index.js

/**
 * Author: petar bojinov - @pbojinov
 * Date: 01/27/16
 */

'use strict';

/**
 * Get client IP address
 *
 * Will return 127.0.0.1 when testing locally
 * Useful when you need the user ip for geolocation or serving localized content
 *
 * @method getClientIp
 * @param req
 * @returns {string} ip
 */
function getClientIp(req, startLevel) {

    // the ipAddress we return
    var ipAddress;

    // workaround to get real client IP
    // most likely because our app will be behind a [reverse] proxy or load balancer
    var clientIp = req.headers['x-client-ip'];
    var forwardedForAlt = req.headers['x-forwarded-for'];
    var realIp = req.headers['x-real-ip'];

    // more obsure ones below
    var clusterClientIp = req.headers['x-cluster-client-ip'];
    var forwardedAlt = req.headers['x-forwarded'];
    var forwardedFor = req.headers['forwarded-for'];
    var forwarded = req.headers['forwarded'];

    // remote address check
    var reqConnectionRemoteAddress = req.connection ? req.connection.remoteAddress : null;
    var reqSocketRemoteAddress = req.socket ? req.socket.remoteAddress : null;
    var reqConnectionSocketRemoteAddress = (req.connection && req.connection.socket) ? req.connection.socket.remoteAddress : null;
    var reqInfoRemoteAddress = req.info ? req.info.remoteAddress : null;

    // x-client-ip
    if (clientIp && startLevel <= 1) {
        ipAddress = clientIp;
    }

    // x-forwarded-for
    // (typically when your node app is behind a load-balancer (eg. AWS ELB) or proxy)
    else if (forwardedForAlt && startLevel <= 2) {
        // x-forwarded-for may return multiple IP addresses in the format: 
        // "client IP, proxy 1 IP, proxy 2 IP" 
        // Therefore, the right-most IP address is the IP address of the most recent proxy 
        // and the left-most IP address is the IP address of the originating client.
        // source: http://docs.aws.amazon.com/elasticloadbalancing/latest/classic/x-forwarded-headers.html
        var forwardedIps = forwardedForAlt.split(',');
        ipAddress = forwardedIps[0];
    }

    // x-real-ip 
    // (default nginx proxy/fcgi)
    else if (realIp && startLevel <= 3) {
        // alternative to x-forwarded-for, used by some proxies
        ipAddress = realIp;
    }

    // x-cluster-client-ip 
    // (Rackspace LB and Riverbed's Stingray)
    // http://www.rackspace.com/knowledge_center/article/controlling-access-to-linux-cloud-sites-based-on-the-client-ip-address
    // https://splash.riverbed.com/docs/DOC-1926
    else if (clusterClientIp && startLevel <= 4) {
        ipAddress = clusterClientIp;
    }

    // x-forwarded
    else if (forwardedAlt && startLevel <= 5) {
        ipAddress = forwardedAlt;
    }

    // forwarded-for
    else if (forwardedFor && startLevel <= 5) {
        ipAddress = forwardedFor;
    }

    // forwarded
    else if (forwarded && startLevel <= 5) {
        ipAddress = forwarded;
    }

    // remote address checks
    else if (reqConnectionRemoteAddress && startLevel <= 6) {
        ipAddress = reqConnectionRemoteAddress;
    }
    else if (reqSocketRemoteAddress && startLevel <= 7) {
        ipAddress = reqSocketRemoteAddress
    }
    else if (reqConnectionSocketRemoteAddress && startLevel <= 8) {
        ipAddress = reqConnectionSocketRemoteAddress
    }
    else if (reqInfoRemoteAddress && startLevel <= 9) {
        ipAddress = reqInfoRemoteAddress
    }

    // return null if we cannot find an address
    else {
        ipAddress = null;
    }

    console.log(ipAddress);
    return ipAddress;
}

/**
 * Expose mode public functions
 */
exports.getClientIp = getClientIp;


/**
 * Expose a default implemtation for a connect middleware
 *
 * @options.attributeName - name of attribute to augment request object with
 * @options.initialLevel - number of the level to start checking (based on how it works section of the documentation)
 */
exports.mw = function (options) {
    if (!options) options = {};
    var attr = options.attributeName || "clientIp";
    var startLevel = options.startLevel || 1;
    return function (req, res, next) {
        req[attr] = getClientIp(req, startLevel);
        next();
    }
};