Source: org/terraswarm/accessor/accessors/web/hosts/node/node_modules/@accessors-modules/discovery/discovery.js

//Copyright (c) 2017 The Regents of the University of California.
//All rights reserved.

//Permission is hereby granted, without written agreement and without
//license or royalty fees, to use, copy, modify, and distribute this
//software and its documentation for any purpose, provided that the above
//copyright notice and the following two paragraphs appear in all copies
//of this software.

//IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
//FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
//ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
//THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
//SUCH DAMAGE.

//THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
//INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
//MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
//PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
//CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
//ENHANCEMENTS, OR MODIFICATIONS.

/**
 * Discover features of the local area network.
 *
 * @module @accessors-modules/discovery
 * @author Christopher Brooks
 * @version $$Id$$
 */

//Stop extra messages from jslint.  Note that there should be no
//space between the / and the * and global.
/*globals Java, actor, error, exports, IncomingMessage, require, util */

"use strict";

var os = require('os');

exports.DiscoveryService = function () {
    // This is called DiscoveryService, because the Cape Code Host has
    // ptolemy/actor/lib/jjs/modules/discovery/DiscoveryHelper.java
    // However, it might make more sense to follow Node and create
    // an os module for Cape Code.
    
    var discoveryService = {};

    /** Return the first IPv4 external IP address.
     *  @return The IP address
     */
    this.getHostAddress = function () {
        var networkInterfaces = os.networkInterfaces();
        for (var interfaceName in networkInterfaces) {
            if (networkInterfaces.hasOwnProperty(interfaceName)) {
                var networkInterface = networkInterfaces[interfaceName]
                for (var i = 0; i < networkInterface.length; i++) {
                    var subInterface = networkInterface[i];
                    if ( subInterface.family === 'IPv4'  && subInterface.internal === false) {
                        return subInterface.address;
                    }
                }
            }
        }
    }

    //return discoveryService;
}