Maarten Balliauw {blog}

ASP.NET, ASP.NET MVC, Windows Azure, PHP, ...

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Version 4 of the Windows Azure SDK for PHP released

Only a few months after the Windows Azure SDK for PHP 3.0.0, Microsoft and RealDolmen are proud to present you the next version of the most complete SDK for Windows Azure out there (yes, that is a rant against the .NET SDK!): Windows Azure SDK for PHP. We’ve been working very hard with an expanding globally distributed team on getting this version out.

The Windows Azure SDK 4 contains some significant feature enhancements. For example, it now incorporates a PHP library for accessing Windows Azure storage, a logging component, a session sharing component and clients for both the Windows Azure and SQL Azure Management API’s. On top of that, all of these API’s are now also available from the command-line both under Windows and Linux. This means you can batch-script a complete datacenter setup including servers, storage, SQL Azure, firewalls, … If that’s not cool, move to the North Pole.

Here’s the official change log:

  • New feature: Service Management API support for SQL Azure
  • New feature: Service Management API's exposed as command-line tools
  • New feature: MicrosoftWindowsAzureRoleEnvironment for retrieving environment details
  • New feature: Package scaffolders
  • Integration of the Windows Azure command-line packaging tool
  • Expansion of the autoloader class increasing performance
  • Several minor bugfixes and performance tweaks

Some interesting links on some of the new features:

Also keep an eye on www.sdn.nl where I’ll be posting an article on scripting a complete application deployment to Windows Azure, including SQL Azure, storage and firewalls.

And finally: keep an eye on http://azurephp.interoperabilitybridges.com and http://blogs.technet.com/b/port25/. I have a feeling some cool stuff may be coming following this release...

Copy packages from one NuGet feed to another

Copy packages from one NuGet feed to another - MyGet NuGet Server

Yesterday, a funny discussion was going on at the NuGet Discussion Forum on CodePlex. Funny, you say? Well yes. Funny because it was about a feature we envisioned as being a must-have feature for the NuGet ecosystem: copying packages from the NuGet feed to another feed. And funny because we already have that feature present in MyGet. You may wonder why anyone wants to do that? Allow me to explain.

Scenarios where copying packages makes sense

The first scenario is feed stability. Imagine you are building a project and expect to always reference a NuGet package from the official feed. That’s OK as long as you have that package present in the NuGet feed, but what happens if someone removes it or updates it without respecting proper versioning? This should not happen, but it can be an unpleasant surprise if it happens. Copying the package to another feed provides stability: the specific package version is available on that other feed and will never change unless you update or remove it. It puts you in control, not the package owner.

A second scenario: enhanced speed! It’s still much faster to pull packages from a local feed or a feed that’s geographically distributed, like the one MyGet offers (US and Europe at the moment). This is not to bash any carriers or network providers, it’s just physics: electrons don’t travel that fast and it’s better to have them coming from a closer location.

But… how to do it? Client side

There are some solutions to this problem/feature. The first one is a hard one: write a script that just pulls packages from the official feed. You’ll find a suggestion on how to do that here. This thing however does not pull along dependencies and forces you to do ugly, user-unfriendly things. Let’s go for beauty :-)

Rob Reynolds (aka @ferventcoder) added some extension sauce to the NuGet.exe:

NuGet.exe Install /ExcludeVersion /OutputDir %LocalAppData%\NuGet\Commands AddConsoleExtension NuGet.exe addextension nuget.copy.extension NuGet.exe copy castle.windsor –destination http://myget.org/F/somefeed

Sweet! And Rob also shared how he created this extension (warning: interesting read!)

But… how to do it? Server side

The easiest solution is to just use MyGet! We have a nifty feature in there named “Mirror packages”. It copies the selected package to your private feed, distributes it across our CDN nodes for a fast download and it pulls along all dependencies.

Mirror a NuGet package - Copy a NuGet package

Enjoy making NuGet a component of your enterprise workflow! And MyGet of course as well!

