I am new to WCF Service. I read that both ASP.NET and WCF Services are synchronous by default. However we can implement both the ASP.NET and WCF Services asynchronously. I want to know whether the generated Web Service Client (Proxy Class) is synchronous or asynchronous by default ?
The default is synchronous.
If you want the async method signatures, too, you need to either specify /async for svcutil.exe
C:\> svcutil (some URL here) /async
or you need to check the Generate asynchronous operations option in your Add Service Reference dialog in Visual Studio.
And of course - once you have generated the async methods, you also need to call those, obviously..... (they are called Begin(YourMethodName) and End(YourMethodName) for each of your service methods)
Related
I'm developing a UWP client project which need to consume some services of a WCF server. I uses the "add service reference" tool of Visual Studio to auto generate service clients(proxies). The binding type is NetTcpBinding. Below is some code snippet which create the service client:
NetTcpBinding tcpBinding = new NetTcpBinding();
tcpBinding.Security.Mode = SecurityMode.None;
tcpBinding.Security.Transport.ClientCredentialType = TcpClientCredentialType.None;
tcpBinding.Security.Message.ClientCredentialType = MessageCredentialType.None;
MainServiceClient = new MainServiceClient(tcpBinding, new EndpointAddress("net.tcp://localhost:8773/MyWCF/MainService/tcp"));
The question is do I need to call OpenAsync() method of MainServiceClient? It seems the service client can be auto opened when it is first called. But I read from this article that auto-opened service client would have some performance penalty. The article was written in 2007. I just wonder if this mechanism have changed today, especially in UWP project. Can anyone share more light on this topic? Thanks!
To explain this case, you should know three ways to do WCF instance management. WCF has provided three ways by which you can control WCF service instances:Per call, Per session, Single instance.
When we configure a WCF service as per call, new service instances are created for every method call you make via a WCF proxy client.
Very often we need to maintain state between method calls or for a particular session. For those kinds of scenarios, we will need to configure the service per session. In per session, only one instance of a WCF service object is created for a session interaction.
Often we would like to create one global WCF instance for all WCF clients. To create a single instance of a WCF service, we need to configure the WCF service as Single instance mode.
And there are three ways by which you can handle concurrency for each service instance in WCF :single, multiple, and reentrant.
Single: A single request has access to the WCF service object at a given moment of time. So only one request will be processed at any given moment of time. The other requests have to wait until the request processed by the WCF service is completed.
Multiple: In this scenario, multiple requests can be handled by the WCF service object at any given moment of time. In other words, requests are processed at the same time by spawning multiple threads on the WCF server object. So you have great throughput here but you need to ensure concurrency issues related to WCF server objects.
Reentrant: A single request thread has access to the WCF service object, but the thread can exit the WCF service to call another WCF service or can also call a WCF client through callback and reenter without deadlock.
In "Instance mode = Per Session and Concurrency = Single" combination, one WCF service instance is created for every WCF client session because the WCF instance mode is set to per session. All the method are executed in a sequential manner one by one. In other words, only one thread is available for all method calls for a particular service instance.
For the above scenario, you should always open WCF client proxy explicitly before you are making any calls. Because it will maintain service state between method calls and obtain high performance.
For more detail you could refer to "WCF Concurrency (Single, Multiple, and Reentrant) and Throttling" and "Three ways to do WCF instance management".
I am migrating a .NET GUI application built in .NET 1.1 to .NET 4.0. The application uses WSE 2.0 for web service communication. Web Service Comm. Module contains web service proxy and other class files implementing asynchronous functioning. The module sits between .NET GUI application and application Server hosting Web Services. Application Server has been implemented in non-Microsoft technology and the migration project should not change the server and the web services.
All the classes and forms in .NET GUI application call synchronous methodName of web service proxy class. Web Service Proxy derives from a custom class which in turn derives from Microsoft.Web.Services2.WebServicesClientProtocol. The custom class overrides “Invoke” method. Method “BeginInvoke” is called inside overrided “Invoke” method. Therefore even though application classes and forms are calling synchronous methodName , finally the web request goes as asynchronous.
Overrided “Invoke” method and the custom class enable to display dialog window with Cancel button for cancelling web request.
Proxy class in WCF has following implementation for a web method call. Is there something in WCF which can allow to customize functioning of call Base.Channel.MethodName(input)? Basically something which can allow changing synchronous web method call to asynchronous at run time?
[System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Advanced)]
getNewCustomerCodeResponse iAccountService.getNewCustomerCode(getNewCustomerCode request)
{
return base.Channel.getNewCustomerCode(request);
}
I am developing a wcf service (basicHttpBinding) that should also be consumed by non .net clients (e.g. Java clients). But now I wonder how the client can define his client config file. Or is this file only needed for .net-clients? (I am thinking of configurations like maxReceivedMessageSize or maxItemsInObjectGraph for example).
Each development platform (call it as you want: SOAP stack, Framework, API) has its own way to configure communication. You don't need to bother with it. You just need to expose correct WSDL and client's developer will be responsible for configuring the client application based on his needs.
If you want to extend documentation of your service in WSDL you can use wsdl:documentation. WCF doesn't offer it by default but you can use this technology sample to extend WCF. You can use such documentation for example to describe that service operation can return large amount of data. Another approach to add wsdl:documentation is using WCF Extras.
From the sound of it, the client shouldn't have access to those configuration options. For instance, why should a client to the WCF service be able to specify the maxReceivedMessageSize?
What you probably want to do is define these configuration options on the server-side. If a client makes a call and there is a conflict with one of your options (i.e. the client exceeds maxReceivedMessageSize), you'll want to throw a SoapException back to the client.
If you want to let the client have access to the configuration settings before he or she sends a request, you can always implement a simple web service method that sends back the values.
Is there any way to enforce that a method call in soap based wcf is called as an HTTP get? I'm not sure if this would be handled on the client or server side. We wanted to have the wcf call process as a get vs. post for cacheability, etc.
I'm also not sure how to monitor a wcf service to determine if calls are doing gets or posts (or if it always does one or the other). Can I use fiddler for this?
I would imagine I could use a restful wcf service to wrap the call, but I wasn't sure if there was a way to do it straight in a soap based service.
Out of the box WCF functionality does not support SOAP HTTP GET. But WCF is extensible so you can try to develop custom binding (with cutom channel or behavior) supporting this feature.
Caching is supported in WCF 4 REST services. REST services allow all basic HTTP methods.
You can use Fiddler to monitor the gets and posts.
Check out this post about calling a WCF service with an HTTP GET.
So I already have a working implementation of StructureMap with the WCF service (including custom instance provider, behaviors, etc.)
When I try to have an object that is instantiated only once per user request, I use the InstanceScope.HttpContext and it throws because the context is null.
Do anyone have a proper way of doing that?
On the server-side of the WCF service? By default, WCF has nothing to do with ASP.NET and thus all your HttpContext etc. aren't there.
By default, your WCF services will be called on a "per-call" basis, e.g. each request gets a brand-new, separate, totally isolated instance of your service class. Why not just put those things into the service class as internal fields??
Or you might want to check out this blog post on how to abstract request state and providing sample implementations for ASP.NET (using HttpContext.Items) and WCF.