Category Archives: socket.io

Yet Another example of WebSockets, socket.io and AngularJs working with a Silex backend

Remember my last post about WebSockets and AngularJs? Today we’re going to play with something similar. I want to create a key-value interface to play with websockets. Let me explain it a little bit.

First we’re going to see the backend. One Silex application with two routes: a get one and a post one:

<?php

include __DIR__ . '/../../vendor/autoload.php';
include __DIR__ . '/SqlLiteStorage.php';

use Silex\Application;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Silex\Provider\DoctrineServiceProvider;

$app = new Application([
    'debug'      => true,
    'ioServer'   => 'http://localhost:3000',
    'httpServer' => 'http://localhost:3001',
]);

$app->after(function (Request $request, Response $response) {
    $response->headers->set('Access-Control-Allow-Origin', '*');
});

$app->register(new G\Io\EmitterServiceProvider($app['httpServer']));
$app->register(new DoctrineServiceProvider(), [
    'db.options' => [
        'driver' => 'pdo_sqlite',
        'path'   => __DIR__ . '/../../db/app.db.sqlite',
    ],
]);
$app->register(new G\Io\Storage\Provider(new SqlLiteStorage($app['db'])));

$app->get('conf', function (Application $app, Request $request) {
    $chanel = $request->get('token');
    return $app->json([
        'ioServer' => $app['ioServer'],
        'chanel'   => $chanel
    ]);
});

$app->get('/{key}', function (Application $app, $key) {
    return $app->json($app['gdb.get']($key));
});

$app->post('/{key}', function (Application $app, Request $request, $key) {
    $content = json_decode($request->getContent(), true);

    $chanel = $content['token'];
    $app->json($app['gdb.post']($key, $content['value']));

    $app['io.emit']($chanel, [
        'key'   => $key,
        'value' => $content['value']
    ]);

    return $app->json(true);
});

$app->run();

As we can see we register one service provider:

$app->register(new G\Io\Storage\Provider(new SqlLiteStorage($app['db'])));

This provider needs an instance of StorageIface

namespace G\Io\Storage;

interface StorageIface
{
    public function get($key);

    public function post($key, $value);
}

Our implementation uses SqlLite, but it’s pretty straightforward to change to another Database Storage or even a NoSql Database.

use Doctrine\DBAL\Connection;
use G\Io\Storage\StorageIface;

class SqlLiteStorage implements StorageIface
{
    private $db;

    public function __construct(Connection $db)
    {
        $this->db = $db;
    }

    public function get($key)
    {
        $statement = $this->db->executeQuery('select value from storage where key = :KEY', ['KEY' => $key]);
        $data      = $statement->fetchAll();

        return isset($data[0]['value']) ? $data[0]['value'] : null;
    }

    public function post($key, $value)
    {
        $this->db->beginTransaction();

        $statement = $this->db->executeQuery('select value from storage where key = :KEY', ['KEY' =>; $key]);
        $data      = $statement->fetchAll();

        if (count($data) > 0) {
            $this->db->update('storage', ['value' => $value], ['key' => $key]);
        } else {
            $this->db->insert('storage', ['key' => $key, 'value' => $value]);
        }

        $this->db->commit();

        return $value;
    }
}

We also register another Service provider:

$app->register(new G\Io\EmitterServiceProvider($app['httpServer']));

This provider’s responsibility is to notify to the websocket’s server when anything changes within the storage:

namespace G\Io;

use Pimple\Container;
use Pimple\ServiceProviderInterface;

class EmitterServiceProvider implements ServiceProviderInterface
{
    private $server;

    public function __construct($url)
    {
        $this->server = $url;
    }

    public function register(Container $app)
    {
        $app['io.emit'] = $app->protect(function ($chanel, $params) use ($app) {
            $s = curl_init();
            curl_setopt($s, CURLOPT_URL, '{$this->server}/emit/?' . http_build_query($params) . '&_chanel=' . $chanel);
            curl_setopt($s, CURLOPT_RETURNTRANSFER, true);
            $content = curl_exec($s);
            $status  = curl_getinfo($s, CURLINFO_HTTP_CODE);
            curl_close($s);

            if ($status != 200) throw new \Exception();

            return $content;
        });
    }
}

The Websocket server is a simple socket.io server as well as a Express server to handle the backend’s triggers.