Windows Azure Accelerator for Web Roles

Windows Azure Accelerator for Web RolesOne of the questions I often get around Windows Azure is: “Is Windows Azure interesting for me?”. It’s a tough one, because most of the time when someone asks that question they currently already have a server somewhere that hosts 100 websites. In the full-fledged Windows Azure model, that would mean 100 x 2 (we want the SLA) = 200 Windows Azure instances. And a stroke at the end of the month when the bill arrives. Microsoft’s DPE team have released something very interesting for those situations though: the Windows Azure Accelerator for Web Roles.

In short, the WAAWR (no way I’m going to write Windows Azure Accelerator for Web Roles out every time!) is a means of creating virtual web sites on the IIS server running on a Windows Azure instance. Add “multi-instance” to that and have a free tool to create a server farm for you!

The features on paper:

  • Deploy sites to Windows Azure in less than 30 seconds
  • Enables deployments to multiple Web Role instances using Web Deploy
  • Saves Web Deploy packages & IIS configuration in Windows Azure storage to provide durability
  • A web administrator portal for managing web sites deployed to the role
  • The ability to upload and manage SSL certificates
  • Simple logging and diagnostics tools

Interesting… Let’s go for a ride!

Obtaining & installing the Windows Azure Accelerator for Web Roles

Installing the WAAWR is as easy as download, extract, buildme.cmd and you’re done. After that, Visual Studio 2010 (or Visual Studio Web Developer Express!) features a new project template:

Create new Windows Azure Accelerator for Web Roles project

Click OK, enter the required information (such as: a storage account that will be used for synchronizing the different server instances and an administrator account). After that, enable remote desktop and publish. That’s it. I’ve never ever setup a web farm more quickly than that.

Creating a web site

After deploying the solution you created in Visual Studio, browse to the live deployment and log in with the administrator credentials you created when creating the project. This will give you a nice looking web interface which allows you to create virtual web sites and have some insight into what’s happening in your server farm.

I’ll create a new virtual website on my server farm:

Create a site in Windows Azure Accelerator for Web Roles

After clicking create we can try to publish an ASP.NET MVC application.

Publishing a web site

For testing purposes I created a simple ASP.NET MVC application. Since the default project template already has a high enough “Hello World factor”, let’s immediately right-click the project name and hit Publish. Deploying an application to the newly created Windows Azure webfarm is as easy as specifying the following parameters:

Windows Azure Web Deploy

One Publish click later, you are done. And deployed on a web farm instance, I can now see the website itself but also… some statistics :-)

Maarten Balliauw Windows Azure

Conclusion

The newly released Windows Azure Accelerator for Web Roles is, IMHO, the easiest, fastest manner to deploy a multi-site webfarm on Windows Azure. Other options like.the ones proposed by Steve Marx on his blog do work, but are only suitable if you are billing your customer by the hour.

The fact that it uses web deploy to publish applications to the system and the fact that this just works behind a corporate firewall and annoying proxy is just fabulous!

This also has a downside: if I want to push my PHP applications to Windows Azure in a jiffy, chances are this will be a problem. Not on Windows (but not ideal there either), but certainly when publishing apps from other platforms. Is that a self-imposed challenge? Nope. Web deploy does not seem to have an open protocol (that I know of) and while reverse engineering it is possible I will not risk the legal consequences :-) However, some reverse-engineering of the WAAWR itself learned me that websites are stored as a ZIP package on blob storage and there’s a PHP SDK for that. A nifty workaround is possible as such, if you get your head around the ZIP file folder structure.

My conclusion in short: if you ever receive the question “Is Windows Azure interesting for me?” from someone who wants to host a bunch of websites on it? It is. And it’s easy.

A hidden gem in the Windows Azure SDK for PHP: command line parsing

It’s always fun to dive into frameworks: often you’ll find little hidden gems that can be of great use in your own projects. A dive into the Windows Azure SDK for PHP learned me that there’s a nifty command line parsing tool in there which makes your life easier when writing command line scripts.

