lowering the degree of parallelism if contention on this wait type becomes a problem. CXPACKET Explanation: When a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. There is an organizer/coordinator thread (thread 0), which takes waits for all the threads to complete and gathers result together to present on the client’s side. The organizer thread has to wait for the all the threads to finish before it can move ahead. The Wait by this organizer thread for slow threads to complete is called CXPACKET wait. Note that not all the CXPACKET wait types are bad. You might experience a case when it totally makes sense. There might also be cases when this is unavoidable. If you remove this particular wait type for any query, then that query may run slower because the parallel operations are disabled for the query. Reducing CXPACKET wait: We cannot discuss about reducing the CXPACKET wait without talking about the server workload type. OLTP: On Pure OLTP system, where the transactions are smaller and queries are not long but very quick usually, set the “Maximum Degree of Parallelism” to 1 (one). This way it makes sure that the query never goes for parallelism and does not incur more engine overhead. EXEC sys.sp_configure N'cost threshold for parallelism', N'1' GO RECONFIGURE WITH OVERRIDE GO Data-warehousing / Reporting server: As queries will be running for long time, it is advised to set the “Maximum Degree of Parallelism” to 0 (zero). This way most of the queries will utilize the parallel processor, and long running queries get a boost in their performance due to multiple processors. EXEC sys.sp_configure N'cost threshold for parallelism', N'0' GO RECONFIGURE WITH OVERRIDE GO Mixed System (OLTP & OLAP): Here is the challenge. The right balance has to be found. I have taken a very simple approach. I set the “Maximum Degree of Parallelism” to 2, which means the query still uses parallelism but only on 2 CPUs. However, I keep the “Cost Threshold for Parallelism” very high. This way, not all the queries will qualify for parallelism but only the query with higher cost will go for parallelism. I have found this to work best for a system that has OLTP queries and also where the reporting server is set up. Here, I am setting ‘Cost Threshold for Parallelism’ to 25 values (which is just for illustration); you can choose any value, and you can find it out by experimenting with the system only. In the following script, I am setting the ‘Max Degree of Parallelism’ to 2, which indicates that the query that will have a higher cost (here, more than 25) will qualify for parallel query to run on 2 CPUs. This implies that regardless of the number of CPUs, the query will select any two CPUs to execute itself. EXEC sys.sp_configure N'cost threshold for parallelism', N'25' GO EXEC sys.sp_configure N'max degree of parallelism', N'2' GO RECONFIGURE WITH OVERRIDE GO Read all the post in the Wait Types and Queue series. Additionally a must read comment of Jonathan Kehayias. Note: The information presented here is from my experience and I no way claim it to be accurate. I suggest you all to read the online book for further clarification. All the discussion of Wait Stats over here is generic and it varies from system to system. It is recommended that you test this on the development server before implementing on the production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • JavaScript local alias pattern

    Heres a little pattern that is fairly common from JavaScript developers but that is not very well known from C# developers or people doing only occasional JavaScript development. In C#, you can use a using directive to create aliases of namespaces or bring them to the global scope: namespace Fluent.IO { using System; using System.Collections; using SystemIO = System.IO; In JavaScript, the only scoping construct there is is the function, but it can also be used as a local aliasing...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • JavaScript local alias pattern

    Heres a little pattern that is fairly common from JavaScript developers but that is not very well known from C# developers or people doing only occasional JavaScript development. In C#, you can use a using directive to create aliases of namespaces or bring them to the global scope: namespace Fluent.IO { using System; using System.Collections; using SystemIO = System.IO; In JavaScript, the only scoping construct there is is the function, but it can also be used as a local aliasing...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Understanding and developing web services

    - by Pankaj Upadhyay
    This question is in conjuction with How would you approach developing a Hotel Reservation System? The solution to a system with different interfaces(or clients i should say) is to go with developing a Web service and have other systems interact with it. I never had the requirement for developing a Web service so i am bit short on it. All i understand is that A web service is a system or application that performs some operations which may include modifying, sending or receiving data over a network using HTTP protocol. (Let me know if the understanding is wrong) Now, from the other question it's clearly understood that i need to develop a web service but i have no idea as to how should i go about it. My language of choice is C# and .NET Framework. Question:: How do we develop a webservice and which tools,technology and framework should i use for the same using C# language?? Question:: How can i interact with this from a desktop WPF application, Website and Mobile app

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  • Why not Green Threads?