var
    express = require('express'),
    expressApp = express(),
    server = require('http').Server(expressApp),
    io = require('socket.io')(server, {origins: 'localhost:*'})
    ;

expressApp.get('/emit', function (req, res) {
    io.sockets.emit(req.query._chanel, req.query);
    res.json('OK');
});

expressApp.listen(3001);

server.listen(3000);

Our client application is an AngularJs application:

<!doctype html>
<html ng-app="app">
<head>
    <script src="//localhost:3000/socket.io/socket.io.js"></script>
    <script src="assets/angularjs/angular.js"></script>
    <script src="js/app.js"></script>
    <script src="js/gdb.js"></script>
</head>
<body>
 
<div ng-controller="MainController">
    <input type="text" ng-model="key">
    <button ng-click="change()">change</button>
</div>
 
</body>
</html>
angular.module('app', ['Gdb'])

    .run(function (Gdb) {
        Gdb.init({
            server: 'http://localhost:8080/gdb',
            token: '4b96716bcb3d42fc01ff421ea2cfd757'
        });
    })

    .controller('MainController', function ($scope, Gdb) {
        $scope.change = function () {
            Gdb.set('key', $scope.key).then(function() {
                console.log(&quot;Value set&quot;);
            });
        };

        Gdb.get('key').then(function (data) {
            $scope.key = data;
        });

        Gdb.watch('key', function (value) {
            console.log(&quot;Value updated&quot;);
            $scope.key = value;
        });
    })
;

As we can see the AngularJs application uses one small library called Gdb to handle the communications with the backend and WebSockets:

angular.module('Gdb', [])
    .factory('Gdb', function ($http, $q, $rootScope) {

        var socket,
            gdbServer,
            token,
            watches = {};

        var Gdb = {
            init: function (conf) {
                gdbServer = conf.server;
                token = conf.token;

                $http.get(gdbServer + '/conf', {params: {token: token}}).success(function (data) {
                    socket = io.connect(data.ioServer);
                    socket.on(data.chanel, function (data) {
                        watches.hasOwnProperty(data.key) ? watches[data.key](data.value) : null;
                        $rootScope.$apply();
                    });
                });
            },

            set: function (key, value) {
                var deferred = $q.defer();

                $http.post(gdbServer + '/' + key, {value: value, token: token}).success(function (data) {
                    deferred.resolve(data);
                });

                return deferred.promise;
            },

            get: function (key) {
                var deferred = $q.defer();

                $http.get(gdbServer + '/' + key, {params: {token: token}}).success(function (data) {
                    deferred.resolve(JSON.parse(data));
                });

                return deferred.promise;
            },

            watch: function (key, closure) {
                watches[key] = closure;
            }
        };

        return Gdb;
    });

And that’s all. You can see the whole project at github.

Playing with websockets, angularjs and socket.io

I’m a big fan of websockets. I’ve got various post about them (here, here). Last months I’m working with angularjs projects and because of that I wanna play a little bit with websockets (with socket.io) and angularjs.

I want to build one angular service.

angular.module('io.service', []).
    factory('io', function ($http) {
        var socket,
            apiServer,
            ioEvent,
            watches = {};

        return {
            init: function (conf) {
                apiServer = conf.apiServer;
                ioEvent = conf.ioEvent;

                socket = io.connect(conf.ioServer);
                socket.on(ioEvent, function (data) {
                    return watches.hasOwnProperty(data.item) ? watches[data.item](data) : null;
                });
            },

            emit: function (arguments) {
                return $http.get(apiServer + '/request', {params: arguments});
            },

            watch: function (item, closure) {
                watches[item] = closure;
            },

            unWatch: function (item) {
                delete watches[item];
            }
        };
    });

And now we can build the application

angular.module('myApp', ['io.service']).