Usually when creating a command line script you would parse $_SERVER['argv'], validate values and check whether required switches are available or not. With the Microsoft_Console_Command class from the Windows Azure SDK for PHP, you can ease up this task. Let’s compare writing a simple “hello” command.

Command-line hello world the ugly way

Let’s start creating a script that can be invoked from the command line. The first argument will be the command to perform, in this case “hello”. The second argument will be the name to who we want to say hello.

$command = null; $name = null; if (isset($_SERVER['argv'])) { $command = $_SERVER['argv'][1]; } // Process "hello" if ($command == "hello") { $name = $_SERVER['argv'][2]; echo "Hello $name"; }

Pretty obvious, no? Now let’s add some “help” as well:

$command = null; $name = null; if (isset($_SERVER['argv'])) { $command = $_SERVER['argv'][1]; } // Process "hello" if ($command == "hello") { $name = $_SERVER['argv'][2]; echo "Hello $name"; } if ($command == "") { echo "Help for this command\r\n"; echo "Possible commands:\r\n"; echo " hello - Says hello.\r\n"; }

To be honest: I find this utter clutter. And it’s how many command line scripts for PHP are written today. Imagine this script having multiple commands and some parameters that come from arguments, some from environment variables, …

Command-line hello world the easy way

With the Windows Azure for SDK tooling, I can replace the first check (“which command do you want”) by creating a class that extends Microsoft_Console_Command.  Note I also decorated the class with some special docblock annotations which will be used later on by the built-in help generator. Bear with me :-)

/** * Hello world * * @command-handler hello * @command-handler-description Hello world. * @command-handler-header (C) Maarten Balliauw */ class Hello extends Microsoft_Console_Command { } Microsoft_Console_Command::bootstrap($_SERVER['argv']);

Also notice that in the example above, the last line actually bootstraps the command. Which is done in an interesting way: the arguments for the script are passed in as an array. This means that you can also abuse this class to create “subcommands” which you pass a different array of parameters.

To add a command implementation, just create a method and annotate it again:

/** * @command-name hello * @command-description Say hello to someone * @command-parameter-for $name Microsoft_Console_Command_ParameterSource_Argv --name|-n Required. Name to say hello to. * @command-example Print "Hello, Maarten": * @command-example hello -n="Maarten" */ public function helloCommand($name) { echo "Hello, $name"; }

Easy, no? I think this is pretty self-descriptive:

  • I have a command named “hello”
  • It has a description
  • It takes one parameter $name for which the value can be provided from arguments (Microsoft_Console_Command_ParameterSource_Argv). If passed as an argument, it’s called “—name” or “-n”. And there’s a description as well.

To declare arguments, I’ve found that there’s other sources for them as well:

  • Microsoft_Console_Command_ParameterSource_Argv – Gets the value from the command arguments
  • Microsoft_Console_Command_ParameterSource_StdIn – Gets the value from StdIn, which enables you to create “piped” commands
  • Microsoft_Console_Command_ParameterSource_Env – Gets the value from an environment variable

The best part: help is generated for you! Just run the script without any further arguments:

(C) Maarten Balliauw Hello world. Available commands: hello Say hello to someone --name, -n Required. Name to say hello to. Example usage: Print "Hello, Maarten": hello -n="Maarten" <default>, -h, -help, help Displays the current help information.

Magic at its best! Enjoy!

A first look at Windows Azure AppFabric Applications

After the Windows Azure AppFabric team announced the availability of Windows Azure AppFabric Applications (preview), I signed up for early access immediately and got in. After installing the tools and creating a namespace through the portal, I decided to give it a try to see what it’s all about. Note that Neil Mackenzie also has an extensive post on “WAAFapps” which I recommend you to read as well.

So what is this Windows Azure AppFabric Applications thing?

