Could websocket support gzip compression?

Question

After the success handshake of WebSocket, could we used gzip compression?

Here are my tests:

1. I use autobahn lib to build a server, then respon to client as:
   HTTP/1.1 101 Switching Protocols content-encoding: gzip Connection: Upgrade Server: AutobahnPython/?.?.? Upgrade: WebSocket Sec-WebSocket-Accept: RIR8KmljoV8Cv9mdiLY7GM2nYMc=
2. then my server uses gzip compression
3. and the chrome browser got the result, but it told me that "could not decode a text frame as UTF-8"

Answer 1

WebSocket compression is enabled in some browsers by default (at the time of writing for example in Chrome, but not in Firefox). The client has to include the 'Sec-WebSocket-Extensions: permessage-deflate' header for this. If the server responds with the same extension, the WebSocket communication is compressed on a frame basis. As far as I know, there is no browser API to enable/disable extensions.

A good article about the topic is: https://www.igvita.com/2013/11/27/configuring-and-optimizing-websocket-compression/

Answer 2

There is a compression extension being worked on by the IETF Websocket (HyBi) working group. I would suggest following their mailing list for up-to-date information. I also recommend checking out this question.

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Update 2017: The extension has now been available for some time, see here: https://www.rfc-editor.org/rfc/rfc7692