    run(function (io) {
        io.init({
            ioServer: 'http://localhost:3000',
            apiServer: 'http://localhost:8080/api',
            ioEvent: 'io.response'
        });
    }).

    controller('MainController', function ($scope, io) {
        $scope.$watch('question', function (newValue, oldValue) {
            if (newValue != oldValue) {
                io.emit({item: 'question', newValue: newValue, oldValue: oldValue});
            }
        });

        io.watch('answer', function (data) {
            $scope.answer = data.value;
            $scope.$apply();
        });
    });

And this’s the html

<!doctype html>
<html>

<head>
    <title>ws experiment</title>
</head>

<body ng-app="myApp">

<div ng-controller="MainController">

    <input type="text" ng-model="question">
    <hr>
    <h1>Hello {{answer}}!</h1>
</div>

<script src="assets/angular/angular.min.js"></script>
<script src="//localhost:3000/socket.io/socket.io.js"></script>

<script src="js/io.js"></script>
<script src="js/app.js"></script>

</body>
</html>

The idea of the application is to watch one model’s variable (‘question’ in this example) and each time it changes we will send the value to the websocket server and we’ll so something (we will convert the string to upper case in our example)

As you can read in one of my previous post I don’t like to send messages from the web browser to the websocket server directly (due do to authentication issues commented here). I prefer to use one server (a Silex server in this example)

include __DIR__ . '/../../vendor/autoload.php';

use Silex\Application;
use Symfony\Component\HttpFoundation\Request;

$app = new Application(['debug' => true]);
$app->register(new G\Io\EmitterServiceProvider());

$app->get('/request', function (Application $app, Request $request) {

    $params = [
        'item'     => $request->get('item'),
        'newValue' => strtoupper($request->get('newValue')),
        'oldValue' => $request->get('oldValue'),
    ];

    try {
        $app['io.emit']($params);
        $params['status'] = true;
    } catch (\Exception $e) {
        $params['status'] = false;
    }

    return $app->json($params);
});

$app->run();

You can see the code within my github account.

How to send the output of Symfony’s process Component to a node.js server in Real Time with Socket.io

Today another crazy idea. Do you know Symfony Process Component? The Process Component is a simple component that executes commands in sub-processes. I like to use it when I need to execute commands in the operating system. The documentation is pretty straightforward. Normally when I want to collect the output of the script (imagine we run those scripts within a crontab) I save the output in a log file and I can check it even in real time with tail -f command.

This approach works, but I want to do it in a browser (call me crazy :)). I’ve written a couple of posts with something similar. What I want to do now? The idea is simple:

First I want to execute custom commands with process. Just follow the process documentation:

<?php
use Symfony\Component\Process\Process;

$process = new Process('ls -lsa');
$process->setTimeout(3600);
$process->run();
if (!$process->isSuccessful()) {
    throw new \RuntimeException($process->getErrorOutput());
}

print $process->getOutput();

Process has one cool feature, we can give feedback in real-time by passing an anonymous function to the run() method:

<?php
use Symfony\Component\Process\Process;

$process = new Process('ls -lsa');
$process->run(function ($type, $buffer) {
    if ('err' === $type) {
        echo 'ERR > '.$buffer;
    } else {
        echo 'OUT > '.$buffer;
    }
});

The idea now is to use this callback to send a TCP socket to one server with node.js

var LOCAL_PORT = 5600;
var server = require('net').createServer(function (socket) {
    socket.on('data', function (msg) {
        console.log(msg);
    });
}).listen(LOCAL_PORT);

server.on('listening', function () {
    console.log("TCP server accepting connection on port: " + LOCAL_PORT);
});

Now we change our php script to

<?php
include __DIR__ . "/../vendor/autoload.php";

use Symfony\Component\Process\Process;

function runProcess($command)
{
    $address = 'localhost';
    $port = 5600;
    $socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
    socket_connect($socket, $address, $port);