Before answering that question, let’s have a brief look at what Windows Azure is today. According to Microsoft, Windows Azure is a “PaaS” (Platform-as-a-Service) offering. What that means is that Windows Azure offers a series of platform components like compute, storage, caching, authentication, a service bus, a database, a CDN, … to your applications.

Consuming those components is pretty low level though: in order to use, let’s say, caching, one has to add the required references, make some web.config changes and open up a connection to these things. Ok, an API is provided but it’s not the case that you can seamlessly integrate caching into an application in seconds (in a manner like one would integrate file system access in an application which you literally can do in seconds).

Meet Windows Azure AppFabric Applications. Windows Azure AppFabric Applications (why such long names, Microsoft!) redefine the concept of Platform-as-a-Service: where Windows Azure out of the box is more like a “Platform API-as-a-Service”, Windows Azure AppFabric Applications  is offering tools and platform support for easily integrating the various Windows Azure components.

This “redefinition” of Windows Azure introduces some new concepts: in Windows Azure you have roles and role instances. In AppFabric Applications you don’t have that concept: AFA (yes, I managed to abbreviate it!) uses so-called Containers. A Container is a logical unit in which one or more services of an application are hosted. For example, if you have 2 web applications, caching and SQL Azure, you will (by default) have one Container containing 2 web applications + 2 service references: one for caching, one for SQL Azure.

Containers are not limited to one role or role instance: a container is a set of predeployed role instances on which your applications will run. For example, if you add a WCF service, chances are that this will be part of the same container. Or a different one if you specify otherwise.

It’s pretty interesting that you can scale containers separately. For example, one can have 2 scale units for the container containing web applications, 3 for the WCF container, … A scale unit is not necessarily just one extra instance: it depends on how many services are in a container? In fact, you shouldn’t care anymore about role instances and virtual machines: with AFA (my abbreviation for Windows Azure AppFabric Applications, remember) one can now truly care about only one thing: the application you are building.

Hello, Windows Azure AppFabric Applications

Visual Studio tooling support

To demonstrate a few concepts, I decided to create a simple web application that uses caching to store the number of visits to the website. After installing the Visual Studio tooling, I started with one of the templates contained in the SDK:

Creating a Windows Azure AppFabric Application

This template creates a few things. To start with, 2 projects are created in Visual Studio: one MVC application in which I’ll create my web application, and one Windows Azure AppFabric Application containing a file App.cs which seems to be a DSL for building Windows Azure AppFabric Application. Opening this DSL gives the following canvas in Visual Studio:

App.cs Windows Azure AppFabric Applications

As you can see, this is the overview of my application as well as how they interact with each other. For example, the “MVCWebApp” has 1 endpoint (to serve HTTP requests) + 2 service references (to Windows Azure AppFabric caching and SQL Azure). This is an important notion as it will generate integration code for you. For example, in my MVC web application I can find the ServiceReferences.g.cs file containing the following code:

1 class ServiceReferences 2 { 3 public static Microsoft.ApplicationServer.Caching.DataCache CreateImport1() 4 { 5 return Service.ExecutingService.ResolveImport<Microsoft.ApplicationServer.Caching.DataCache>("Import1"); 6 } 7 8 public static System.Data.SqlClient.SqlConnection CreateImport2() 9 { 10 return Service.ExecutingService.ResolveImport<System.Data.SqlClient.SqlConnection>("Import2"); 11 } 12 }

Wait a minute… This looks like a cool thing! It’s basically a factory for components that may be hosted elsewhere! Calling ServiceReferences.CreateImport1() will give me a caching client that I can immediately work with! ServiceReferences.CreateImport2() (you can change these names by the way) gives me a connection to SQL Azure. No need to add connection strings in the application itself, no need to configure caching in the application itself. Instead, I can configure these things in the Windows Azure AppFabric Application canvas and just consume them blindly in my code. Awesome!

Here’s the code for my HomeController where I consume the cache/. Even my grandmother can write this!

