Send HTTP Request only when network connection is available in ionic

Question

I am working on ionic. I am sending multiple http requests.

I want to send http request only when network connection is available.

Sometime our network connection is available. while playing within app we do offline.

Can we detect this and how ?

Thanks

Answer 1

As Sabarish already noted, use the Network information plugin.

Nic Raboy's blog post is good, though you may want to check the post I wrote which goes literally step by step telling you where and why you should put some piece of code (may be useful if you're just starting with Ionic): http://www.nikola-breznjak.com/blog/codeproject/check-network-information-change-with-ionic-famework/.

Also, I made the example code available freely on Github: https://github.com/Hitman666/IonicNetworkInfo.

edit: As per StackOverflow's rules, I'm adding the post content here as well:

Step by step on how to make this yourself

Start a new Ionic project by doing:

ionic start IonicNetworkInfo blank

Then, change the directory to the newly created IonicNetworkInfo:

cd IonicNetworkInfo

Install ngCordova with Bower:

bower install ngCordova

If by some chance you don’t have bower installed, you can install it with npm:

npm install bower -g

Open up the www/index.html file in your favorite editor, and add the reference to ngCordova (just above the cordova.js script):

<!-- This is what you should add, the cordova below you'll already have -->
<script src="lib/ngCordova/dist/ng-cordova.min.js"></script>

<!-- cordova script (this will be a 404 during development) -->
<script src="cordova.js"></script>

Install the ngCordova network plugin by executing the following command in your Terminal/Command prompt (you should do this from the root directory of your app; so, in our case the IonicNetworkInfo directory):

cordova plugin add org.apache.cordova.network-information

To check if you have successfully installed the plugin, you can run the following command (from the root directory – I won’t be repeating this anymore; when I say you should run some command from the Terminal/Command prompt that, in this case, means from the root directory of the application):

cordova plugin list

You should see the following output:

> cordova plugin list                                                                                                                           
com.ionic.keyboard 1.0.4 "Keyboard"
org.apache.cordova.network-information 0.2.15 "Network Information"

Open up the www/js/app.js file and add ngCordova to the dependencies list, so that basically the first line looks like this:

angular.module('starter', ['ionic', 'ngCordova'])

Create a new controller in the www/js/app.js file called MyCtrl, with the following content:

.controller('MyCtrl', function($scope, $cordovaNetwork, $rootScope) {
    document.addEventListener("deviceready", function () {

        $scope.network = $cordovaNetwork.getNetwork();
        $scope.isOnline = $cordovaNetwork.isOnline();
        $scope.$apply();

        // listen for Online event
        $rootScope.$on('$cordovaNetwork:online', function(event, networkState){
            $scope.isOnline = true;
            $scope.network = $cordovaNetwork.getNetwork();

            $scope.$apply();
        })

        // listen for Offline event
        $rootScope.$on('$cordovaNetwork:offline', function(event, networkState){
            console.log("got offline");
            $scope.isOnline = false;
            $scope.network = $cordovaNetwork.getNetwork();

            $scope.$apply();
        })

  }, false);
})

In this controller you attach an event listener on the deviceready event (because it could be that the device would not have been yet initialized when this code runs) and you get the network information with:

$cordovaNetwork.getNetwork();

The information, about weather you’re connected to the internet is obtained with the following line:

$scope.isOnline = $cordovaNetwork.isOnline();

Then, you register two events $cordovaNetwork:online and $cordovaNetwork:online which trigger when the device gets online/offline. In them you then just update the $scope variables (). Just for reference, the whole content of the www/js/app.js file should be:

// Ionic Starter App

// angular.module is a global place for creating, registering and retrieving Angular modules
// 'starter' is the name of this angular module example (also set in a <body> attribute in index.html)
// the 2nd parameter is an array of 'requires'
angular.module('starter', ['ionic', 'ngCordova'])

.run(function($ionicPlatform, $cordovaNetwork, $rootScope) {
  $ionicPlatform.ready(function() {
    // Hide the accessory bar by default (remove this to show the accessory bar above the keyboard
    // for form inputs)
    if(window.cordova && window.cordova.plugins.Keyboard) {
      cordova.plugins.Keyboard.hideKeyboardAccessoryBar(true);
    }
    if(window.StatusBar) {
      StatusBar.styleDefault();
    }

  });
})

.controller('MyCtrl', function($scope, $cordovaNetwork, $rootScope) {
    document.addEventListener("deviceready", function () {

        $scope.network = $cordovaNetwork.getNetwork();
        $scope.isOnline = $cordovaNetwork.isOnline();
        $scope.$apply();

        // listen for Online event
        $rootScope.$on('$cordovaNetwork:online', function(event, networkState){
            $scope.isOnline = true;
            $scope.network = $cordovaNetwork.getNetwork();

            $scope.$apply();
        })

        // listen for Offline event
        $rootScope.$on('$cordovaNetwork:offline', function(event, networkState){
            console.log("got offline");
            $scope.isOnline = false;
            $scope.network = $cordovaNetwork.getNetwork();

            $scope.$apply();
        })

  }, false);
});

In the index.html file, inside the ion-content tag paste the following content:

<div class="card">
    <div class="item item-text-wrap">
        <h1>Network: {{network}}</h1>
    </div>
</div>


<div class="card">
    <div class="item item-text-wrap">
        <ion-toggle ng-model="isOnline" ng-checked="item.checked">
            <h1 ng-show="isOnline">I'm online</h1>
            <h1 ng-show="! isOnline">I'm offline</h1>
        </ion-toggle>
    </div>
</div>

Basically what we do here is we show the contents of the network variable (which is attached to the $scope via the controller). Also, by using the ion-toggle component we show the “I’m online” / “I’m offline” notifications.

Just for reference, the content of the whole index.html file should look like this:

    <!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no, width=device-width">
    <title></title>

    <link href="lib/ionic/css/ionic.css" rel="stylesheet">
    <link href="css/style.css" rel="stylesheet">

    <!-- IF using Sass (run gulp sass first), then uncomment below and remove the CSS includes above
    <link href="css/ionic.app.css" rel="stylesheet">
    -->

    <!-- ionic/angularjs js -->
    <script src="lib/ionic/js/ionic.bundle.js"></script>

    <script src="lib/ngCordova/dist/ng-cordova.min.js"></script>
    <!-- cordova script (this will be a 404 during development) -->
    <script src="cordova.js"></script>

    <!-- your app's js -->
    <script src="js/app.js"></script>
</head>
<body ng-app="starter" ng-controller="MyCtrl">

    <ion-pane>
        <ion-header-bar class="bar-stable">
            <h1 class="title">Ionic Blank Starter</h1>
        </ion-header-bar>

        <ion-content padding="true">
            <div class="card">
                <div class="item item-text-wrap">
                    <h1>Network: {{network}}</h1>
                </div>
            </div>

            <div class="card">
                <div class="item item-text-wrap">
                    <ion-toggle ng-model="isOnline" ng-checked="item.checked">
                        <h1 ng-show="isOnline">I'm online</h1>
                        <h1 ng-show="! isOnline">I'm offline</h1>
                    </ion-toggle>
                </div>
            </div>

        </ion-content>
    </ion-pane>
</body>
</html>

In order to test this application you should run it on your device (because you can’t disable network in iOS simulator). If you have an Android device plugged to your computer (and all the SDKs in place) you can run the following to commands to get your application running on your Android device:

ionic build android && ionic run android