Test a WebSocket using curl.

curl-websocket.sh

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" \
     http://example.com:80/

Worked for me. Thanks

response

HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: qGEgH3En71di5rrssAZTmtRTyFk=

Thanks for the information. Will this curl causes a websocket connection leak if i don't kill the command?

it's a short-lived connection.

Just for my convenience:

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" \
    http://example.com:80/

I recommend adding --http1.1 to your curl command. The Connection and Upgrade headers are not valid in http/2 and curl will use http/2 if your server supports it.

I lost a few hours trying to figure out why these headers were disappearing when debugging my httpd web socket rewrite rules for the first time.

Once curl opens up the connection to the websocket, how to send other commands

I recommend adding --http1.1 to your curl command. The Connection and Upgrade headers are not valid in http/2 and curl will use http/2 if your server supports it.

I lost a few hours trying to figure out why these headers were disappearing when debugging my httpd web socket rewrite rules for the first time.

^^ this. and also -o - after the curl command so you dont get the binary output warning.

curl -o - --http1.1 --include \

For those who failed the request with Sec-WebSocket-Key, RFC 6455 does require the key to be 16 bytes and the resulting base64 encoded string must be 24 bytes long as @moolitayer quoted. The example from Wikipedia "x3JJHMbDL1EzLkh9GBhXDw==" does a great job. Or simply add some padding to the gist SGVsbG8sIHdvcmxkIQAAAA== also works.

with recent browsers like firefox92, copy as curl in network will add the required settings, you only have to change wss:// to http://

did anybody try same command using TLS? to "wss://echo.websocket.org"

Replacing "http://" with "https://" in the curl command seems to do the trick.

Curious whether anyone has gotten a clean termination after the first message, along the lines of websocat --one-message .... I tried using --max-time, but the curl return status ends up being nonzero.

I recommend adding --http1.1 to your curl command. The Connection and Upgrade headers are not valid in http/2 and curl will use http/2 if your server supports it.

I lost a few hours trying to figure out why these headers were disappearing when debugging my httpd web socket rewrite rules for the first time.

Thanks, it works!

curl --include \
   --header "Connection: Upgrade" \
   --header "Upgrade: websocket" \
   --header "Sec-WebSocket-Key: qwerty" \
   http://localhost:8000/

This worked for me. I didn't need all the header items

Anyone know if you can use this to send data (i.e. from stdin or a file) through the web socket? I tried -T -, but that doesn't seem to work.

curl --include \
    -H "Connection: Upgrade" \
    -H "Upgrade: websocket" \
    -H "Sec-WebSocket-Key: qwerty" \
    -H "Sec-WebSocket-Version: 13" \
    https://example.com -k

Hi,

@silvioprog @jageee

I am also using this command:

curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: echo.websocket.org" -H "Origin: https://www.websocket.org" https://echo.websocket.org

but I am getting a 200 response instead of the 101.

Any ideas?

1. You need to use HTTP/1.1
2. You have specified too few headers

$ curl --http1.1 -i -N -H 'Sec-Websocket-Version: 13' -H 'Sec-Websocket-Key: QUo86XL2bHszCCpigvKqHg==' -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: echo.websocket.org" -H "Origin: https://www.websocket.org" https://echo.websocket.org
HTTP/1.1 101 Switching Protocols
upgrade: websocket
connection: Upgrade
sec-websocket-accept: 8dlVwoWynsF/RauFo6HjkWl7dLk=
date: Thu, 25 Apr 2024 14:28:01 GMT
server: Fly/610c12e9 (2024-04-23)
via: 1.1 fly.io
fly-request-id: 01HWATFYXA0Y3STERG1SCHNQS2-ams

 Request served by 7811941c69e658

Thanks @vi that worked perfectly!

I recommend adding --http1.1 to your curl command. The Connection and Upgrade headers are not valid in http/2 and curl will use http/2 if your server supports it.

I lost a few hours trying to figure out why these headers were disappearing when debugging my httpd web socket rewrite rules for the first time.

You saved my life haha. I wasted so much time thinking my move to E2EE was the issue but stupid ActionCable and AWS Target Group using HTTP/2 was the issue! 🤦

Time to look into AnyCable or something else. Thank you!

I got status code 400 :"

I tried to connect to websocket server with simple setup using ws library:

const { WebSocketServer } = require('ws');

const wss = new WebSocketServer({ port: 8080 });

wss.on('connection', function connection(ws) {
  ws.on('error', console.error);

  ws.on('message', function message(data) {
    console.log('received: %s', data);
  });

  ws.send('something');
});

and I can't use curl to test it:

curl --include \
     --no-buffer \
     --header "Connection: Upgrade" \
     --header "Upgrade: websocket" \
     --header "Host: localhost:8080" \
     --header "Origin: http://localhost:8080" \
     --header "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \
     --header "Sec-WebSocket-Version: 13" \
     http://localhost:8080/
HTTP/1.1 400 Bad Request
Connection: close
Content-Type: text/html
Content-Length: 43

Missing or invalid Sec-WebSocket-Key header

browser developer tools on the network tab have copy as curl value, however it seems still no luck:

curl 'ws://localhost:8080/' -H 'User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0' -H 'Accept: */*' -H 'Accept-Language: en-US,en;q=0.7,id;q=0.3' -H 'Accept-Encoding: gzip, deflate, br, zstd' -H 'Sec-WebSocket-Version: 13' -H 'Origin: null' -H 'Sec-WebSocket-Extensions: permessage-deflate' -H 'Sec-WebSocket-Key: 3tMWYzcHwmObiLR3nWOgsg==' -H 'Connection: keep-alive, Upgrade' -H 'Sec-Fetch-Dest: empty' -H 'Sec-Fetch-Mode: websocket' -H 'Sec-Fetch-Site: cross-site' -H 'Pragma: no-cache' -H 'Cache-Control: no-cache' -H 'Upgrade: websocket'
curl: (22) Refused WebSockets upgrade: 400

okay, changing Sec-WebSocket-key with the one provided from browser works (not sure why):

curl --include \
     --no-buffer \
     --header "Connection: Upgrade" \
     --header "Upgrade: websocket" \
     --header "Host: localhost:8080" \
     --header "Origin: http://localhost:8080" \
     --header "Sec-WebSocket-Key: 3tMWYzcHwmObiLR3nWOgsg==" \
     --header "Sec-WebSocket-Version: 13" \
     http://localhost:8080/
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: YLxhg+bEzrZXCaOyyI5QkRBIdT4=

�       something

EDIT:
after reading the wikipedia, turned out it just a random 16-byte encoded with base64, on Linux, you can generate it with:

head -c 16 /dev/urandom | base64