How to read websocket response in linux shell

Question

Writing a bash script to connect to GDAX\'s Websocket Feed at wss://ws-feed.gdax.com but curl doesn\'t seem to support this as I get

curl \"wss://ws-feed.gd         


        

Answer 1

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

Answer 2

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"

Answer 3

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.

Answer 4

You can connect to your server using Telnet also

     telnet 120.22.37.128 6870

Once you connect you can send request in Json format

     {"requestType":"hi"}     

Here 6870 is port port and to open port you need to run

     sudo ufw allow 6870 

And to check pm2 logs you required to use below command

    pm2 logs 0

Hope this hepls.

Answer 5

ws start connection by http protocol, you have to change ws to http and some extra headers like this:

curl --include \
     --no-buffer \
     --header "Connection: Upgrade" \
     --header "Upgrade: websocket" \
     --header "Host: example.com:80" \
     --header "Origin: http://example.com:80" \
     --header "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \
     --header "Sec-WebSocket-Version: 13" \
     "https://ws-feed.gdax.com"

https://gist.github.com/htp/fbce19069187ec1cc486b594104f01d0