    - by redjamjar
    Whilst I know questions on this have been covered already (e.g. http://stackoverflow.com/questions/5713142/green-threads-vs-non-green-threads), I don't feel like I've got a satisfactory answer. The question is: why don't JVM's support green threads anymore? It says this on the code-style Java FAQ: A green thread refers to a mode of operation for the Java Virtual Machine (JVM) in which all code is executed in a single operating system thread. And this over on java.sun.com: The downside is that using green threads means system threads on Linux are not taken advantage of and so the Java virtual machine is not scalable when additional CPUs are added. It seems to me that the JVM could have a pool of system processes equal to the number of cores, and then run green threads on top of that. This could offer some big advantages when you have a very number large of threads which block often (mostly because current JVM's cap the number of threads). Thoughts?

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  • Why is String Templating Better Than String Concatenation from an Engineering Perspective?

    - by stephen
    I once read (I think it was in "Programming Pearls") that one should use templates instead of building the string through the use of concatenation. For example, consider the template below (using C# razor library) <in a properties file> Browser Capabilities Type = @Model.Type Name = @Model.Browser Version = @Model.Version Supports Frames = @Model.Frames Supports Tables = @Model.Tables Supports Cookies = @Model.Cookies Supports VBScript = @Model.VBScript Supports Java Applets = @Model.JavaApplets Supports ActiveX Controls = @Model.ActiveXControls and later, in a separate code file private void Button1_Click(object sender, System.EventArgs e) { BrowserInfoTemplate = Properties.Resources.browserInfoTemplate; // see above string browserInfo = RazorEngine.Razor.Parse(BrowserInfoTemplate, browser); ... } From a software engineering perspective, how is this better than an equivalent string concatentation, like below: private void Button1_Click(object sender, System.EventArgs e) { System.Web.HttpBrowserCapabilities browser = Request.Browser; string s = "Browser Capabilities\n" + "Type = " + browser.Type + "\n" + "Name = " + browser.Browser + "\n" + "Version = " + browser.Version + "\n" + "Supports Frames = " + browser.Frames + "\n" + "Supports Tables = " + browser.Tables + "\n" + "Supports Cookies = " + browser.Cookies + "\n" + "Supports VBScript = " + browser.VBScript + "\n" + "Supports JavaScript = " + browser.EcmaScriptVersion.ToString() + "\n" + "Supports Java Applets = " + browser.JavaApplets + "\n" + "Supports ActiveX Controls = " + browser.ActiveXControls + "\n" ... }

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  • Code Trivia #6

    - by João Angelo
    It’s time for yet another code trivia and it’s business as usual. What will the following program output to the console? using System; using System.Drawing; using System.Threading; class Program { [ThreadStatic] static Point Mark = new Point(1, 1); static void Main() { Thread.CurrentThread.Name = "A"; MoveMarkUp(); var helperThread = new Thread(MoveMarkUp) { Name = "B" }; helperThread.Start(); helperThread.Join(); } static void MoveMarkUp() { Mark.Y++; Console.WriteLine("{0}:{1}", Thread.CurrentThread.Name, Mark); } }

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  • How to automatically mount hibernated NTFS to read-only?

    - by Piotr
    Is there any way to set up Ubuntu this way: If I can't mount the filesystem in rw mode, then mount it in ro mode in the same directory. In result I should not come across the notification that the system can't mount the filesystem (Skip or manual fix notification). SO when I start the system I should have my ntfs partitions mounted either in rw or ro mode depends if the windows is hibernated. fstab entry: #/dev/sda7 UUID=D0B43178B43161E0 /media/Dane ntfs defaults,errors=remount-ro 0 1 "mount -a" result: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount '/dev/sda7': Operation not permitted The NTFS partition is in an unsafe state. Please resume and shutdown Windows fully (no hibernation or fast restarting), or mount the volume read-only with the 'ro' mount option. I have ubuntu 13.10 and win8. I use uefi secure boot.

