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Your first Web Service Explained

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

As you have seen, the convention for response DTO is RequestDTO and RequestDTOResponse. 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 : IReturn<HelloResponse>
{
    public string Name { get; set; }
}

// Response DTO (follows naming convention)
public class HelloResponse
{
    public string Result { get; set; }

    public ResponseStatus ResponseStatus { get; set; } //Automatic exception handling
}

Services are implemented in a class that either inherits from the Service base class or implements the IService empty marker interface. Inheriting from the convenient Service base class 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 can be 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 limit the Service to only handle HTTP GET requests:

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

Calling Web Services

Thanks to the above IReturn<T> interface marker you’ll be able to use the terse, typed Service Client APIs, e.g:

var client = new JsonServiceClient(BaseUri);

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

Request DTOs that don’t implement IReturn<T> will need to explicitly specify the Response DTO on their call-site, e.g:

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

Alternatively you could use a general purpose HTTP Client like HTTP Utils:

HelloResponse response = "http://base.url/hello/World"
    .GetJsonFromUrl()
    .FromJson<HelloResponse>();

We highly recommend annotating Request DTO’s with the above IReturn<T> marker as it enables a generic typed API without clients having to know and specify the Response at each call-site, which would be invalidated and need to be manually updated if the Service Response Type changes.

More details on the Service Clients is available on the C#/.NET Service Clients page.

Registering Custom Routes

If no routes are defined the .NET Service Clients will use the pre-defined Routes. You can annotate your Request DTO with the [Route] attribute to register additional Custom Routes, e.g:

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

The .NET ServiceClients will then use the best matching Route based on the populated properties on the Request DTO.

Routing Tips

No ?queryString or POST Form Data should be included in the route as ServiceStack automatically populates Request DTOs with all matching params, e.g:

[Route("/hello")]

Matches both /hello and /hello?name=World with the latter populating the Name Request DTO public property.

When the route includes a variable, e.g:

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

It only matches:

/hello/name

Whereas using a wildcard:

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

Matches all routes:

/hello
/hello/name
/hello/my/name/is/ServiceStack 

More details about Routing is available on the Routing page.