chat.js

// http://ahoj.io/nodejs-and-websocket-simple-chat-tutorial

// http://ejohn.org/blog/ecmascript-5-strict-mode-json-and-more/
"use strict";

// Optional. You will see this name in eg. 'ps' or 'top' command
process.title = 'node-chat';

// Port where we'll run the websocket server
var webSocketsServerPort = 1338;

// websocket and http servers
var webSocketServer = require('websocket').server;
var http = require('http');
var fs = require('fs');
var S = require('string');

/**
 * Global variables
 */
// latest 100 messages
var history = [ ];
// list of currently connected clients (users)
var clients = [ ];
var userNames = [ ];

/**
 * Helper function for escaping input strings
 */
function htmlEntities(str) {
    return String(str).replace(/&/g, '&amp;').replace(/</g, '&lt;')
                      .replace(/>/g, '&gt;').replace(/"/g, '&quot;');
}

Object.size = function(obj) {
    var size = 0, key;

    for (key in obj) {
        if (obj.hasOwnProperty(key)) size++;
    }

    return size;
};

var sslOptions = {};

sslOptions = {
    key: fs.readFileSync("/etc/letsencrypt/live/comniemeer.de/privkey.pem"),
    cert: fs.readFileSync("/etc/letsencrypt/live/comniemeer.de/cert.pem")
};

/**
 * HTTP server
 */
var server = http.createServer(function(request, response) {
    console.log((new Date()) + " HTTP Server received request for " + request.url);
});

server.listen(webSocketsServerPort, function() {
    console.log((new Date()) + " HTTP Server is listening on port " + webSocketsServerPort);
});

/**
 * WebSocket server
 */
var wsServer = new webSocketServer({
    // WebSocket server is tied to a HTTP server. WebSocket request is just
    // an enhanced HTTP request. For more info http://tools.ietf.org/html/rfc6455#page-6
    httpServer: server
});

// This callback function is called every time someone
// tries to connect to the WebSocket server
wsServer.on('request', function(request) {
    console.log((new Date()) + ' Connection from origin ' + request.origin + '.');

    // accept connection - you should check 'request.origin' to make sure that
    // client is connecting from your website
    // (http://en.wikipedia.org/wiki/Same_origin_policy)
    var connection;

    if (request.origin != "http://agarchat.comniemeer.de") {
        connection = request.reject(102, 'gtfo');
        return;
    } else {
        connection = request.accept(null, request.origin);
    }

    var index = clients.push(connection) - 1;
    var userName = false;

    console.log((new Date()) + ' Connection accepted. IP: ' + connection.remoteAddress);

    // send back chat history
    if (history.length > 0) {
        connection.sendUTF(JSON.stringify( { type: 'history', data: history} ));
    }

    console.log("User verbunden: " + userNames.length);

    // user sent some message
    connection.on('message', function(message) {
        if (message.type === 'utf8') { // accept only text
            if (userName === false) {
                var requestedName = htmlEntities(message.utf8Data);

                if (userNames.indexOf(requestedName) != -1) {
                    var obj = {
                        time: (new Date()).getTime(),
                        text: "Der Name " + requestedName + " ist bereits vergeben."
                    };

                    connection.sendUTF(JSON.stringify({ type: 'command', data: obj }));
                } else if (requestedName.length > 20) {
                    var obj = {
                        time: (new Date()).getTime(),
                        text: "Der Name " + requestedName + " ist zu lang."
                    };

                    connection.sendUTF(JSON.stringify({ type: 'command', data: obj }));
                } else if (!requestedName.match("^[A-Za-zß0-9_.]+$")) {
                    var obj = {
                        time: (new Date()).getTime(),
                        text: "Der Name " + requestedName + " enthält ungültige Zeichen."
                    };

                    connection.sendUTF(JSON.stringify({ type: 'command', data: obj }));
                } else {
                    userName = requestedName;
                    userNames.push(userName);

                    connection.sendUTF(JSON.stringify({ type: 'login', name: userName}));

                    console.log((new Date()) + ' User is known as: ' + userName);
                }
            } else { // log and broadcast the message
                console.log((new Date()) + ' Received Message from ' + userName + ': ' + message.utf8Data);

                if (S(message.utf8Data).startsWith("/")) {
                    var command = message.utf8Data.replace("/", "");
                    var obj;

                    if (command == "help") {
                        obj = {
                            time: (new Date()).getTime(),
                            text: "Verfügbare Befehle:"
                                + "<br>/help - Zeigt alle Befehle an"
                                + "<br>/users - Zeigt aktuell verbundene User an"
                        };
                    } else if (command == "users") {
                        var usersString = "Angemeldete User: ";
                        var usersSize = userNames.length;

                        for (var i = 0; i < usersSize; i++) {
                            usersString += userNames[i];

                            if (i + 1 < usersSize) {
                                usersString += ", ";
                            }
                        }

                        obj = {
                            time: (new Date()).getTime(),
                            text: htmlEntities(usersString)
                        };
                    } else {
                        obj = {
                            time: (new Date()).getTime(),
                            text: htmlEntities("Unbekannter Befehl!")
                        };
                    }

                    var json = JSON.stringify({ type: 'command', data: obj });

                    connection.sendUTF(json);
                } else {
                    // we want to keep history of all sent messages
                    var obj = {
                        time: (new Date()).getTime(),
                        text: htmlEntities(message.utf8Data),
                        author: userName
                    };

                    history.push(obj);
                    history = history.slice(-100);

                    // broadcast message to all connected clients
                    var json = JSON.stringify({ type: 'message', data: obj });

                    for (var i = 0; i < clients.length; i++) {
                        clients[i].sendUTF(json);
                    }
                }
            }
        }
    });

    // user disconnected
    connection.on('close', function(connection) {
        if (userName !== false) {
            console.log((new Date()) + " Peer " + connection.remoteAddress + " disconnected.");
            clients.splice(index, 1);

            var userIndex = userNames.indexOf(userName);

            if (userIndex > -1) {
                userNames.splice(userIndex, 1);
            }
        }
    });
});