[undertow-dev] Proposed Low Level Web Sockets API

[Stuart Douglas]

Hi Guys,

So I have just been thinking about the low level web socket API, and 
basically I think it should look something like:

class WebSocketChannel {

   /**
    * Async receive, returns null if no frame is ready. Otherwise 
returns a channel that can be used to read the frame contents.
    */
   StreamSourceFrameChannel receive();

   /**
    * Returns a new frame channel for sending. If this is called 
multiple times subsequent channels will not be writable until all 
previous frame have been completed.
    */
   StreamSinkFrameChannel send();

   /**
    * Lister to call when a new frame is ready
    */
   ChannelListener.Setter<? extends WebSocketChannel> getReceiveSetter();

   ChannelListener.Setter<? extends WebSocketChannel> getCloseSetter();

}

Basically once the connection is established, this channel can be used 
to get FrameChannels to send and receive frames. A FrameChannel will act 
like a normal Source/Sink Channel, however with some extra methods for 
determining the type of frame.

the undertow integration will consist of a handler that performs the 
initial handshake, and set up the connection. Once the handler has 
creates this WebSocketChannel, it hands it off to the user (the user 
will register a ChannelListener with the handler for this purpose), and 
this is where Undertow core stops having anything to do with the 
connection, and the web socket library takes over.

All higher level web socket functionality will be based on this low 
level API.

Thoughts?

Stuart