22

I created my first WCF service and tested it on my computer, and it works.

The files present are an interface, an implementation of that interface, and an app.config file.

Now that it is time to host this on a real server with IIS, I was told IIS looks for a .svc file when receiving incoming calls.

Here is what I found:

WCF services hosted in IIS are represented as special content files (.svc files) inside the IIS application. This model is similar to the way ASMX pages are represented inside of an IIS application as .asmx files. A .svc file contains a WCF-specific processing directive (@ServiceHost) that allows the WCF hosting infrastructure to activate hosted services in response to incoming messages.

Can someone please guide me as to how I can create this file so that I may host it?

Thanks!

Brad Christie
  • 100,477
  • 16
  • 156
  • 200
TheGateKeeper
  • 4,420
  • 19
  • 66
  • 101
  • 2
    http://msdn.microsoft.com/en-us/library/ms733766.aspx – Renatas M. Mar 29 '12 at 13:08
  • So service.svc is basically another way to declare endpoints? What is the use of app.config then? – TheGateKeeper Mar 29 '12 at 13:11
  • 1
    @TheGateKeeper: It's almost defining an endpoint, but not really. You have to remember an IIS setting is request-driven so providing the .svc just tells IIS that that's the location you'd like the service. It would behave differently if this were a TCP service or a windows service-hosted solution. Remember you're sharing web page requests with your service. -- BTW, follow-up to the comment by Reniuz: http://msdn.microsoft.com/en-us/library/aa751792.aspx – Brad Christie Mar 29 '12 at 13:16
  • 1
    The .svc file tells IIS to instantiate a service host, which type of service host to instantiate, and the type to instantiate it for. The service host references the endpoint configuration. Like @BradChristie says, it also provides a reference point to call into the service. – Japple Mar 29 '12 at 14:24

2 Answers2

23

The thing you need to keep in mind is that IIS is first-and-foremost a web server, and WCF host secondly.

The webserver's job is to render data based on an incoming request. Most of this data is content (the request path correlated directly to a file on the server) but in the case of a WCF service IIS needs to know where to go from here (thus the SVC file and the "directives" to IIS to spin up your service).

All the SVC file is doing is saying that at /x/y/z.svc I have a WCF service which is capable of a lot more than just server-side pages and content files. So please spin it up, make it available and allow my incoming connections to be processed.

If this were a WCF service hosted on it's own dedicated port, this would be a different story because it's no longer contending with additional requests for /Styles/base.css in addition to /MyService/GetSomeObject/.

Brad Christie
  • 100,477
  • 16
  • 156
  • 200
  • Hi, can you help me with one last bit? Over at http://msdn.microsoft.com/en-us/library/ms733766.aspx, at step 8, it asks you to create the interface in service.cs class. I have my interface as part of a .dll, do I still need to do this part? – TheGateKeeper Mar 30 '12 at 08:43
  • Reference it using the namespace `My.Custom.Assembly.IService` – Brad Christie Mar 30 '12 at 12:27
14

IIS Hosted .svc file consists of the @ServiceHost directive and attribute, Service. 

<% @ServiceHost Service="MyNamespace.MyServiceImplementationTypeName" %>

The value of the Service attribute is the CLR type name of your service implementation. Using this directive is basically equivalent to creating a service host using the following code in your self hosting console program.

new ServiceHost(typeof(MyNamespace.MyServiceImplementationTypeName ));

And If your self hosted application are using WCF configuration like 'endpoint', 'binding',etc in the app.config, you can also put that in web.config. IIS-hosted service use the same configuration elements and syntax as WCF services hosted outside of IIS. (Except something like you can't control base/endpoint address in IIS-hosted service.) And put your precompiled .dll file to application’s \bin directory of your IIS Site.

And the address of IIS-hosted service will be the address of .svc file. (http://localhost/Application1/MyService.svc).

Please check the below msdn - Deploying an IIS-Hosted WCF Service.

http://msdn.microsoft.com/en-us/library/aa751792.aspx

Min Min
  • 6,188
  • 2
  • 19
  • 17