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