Client is not using the websocket protocol: 'upgrade' token not found in 'Connection' header

Question

I am using Gorilla Websocket package to implement a websocket.

conn, err := upgrader.Upgrade(w, r, nil)

    if err != nil {
        // handle error
        fmt.Println(err)
    }
    defer conn.Close()

I am see the below error

websocket: the client is not using the websocket protocol: 'upgrade' token not found in 'Connection' header

I printed on the header of my request, and I am seeing the below

Sec-Fetch-User ?1
Sec-Fetch-Dest document
Referer http://localhost:4747/home
Cookie myGoLiveCookie=369d99fa-901d-4b23-a64b-4731247de304
Sec-Ch-Ua "Google Chrome";v="87", " Not;A Brand";v="99", "Chromium";v="87"
Sec-Ch-Ua-Mobile ?0
User-Agent Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/87.0.4280.88 Safari/537.36
Sec-Fetch-Site same-origin
Accept-Encoding gzip, deflate, br
Upgrade-Insecure-Requests 1
Accept text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Sec-Fetch-Mode navigate
Accept-Language en-GB,en-US;q=0.9,en;q=0.8
Connection keep-alive

There is no Upgrade websocket or Connection Upgrade as per expected

I believe I am facing the exact same issue as this one.

Answer 1

The browser js request ws connection method is wrong, the correct ws request code var ws = new WebSocket("ws://localhost:4747/ws");.

A correct ws request header, each header in it is necessary, but the value is different.

GET /chat HTTP/1.1
Host: example.com
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Key: x3JJHMbDL1EzLkh9GBhXDw==
Sec-WebSocket-Protocol: chat, superchat
Sec-WebSocket-Version: 13
Origin: http://example.com

Answer 2

If you are deploying the WS server in a VM and want this header to be there by default, update your Nginx config file like:

location /ws/ {
        proxy_set_header   X-Forwarded-For $remote_addr;
        proxy_set_header   Host $http_host;
        proxy_set_header Upgrade websocket;
        proxy_set_header Connection Upgrade;
        proxy_pass         "http://127.0.0.1:8089";
    }

proxy_set_header Upgrade websocket; proxy_set_header Connection Upgrade; will do the job for you even if the client has not passed the headers.