Sajay : Asp.net

WCF Scalability and IIS

Sajay — Wed, 20 Aug 2008 00:03:00 GMT

Couldn't get better than this. Wenlong has pretty much detailed out to the gory details of understanding WCF scalability in these posts.

The fact you realize is that one bottle neck is enough to kill your scalability.

Timeouts and WCF - httpRuntime

Sajay — Tue, 24 Jul 2007 10:42:00 GMT

There seems to be very little documentation around the timeout behaviors for the client and service and configuring so many knobs can get you in a fix if you dont know what you are tweaking. The below snippet shows how enable one of these scenarios to keep connections open for long processing message. Bad as it sounds this might be required if we are designing a synchonour system with large processing times per service.

The underlying fact is that in v1 of WCF there is more than the knobs.
The underlying httpRuntime is also responsible for the connection and this knob also needs to be set to accept long calls and large execution times.

<system.web>
<httpRuntime executionTimeout="400000"/>
</system.web>

The next setting required to be done is on the client. We also need t specify the sendTimeout if we know that the send process is going to take a while.

ChannelFactory<ServiceReference.IService1> cf = new ChannelFactory<Client.ServiceReference.IService1>("BasicHttpBinding_IService1");

BasicHttpBinding b = (cf.Endpoint.Binding as BasicHttpBinding);

b.SendTimeout = new TimeSpan(0,6,10);

IService1 proxy = cf.CreateChannel();

try

{

Console.WriteLine(proxy.GetData(6));

Console.ReadLine();

}

finally

{

if((proxy as IChannel).State == CommunicationState.Opened)

(proxy as IChannel).Close();

}

Disabling Anonymous Authenticaiton on IIS for Message Security and Impersonation

Sajay — Fri, 01 Dec 2006 02:10:00 GMT

When hosting WCF services in IIS we would ideally want to disable anonymous authenticaion on a website when there are other resources or type of endoints being hosted on that site. The solution to this is not quite obvious.The problem basically is that we have a situation where there are double identities coming into play. Basically this is because the message identintiy for message secuirty and the transport identity from IIS, both come into the picture and WCF doest know which one to pick and hence falls back to anonymous and then you get this exception.

“Cannot start impersonation because the SecurityContext for the UltimateReceiver role from the request message with the 'http://tempuri.org/<Service>/<Action>' action is not mapped to a Windows identity.”

I was out the whole day trying to figure out how can i get this thing working. Finally Wenlong put up a full post "Impersonation with Double Identities" that explained this whole scenario.

But if you just want to get your binding up and running with impersonation and message level security this should work with anonymous authentication.

</security>

</binding>

</customBinding>

Pleaes note that you dont need to enable integrated windows authentication for this to work and SspiNegotiated will take care of this and your identity will flow through even if your Virtual directory is not setup with integrated windows authentication.

Custom Databinding using Property Descriptors

Sajay — Fri, 29 Sep 2006 15:51:00 GMT

Creating large flat classes for data binding is one way of doing things. But you should check out this article before anyone decides to tightly couple your object model with your data representation. Mike has put this down beatifully.

http://blogs.msdn.com/mikechr/archive/2006/05/17/600697.aspx

Hiding UpdatePanel during UpdateProgress

Sajay — Thu, 24 Aug 2006 11:51:00 GMT

This was a very simple requirement to hide the currently updating controls. I first ran to the the forums and came across this. The trick was quite simple. When we depend control inside the updatePanel this technique fails. The idea is to wrap the update panel inside say another container like a div and set the control ID to that. The below script triggers the hiding of the control and kicks off the UpdateProgress.

</bindings>

</control>

</components>

</page>

</script>

Atlas rules :)

For those of you guys who arent convinced yet, I have attached a hello world version to this.

DatacontractSerializer and ASMX service using types with Namespaces

Sajay — Wed, 23 Aug 2006 09:21:00 GMT

When we try to generate a proxy out of an ASMX service with svcutil, there might be some interesting scenarios. One that I came across is when the service exposes types that have a root namespace. Now if you had only that type as the parameter then these doesnt seem to be any issue. As soon as you mix a primitive type with them then you get this error.