1 [HandleError] 2 public class HomeController : Controller 3 { 4 public ActionResult Index() 5 { 6 var count = 1; 7 var cache = ServiceReferences.CreateImport1(); 8 var countItem = cache.GetCacheItem("visits"); 9 if (countItem != null) 10 { 11 count = ((int)countItem.Value) + 1; 12 } 13 cache.Put("visits", count); 14 15 ViewData["Message"] = string.Format("You are visitor number {0}.", count); 16 17 return View(); 18 } 19 20 public ActionResult About() 21 { 22 return View(); 23 } 24 }

Now let’s go back to the Windows Azure AppFabric Application canvas, where I can switch to “Deployment View”:

Windows Azure AppFabric Application Deployment View

Deployment View basically lets you decide in which container one or more applications will be running and how many scale units a container should span (see the properties window in Visual Studio for this).

Right-clicking and selecting “Deploy…” deploys my Windows Azure AppFabric Application to the production environment.

The management portal

After logging in to http://portal.appfabriclabs.com, I can manage the application I just published:

Windows Azure AppFabric Application Management Portal

I’m not going to go in much detail but will highlight some features. The portal enables you to manage your application: deploy/undeploy, scale, monitor, change configuration, …  Basically everything you would expect to be able to do. And more! If you look at the monitoring part, for example, you will see some KPI’s on your application. Here’s what my sample application shows after being deployed for a few minutes:

Windows Azure AppFabric Applications monitoring and latency

Pretty slick. It even monitors average latencies etc.!

Conclusion

As you can read in this blog post, I’ve been exploring this product and trying out the basics of it. I’m no sure yet if this model will fit every application, but I’m sure a solution like this is where the future of PaaS should be: no longer caring about servers, VM’s or instances, just deploy and let the platform figure everything out. My business value is my application, not the fact that it spans 2 VM’s.

Now when I say “future of PaaS”, I’m also a bit skeptical… Most customers I work with use COM, require startup scripts to configure the environment, care about the server their application runs on. In fact, some applications will never be able to be deployed on this solution because of that. Where Windows Azure already represents a major shift in terms of development paradigm (a too large step for many!), I thing the step to Windows Azure AppFabric Applications is a bridge too far for most people. At present.

But then there’s corporations… As corporations always are 10 steps behind, I foresee that this will only become mainstream within the next 5-8 years (for enterpise). Too bad! I wish most corporate environments moved faster…

If Microsoft wants this thing to succeed I think they need to work even more on shifting minds to the cloud paradigm and more specific to the PaaS paradigm. Perhaps Windows 8 can be a utility to do this: if Windows 8 shifts from “programming for a Windows environment” to “programming for a PaaS environment”, people will start following that direction. What the heck, maybe this is even a great model for Joe Average to create “apps” for Windows 8! Just like one submits an app to AppStore or Marketplace today, he/she can submit an app to “Windows Marketplace” which in the background just drops everything on a technology like Windows Azure AppFabric Applications?

Officially a cloudhead now! (or: re-awarded MVP)

View Maarten Balliauw's MVP profileWoohoo! I just received the great mail I expect yearly on the first of July:

Dear Maarten Balliauw,

Congratulations! We are pleased to present you with the 2011 Microsoft® MVP Award! This award is given to exceptional technical community leaders who actively share their high quality, real world expertise with others. We appreciate your outstanding contributions in Windows Azure technical communities during the past year.

The Microsoft MVP Award provides us the unique opportunity to celebrate and honor your significant contributions and say "Thank you for your technical leadership."

Toby Richards
General Manager
Community & Online Support

This e-mail is not that clear about what technology one is an MVP, so I dug in… It seems that I will be leaving the largest group of MVP’s around: ASP.NET (sorry guys, you were great!) and joining the cloudheads of the Windows Azure group.

Thanks everyone for keeping me motivated in working with the community, sharing knowledge and providing me time to do all this. That last one means: thank you, boss, and thank you to my lovely wife!

