Monthly Archives: October 2014

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.

Upgrading Cordova-iOS apps outside Apple Store

In one of my last post I explained how to upgrade Cordova-Android apps outside Google Play Store with angularjs. Today is the turn of iOS applications.

If you work with in-house iOS applications you need to define a distribution strategy (you cannot use Apple Store, indeed). Apple provides documentation to do it. Basically we need to place our ipa file in addition to the plist file (generated when we archive our application with xCode). I’m not going to explain how to do it here. As I said before it’s well documented. Here I’m going to explain how to do the same trick than the Android’s post but now with our iOS application.

With iOS, to install the application, we only need to provide the iTunes link to our plist application (something like this: itms-services://?action=download-manifest&url=http://url.to.plist) and open it with the InAppBrowser plugin.

First we install the InAppBrowser plugin:

    $ cordova plugin add https://git-wip-us.apache.org/repos/asf/cordova-plugin-inappbrowser.git

And now we only need to open the url using the plugin:

var iosPlistUrl = 'http://url.to.plist';
cordova.exec(null, null, "InAppBrowser", "open", [encodeURI("itms-services://?action=download-manifest&url=" + iosPlistUrl), "_system"]);

We can use exactly the same angularJs used the the previous post to check the version and the same server-side verification.

We also can detect the platform with Device plugin and do one thing or another depending on we are using Android or iOS.

Here you can see one example using ionic framework. This example uses one $http interceptor to send version number within each request and we trigger ‘wrong.version’ to the event dispatcher when it detects a wrong versions between client and server

angular.module('G', ['ionic'])

    .value('appConf', {
        version: 1,
        apiHost: 'http://localhost:8080'
    })

    .config(function ($httpProvider, $urlRouterProvider, $stateProvider) {
        $httpProvider.interceptors.push('versionInterceptor');

        $stateProvider
            .state('home', {
                url: '/home',
                templateUrl: 'partials/home.html',
                controller: 'HomeController'
            })
            .state('upgrade', {
                url: '/upgrade',
                templateUrl: 'partials/upgrade.html',
                controller: 'UpgradeController'
            })
        ;

        $urlRouterProvider.otherwise('/home');

    })

    .run(function ($ionicPlatform, $rootScope, $state) {
        $ionicPlatform.ready(function () {
            if (window.cordova && window.cordova.plugins.Keyboard) {
                cordova.plugins.Keyboard.hideKeyboardAccessoryBar(true);
            }
            if (window.StatusBar) {
                StatusBar.styleDefault();
            }
        });

        $rootScope.$on('wrong.version', function () {
            $state.go("upgrade");
        });
    })

    .controller('HomeController', function ($scope, $http, appConf) {
        $scope.someAction = function () {
            $http.get(appConf.apiHost + "/hello", function (data) {
                alert(data);
            });
        }
    })

    .controller('UpgradeController', function ($scope) {
        $scope.upgrade = function () {
            cordova.exec(null, null, "InAppBrowser", "open", [encodeURI("itms-services://?action=download-manifest&url=https://path/to/plist.plist"), "_system"]);
        }
    })

    .factory('versionInterceptor', function ($rootScope, appConf) {
        var versionInterceptor = {
            request: function (config) {
                config.url = config.url + '?_version=' + appConf.version;

                return config;
            },
            responseError: function(response) {
                if (response.status == 410) {
                    $rootScope.$emit('wrong.version');
                }
            }
        };

        return versionInterceptor;
    })
;