E:\Sajay\Visual Studio 2005\WebSites\AsmxDC>svcutil http://localhost:2665/AsmxD

C/Service.asmx?WSDL

Microsoft (R) Service Model Metadata Tool

[Microsoft (R) Windows (R) Communication Foundation, Version 3.0.4312.0]

Attempting to download metadata from 'http://localhost:2665/AsmxDC/Service.asmx?

WSDL' using WS-Metadata Exchange or DISCO.

Error: An error occurred in the tool.

Error: Wrapper type for message HelloWorldRequest cannot be projected as a data

contract type since it has multiple namespaces. Consider using the XmlSerializer

Now if we really wanted to use the Datacontract serializer then its quite simple. Provided we didnt get this exception before we added primitive type parameter and the type itself can use the DatacontractSerializer then we can add the XML namespace attribute to the parameter.

using System;

using System.Web;

using System.Web.Services;

using System.Web.Services.Protocols;

using System.Xml.Serialization;

[XmlRoot(Namespace="http://mywebSite/Types")]

public class Item

{

public string Name;

public string Description;

}

[WebService(Namespace = "http://myWebsite/")]

[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]

public class Service : System.Web.Services.WebService

{

[WebMethod]

public string HelloWorld([XmlElement(Namespace = "http://mywebSite/Types")]string name,

Item item)

{

return name+" says Hello World";

}

WCF Service with .asmx extensions

Sajay — Sun, 06 Aug 2006 23:40:00 GMT

We already have quite a large number of ASMX services and clients. One major point to be kept in mind is that WCF and asmx services can co-exist without any problem and migration to WCF should be your first and only choice unless there is a reason like using security that you do not have already. Or other WS protocols that you need for expanding your serivce.

When migrating there are a number of scenarios one can encounter. One of them is moving an asmx service to WCF withouth changing the undelying client. This would also include not changing the endpoint address to which the client talks to. Now if the client points to something like http://MyServer.com/Service.asmx how can you make this a WCF service? There are 2 main scenarios when doing this.

Without AspNetCompatibility mode.

This is a rather strainght forward approach and can be achieved through the following steps.

1. Add a service host file called service.asmx with the following

<%@ServiceHost language=c# Debug="true" Service="WCFAspCompat.service1" %>

2. Add the following to your web.config file

<system.web>

</buildProviders>

</compilation>

</system.web>

With AspNetCompatibility

This requires one more configuration for the httpHandlers and can be achieved with the following steps.

1. Add a service host file called service.asmx with the following

<%@ServiceHost language=c# Debug="true" Service="WCFAspCompat.service1" %>

2. You have to remove the .asmx handler initially. Add the following to you Web.config to get this working.

<system.web>

<add path="*.asmx" verb="*" type="System.ServiceModel.Activation.HttpHandler, System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"

validate="false" />

</httpHandlers>

</buildProviders>

</compilation>

</system.web>

3. Get your service setup as a aspNet Compatibile service
refer this post.

Using a Session in WCF through AspNetCompatibility

Sajay — Thu, 03 Aug 2006 11:22:00 GMT

Firstly let us all thank Steve Main . The session/state model is the same that is leveraged by the asp.net framework and hence all the feature of state management comes bundled with it.

On a moral note its the responsibility of using this is upto the designers. But there might be applications and scenarios that may exist or require this to be supported.

The basic steps are quite simple for this.

1. Enable asp.net compatibilty on the serivce hosting environment.

<system.serviceModel>
<serviceHostingEnvironment aspNetCompatibilityEnabled="true">....

2. The service type should next specify the asp.net compatibility requirements. Please keep in mind that this is specified on the ServiceType and not on the Contract as it is the service type that handles the implementation.

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Required)]
public class service1 : IService1{....}

3. The final piece in this is that the client should enable this stateful communicaiton with the service. This is done by specifying the allowCookies to true in the binding. If you do not enable this then you wont find the session behaving as you want it. You will find that the session for each request is different even if the call is against the same proxy. Another important point to note here is that the session is tied to the instance of the proxy. So with each instance you need to remember thats it comes with a new session. This is the configuration that you have to tie with the endpoint consuming the service.