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  • Big Data – Operational Databases Supporting Big Data – RDBMS and NoSQL – Day 12 of 21

    - by Pinal Dave
    In yesterday’s blog post we learned the importance of the Cloud in the Big Data Story. In this article we will understand the role of Operational Databases Supporting Big Data Story. Even though we keep on talking about Big Data architecture, it is extremely crucial to understand that Big Data system can’t just exist in the isolation of itself. There are many needs of the business can only be fully filled with the help of the operational databases. Just having a system which can analysis big data may not solve every single data problem. Real World Example Think about this way, you are using Facebook and you have just updated your information about the current relationship status. In the next few seconds the same information is also reflected in the timeline of your partner as well as a few of the immediate friends. After a while you will notice that the same information is now also available to your remote friends. Later on when someone searches for all the relationship changes with their friends your change of the relationship will also show up in the same list. Now here is the question – do you think Big Data architecture is doing every single of these changes? Do you think that the immediate reflection of your relationship changes with your family member is also because of the technology used in Big Data. Actually the answer is Facebook uses MySQL to do various updates in the timeline as well as various events we do on their homepage. It is really difficult to part from the operational databases in any real world business. Now we will see a few of the examples of the operational databases. Relational Databases (This blog post) NoSQL Databases (This blog post) Key-Value Pair Databases (Tomorrow’s post) Document Databases (Tomorrow’s post) Columnar Databases (The Day After’s post) Graph Databases (The Day After’s post) Spatial Databases (The Day After’s post) Relational Databases We have earlier discussed about the RDBMS role in the Big Data’s story in detail so we will not cover it extensively over here. Relational Database is pretty much everywhere in most of the businesses which are here for many years. The importance and existence of the relational database are always going to be there as long as there are meaningful structured data around. There are many different kinds of relational databases for example Oracle, SQL Server, MySQL and many others. If you are looking for Open Source and widely accepted database, I suggest to try MySQL as that has been very popular in the last few years. I also suggest you to try out PostgreSQL as well. Besides many other essential qualities PostgreeSQL have very interesting licensing policies. PostgreSQL licenses allow modifications and distribution of the application in open or closed (source) form. One can make any modifications and can keep it private as well as well contribute to the community. I believe this one quality makes it much more interesting to use as well it will play very important role in future. Nonrelational Databases (NOSQL) We have also covered Nonrelational Dabases in earlier blog posts. NoSQL actually stands for Not Only SQL Databases. There are plenty of NoSQL databases out in the market and selecting the right one is always very challenging. Here are few of the properties which are very essential to consider when selecting the right NoSQL database for operational purpose. Data and Query Model Persistence of Data and Design Eventual Consistency Scalability Though above all of the properties are interesting to have in any NoSQL database but the one which most attracts to me is Eventual Consistency. Eventual Consistency RDBMS uses ACID (Atomicity, Consistency, Isolation, Durability) as a key mechanism for ensuring the data consistency, whereas NonRelational DBMS uses BASE for the same purpose. Base stands for Basically Available, Soft state and Eventual consistency. Eventual consistency is widely deployed in distributed systems. It is a consistency model used in distributed computing which expects unexpected often. In large distributed system, there are always various nodes joining and various nodes being removed as they are often using commodity servers. This happens either intentionally or accidentally. Even though one or more nodes are down, it is expected that entire system still functions normally. Applications should be able to do various updates as well as retrieval of the data successfully without any issue. Additionally, this also means that system is expected to return the same updated data anytime from all the functioning nodes. Irrespective of when any node is joining the system, if it is marked to hold some data it should contain the same updated data eventually. As per Wikipedia - Eventual consistency is a consistency model used in distributed computing that informally guarantees that, if no new updates are made to a given data item, eventually all accesses to that item will return the last updated value. In other words -  Informally, if no additional updates are made to a given data item, all reads to that item will eventually return the same value. Tomorrow In tomorrow’s blog post we will discuss about various other Operational Databases supporting Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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  • How to Force Graphics Options in PC Games with NVIDIA, AMD, or Intel Graphics

