Thanks for explaining the option with getRequestChannel! Got it working by reading content into a pre-allocated ByteBuffer.
if it returns 0 register a read listener and call resumeReads()
One thing I don't fully understand though is your note about registering a read listener (+ calling resumeReads) and why this is needed. Is it a mandatory step, and if it is, are you referring to application-specific read listener or Undertow's io.undertow.server.protocol.http.HttpReadListener? I guess this is pretty basic question, so it would be great if you can just point me to the right place at documentation, so that I can figure it out.
Thinking about it we probably just need some way to buffer a complete/partial message and then invoke a callback with the data.
Yep, I guess this would be easier for the app developer to use.