How to add headers when connecting to a websocket in Haskell

Question

I'm trying to create a WebSocket client to connect to an existing server ( mtgox api ).

As a starting point, to figure out connecting to WebSockets, I found this example code https://github.com/jaspervdj/websockets/blob/master/example/client.hs

The problem is that Mtgox requires headers to be sent along when it connects, I'm just not sure how to send them.

Update: To help work this out, I created a simple websocket server too. When I connect to it via a JavaScript WebSocket from my Chrome JavaScript console, I see the following headers:

 requestHeaders = [("Upgrade","websocket"),("Connection","Upgrade"),
("Host","127.0.0.1:8001"),("Origin","chrome://newtab"),("Pragma","no-cache"),
("Cache-Control","no-cache"),("Sec-WebSocket-Key","yOsPEMHx9AyT9u3ssNma/Q=="),
("Sec-WebSocket-Version","13"),("Sec-WebSocket-Extensions","x-webkit-deflate-frame"),
("User-Agent","Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.95 Safari/537.36")]

Whereas, when I connect through via the Haskell client, I see only the following headers:

requestHeaders = [("Host","127.0.0.1"),("Connection","Upgrade"),
("Upgrade","websocket"),("Sec-WebSocket-Key","X3hMDW4fAau53dbz7w4MTw=="),
("Sec-WebSocket-Version","13")]

I don't know which of the headers are actually required by MtGox, but my plan was to just send the same ones that Chrome sends, since that works.

Answer 1

根据以下答案，除了WebSocket-Protocol标头外，这是不可能的： Websockets客户端API中的HTTP标头

Answer 2

Instead of using connect I used connectWith , which allows the "Origin" header to be set. Although I can't see how to add any other headers, this is the one that MtGox requires. As long as I provide an origin, with some kind of http-based url, it connects successfully.

WS.connectWith "websocket.mtgox.com" 80 "/mtgox" (Just "http://anything") Nothing app

It would seem that it is mostly unnecessary to add any further headers, and presumably that is why no mechanism is provided. However, looking at the source , it's possible by copy-pasting the code of connectWith and connectWithSocket to change the headers that are added to the Request object.