Let’s start working on earning the award for next year…

Delegate feed privileges to other users on MyGet

MyGetOne of the first features we had envisioned for MyGet and which seemed increasingly popular was the ability to provide other users a means of managing packages on another user’s feed.

As of today, we’re proud to announce the following new features:

  • Delegating feed privileges to other users – This allows you to make another MyGet user “co-admin” or “contributor” to a feed. This eases management of a private feed as that work can be spread across multiple people.
  • Making private feeds private by requiring authentication – It’s now possible to configure a feed so that nobody can consult its list of packages unless a valid login is provided. This feature is not yet available for use with NuGet 1.4.
  • Global deployment – We’ve updated our deployment so managing feeds can now be done on a server that’s closer to you.

Now when is Microsoft going to buy us out :-)

Delegating feed privileges to other users

MyGet now allows you to make another MyGet user “co-admin” or “contributor” to a feed. This eases management of a private feed as that work can be spread across multiple people. If combined with the “private feeds” option, it’s also possible to give some users read access to the feed while unauthenticated users can not access the feed created.

To delegate privileges to a user, navigate to the feed details and click the Feed security tab. This tab allows you to change feed privileges for different users. Adding feed privileges can be done by clicking the Add feed privileges… button (duh!).

Add MyGet feed privileges

Available privileges are:

  • Has no access to this feed (speaks for itself)
  • Can consume this feed (allows the user to use the feed in Visual Studio / NuGet)
  • Can manage packages for this feed (allows the user to add packages to the feed via the website and via the NuGet push API)
  • Can manage users and packages for this feed (extends the above with feed privilege management capabilities)

After selecting the privileges, the user receives an e-mail in which he/she can claim the acquired privileges:

Claim MyGet feed privileges

Privileges are not granted per direct: after assigning privileges, the user has to claim these privileges by clicking a link in an automated e-mail that has been sent.

Making private feeds private by requiring authentication

It’s now possible to configure a feed so that nobody can consult its list of packages unless a valid login is provided. Combined with the feed privilege delegation feature one can granularly control who can and who can not consume a feed from MyGet. Note that his feature is not yet available for use with NuGet 1.4, we hope to see support for this shipping with NuGet 1.5.

In order to enable this feature, on the Feed security tab change feed privileges for Everyone to Has no access to this feed.

NuGet feed authentication

This will instruct MyGet to request for basic authentication when someone accesses a MyGet feed. For example, try our sample feed: http://www.myget.org/F/mygetsample/

Global deployment

We’ve updated our deployment so managing feeds can now be done on a server that’s closer to you. Currently we have a deployment running in a European datacenter and one in the US. We hope to expand this further as well as leverage a content delivery network for high-speed distribution of packages.

image

We need your opinion!

As features keep popping into our head, the time we have to work on MyGet in our spare time is not enough. To support some extra development, we are thinking along the lines of introducing a premium version which you can host in your own datacenter or on a dedicated cloud environment. We would love some feedback on the following survey:

Enabling conditional Basic HTTP authentication on a WCF OData service

imageYes, a long title, but also something I was not able to find too easily using Google. Here’s the situation: for MyGet, we are implementing basic authentication to the OData feed serving available NuGet packages. If you recall my post Using dynamic WCF service routes, you may have deducted that MyGet uses that technique to have one WCF OData service serving the feeds of all our users. It’s just convenient! Unless you want basic HTTP authentication for some feeds and not for others…

After doing some research, I thought the easiest way to resolve this was to use WCF intercepting. Convenient, but how would you go about this? And moreover: how to make it extensible so we can use this for other WCF OData (or WebAPi) services in the future?

The solution to this was to create a message inspector (IDispatchMessageInspector). Here’s the implementation we created for MyGet: (disclaimer: this will only work for OData services and WebApi!)