    - by Chris Hoffman
    PC games usually have built-in graphics options you can change. But you’re not limited to the options built into games — the graphics control panels bundled with graphics drivers allow you to tweak options from outside PC games. For example, these tools allow you to force-enabling antialiasing to make old games look better, even if they don’t normally support it. You can also reduce graphics quality to get more performance on slow hardware. If You Don’t See These Options If you don’t have the NVIDIA Control Panel, AMD Catalyst Control Center, or Intel Graphics and Media Control Panel installed, you may need to install the appropriate graphics driver package for your hardware from the hardware manufacturer’s website. The drivers provided via Windows Update don’t include additional software like the NVIDIA Control Panel or AMD Catalyst Control Center. Drivers provided via Windows Update are also more out of date. If you’re playing PC games, you’ll want to have the latest graphics drivers installed on your system. NVIDIA Control Panel The NVIDIA Control Panel allows you to change these options if your computer has NVIDIA graphics hardware. To launch it, right-click your desktop background and select NVIDIA Control Panel. You can also find this tool by performing a Start menu (or Start screen) search for NVIDIA Control Panel or by right-clicking the NVIDIA icon in your system tray and selecting Open NVIDIA Control Panel. To quickly set a system-wide preference, you could use the Adjust image settings with preview option. For example, if you have old hardware that struggles to play the games you want to play, you may want to select “Use my preference emphasizing” and move the slider all the way to “Performance.” This trades graphics quality for an increased frame rate. By default, the “Use the advanced 3D image settings” option is selected. You can select Manage 3D settings and change advanced settings for all programs on your computer or just for specific games. NVIDIA keeps a database of the optimal settings for various games, but you’re free to tweak individual settings here. Just mouse-over an option for an explanation of what it does. If you have a laptop with NVIDIA Optimus technology — that is, both NVIDIA and Intel graphics — this is the same place you can choose which applications will use the NVIDIA hardware and which will use the Intel hardware. AMD Catalyst Control Center AMD’s Catalyst Control Center allows you to change these options on AMD graphics hardware. To open it, right-click your desktop background and select Catalyst Control Center. You can also right-click the Catalyst icon in your system tray and select Catalyst Control Center or perform a Start menu (or Start screen) search for Catalyst Control Center. Click the Gaming category at the left side of the Catalyst Control Center window and select 3D Application Settings to access the graphics settings you can change. The System Settings tab allows you to configure these options globally, for all games. Mouse over any option to see an explanation of what it does. You can also set per-application 3D settings and tweak your settings on a per-game basis. Click the Add option and browse to a game’s .exe file to change its options. Intel Graphics and Media Control Panel Intel integrated graphics is nowhere near as powerful as dedicated graphics hardware from NVIDIA and AMD, but it’s improving and comes included with most computers. Intel doesn’t provide anywhere near as many options in its graphics control panel, but you can still tweak some common settings. To open the Intel graphics control panel, locate the Intel graphics icon in your system tray, right-click it, and select Graphics Properties. You can also right-click the desktop and select Graphics Properties. Select either Basic Mode or Advanced Mode. When the Intel Graphics and Media Control Panel appears, select the 3D option. You’ll be able to set your Performance or Quality setting by moving the slider around or click the Custom Settings check box and customize your Anisotropic Filtering and Vertical Sync preference. Different Intel graphics hardware may have different options here. We also wouldn’t be surprised to see more advanced options appear in the future if Intel is serious about competing in the PC graphics market, as they say they are. These options are primarily useful to PC gamers, so don’t worry about them — or bother downloading updated graphics drivers — if you’re not a PC gamer and don’t use any intensive 3D applications on your computer. Image Credit: Dave Dugdale on Flickr     

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  • TFS 2010 SDK: Integrating Twitter with TFS Programmatically

