如何在 Node.js 中使用“x-forwarded-for”（如果可能，不使用 Express）

Question

For my current project, I need to get the remote IP address in a Node.js http.createServer((req,res)=>{}); function. I've tried looking through the API documentation for Node.js itself, with no luck, then turning to Google, with most answers appearing to use Express.js. The answers seemed to point at req.connection.remoteAddress (which works, but breaks if used with a proxy) or req.headers['x-forwarded-for'], however this returned undefined when I tried to use it. Any help is greatly appreciated.

Answer 1

You almost had it, try:

var clientip = req.headers['x-forwarded-for'] || req.connection.remoteAddress;

This will set clientip to the correct value if a proxy is used. If no proxy is used, clientip gets set to the ip address of the client initiating the connection.

Answer 2

'connection' is deprecated. since v13.0.0 - Use socket instead.

const clientip = req.headers['x-forwarded-for'] || req.socket.remoteAddress;