SetResponseOnHttpContext can throw - Improper use of content.Length

[davidni]

Expected Behavior

Proxying should work with a custom IHttpRequester

Actual Behavior

Proxying fails if the custom IHttpRequester returns a response whose content isn't wrapping a MemoryStream. Things work by default because HttpClient.SendAsync's default is to buffer the entire response into an internal MemoryStream, which supports Stream.Length.

However, if a custom IHttpRequester uses HttpClient.SendAsync(..., HttpCompletionOption.ResponseHeadersRead), the resulting content will wrap a non-seekable stream. This will throw if trying to read Stream.Length.

Culprit is HttpContextResponder.SetResponseOnHttpContext:

AddHeaderIfDoesntExist(context, new Header("Content-Length", new []{ content.Length.ToString() }) );

Steps to Reproduce the Problem

1. Implement a custom IHttpRequester that calls HttpClient.SendAsync(..., HttpCompletionOption.ResponseHeadersRead)
2. Make a request to a target that returns a response body

Specifications

• Version: 10.0.2
• Platform: Windows 10, .NET Framework 4.6.2

[TomPallister]

@davidni what do you think the best fix is here? I guess I need a failing test first! But was thinking...

 if(response.Content.Headers.ContentLength != null)
            {
                AddHeaderIfDoesntExist(context, new Header("Content-Length", new []{ response.Content.Headers.ContentLength.ToString() }) );
            }

[TomPallister]

Should be fixed in 10.0.4! Let me know if any problems.