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.gdax.com"
curl: (1) Protocol "wss" not supported or disabled in libcurl

I've suggested changing `bash` tag as the question does not specifically regard it but any command line interface. — Matheus Santana, Mar 23 '18 at 11:16

score 80 · Answer 1 · answered Dec 18 '17 at 03:52

80

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"

answered Dec 18 '17 at 03:52

Travis Clarke

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I think you mean ws not wss as the protocol? – Rambatino Jul 07 '19 at 07:11
3

@Rambatino - The WebSocket protocol [specification](https://tools.ietf.org/html/rfc6455) defines both `ws` (WebSocket) and `wss` (WebSocket Secure). – Travis Clarke Jul 12 '19 at 18:05
aha neat! Thanks for the info :) – Rambatino Jul 19 '19 at 10:36
2

On Ubuntu Bionic it only worked via `sudo apt install node-ws` – Gaia Oct 04 '20 at 04:44
not working with linux pipes – Somebody Dec 08 '21 at 10:40

score 37 · Accepted Answer · answered Dec 18 '17 at 00:36

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

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

score 18 · Answer 3 · edited Nov 10 '19 at 14:33

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.

You forgot to mention that you need to enter the correct JSON request, so I added it. — not2qubit, Nov 10 '19 at 14:23
`websocat` got me running instantly, even on MacOS! `brew install websocat` then just give the socket server address on the command line and you have a conversation! Awesome! — NeilG, May 08 '21 at 12:36

score 3 · Answer 4 · answered Nov 10 '20 at 09:42

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

score 2 · Answer 5 · answered Jan 30 '20 at 11:40

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.

How to read websocket response in linux shell

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