    $process = new Process($command);
    $process->setTimeout(3600);
    $process->run(
        function ($type, $buffer) use ($socket) {
            if ('err' === $type) {
                socket_write($socket, "ERROR\n", strlen("ERROR\n"));
                socket_write($socket, $buffer, strlen($buffer));
            } else {

                socket_write($socket, $buffer, strlen($buffer));
            }
        }
    );
    if (!$process->isSuccessful()) {
        throw new \RuntimeException($process->getErrorOutput());
    }
    socket_close($socket);
}

runProcess('ls -latr /');

Now with the node.js started, if we run the php script, we will see the output of the process command in the node’s terminal. But we want to show it in a browser. What can we do? Of course, socket.io. We change the node.js command to:

var LOCAL_PORT = 5600;
var SOKET_IO_PORT = 8000;
var ioClients = [];

var io = require('socket.io').listen(SOKET_IO_PORT);

var server = require('net').createServer(function (socket) {
    socket.on('data', function (msg) {
        ioClients.forEach(function (ioClient) {
            ioClient.emit('log', msg.toString().trim());
        });
    });
}).listen(LOCAL_PORT);

io.sockets.on('connection', function (socketIo) {
    ioClients.push(socketIo);
});

server.on('listening', function () {
    console.log("TCP server accepting connection on port: " + LOCAL_PORT);
});

and finally we create a simple web client:

<script src="http://localhost:8000/socket.io/socket.io.js"></script>
<script>
    var socket = io.connect('http://localhost:8000');
    socket.on('log', function (data) {
        console.log(data);
    });
</script>

Now if we start one browser we will see the output of our command line process within the console tab of the browser.

If you want something like webConsole, I also have created the example, With a Web UI enabling to send custom commands. You can see it in github.

Obviously that’s only one experiment with a lot of security issues that we need to take into account if we want to use it in production. What do you think?

Scroll desktop’s Web pages remotely with our smartphone, using Node.js and WebSockets

Why this script? OK. It was a crazy idea. It started with one “Is it possible? Yes, let’s code it” in my mind. Let start. I want to scroll one web page in the TV’s web browser (or PC’s browser) using my smartphone lying on my couch. I’ve got a wireless mouse so I don’t really need it, but scroll the TV browser with the smartphone sounds cool, isn’t it?

The idea is the following one:

  • One QR code in our web page (added dinamically with JavaScrip with Google’s Chart API ). Write urls with the smartphone is hard and QR has a good hype, so we will add a QR code at the bottom of the web page with the link to the node.js server.
  • One socket.io server built with a node.js server for the real time communications. This node.js server will serve also a jQuery Mobile application with four buttons (with express and jade):
  • The server will register the WebSocket and send the real time commands to the browser (with one easy-to-hack security token).
  • The browser will handle the socket.io actions and controls the scroll of the web page.

The code is probably crowded by bugs and security problems, but it works and it was enough in my experiment :) :

The node.js server:

var io = require('socket.io').listen(8080);

var app = require('express').createServer();
app.set('view engine', 'jade');

app.set('view options', {
    layout:false
});

app.get('/panel/:key', function (req, res) {
    var key = req.params.key;
    console.log(key);
    res.render('mobile.jade', {key:key});
});

app.get('/action/:key/:y/:action', function (req, res) {
    var key = req.params.key;
    var y = req.params.y;
    var action = req.params.action;
    sockets[key].emit('scrollTo', {y:y, action:action});
    res.send('OK');
});

app.listen(8000);

var sockets = {};
io.sockets.on('connection', function (socket) {
    socket.on('setKey', function (key) {
        sockets[key] = socket;
    });
});

The jade template with the jquery mobile application:

!!! 5
html
    head
        meta(charset="utf-8")
        meta(name="viewport", content="width=device-width, initial-scale=1")
        title title
        link(rel='stylesheet', href='http://code.jquery.com/mobile/1.1.0/jquery.mobile-1.1.0.min.css')
        script(src='http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js')
        script(src='http://code.jquery.com/mobile/1.1.0/jquery.mobile-1.1.0.min.js')
        script(type='text/javascript')
            $(document).bind('pageinit', function() {
                $('#toTop').tap(function() {
                    $.get('/action/#{key}/0/go', function() {});
                });
                $('#toBotton').tap(function() {
                    $.get('/action/#{key}/max/go', function() {});
                });
                $('#toUp').tap(function() {
                    $.get('/action/#{key}/100/rew', function() {});
                });
                $('#toDown').tap(function() {
                    $.get('/action/#{key}/100/ffd', function() {});
                });
            });
    body
        #page1(data-role="page")
            #header(data-theme="a", data-role="header")
                h3 Header
            #content(data-role="content")
                a(data-role="button", data-transition="fade", data-theme="a", href="#", id="toTop", data-icon="minus", data-iconpos="left") Top
                a(data-role="button", data-transition="fade", href="#", id="toUp", data-icon="arrow-u", data-iconpos="left") Up
                a(data-role="button", data-transition="fade", href="#", id="toDown", data-icon="arrow-d", data-iconpos="left") Down
                a(data-r

Our Html client page

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <title>jQuery Smooth Scroll - Design Woop</title>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
</head>
<body>
<p>
    Lorem ipsum ….. put a big lorem ipsum here to make possible the scroll
</p>
<script src="http://localhost:8080/socket.io/socket.io.js"></script>
<script src="client.js"></script>
</body>
</html>

And finally our client magic with the QR code and the functions to handle the node.js actions

var key = "secret";
function getDocHeight() {
    var D = document;
    return Math.max(
            Math.max(D.body.scrollHeight, D.documentElement.scrollHeight),
            Math.max(D.body.offsetHeight, D.documentElement.offsetHeight),
            Math.max(D.body.clientHeight, D.documentElement.clientHeight)
    );
}
var socket = io.connect('http://localhost:8080');
var y = 0;

socket.emit('setKey', key);
socket.on('scrollTo', function (data) {
    if (data.y == 'max') {
        y = getDocHeight();
    } else {
        if (data.action == 'ffd') {
            y += parseInt(data.y);
        } else if (data.action == 'go') {
            y = parseInt(data.y);
        } else {
            y -= parseInt(data.y);
        }
    }
    window.scrollTo(0, y);

});
document.write('<img src="https://chart.googleapis.com/chart?chs=150x150&cht=qr&chl=http://192.168.2.3:8000/panel/' + key + '&choe=UTF-8" alt=""/>');

You can see the code in github too. We also can see the script in action here:

We can also add more features to our application but that’s enought for this experiment. What do you think?

Asynchronous queries to PostgreSql database from the browser with node.js and socket.io

Normally we perform our database connection at server side with PHP and PDO for example. In this post I will show a simple technique to send queries to our database (PostgreSql in this example) asynchronously using node.js and socket.io.

The idea is pretty straightforward. We will send the SQL string and the values with a WebSocket and we will execute a callback in the client when the server (node.js script) fetches the recordset.

Our server:

var pg = require('pg');

var conString = "tcp://user:password@localhost:5432/db";
var client = new pg.Client(conString);
client.connect();

var io = require('socket.io').listen(8888);

io.sockets.on('connection', function (socket) {
    socket.on('sql', function (data) {
        var query = client.query(data.sql, data.values);
        query.on('row', function(row) {
            socket.emit('sql', row);
        });
    });
});

And our client:

<script src="http://localhost:8888/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://vmserver:8888');

function sendSql(sql, values, cbk) {
    socket.emit('sql', { sql: sql, values : values});
    socket.on('sql', function(data){
        console.log(data);
    });
}
</script>    
<p>
<a href="#" onclick="sendSql('select * from users', [], function(data) {console.log(data);})">select * from users</a>
</p>
<p>
<a href="#" onclick="sendSql('select * from users where uid=$1', [4], function(data) {console.log(data);})">select * from users where uid=$1</a>
</p>

Simple, isn’t it?
You must take care if you use this script at production. Our database is exposed to raw SQL sent from the client. It’s a concept example. Maybe it would be better not to send the SQL. Store them into key-value table in the server and send only an ID from the browser.