 

1 public class ConditionalBasicAuthenticationMessageInspector : IDispatchMessageInspector 2 { 3 protected IBasicAuthenticationCondition Condition { get; private set; } 4 protected IBasicAuthenticationProvider Provider { get; private set; } 5 6 public ConditionalBasicAuthenticationMessageInspector( 7 IBasicAuthenticationCondition condition, IBasicAuthenticationProvider provider) 8 { 9 Condition = condition; 10 Provider = provider; 11 } 12 13 public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext) 14 { 15 // Determine HttpContextBase 16 if (HttpContext.Current == null) 17 { 18 return null; 19 } 20 HttpContextBase httpContext = new HttpContextWrapper(HttpContext.Current); 21 22 // Is basic authentication required? 23 if (Condition.Evaluate(httpContext)) 24 { 25 // Extract credentials 26 string[] credentials = ExtractCredentials(request); 27 28 // Are credentials present? If so, is the user authenticated? 29 if (credentials.Length > 0 && Provider.Authenticate(httpContext, credentials[0], credentials[1])) 30 { 31 httpContext.User = new GenericPrincipal( 32 new GenericIdentity(credentials[0]), new string[] { }); 33 return null; 34 } 35 36 // Require authentication 37 HttpContext.Current.Response.StatusCode = 401; 38 HttpContext.Current.Response.StatusDescription = "Unauthorized"; 39 HttpContext.Current.Response.Headers.Add("WWW-Authenticate", string.Format("Basic realm=\"{0}\"", Provider.Realm)); 40 HttpContext.Current.Response.End(); 41 } 42 43 return null; 44 } 45 46 public void BeforeSendReply(ref Message reply, object correlationState) 47 { 48 // Noop 49 } 50 51 private string[] ExtractCredentials(Message requestMessage) 52 { 53 HttpRequestMessageProperty request = (HttpRequestMessageProperty)requestMessage.Properties[HttpRequestMessageProperty.Name]; 54 55 string authHeader = request.Headers["Authorization"]; 56 57 if (authHeader != null && authHeader.StartsWith("Basic")) 58 { 59 string encodedUserPass = authHeader.Substring(6).Trim(); 60 61 Encoding encoding = Encoding.GetEncoding("iso-8859-1"); 62 string userPass = encoding.GetString(Convert.FromBase64String(encodedUserPass)); 63 int separator = userPass.IndexOf(':'); 64 65 string[] credentials = new string[2]; 66 credentials[0] = userPass.Substring(0, separator); 67 credentials[1] = userPass.Substring(separator + 1); 68 69 return credentials; 70 } 71 72 return new string[] { }; 73 } 74 }

Our ConditionalBasicAuthenticationMessageInspector implements a WCF message inspector that, once a request has been received, checks the HTTP authentication headers to check for a basic username/password. One extra there: since we wanted conditional authentication, we have also implemented an IBasicAuthenticationCondition interface which we have to implement. This interface decides whether to invoke authentication or not. The authentication itself is done by calling into our IBasicAuthenticationProvider. Implementations of these can be found on our CodePlex site.

If you are getting optimistic: great! But how do you apply this message inspector to a WCF service? No worries: you can create a behavior for that. All you have to do is create a new Attribute and implement IServiceBehavior. In this implementation, you can register the ConditionalBasicAuthenticationMessageInspector on the service endpoint. Here’s the implementation:

