How to read websocket response in linux shell

I'd like to add my own tool for this: websocat.

Example session with the service in question:

$ rlwrap  websocat wss://ws-feed.gdax.com

# Now enter this line (without the #) for the required JSON request:
# {"type":"subscribe","channels": [{ "name": "heartbeat", "product_ids": ["BTC-USD"] }]}

{"type":"subscriptions","channels":[{"name":"heartbeat","product_ids":["BTC-USD"]}]}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312079752,"time":"2018-07-12T22:32:42.655000Z"}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312079800,"time":"2018-07-12T22:32:43.656000Z"}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312079834,"time":"2018-07-12T22:32:44.656000Z"}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312079945,"time":"2018-07-12T22:32:45.656000Z"}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312079990,"time":"2018-07-12T22:32:46.657000Z"}
{"type":"heartbeat","last_trade_id":46274575,"product_id":"BTC-USD","sequence":6312080042,"time":"2018-07-12T22:32:47.657000Z"}
{"type":"heartbeat","last_trade_id":46274576,"product_id":"BTC-USD","sequence":6312080169,"time":"2018-07-12T22:32:48.657000Z"}

# To stop the feed, type this line: 
{"type":"unsubscribe","channels": [{ "name": "heartbeat", "product_ids": ["BTC-USD"] }]}
{"type":"subscriptions","channels":[]}

Besides a websocket client, websocat supports WebSocket server and other modes and is aimed to integrate websockets into "UNIX" world in general.


Well, you can try to mimic the required headers to get some response using curl:

  • https://gist.github.com/htp/fbce19069187ec1cc486b594104f01d0 or
  • Linux Bash: How to open a websocket connection as client

Also, there are other ways to communicate with a WebSocket server, e.g.

  • https://github.com/websockets/wscat
  • https://github.com/bwasti/webpipe
  • https://github.com/progrium/wssh

Assuming you have node installed, I would give wscat a shot; it is simple, intuitive, and powerful. Otherwise, @Pavel's answer has an abundance of venerable websocket client alternatives.

# install
npm install -g wscat

# use
wscat -c "wss://ws-feed.gdax.com"

Tags:

Linux

Curl

Websocket

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