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Your first webservice explained

mythz edited this page Sep 25, 2012 · 8 revisions

Let's look a bit deeper into the Hello World service you created:

As you have seen, the convention for response DTO is {Request DTO Name} + Response. Note, request and response DTO should be in the same namespace if you want ServiceStack to recognize the DTO pair.

To support automatic exception handling, you also need to add a ResponseStatus property to the response DTO:

//Request DTO
public class Hello
{
    public string Name { get; set; }
}

//Response DTO
//Follows naming convention
public class HelloResponse
{
    public ResponseStatus ResponseStatus { get; set; } //Automatic exception handling
    
    public string Result { get; set; }
}

At the lowest level all services inherit from the empty IService interface. Although you generally will want to inherit from the convenient Service base class which provides easy access to the most common functionality.

public class HelloService : Service
{
    public object Any(Hello request)
    {
        return new HelloResponse { Result = "Hello, " + request.Name };
    }
}

The above service will get called with Any HTTP Verb (e.g. GET, POST,..) from any endpoint or format (e.g. JSON, XML, etc). You can also choose to handle a specific Verb by changing the method name to suit, e.g. here's how to change it so you only handle HTTP GET requests:

public class HelloService : Service
{
   public object Get(Hello  request)
   {
   	return new HelloResponse { Result = "Hello, " + request.Name };
   }
}

Let's look at the AppHost's Configure method:

public override void Configure(Container container)
{
    //register user-defined REST-ful urls (Optional):
    Routes
        .Add<Hello>("/hello")
        .Add<Hello>("/hello/{Name}");
}

To register your custom REST URLs, you can either use the Route attribute on the request DTO instead of Routes.Add in the AppHost:

//Request DTO
[Route("/hello")]
[Route("/hello/{Name}")]
public class Hello
{
    public string Name { get; set; }
}

Calling your web service

The above service can now be called with:

var client = new JsonServiceClient(BaseUri);
HelloResponse response = client.Get<HelloResponse>("/hello/World!"); 

You can also make it even easier for your C# clients if you also provide the expected return type. E.g. if you add the IReturn<T> interface marker to your Request DTO like:

public class Hello : IReturn<HelloResponse>
{
    public string Name { get; set; }
}

Your clients will now also be able to make the same call above but with a fully-typed C# API, i.e:

HelloResponse response = client.Get(new Hello { Name = "World!" });

In general we think you should look to decorate your Request DTO's with the above marker as it will give your clients the choice on which C# client API they prefer to use.

Routing Tips:

[Route("/hello/{Name}")]

only matches:

  • /hello/name

where as:

[Route("/hello/{Name*}")]

matches:

  • /hello
  • /hello/name
  • /hello/my/name/is/ServiceStack
  • ...

More details about Routing is explained in this answer on StackOverflow

In the Configure method, you can also access the built-in IoC container and set other application-wide configurations. You can find out more about the IoC container in the next wiki page!

Next wikipage: [[The IoC container]]

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