I'm fairly new to node.js and recently started to make some modules. However I've come to a point where communication between modules is required. Since this is not a problem I've encountered in the past I'm stuck with finding a clean solution.
This is the boilerplate I currently got (Left out some checks to make the code a bit smaller). The basic idea atm is joining any irc channel given by an http post.
bot.js
//Include services
var Webservice = require('./Webservice');
var Ircservice = require('./Ircservice');
//Create service instances
var webservice = new Webservice();
var ircservice = new Ircservice();
//Initialize services
webservice.init(1337);
ircservice.init('alt-irc.snoonet.org', 80, 'User');
//Handle events
ircservice.on('irc-registered', function(msg){
console.log(ircservice.connected);
ircservice.joinChannel('#testchannel')
});
ircservice.on('irc-join', function(channel){
console.log('Successfuly joined: ' + channel);
});
webservice.on('web-join', function(streamer){
ircservice.joinChannel('#' + streamer);
});
Webservice.js
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var util = require('util');
var EventEmitter = require('events').EventEmitter;
app.use(bodyParser.urlencoded({
extended: true
}));
var Webservice = function(){
EventEmitter.call(this);
};
Webservice.prototype.init = function(port){
app.listen(port, function () {
console.log('Webserver listening on ' + port);
});
this.initRoutes();
};
Webservice.prototype.initRoutes = function(){
var self = this;
//join a irc-channel
app.post('/join', function (req, res) {
var streamer = req.body.name;
self.emit('web-join', streamer);
res.send('Received')
});
};
util.inherits(Webservice, EventEmitter);
module.exports = Webservice;
Ircservice.js
var irc = require('irc');
var util = require('util');
var EventEmitter = require('events').EventEmitter;
var Ircservice = function(){
EventEmitter.call(this);
}
Ircservice.prototype.init = function(server, port, nick){
this.client = new irc.Client(server, nick, {
port: parseInt(port)
});
this.initListerners();
};
Ircservice.prototype.initListerners = function(){
var self = this;
this.client.addListener('message', function (from, to, message) {
console.log(from + ' => ' + to + ': ' + message);
});
this.client.addListener('join', function(channel, nick, message){
self.emit('irc-join', channel);
});
};
Ircservice.prototype.joinChannel = function(channel){
this.client.join(channel, null);
};
util.inherits(Ircservice, EventEmitter);
module.exports = Ircservice;
This example works perfectly, but as you can see the communication between my webservice and ircservice is handled by the bot.js. While this is perfectly fine for this example, I cannot use this method whenever I want.
Let say in the future I want to keep a list in my ircservice of all channels he has joined and display this through a webpage. I could keep a local array on my ircservice and on the join event add that channel to the array. But how do I continue on the webservice end. I can write an endpoint '/getchannels' but my webservice itself is not aware of the ircserver to get the channels (ircservice.getChannels or something similar) and firing an event in my web request doesn't feel like the way to go.
One solution that came up in my mind was passing the instances of the services to each other like webservice.setIrcservice(ircservice) and the other way around in the bot.js. But this feels like dirty code and a hard depency.
So how can I communicate between modules when I need data instantaneously and events are no option?
Related
I am using an eye tracker and I want to create a website that displays this data in real time. I have the eye tracker notifying a Node js server and it provides data really consistently but when I used socket.io to send the data over it was buffering really slowly. I want a way to receive this data in a script in my index.html from the Node js server in real time or as close as possible. Any suggestions?
