RequestFilter - return response with DTO

ServiceStack
1

When creating a RegisterTypedRequestFilter I am trying to terminate the processing of the request whilst including a Response DTO - is this doable?

I am trying to set the res.Dto property then calling req.EndRequest, but the result is empty content. I assumed that since there is a method called EndRequestWithNoContent, that the plain EndRequest would include content (the dto), but it looks like I am missing a step.

Any thoughts?

appHost.RegisterTypedRequestFilter<Foo>((req, res, dto) =>
{
// determine if request should be bypassed or whatnot
   res.Dto = new FooResponse();
   res.EndRequest();
});
2

You need to write what you want directly to the response, EndRequest() is how to short-circuit the Request pipeline, whilst EndRequestWithNoContent() sends back a 204 NoContent response with a 0 Content-Length:

You can use WriteToResponse() but as that’s async you should only do that within an Async Request Filter:

GlobalRequestFiltersAsync.Add(async (req, res, dto) => {
    if (dto is Foo foo)
    {
        await res.WriteToResponse(req, new FooResponse());
        return;
    }
});

If you’re not using .NET Core you can write to the response OutputStream synchronously, e.g.

appHost.RegisterTypedRequestFilter<Foo>((req, res, dto) =>
{
   res.ContentType = MimeTypes.Json;
   JsonSerializer.SerializeToStream(new FooResponse(), res.OutputStream);
   res.EndRequest(skipHeaders:true);
});

You can also do this in .NET Core but in v3 they’re going to disable sync writes by default.

3

Fantastic. I guess what threw me off was that I had a public setter on the response dto giving me the impression that it would be set, then terminate the request. But writing to the output stream or response should be fine.

thank you as always for a great reply!