check real-ip IP address with javascript for nodejs

Question

check real-ip IP address with javascript for nodejs

I have this code as part of a nodejs application that runs behind an nginx proxy:

var ip_address = (request.headers['x-real-ip']);
if (ip_address !== "127.0.0.1") {
    var ip = request.headers['x-real-ip'];
    console.log(ip);    
}
else {
    var ip = "173.194.41.100";
    console.log(ip);
}

What I am trying to achieve is that on my local dev machine, for testing i use a fixed IP address, otherwise it reads the x-real-ip from the request header.

My question, is there a way to make this more full proof, for example, is there a way to by pass this loop thus making the var ip return null, which would create a traceback on my app?

javascript
node.js

Answer 1

My question, is there a way to make this more full proof, for example, is there a way to by pass this loop thus making the var ip return null, which would create a traceback on my app?

If you change it slightly, we can be sure that ip will not be null:

var ip, ip_address;
ip = ip_address = request.headers['x-real-ip'];
if (ip === null || ip === "127.0.0.1") {
    ip = "173.194.41.100";
}
console.log(ip);

Your original code would make ip null if request.headers['x-real-ip'] evaluated to null, because your condition (ip_address !== "127.0.0.1") would be true, and you'd grab request.headers['x-real-ip'] (null) into ip.

With the modified code above, we don't have that problem, and we've been able to make it a bit more concise as well.