How to get client IP address in Azure Functions node.js?

Question

I have an Azure function written on node.js. How could I retrieved an IP address of a client that called the function?

What I've found so far:

1. An answer to the same question, but using C#.

2. It is possible to read it from headers:

    module.exports = function (context, req) { var ip = req.headers['x-forwarded-for'] }

Is it reliable to get the ip this way, since it can be easily changed on the way to the function?

Answer 1

是的，它是可靠的，因为 Azure Web 服务器将覆盖 x-forwarded-for，因为它知道它是从负载均衡器转发的。

Answer 2

If you're using express , consider setting app.set('trust proxy');

For more information, check the express manual page on 'Express behing proxies'

Answer 3

I came across this question while looking for how to determine the client IP address. Did a quick test and it seems this is no longer correct. Azure happily forwards anything I put in the x-forwarded-for header to the node server. It does appear to append the correct IPs on the end however.

From my research it seems that "client-ip" is not forwarded and does contain the correct IP, but I've not been able to confirm this yet.

Screenshot below is from Postman where I've provided x-forwarded-for and client-ip headers and the returned body is a simple dump of all headers from a nodeJs express application.

app.get("/headers", (req, res) => {
  res.send(req.headers)
})

x-forwarded-for does contain the client ip, but also the one I specified. client-ip however does not. I've not been able to find any documentation on this yet. I'll try to update this answer with a sourced link if I can find one.