Angular Js and google api client.js (gapi)

It took me one day to make it works so I think my experience may be useful from someone. And maybe some others will find improvement.

So I start angularJS two days ago. And I want it works with Google Cloud Endpoints to create a backend interface. Here comes the trouble for me.

The javascript client for gapi comes with asynchronous loading, so angular initialization will crash having gapi undefined.

So you need to bootstrap angular when gapi is initialized:

  1. remove ng-app="myApp"
  2. Add <script src="https://apis.google.com/js/client.js?onload=googleOnLoadCallback"></script>
  3. Add the callback:

    function googleOnLoadCallback(){  
        var apisToLoad = 1; // must match number of calls to gapi.client.load()  
        var gCallback = function() {  
            if (--apisToLoad == 0) {  
                //Manual bootstraping of the application  
                var $injector = angular.bootstrap(document, ['myApp']);  
                console.log('Angular bootstrap complete ' + gapi);  
            };  
        };  
        gapi.client.load('helloWorld', 'v1', gCallback, '//' + window.location.host + '/_ah/api');  
    }
    

Feel good but how about a call ?

So here is the controller:

angular.module('myApp.controllers', []).  
    .controller('MyCtrl', ['$scope' ,'helloWorldService',  
        function($scope,greetingsService) {
          helloWorldService.loadData($scope);  
    }]);

And here is the service:

angular.module('myApp.services', [])
service('helloWorldService', [function() {
   this.loadData = function($scope)  {
     //Async call to google service
     gapi.client.helloWorld.greetings.listGreeting().execute(
        function(resp) {
            if (!resp.code) {
                console.debug(resp);
                $scope.greetings = resp.items;
                // Because it's a callback,
                // we need to notify angular of the data refresh...
                $scope.$apply();
            }
      });
   };
}]);

And magically your page updates thanks to angular.

Feel free to mark anywhere I go wrong.

Answers:

Answer

Rather than bootstrapping or setting a timeout, it's most efficient to let Angular load before/while you're making the server requests. I followed the advice described in AngularJS + Cloud Endpoints: A Recipe for Building Modern Web Applications, which does the following.

Keep your ng-app directive as usual (no bootstrapping)

<html ng-app="myApp">
<head>
  <script src="angular.js" type="text/javascript"></script>
  <script src="app.js" type="text/javascript"></script>
  <script src="https://apis.google.com/js/client.js?onload=init"></script>
</head>
<body ng-show="backendReady">

Create a global variable for the GAPI callback function anywhere in your JS

var app = angular.module('myApp', []);

var init = function() {
  window.initGapi();
}

app.controller('MainController', function($scope, $window, gapiService) {
  var postInitiation = function() {
    // load all your assets
  }
  $window.initGapi = function() {
    gapiService.initGapi(postInitiation);
  }
});

app.service('gapiService', function() {
  this.initGapi = function(postInitiation) {
    gapi.client.load('helloWorld', 'v1', postInitiation, restURL);
  }
});

From link above:

The reason why you would not want to execute the initialization in the first init() method is so you can put as much of the code as possible in the AngularJS world, such as controllers, services and directives. As a result, you can harness the full power of AngularJS and have all your unit tests, integrations tests,and so forth.

This may seem like a roundabout way of doing things, but it optimizes for speed, testability, and separation of concerns.

Answer

Nice post and thanks! This approach worked for me. It might matter what order that the code appears in your index.html file. It did not work for me until I had things inthis order.

...
<script>
  function googleOnLoadCallback(){
      alert('googleOnLoadCallback called');
      var apisToLoad = 1; // must match number of calls to gapi.client.load()
      var gCallback = function() {
          if (--apisToLoad == 0) {
              //Manual bootstraping of the application
              var $injector = angular.bootstrap(document, ["myApp"]);
              console.log("myApp bootstrap complete " + gapi);
          };
      };
      gapi.client.setApiKey("my_client_id");
      gapi.client.load("translate", "v2", gCallback);

  }
</script>
<!-- See https://developers.google.com/api-client-library/javascript/samples/samples -->
<script src="https://apis.google.com/js/client.js?onload=googleOnLoadCallback"></script>
</head>
Answer

Although pretty much on progress maybe also worth to mention angular-googleapi, which wraps nicely some Google Calendar and Google Plus API calls and easy extendable.