I have found my solution in socket.io-streams. Here's what I did:
in the app.js:
var ss = require('socket.io-stream');
var Readable = require('stream').Readable;
const io = require('socket.io')(http);
io.of('/data').on('connection', socket => {
var eyeTracker = ...
var listener = {
...
onGazeData:function(gazeData){ //trigger for recieving a gaze location
var s = new Readable()
s._read = function() {};
var stream = ss.createStream();
toSend = gazeData.x + "," + gazeData.y
s.push(toSend);
s.pipe(stream);
ss(socket).emit('gaze',stream);
}
}
eyeTracker.setListener(listener);
});
app.get('/', function (req, res) {
res.sendFile(path.join(__dirname, 'index.html'));
}
and in the index.js (linked to index.html) I put:
var ss = require('socket.io-stream');
$(function(){
var socket = io.connect('http://localhost:3000/data'); //or where ever you are running
socket.on('connect', function() {
ss(socket).on('gaze', function(stream) {
stream.on('data', function(data) {
//do what you want with data
})
})
});
//other parts of script outside of socket
});
This solution was able to keep up with the data being streamed.
I'm trying to build my first node app. My app.js file is shown below. I want to access this from aother module by doing 'app = require('app')'. I then want to access app.app, app.dbConn and app.models
The problem is that when I require this module, app.models is not present on the resulting object.
var express = require('express');
var path = require('path');
var orm = require('orm');
var settings = require('./config/settings');
var mainRouter = require('./config/routes');
var environment = require('./config/environment');
var db = require('./config/db');
var auth = require('./modules/auth');
module.exports = new function(){
this.app = express();
// middlewares must be added in order - start with the basics
environment(this.app);
if (process.env.TESTING) { dbSettings = settings.dbTesting; }
else { dbSettings = settings.db; }
// add models to the request early in the middleware chain
this.dbConn = orm.connect(dbSettings, function(err){
if (err) return console.error('DB Connection error: ' + err);
else{
this.models = db.init(this.dbConn);
this.app.use(function(req,res,next){
req.models = this.models;
next();
});
passport = auth.init(this.models);
authRouter = auth.router(passport)
this.app.use('/users', authRouter);
this.app.use(mainRouter);
}
}.bind(this));
this.app.listen(settings.port);
console.log('Server started... listening on port ' + settings.port)
}
The only way to implement what I wanted was with a function that takes a callback, in the end I rewrote my code thus:
var express = require('express');
var path = require('path');
var orm = require('orm');
var settings = require('./config/settings');
var mainRouter = require('./config/routes');
var environment = require('./config/environment');
var db = require('./config/db');
var auth = require('./modules/auth');
var app;
module.exports = function(cb){
app = express();
// middlewares must be added in order - start with the basics
environment(app);
if (process.env.TESTING) { dbSettings = settings.dbTesting; }
else { dbSettings = settings.db; }
// add models to the request early in the middleware chain
dbConn = orm.connect(dbSettings, function(err){
if (err) return console.error('DB Connection error: ' + err);
else{
models = db.init(dbConn);
app.use(function(req,res,next){
req.models = models;
next();
});
passport = auth.init(this.models);
authRouter = auth.router(passport)
app.use('/users', authRouter);
app.use(mainRouter);
cb({
dbConn: dbConn,
app: app,
models: models
});
}
});
}
if (!process.env.TESTING) {
module.exports(function(server){
server.app.listen(settings.port);
console.log('Server started... listening on port ' + settings.port)
});
}
app.models is defined only once database connection is completed: you cannot use it right away after requiring the module. You should provide an entry point that accepts a function to call once the connection is ready and call this function inside the orm.connect callback.
Even the "server started" message is a bit misleading as it's shown before the server can actually do anything because the function passed to orm.connect has not been called yet.
app.models is never defined so it is never available.
Instead, try
app.set('models', db.init(this.dbConn);
sorry for posting this issue again, but most of the posts related don't answer my question.
i'm having issues to use multiple connections with the socket.io
i don't get the "socket.socket.connect" method to work, yet i get feedbacks from the first connection.