1 [AttributeUsage(AttributeTargets.Class)] 2 public class ConditionalBasicAuthenticationInspectionBehaviorAttribute 3 : Attribute, IServiceBehavior 4 { 5 protected IBasicAuthenticationCondition Condition { get; private set; } 6 protected IBasicAuthenticationProvider Provider { get; private set; } 7 8 public ConditionalBasicAuthenticationInspectionBehaviorAttribute( 9 IBasicAuthenticationCondition condition, IBasicAuthenticationProvider provider) 10 { 11 Condition = condition; 12 Provider = provider; 13 } 14 15 public ConditionalBasicAuthenticationInspectionBehaviorAttribute( 16 Type condition, Type provider) 17 { 18 Condition = Activator.CreateInstance(condition) as IBasicAuthenticationCondition; 19 Provider = Activator.CreateInstance(provider) as IBasicAuthenticationProvider; 20 } 21 22 public void AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, Collection<ServiceEndpoint> endpoints, BindingParameterCollection bindingParameters) 23 { 24 // Noop 25 } 26 27 public void ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 28 { 29 foreach (ChannelDispatcher channelDispatcher in serviceHostBase.ChannelDispatchers) 30 { 31 foreach (EndpointDispatcher endpointDispatcher in channelDispatcher.Endpoints) 32 { 33 endpointDispatcher.DispatchRuntime.MessageInspectors.Add( 34 new ConditionalBasicAuthenticationMessageInspector(Condition, Provider)); 35 } 36 } 37 } 38 39 public void Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 40 { 41 // Noop 42 } 43 }

One step to do: apply this service behavior to our OData service. Easy! Just add an attribute to the service class and you’re done! Note that we specify the IBasicAuthenticationCondition and IBasicAuthenticationProvider on the attribute.

1 [ConditionalBasicAuthenticationInspectionBehavior( 2 typeof(MyGetBasicAuthenticationCondition), 3 typeof(MyGetBasicAuthenticationProvider))] 4 public class PackageFeedHandler 5 : DataService<PackageEntities>, 6 IDataServiceStreamProvider, 7 IServiceProvider 8 { 9 }

Enjoy!

Community Day 2011 - Fun with ASP.NET MVC, MEF and NuGet

To start the blog post: AWESOME! That’s what I have to say about the latest edition of Community Day 2011. I had the privilege of doing a session on ASP.NET MVC 3, MEF and NuGet, and as promised to the audience: here are the slides. For those who want to see the session, the recording can be found on Channel 9 from a previous event.

“Fun with ASP.NET MVC3, MEF and NuGet”
Community Day 2011, Mechelen, Belgium, 23/06/2011

Abstract: “So you have a team of developers… And a nice architecture to build on… How about making that architecture easy for everyone and getting developers up to speed quickly? Learn all about integrating the managed extensibility framework (MEF) and ASP.NET MVC with some NuGet sauce for creating loosely coupled, easy to use architectures that anyone can grasp.

Here’s the slides:

Here’s the example code: Fun with ASP.NET MVC 3 MEF - CommunityDay 2011.zip (6.79 mb)

Some resources:

Advanced scenarios with Windows Azure Queues

For DeveloperFusion, I wrote an article on Windows Azure queues. Interested in working with queues and want to use some advanced techniques? Head over to the article:

Last week, in Brian Prince’s article, Using the Queuing Service in Windows Azure, you saw how to create, add messages into, retrieve and consume those messages from Windows Azure Queues. While being a simple, easy-to-use mechanism, a lot of scenarios are possible using this near-FIFO queuing mechanism. In this article we are going to focus on three scenarios which show how queues can be an important and extremely scalable component in any application architecture:

  • Back off polling, a method to lessen the number of transactions in your queue and therefore reduce the bandwidth used.
  • Patterns for working with large queue messages, a method to overcome the maximal size for a queue message and support a greater amount of data.
  • Using a queue as a state machine.

The techniques used in every scenario can be re-used in many applications and often be combined into an approach that is both scalable and reliable.

To get started, you will need to install the Windows Azure Tools for Microsoft Visual Studio. The current version is 1.4, and that is the version we will be using. You can download it from http://www.microsoft.com/windowsazure/sdk/.

N.B. The code that accompanies this article comes as a single Visual Studio solution with three console application projects in it, one for each scenario covered. To keep code samples short and to the point, the article covers only the code that polls the queue and not the additional code that populates it. Readers are encouraged to discover this themselves.

Want more content? Check Advanced scenarios with Windows Azure Queues. Enjoy!