What do you think?

Talk about node.js and WebSockets

Last friday I spoke about node.js and Websockets with the people of The Mêlée. The talk was an introduction to node.js and focused in the new HTML5 feature: the WebSockets.

When I spoke about Websockets I also introduced the great library socket.io. The jQuery of WebSockets.

Real time notifications (part II). Now with node.js and socket.io

In one of my previous posts I wrote about Real time notifications with PHP. I wanted to create a simple comet system fully written in PHP and JavaScript. It worked but as Scott Mattocks told me in a comment this implementation was still just doing short polling. The performance with this solution may be bad in a medium/hight traffic site. This days I’m playing with node.js and I want to create a simple test. I want to do exactly the same than the previous post but now with node.js instead of my PHP+js test. Let’s start

Now I want to use socket.io instead of pure web-sockets like my previous posts about node.js. For those who don’t know, socket.io is amazing library that allows us to use real-time technologies within every browsers (yes even with IE6). It uses one technology or another depending on the browser we are using, with the same interface for the developer. That’s means if we’re using Google Chrome we will use websockets, but if our browser does’t support them, socket.io will choose another supported transports. Definitely socket.io is the jQuery of the websockets. The supporter transports are:

  • WebSocket
  • Adobe Flash Socket
  • AJAX long polling
  • AJAX multipart streaming
  • Forever Iframe
  • JSONP Polling

First we create our node.js server. A really simple one.

var http = require('http');
var io = require('socket.io');

server = http.createServer(function(req, res){
});
server.listen(8080);

// socket.io 
var socket = io.listen(server);

socket.on('connection', function(client){
  client.on('message', function(msg){
      socket.broadcast(msg);
  })
}); 

This server will broadcast the message received from the browser to all connected clients.

Our HTML page will look like that:

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>Comet Test</title>
    </head>
    <body>
        <p><a id='customAlert' href="#" onclick='socket.send("customAlert")'>publish customAlert</a></p>
        <p><a id='customAlert2' href="#" onclick='socket.send("customAlert2")'>publish customAlert2</a></p>
        <script src="http://localhost:8080/socket.io/socket.io.js" type="text/javascript"></script>
        <script type="text/javascript">

// Start the socket
var socket = new io.Socket(null, {port: 8080});
socket.connect();

socket.on('message', function(msg){
    console.log(msg);
});
        </script>
    </body>
</html>

As we can see we are including the js script called socket.io/socket.io.js. This script is served by our node server.

In fact we can use our node.js to serve everything (HTML, js, CSS) but in our example we will use only node.js for real-time stuff. Apache will serve the rest of the code (only a HTML file in this case).

And that’s all. Those few lines perform the same thing than our PHP and js code in the other post’s example. Our node.js implementation is definitely smarter than the PHP one. The socket.io library also allows us to use the example with all browser. Same code and without any browser nightmare (just like jQuery when we work with DOM).

Here I have a little screencast with the working example. As we will see there We will connect to the node server with firefox and chrome. Firefox will use xhr multipart and Chrome will use Websokets.

Another important issue of socket.io library is that we forget about the reconnection to the web-socket server, if something wrong happens (as we can see in Real time monitoring PHP applications with web-sockets and node.js). If we use raw WebSocket implementations and our connection with the web-socket server crashes or if we stop the server, our application will raise disconnect event and we need to create something to reconnect to the server. socket.io does it for us. With our small piece of JavaScript code we will get a high performance real-time applicatrion. Node is cool. Really cool. Kinda wierd at the beginning but the learning effort will be worthwhile. A few js lines and a real time applications.

I’ve got a problem within our node.js application. If we’ve got some kind of security within our application (imagine for example it’s behind a session based auth form) we need to share this security layer with our node.js server to ensure that non authenticated users aren’t allowed to use our websockets. I don’t know how to do it just now, but I’m investigating. Do you have any idea?

Full code Code at github. Ensure you’re using the stable version of node.js. With the last versión available on github of node.js there’s a bug and server dies when we connect with Google Chrome.

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