Here's my structure:
var iosocket = null;
var firstconnection = true;
var ip = "http://xxx.xxx.xxx"
var ipPort = 8081
function callSocket() {
iosocket = null;
iosocket = io.connect(ip,{port:ipPort,rememberTransport:true, timeout:1500});
if (firstconnection) {
firstconnection= false;
iosocket = io.connect(ip,{port:ipPort,rememberTransport:true, timeout:1500});
iosocket.on('connect', function () {console.log("hello socket");});
iosocket.on('message', function(message) {});//end of message io.socket
iosocket.on('disconnect', function () {console.log("disconnected");});
} else {
if (iosocket.connected === true) {
console.log("heyhey still connected");
iosocket.disconnect();
}
iosocket.socket.connect(ip,{port:ipPort,rememberTransport:true,timeout:1500});
}
};
it simply doesn't get any feedback from the second connection
i simply solved that IE8 bug by adding
<!DOCTYPE html>
at the top of the html
I think I know why this isn't working. For server-side code, this doesn't seem correct for socket.io. The connect method is used for clients and not servers. I think you are trying to make the server listen on a port. In that case, you should do:
var socket = require('socket.io');
var express = require('express');
var http = require('http');
var app = express();
var server = http.createServer(app);
var io = socket.listen(server);
io.on('connection', function (client) {
client.on('someEvent', function(someVariables){
//Do something with someVariables when the client emits 'someEvent'
io.emit('anEventToClients', someData);
});
client.on('anotherEvent', function(someMoreVariables){
//Do more things with someMoreVariables when the client emits 'anotherEvent'
io.emit('anotherEventToClients', someMoreData);
});
});
server.listen(8000);
I'm going through a Node, Express, & Socket.io chat tutorial. I decided to use Redis to store the chat history and have successfully set it up so that my information is correctly posting to the database. I am now trying to access that information to use on the client-side (in this case I'm trying to access the list of users currently in the chat so I can show them to the side of the chat). I am using $.getJSON to make a GET request. Right now I have it setup so that the file it tries to access only has this JSON object : {"dog" : "2","cat":"3"} just to test it, and that is working, but I'm not sure where to go from there because anytime I try adding a function into that file, even if I specify to return a JSON object and call that function, the request stops returning the correct information.
For example I tried :
var data = function(){
return {"dog" : "2","cat":"3"}
}
data();
and that doesn't return anything ( I understand that when I make a GET request the function isn't run, but it doesn't even return that text, and if it doesn't run a function than I'm not sure how I can access redis from this file)
Here's what I'm thinking:
var redis = require('redis')
//figure out how to access the redis client that I have at localhost:6379, something like var db = redis.X
//and then call (for example) db.smembers('onlineUsers') and be returned the object which I can iterate through
Here's my relevant code:
server.js:
var jade = require('jade');
var PORT = 8080;
var redis = require('redis');
var db = redis.createClient();
var pub = redis.createClient();
var sub = redis.createClient();
var http = require('http');
var express = require('express');
var app = express();
var server = http.createServer(app);
var io = require('socket.io').listen(server);
server.listen(PORT, function(){
console.log("Now connected on localhost:" + PORT)
});
app.set('views', __dirname + '/views');
app.set('view engine', 'jade');
app.set("view options", {layout: false});
app.use(express.static(__dirname + '/public'));
app.get('/', function(req, res){
res.render('home');
});
io.sockets.on('connection', function(client){
sub.subscribe("chatting");
sub.on("message", function (channel, message) {
console.log("message received on server from publish");
client.send(message);
});
client.on("sendMessage", function(msg) {
pub.publish("chatting",msg);
});
client.on("setUsername", function(user){
pub.publish("chatting","A new user in connected:" + user);
db.sadd("onlineUsers",user);
}
);
client.on('disconnect', function () {
sub.quit();
pub.publish("chatting","User is disconnected :" + client.id);
});
});
script.js:
$(document).ready( function(){
$client = io.connect();
initialize();