    - by Tarun Arora
    Technorati Tags: Team Foundation Server 2010,TFS API,Integrate Twitter TFS,TFS Programming,ALM,TwitterSharp   Friends at ‘Twitter Sharp’ have created a wonderful .net API for twitter. With this blog post i will try to show you a basic TFS – Twitter integration scenario where i will retrieve the Team Project details programmatically and then publish these details on my twitter page. In future blogs i will be demonstrating how to create a windows service to capture the events raised by TFS and then publishing them in your social eco-system. Download Working Demo: Integrate Twitter - Tfs Programmatically   1. Setting up Twitter API Download Tweet Sharp from => https://github.com/danielcrenna/tweetsharp  Before you can start playing around with this, you will need to register an application on twitter. This is because Twitter uses the OAuth authentication protocol and will not issue an Access token unless your application is registered with them. Go to https://dev.twitter.com/ and register your application   Once you have registered your application, you will need ‘Customer Key’, ‘Customer Secret’, ‘Access Token’, ‘Access Token Secret’ 2. Connecting to Twitter using the Tweet Sharp API Create a new C# windows forms project and add reference to ‘Hammock.ClientProfile’, ‘Newtonsoft.Json’, ‘TweetSharp’ Add the following keys to the App.config (Note – The values for the keys below are in correct and if you try and connect using them then you will get an authorization failure error). Add a new class ‘TwitterProxy’ and use the following code to connect to the TwitterService (Read more about OAuthentication - http://dev.twitter.com/pages/auth) using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Configuration;using TweetSharp; namespace WindowsFormsApplication2{ public class TwitterProxy { private static string _hero; private static string _consumerKey; private static string _consumerSecret; private static string _accessToken; private static string _accessTokenSecret;  public static TwitterService ConnectToTwitter() { _consumerKey = ConfigurationManager.AppSettings["ConsumerKey"]; _consumerSecret = ConfigurationManager.AppSettings["ConsumerSecret"]; _accessToken = ConfigurationManager.AppSettings["AccessToken"]; _accessTokenSecret = ConfigurationManager.AppSettings["AccessTokenSecret"];  return new TwitterService(_consumerKey, _consumerSecret, _accessToken, _accessTokenSecret); } }} Time to Tweet! _twitterService = Proxy.TwitterProxy.ConnectToTwitter(); _twitterService.SendTweet("Hello World"); SendTweet will return the TweetStatus, If you do not get a 200 OK status that means you have failed authentication, please revisit the Access tokens. --RESPONSE: https://api.twitter.com/1/statuses/update.json HTTP/1.1 200 OK X-Transaction: 1308476106-69292-41752 X-Frame-Options: SAMEORIGIN X-Runtime: 0.03040 X-Transaction-Mask: a6183ffa5f44ef11425211f25 Pragma: no-cache X-Access-Level: read-write X-Revision: DEV X-MID: bd8aa0abeccb6efba38bc0a391a73fab98e983ea Cache-Control: no-cache, no-store, must-revalidate, pre-check=0, post-check=0 Content-Type: application/json; charset=utf-8 Date: Sun, 19 Jun 2011 09:35:06 GMT Expires: Tue, 31 Mar 1981 05:00:00 GMT Last-Modified: Sun, 19 Jun 2011 09:35:06 GMT Server: hi Vary: Accept-Encoding Content-Encoding: Keep-Alive: timeout=15, max=100 Connection: Keep-Alive Transfer-Encoding: chunked   3. Integrate with TFS In my blog post Connect to TFS Programmatically i have in depth demonstrated how to connect to TFS using the TFS API. 1: // Update the AppConfig with the URI of the Team Foundation Server you want to connect to, Make sure you have View Team Project Collection Details permissions on the server 2: private static string _myUri = ConfigurationManager.AppSettings["TfsUri"]; 3: private static TwitterService _twitterService = null; 4:   5: private void button1_Click(object sender, EventArgs e) 6: { 7: lblNotes.Text = string.Empty; 8:   9: try 10: { 11: StringBuilder notes = new StringBuilder(); 12:   13: _twitterService = Proxy.TwitterProxy.ConnectToTwitter(); 14:   15: _twitterService.SendTweet("Hello World"); 16:   17: TfsConfigurationServer configurationServer = 18: TfsConfigurationServerFactory.GetConfigurationServer(new Uri(_myUri)); 19:   20: CatalogNode catalogNode = configurationServer.CatalogNode; 21:   22: ReadOnlyCollection<CatalogNode> tpcNodes = catalogNode.QueryChildren( 23: new Guid[] { CatalogResourceTypes.ProjectCollection }, 24: false, CatalogQueryOptions.None); 25:   26: // tpc = Team Project Collection 27: foreach (CatalogNode tpcNode in tpcNodes) 28: { 29: Guid tpcId = new Guid(tpcNode.Resource.Properties["InstanceId"]); 30: TfsTeamProjectCollection tpc = configurationServer.GetTeamProjectCollection(tpcId); 31:   32: notes.AppendFormat("{0} Team Project Collection : {1}{0}", Environment.NewLine, tpc.Name); 33: _twitterService.SendTweet(String.Format("http://Lunartech.codeplex.com - Connecting to Team Project Collection : {0} ", tpc.Name)); 34:   35: // Get catalog of tp = 'Team Projects' for the tpc = 'Team Project Collection' 36: var tpNodes = tpcNode.QueryChildren( 37: new Guid[] { CatalogResourceTypes.TeamProject }, 38: false, CatalogQueryOptions.None); 39:   40: foreach (var p in tpNodes) 41: { 42: notes.AppendFormat("{0} Team Project : {1} - {2}{0}", Environment.NewLine, p.Resource.DisplayName,  "This is an open source project hosted on codeplex"); 43: _twitterService.SendTweet(String.Format(" Connected to Team Project: '{0}' – '{1}' ", p.Resource.DisplayName, "This is an open source project hosted on codeplex")); 44: } 45: } 46: notes.AppendFormat("{0} Updates posted on Twitter : {1} {0}", Environment.NewLine, @"http://twitter.com/lunartech1"); 47: lblNotes.Text = notes.ToString(); 48: } 49: catch (Exception ex) 50: { 51: lblError.Text = " Message : " + ex.Message + (ex.InnerException != null ? " Inner Exception : " + ex.InnerException : string.Empty); 52: } 53: }   The extensions you can build integrating TFS and Twitter are incredible!   Share this post :