You'd need to add this bit to your controller when checking for authorisation:

$scope.authenticated = false;

$scope.$on("google:authenticated", function(){
   $scope.authenticated = true;
   $scope.$on('googleCalendar:loaded', function(){
       # work your magic here
       # $scope.calendars = googleCalendar.listCalendars();
       # $scope.$apply();
   });
});

function checkAuth() {
   setTimeout(function(){
       gapi.auth === undefined ? checkAuth() : googleLogin.checkAuth();
   }, 20);
}

checkAuth();
Answer

I wrote a simple directive to load the google map API asynchronously :

// js/directives/gmapAsync.js

(function(){
'use strict';

angular.module('app').directive('gmapAsync',
    ['$window', '$rootScope', gmapAsync]
);

function gmapAsync($window, $rootScope){

    var gmapScript = $window.document.createElement('script');  

    $window.onGmapScriptLoaded = function(){
        console.log('google maps script loaded');

        $rootScope.gmapApiLoaded = true;
        $rootScope.$broadcast('gmap.api.loaded');

    };

    return {
        restrict: 'A',
        transclude: false,
        scope:false,
        link:   function(scope, element, attributes){

            if (navigator.onLine) {
                appendScript();
            } else {
                $window.addEventListener('online',appendScript);
            }

            function appendScript(){
                gmapScript.type = 'text/javascript';
                gmapScript.src = 'https://maps.googleapis.com/maps/api/js?v=3.exp&' + 'callback=onGmapScriptLoaded';
                $window.document.body.appendChild(gmapScript);
            }
        }
    };
}
})();

Then in your main controller, you can handle the event :

// js/controllers/AppCtrl.js

(function(){
'use strict';

    angular.module('app').controller('AppCtrl',[$scope,AppCtrl])

    function AppCtrl($scope){

        $scope.$on('gmap.api.loaded',function(){
            // your stuff to init after the api is loaded
        });
    }

})();

You just have to declare the directive in your body tag :

<!DOCTYPE html>
<html>

    <head></head>

    <body data-ng-app="app" data-gmap-async data-ng-controller="AppCtrl">

        <!-- template body -->

        <script type="text/javascript" src="js/app.js"></script>
        <script type="text/javascript" src="js/controllers/AppCtrl.js"></script>
        <script type="text/javascript" src="js/directives/gmapAsync.js"></script>
    </body>

</html>
Answer

I did the following

gapi-service.js

'use strict';

app.factory('Gapi', ['ENV', function(ENV) {

return {
load: function load() {
  console.log('loading google apis...');
  if (typeof gapi.client === 'undefined') {
    setTimeout(load, 500);
  } else {
    gapi.client.setApiKey(ENV.googleToken);
    gapi.client.load('storage', 'v1', function() {
      console.log('loaded! :)');
      var request = gapi.client.storage.buckets.list({ project: ''});
      console.log(request);
      request.execute(function(response) { console.log(response); });
    });
  }
}
  };
}]);

index.html

<!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>"Txtbinge"</title>
  </head>

  <body ng-app="myApp">
<script src="bower_components/jquery/dist/jquery.js"></script>
<script src="bower_components/angular/angular.js"></script>

<script src="scripts/client.js"></script>
<script src="scripts/app.js"></script>
<script src="scripts/gapi-service.js"></script>


  </body>
</html>

controllers.js

'use strict';

app.controller('AppController', function($scope, $state, Camera, Gapi) {

  Gapi.load();

});
Answer

Take look at this: https://github.com/canemacchina/angular-google-client.

I've write this module to use Google Api or Google Cloud Endpoint in an Angular application.

Answer

So I was having the same problem. Putting this code in my factory worked

var initialize = function() {
    if(gapi.client == undefined) {
        setTimeout(function() {
            initialize()
        }, 1000);
    } else {
        gapi.client.setApiKey("<api_key>");
        gapi.client.load('youtube', 'v3').then(function() {
            console.log("youtube is ready")
        });
    }
};

initialize()

Basically, the problem is trying to call gapi.client before it loaded. If you just check that it's loaded, and if it isn't then try again in a second (you can set the time for whatever you want, set it lower if you expect the user to need this relatively quickly after the page loads).

I was struggling with this for a while, and this is all that worked for me...Hope this helps!

Answer

I used a solution similar to willlma, but my application makes use of UI Router, so there's no knowing which controller will be called.

I was able to solve this with a Javascript Promise.

index.html

<html ng-app="myApp">
<head>
    <script src="angular.js" type="text/javascript"></script>
    <script src="app.js" type="text/javascript"></script>
    <script src="https://apis.google.com/js/client.js?onload=init">
</head>

app.js

var app = angular.module('myApp', []);

app.controller('MainController', function($scope, gapiService) {
    gapiService.then(function(gapi) {
        // You can use gapi normally here;
    });
});

app.service('gapiService', function($window) {
    return new Promise(function(resolve, reject) {
        if ($window.gapi !== undefined) {
            console.log("Have gapi already");
            resolve($window.gapi);
        } else {
            console.log("Waiting for gapi");
            $window.init = function() {
                resolve($window.gapi);
            }
        }
    });
});

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