DevOps
NGINX Problems with configuring the websocket
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Introduction
Everything works ok when you deploy the app using nginx reverse proxy. But when you try to use webhooks it fails to access. So here is the solution to the webhook problem.
Managing Nginx Configuration and Websocket Connection Problems
When creating a WebSocket connection, the 'Unexpected server response: 400' problem can occur. This post explains how to fix it. This error is frequently caused by client or server-side configuration errors, particularly with regard to Nginx reverse proxy settings. It contains the required Nginx settings for WebSocket functionality, as well as possible problems and fixes.
Potential Causes and Solutions
1. The server's WebSocket is not configured correctly:
- Check that the server is set up correctly to manage connections via WebSocket on the designated endpoint. For WebSocket handshake, the server must support `Upgrade} and `Connection` headers.
- Example of setting up Nginx for WebSocket:
server { listen 80; server_name <domain_url>; location /socket.io/ { proxy_pass http://backend_server; proxy_http_version 1.1; proxy_set_header Upgrade $http_upgrade; proxy_set_header Connection "Upgrade"; proxy_set_header Host $host; proxy_set_header Sec-WebSocket-Key $http_sec_websocket_key; proxy_set_header Sec-WebSocket-Version $http_sec_websocket_version; proxy_set_header Sec-WebSocket-Extensions $http_sec_websocket_extensions; } }
2. Invalid Request Format:
Verify that the format of request complies with the WebSocket handshake requirements. The server may reject the request if any headers are missing/incorrect.
3. Server Blocking WebSocket Connection (Firewall/Proxy Issues):
Make sure that firewall or proxy between the client and server is blocking WebSocket traffic. Certain security setups, such as a Web Application Firewall (WAF), can prevent WebSocket connections.
4. Version Mismatch or Server Error:
To prevent version mismatches that result in unsuccessful handshakes, make sure that the client and server are running compatible versions of WebSocket libraries, such as Socket.IO.
5. Problems with SSL/TLS Configuration:
WebSocket connections may use HTTPS (wss://), therefore make sure SSL certificates are set up correctly and are functioning. The `openssl` command can be used to test SSL connectivity.
Changing the Nginx Configuration to Support WebSockets
You must set up Nginx to handle WebSocket handshakes by forwarding the relevant headers if your WebSocket connection is proxied via Nginx.
Modified configuration is shown below:
server {
listen 80;
server_name <domain_url>;
location / {
proxy_pass http://<IP>:<port>;
# WebSocket headers
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "Upgrade";
# Forwarding headers
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
# Optional: increase timeout for long-living WebSocket connections
proxy_read_timeout 86400s;
proxy_send_timeout 86400s;
}
}
To implement configuration, reload Nginx after making the modifications:
sudo nginx -s reload
To make sure the connection is formed correctly, you may also test the WebSocket connection with tools like `postman`.
Conclusion
It is frequently necessary to configure the server and proxy correctly in order to handle WebSocket problems, especially the Unexpected server response: 400. Verifying SSL/TLS setups, resolving possible version discrepancies between client and server libraries, and making sure WebSocket headers like Upgrade and Connection are appropriately delivered through Nginx are important considerations. These problems can be successfully fixed, resulting in a reliable WebSocket connection, with the right Nginx setup and debugging techniques including examining network traffic and server logs.
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