Node.js将JavaScript连接到app.js

Question

This is a super simple question but i am really new to Node, i'm reading all the beginners guide now so no need to direct me to them! guides tell you how to use node not how to get the thing working!

I'm finding node.js tutorials assume way too much knowledge and set up.

i have my app.js file which contains:

SERVER SIDE

/**
 * Module dependencies.
 */

var express = require('express');
var routes = require('./routes');
var user = require('./routes/user');
var http = require('http');
var path = require('path');

// New Code

var mongo = require('mongojs');
var db = mongo('site');
var app = express();

// all environments
app.set('port', process.env.PORT || 80);
app.set('views', path.join(__dirname, 'views'));
app.engine('html', require('ejs').renderFile);
app.use(express.favicon());
app.use(express.logger('dev'));
app.use(express.json());
app.use(express.urlencoded());
app.use(express.methodOverride());
app.use(express.cookieParser('your secret here'));
app.use(express.session());
app.use(app.router);
app.use(express.static(path.join(__dirname, 'public')));

// development only
if ('development' == app.get('env')) {
  app.use(express.errorHandler());
}



app.get('/libraries/*', function(req, res){
    req.url.replace('/libraries', ''); // remove libraries prefix
    var path = req.url.split("/libraries").pop();
    console.log(path);
    switch (path) {
        case '/socket.io/socket.io.js':
            res.sendfile('node_modules/socket.io/node_modules/socket.io-client/dist/socket.io.js');
            break;
    }

});

// setup server
var server = http.createServer(app).listen(app.get('port'), function(){
  console.log('Express server listening on port ' + app.get('port'));
});

// setup socket
var io = require('socket.io').listen(server);

CLIENT SIDE:

var socket = io.connect();
socket.on('ready', function (data) {
    marketData = data; // raw data from the DB 
});

All good and well.

I want to console log 'test' into the website console.

My assumption is i define a function server side and call it client side... How on earth do I do this?!?!

I just want them to talk to each other.

Server side i would like to define a var and call it client side.

My assumption:

Server side:

function test () {
console.log ('test');
}

Client side:

test();

Console on my website says: 'test'.

Answer 1

Expeting that you want to do communications with Socket.io, add to the bottom of your server script:

io.sockets.on('connection', function (socket) {
    // Do what you need to do here and finally emit "read"
    // here setTimeout simulates your database query or similar
    // process of building the data you want to send to the client
    setTimeout(function (data) {
        socket.emit('ready', data);
    }, 1000);
});

then at the client side have:

var socket = io.connect();
socket.on('ready', function (data) {
    marketData = data; // raw data from the DB 
    test();
});

When your client connects, the server will run your business logics and send back the data by emitting "ready" event to the client. I added call for test() in your client event handler that might help on understanding the process.

Answer 2

To get a connection between your javascript (client side) and the server the below should work:

Client side:

socket.on('news', function (data) {
  console.log(data);
});

Server side:

io.sockets.on('connection', function (socket) {
    socket.emit('news', { hello: 'world' });
});

Will console log your data which is an object { hello: 'world' }