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  • HTG Explains: What The Windows Event Viewer Is and How You Can Use It

    - by Chris Hoffman
    The Windows Event Viewer shows a log of application and system messages – errors, information messages, and warnings. Scammers have used the Event Viewer to deceive people – event a properly functioning system will have error messages here. In one infamous scam, a person claiming to be from Microsoft phones someone up and instructs them to open the Event Viewer. The person is sure to see error messages here, and the scammer will ask for the person’s credit card number to fix them. As a rule of thumb, you can generally ignore all of the errors and warnings that appear in the Event Viewer – assuming your computer is working properly. HTG Explains: What The Windows Event Viewer Is and How You Can Use It HTG Explains: How Windows Uses The Task Scheduler for System Tasks HTG Explains: Why Do Hard Drives Show the Wrong Capacity in Windows?

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  • LiveCD does not work on my desktop

    - by Boris
    I've installed Oneiric on my laptop without any issue using the LiveCD downloaded here (from the French Ubuntu community server). But on my desktop, weird things happen: During the 1st try booting with the LiveCD on my desktop, my 2 year old child just hit the keyboard, and after several error messages the desktop loaded and I've been able to test Oneiric. But I wanted to redo a boot before installing Oneiric to avoid mistakes. So during the 2nd time I tried to boot with the LiveCD, I couldn't access to the point where I can choose to test or install. Before trying a 3rd time, I've "cleaned the system" from System Parameter System. But after that I'm still not able to access to the point where I can choose to test or install. Now it stops all the time on a black screen. I do not understand why several boot attempts with same CD have several results. So I wonder if the state of my current installation 11.04 can affect re-booting with my CD 11.10 ?

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