});
var setUsername = function(){
var username = $("#usernameInput").val();
if (username)
{
var user = username;
$client.emit('setUsername', username);
$('#chatControls').show();
$('#usernameInput').hide();
$('#usernameSet').hide();
showCurrentUsers();
}
}
var showCurrentUsers = function(){
$('#list_of_users').empty();
$.getJSON('getusers.js', function(data){
for (var i = 0; i < data.length; i++){
$('list_of_users').append("<li>"+data[i]+"</li>")
}
})
}
var sendMessage = function(){
var msg = $('#messageInput').val();
var username = $("#usernameInput").val();
if (msg)
{
var data = {msg: msg, user: username}
$client.emit('message', data);
addMessage(data);
$('#messageInput').val('');
// populate(username,msg);
}
}
var addMessage = function(data) {
$("#chatEntries").append('<div class="message"><p>' + data.user + ' : ' + data.msg + '</p></div>');
}
// var populate = function(username,msg) {
// var data ;
// }
var initialize = function(){
$("#chatControls").hide();
$("#usernameSet").on('click', setUsername);
$("#submit").on('click',sendMessage);
showCurrentUsers();
}
and right now all that the getusers.js file has in it is:
{"dog" : "2","cat":"3"}
It looks like you're expecting your call to $.getJSON to load and execute the javascript it loads. It doesn't work this way. You need to make a node endpoint (via a route) which renders the JSON. The node endpoint would then do the data manipulation / querying redis:
Node:
In routes.js:
app.get('/chatdata', ChatController.getChatData);
In ChatController.js (manipulate, create the data as you like here)
exports.getChatData = function (req, res) {
var data = function(){
return {"dog" : "2","cat":"3"}
};
res.JSON(data);
};
Front-end
$.getJSON('getChatData', function(data){
//...
})
I think you need to setup a route to handle the GET request that $.getJSON makes, or if getusers.js is in the /public directory, then you need to modify your $.getJSON call as follows:
$.getJSON('http://localhost:8080/public/getusers.js', function(data){
Ok, it looks like it is a problem with your getusers.js file. $.getJSON seems to prefer double quotes. Try formatting it like this:
{
"dog" : "2",
"cat" : "3"
}
Also, try using this to display the data:
$.getJSON('getusers.js', function(data){
var items = [];
$.each( data, function( key, val ) {
items.push("<li id='" + key + "'>" + val +"</li>");
});
$('#list_of_users').append(items.join(""));
});
Lets say I have a JavaScript file that needs to communicate with other JavaScript file. So I could use this data in different javascript file.
In this case I have a game_server.js. In the gameserver.js I have two variables which I would like to use in the gamecore.js
var host // host of the game
var client // client that had joined the game
I would like to send them to the socket.io in de app.js and then use this variables in the game_core.js. So I can have data about the host and the client.
In the gamecore class i would like to have something like this
game_core.prototype.getPlayerInformation = function(data) {
this.host = data.host
this.client = data.client
}
It is all about getting information from the serverside to the clientside and the best way to do it is trough socket.io but i really don't know how
Also in the game_server script there is a instance for a game
game_server.createGame = function(player) {
//Create a new game instance
var thegame = {
id : UUID(), //generate a new id for the game
player_host:player, //so we know who initiated the game
player_client:null, //nobody else joined yet, since its new
player_count:1 //for simple checking of state
};
In the game_core the instance of a game is declared
var game_core = function(game_instance) {
//Store the instance, if any
this.instance = game_instance;
}
So it should be possible to get the player_host and player_client?
server.js
var app = require('express')()
, server = require('http').createServer(app)
, io = require('socket.io').listen(server);
server.listen(80);
var Game_core = function(){}
Game_core.prototype.getPlayerInformation = function(data)
{
this.host = data.host
this.client = data.client
return {host: this.host, client: this.client}
}
var game_core = new Game_core()
io.sockets.on('connection', function (socket) {
socket.emit('login', game_core.getPlayerInformation);
});
client.js
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('login', function(data){
console.log(data); // {host: xx, client: xx}
})
</script>