Cloned DMOJ

websocket/daemon.js

@@ -0,0 +1,206 @@
+var config = require('./config');
+var set = require('simplesets').Set;
+var queue = require('qu');
+var WebSocketServer = require('ws').Server;
+var wss_receiver = new WebSocketServer({host: config.get_host, port: config.get_port});
+var wss_sender = new WebSocketServer({host: config.post_host, port: config.post_port});
+var messages = new queue();
+var followers = new set();
+var pollers = new set();
+var max_queue = config.max_queue || 50;
+var long_poll_timeout = config.long_poll_timeout || 60000;
+var message_id = Date.now();
+
+if (typeof String.prototype.startsWith != 'function') {
+    String.prototype.startsWith = function (str){
+        return this.slice(0, str.length) == str;
+    };
+}
+
+messages.catch_up = function (client) {
+    this.each(function (message) {
+        if (message.id > client.last_msg)
+            client.got_message(message);
+    });
+};
+
+messages.post = function (channel, message) {
+    message = {
+        id: ++message_id,
+        channel: channel,
+        message: message
+    };
+    this.push(message);
+    if (this.length > max_queue)
+        this.shift();
+    followers.each(function (client) {
+        client.got_message(message);
+    });
+    pollers.each(function (request) {
+        request.got_message(message);
+    });
+    return message.id;
+};
+
+messages.last = function () {
+    return this.tail().id;
+};
+
+wss_receiver.on('connection', function (socket) {
+    socket.channel = null;
+    socket.last_msg = 0;
+
+    var commands = {
+        start_msg: function (request) {
+            socket.last_msg = request.start;
+        },
+        set_filter: function (request) {
+            var filter = {};
+            if (Array.isArray(request.filter) && request.filter.length > 0 &&
+                request.filter.every(function (channel, index, array) {
+                    if (typeof channel != 'string')
+                        return false;
+                    filter[channel] = true;
+                    return true;
+            })) {
+                socket.filter = filter;
+                followers.add(socket);
+                messages.catch_up(socket);
+            } else {
+                socket.send(JSON.stringify({
+                    status: 'error',
+                    code: 'invalid-filter',
+                    message: 'invalid filter: ' + request.filter
+                }));
+            }
+        },
+    };
+
+    socket.got_message = function (message) {
+        if (message.channel in socket.filter)
+            socket.send(JSON.stringify(message));
+        socket.last_msg = message.id;
+    };
+
+    socket.on('message', function (request) {
+        try {
+            request = JSON.parse(request);
+        } catch (err) {
+            socket.send(JSON.stringify({
+                status: 'error',
+                code: 'syntax-error',
+                message: err.message
+            }));
+            return;
+        }
+        request.command = request.command.replace(/-/g, '_');
+        if (request.command in commands)
+            commands[request.command](request);
+        else
+            socket.send(JSON.stringify({
+                status: 'error',
+                code: 'bad-command',
+                message: 'bad command: ' + request.command
+            }));
+    });
+
+    socket.on('close', function(code, message) {
+        followers.remove(socket);
+    });
+});
+
+wss_sender.on('connection', function (socket) {
+    var commands = {
+        post: function (request) {
+            if (typeof request.channel != 'string')
+                return {
+                    status: 'error',
+                    code: 'invalid-channel'
+                };
+            return {
+                status: 'success',
+                id: messages.post(request.channel, request.message)
+            };
+        },
+        last_msg: function (request) {
+            return {
+                status: 'success',
+                id: message_id,
+            };
+        }
+    };
+    socket.on('message', function (request) {
+        try {
+            request = JSON.parse(request);
+        } catch (err) {
+            socket.send(JSON.stringify({
+                status: 'error',
+                code: 'syntax-error',
+                message: err.message
+            }));
+            return;
+        }
+        request.command = request.command.replace(/-/g, '_');
+        if (request.command in commands)
+            socket.send(JSON.stringify(commands[request.command](request)));
+        else
+            socket.send(JSON.stringify({
+                status: 'error',
+                code: 'bad-command',
+                message: 'bad command: ' + request.command
+            }));
+    });
+});
+
+var url = require('url');
+require('http').createServer(function (req, res) {
+    var parts = url.parse(req.url, true);
+
+    if (!parts.pathname.startsWith('/channels/')) {
+        res.writeHead(404, {'Content-Type': 'text/plain'});
+        res.end('404 Not Found');
+        return;
+    }
+
+    var channels = parts.pathname.slice(10).split('|');
+    if (channels.length == 1 && !channels[0].length) {
+        res.writeHead(400, {'Content-Type': 'text/plain'});
+        res.end('400 Bad Request');
+        return;
+    }
+
+    req.channels = {};
+    req.last_msg = parseInt(parts.query.last);
+    if (isNaN(req.last_msg)) req.last_msg = 0;
+
+    channels.forEach(function (channel) {
+        req.channels[channel] = true;
+    });
+
+    req.on('close', function () {
+        pollers.remove(req);
+    });
+
+    req.got_message = function (message) {
+        if (message.channel in req.channels) {
+            res.writeHead(200, {'Content-Type': 'application/json'});
+            res.end(JSON.stringify(message));
+            pollers.remove(req);
+            return true;
+        }
+        return false;
+    };
+    var got = false;
+    messages.each(function (message) {
+        if (!got && message.id > req.last_msg)
+            got = req.got_message(message);
+    });
+    if (!got) {
+        pollers.add(req);
+        res.setTimeout(long_poll_timeout, function () {
+            pollers.remove(req);
+            res.writeHead(504, {'Content-Type': 'application/json'});
+            res.end('{"error": "timeout"}');
+        });
+    }
+}).listen(config.http_port, config.http_host);