WebSocket subprotocol support about http-kit HOT 7 CLOSED

Hi, currently, with-channel does not allow send the handshake aromatically, and does not allow customization.

If you want to, you can look at the implementation detail:
https://github.com/http-kit/http-kit/blob/master/src/org/httpkit/server.clj#L88

Here is an example

(defn handler [request]
  (let [^AsyncChannel channl (:async-channel request)]
    (if (:websocket? ~request)
      (if-let [key# (get-in ~request [:headers "sec-websocket-key"])]
        (do (.sendHandshake channl
                            {"Upgrade"    "websocket"
                             "Connection" "Upgrade"
                             "X-Your-other-header" "value"
                             "Sec-WebSocket-Accept" (accept key#)})
            ;; DO what is required, like save the channel
            ;; return the channel is required
            channl
            )))))

What do you think?
If there is a way to allow customize the handeshake, and does not complicate the API, I will be more than glad to add it.

from http-kit.

Thanks for the overview!
My first thoughts were around making a custom with-channel macro in my application and merging a custom header map during .sendHandshake, ie:

(defmacro with-channel-and-headers [request ch-name handshake-headers & body]
;;...
  (do (.sendHandshake channl
        (merge handshake-headers
          {"Upgrade"    "websocket"
           "Connection" "Upgrade"
           "X-Your-other-header" "value"
           "Sec-WebSocket-Accept" (accept key#)}))
;;...

But now that I'm reading the WebSocket rfc6455 spec, there may be some deeper logic required during .sendHandshake:

If the response includes a |Sec-WebSocket-Protocol| header field
and this header field indicates the use of a subprotocol that was
not present in the client's handshake (the server has indicated a
subprotocol not requested by the client), the client MUST _Fail
the WebSocket Connection_.

This implies some comparison is done with the client's request Sec-WebSocket-Protocol header?

I'll do some more research into this protocol handshaking and look through the Java .sendHandshake code to orient myself. Thanks again!

from http-kit.

I have a pretty good idea now how to do this with a custom with-channel macro. I'll get it working in my app first and then share it here. Going to close this one since I don't have any other questions. Thanks again for the pointers.

from http-kit.

In case it's of any interest, here is what I did to validate the websocket subprotocol (and origin header) during the handshake:
https://gist.github.com/cgmartin/5880732

The current with-channel is great for most cases I think (and flexible to support the long-polling fallback). I'm not sure if you'd like this one in http-kit proper, but you're more than welcome to use it.

Cheers!

from http-kit.

I add it to the documentation: http://http-kit.org/server.html#handshake

from http-kit.

I came across another use-case for customizing the handshake: Sending a "Set-Cookie" header. Would be nice to have some way to customize the handshake headers.

from http-kit.

Would the Websocket handshake be an appropriate place to authenticate websocket connections, where the handshake looks for some headers or data in the Upgrade request? On client websocket connection, server would issue a session token based on initial data or headers, which would have to be verifiable going forward.

from http-kit.