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/

I keep getting

HTTP/1.1 400 bad Sec-WebSocket-Key (length must be 24 ASCII chars) 'SGVsbG8sIHdvcmxkIQ=='
Where do I get this key from?

You don't need a specific key - the one supplied here should work.
The pourpose of that header is to prevent caching of websocket requests.

See https://en.wikipedia.org/wiki/WebSocket#Protocol_handshake

I get 400 error,

curl -i --no-buffer -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: localhost:9191" -H "Origin: http://localhost:9191" -H "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" -H "Sec-WebSocket-Version: 13" localhost:9191/chat?q=a
HTTP/1.1 400 Bad Request
Server: akka-http/10.0.10
Date: Mon, 04 Dec 2017 08:36:32 GMT
Content-Type: text/plain; charset=UTF-8
Content-Length: 34

Expected WebSocket Upgrade request

It works when I use Dark WSock terminal(a chrome plugin).

Akka Http Endpoint

  val handle: Flow[Message, Message, _] = Flow[Message].map {
    case TextMessage.Strict(event) =>
      sentimentProcessor ? event match {
        case emitted: Seq[ActionResult] =>
          TextMessage(emitted.head)
      }
    case _ => TextMessage("Event type unsupported")
  }

      path("chat") {
        get {
          handleWebSocketMessages(handle)
        }
      }

What if you want to send data on the web socket? Right now it looks like you're just sending a bunch of headers. I assume "--no-buffer" means there is no data being sent to the endpoint.

this command works for me:
curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" -H "Host: echo.websocket.org" -H "Origin: https://www.websocket.org" https://echo.websocket.org

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

@jageee I tried your above command and Mac OS returned, "no URL Specified!" And also https://echo.websocket.org returns 404 if visited.

I'd like to advertise my new tool websocat. It is designed to make easy to do tricky things with websockets.

You can check availability of a web socket without transferring any data:

$ websocat -q -uU ws://echo.websocket.org/ 2> /dev/null; echo  $?
0
$ websocat -q -uU ws://echo.websocket.org/404 2> /dev/null; echo  $?
1

@jageee you should just add the "--cacert" cURL option with the CA certificate (pem/der)
curl -i -N --cacert cafile.pem -H ....

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!