How to have "service" pages in ASP.NET MVC?

MVC newbie here:

I've more or less worked out the page navigation aspect of MVC. But let's say I don't want to navigate to a View, but rather I want to get a response out of the we开发者_C百科b site, e.g. by sending a request to http://mysite.com/Services/GetFoo/123 I want to make a database request to select a Foo object with ID 123 and return it serialized as XML.

How do you do that?

I would write a custom action result:

public class XmlResult : ActionResult
{
    private readonly object _data;
    public XmlResult(object data)
    {
        if (data == null)
        {
            throw new ArgumentNullException("data");
        }
        _data = data;
    }

    public override void ExecuteResult(ControllerContext context)
    {
        // You could use any XML serializer that fits your needs
        // In this example I use XmlSerializer
        var serializer = new XmlSerializer(_data.GetType());
        var response = context.HttpContext.Response;
        response.ContentType = "text/xml";
        serializer.Serialize(response.OutputStream, _data);
    }
}

and then in my controller:

public ActionResult GetFoo(int id)
{
    FooModel foo = _repository.GetFoo(id);
    return new XmlResult(foo);
}

And if this return new XmlResult(foo); feels ugly to your eyes, you could have an extension method:

public static class ControllersExtension
{
    public static ActionResult Xml(this ControllerBase controller, object data)
    {
        return new XmlResult(data);
    }
}

and then:

public ActionResult GetFoo(int id)
{
    FooModel foo = _repository.GetFoo(id);
    return this.Xml(foo);
}

Sounds like you want to create a REST API.

Have a look at Siesta which will do all the heavy lifting.

Alternatively you could write an action method which returns a view which renders as XML rather than HTML.

Something like:

<%@ Page Language="C#" Inherits="System.Web.Mvc.ViewPage<MyModel>" ContentType="text/xml" %>
<%= SerializationHelper.SerializeAsXml(Model) %>

If you could live with a JSON result, the following should work:

public class ServicesController : Controller
{
    public ActionResult GetFoo(int id)
    {
        var dbResult = SomeDbUtil.GetFoo(id);
        return this.Json(dbResult);
    }
}

This would give you pretty a basic JSON query result. However, if you want your services to be discoverable SOAP XML services etc., setting up another project/website that acts as the web service would seem to be the better idea to me.

You can probably find an answer to your question here:

See Return XML from a controller's action in as an ActionResult?