Add IRequestBodyPipeFeature and IResponseBodyPipeFeature

[jkotalik]

The IRequestBodyPipeFeature and IResponseBodyPipeFeature will be used to detect if the HttpContext has an underlying Pipe behind the HttpRequest.Body/HttpResponse.Body.

When calling HttpRequest.PipeReader/ HttpResponse.PipeWriter, instead of created an adapted stream, if the corresponding feature is set, it will return the pipe directly rather than creating an adapter.

[davidfowl]

Strawman:

public interface IRequestBodyPipeFeature 
{
    PipeReader PipeReader { get; set; }
}

public interface IResponseBodyPipeFeature 
{
    PipeWriter PipeWriter { get; set; }
}

public class HttpRequest
{
    public PipeReader PipeReader { get; set; }
}

public class HttpResponse
{
    public PipeWriter PipeWriter { get; set; }
}

[benaadams]

One interface and inherit from IDuplexPipe?

public interface IBodyPipeFeature : IDuplexPipe
{
    new PipeReader Input { get; set; } // override to add setter
    new PipeWriter Output { get; set; } // override to add setter
}

public class HttpRequest
{
    public PipeReader PipeReader { get; set; }
}

public class HttpResponse
{
    public PipeWriter PipeWriter { get; set; }
}

Then its a single lookup to get both request and response pipes

[davidfowl]

No, we discussed this, we want it to be possible to replace one feature without impacting the other. Nothing deals manipulating both the request body and response body at the same tine.

[benaadams]

DefaultHttpContext deals with setting them both up at the same time; then for changing one at a time its the same cost as two interfaces (as it just ignores the other property).

Unless you are thinking of lazy creating the reader/writer even when its defined (i.e. only when HttpRequest.PipeReader is called the first time)?

[Tratcher]

Specifically we don't have any examples of middleware that deal with both request and response body. E.g. if response compression wants to wrap / adapt the body it's only going to be dealing with the response body, nothing changes for the request.