Data in callback when using 'Controller as' pattern in Angular - angularjs

I have the simplest angular controller:
tc.controller('PurchaseCtrl', function () {
var purchase = this;
purchase.heading = 'Premium Features';
this.onSuccess = function (response) {
console.log('Success', response);
lib.alert('success', 'Success: ', 'Loaded list of available products...');
purchase.productList = response;
};
this.onFail = function (response) {
console.log('Failure', response);
};
console.log('google.payments.inapp.getSkuDetails');
lib.alert('info', 'Working: ', 'Retreiving list of available products...');
google.payments.inapp.getSkuDetails(
{
'parameters': {'env': 'prod'},
'success': purchase.onSuccess,
'failure': purchase.onFail
});
});
And the view:
<div class="col-md-6 main" ng-controller="PurchaseCtrl as purchase">
{{purchase}}
</div>
This prints out:
{"heading":"Premium Features"}
I thought that when the callback returned, the view would be update with any new data. Am I missing something? The callback returns and I see the dtaa in the console.
Using the $scope pattern I think that I would use $scope.$apply to async method, but I'm not sure how to do that here.

Using controllerAs does not change the way digest cycle works or anything. It is just a sugar that adds a property (with the name same as alias name when used) to the current scope with its value pointing to the controller instance reference. So you would need to manually invoke the digest cycle (using scope.$apply[Asyc]() or even with a dummy $timeout(angular.noop,0) or $q.when() etc) in this case as well. But you can avoid injecting scope by abstracting it out into an angular service and returning a promise from there, i.e
myService.$inject = ['$q'];
function myService($q){
//pass data and use it where needed
this.getSkuDetails = function(data){
//create deferred object
var defer = $q.defer();
//You can even place this the global variable `google` in a
//constant or something an inject it for more clean code and testability.
google.payments.inapp.getSkuDetails({
'parameters': {'env': 'prod'},
'success': function success(response){
defer.resolve(response);// resolve with value
},
'failure': function error(response){
defer.reject(response); //reject with value
}
});
//return promise
return defer.promise;
}
}
//Register service as service
Now inject myService in your controller and consume it as:
myService.getSkuDetails(data).then(function(response){
purchase.productList = response;
}).catch(function(error){
//handle Error
});

Related

Using the service data in the controller

I have placed the service and the controller in the same js file. So Im trying to fetch the data from the service and use it in my html. In my code Im able to generate the data from the service but not able to assign it to a $scope in the controller and use it in the html. So how do I get the data and assign it to the $scope so that I can use it in my html.
var app = angular.module("app",[]);
app.factory('factoryServices',function($http){
var newObject = {};
var _getChart= function(){
$http.get("http://citibikenyc.com/stations/json")
.success(function(data, status){
if(data) {
return data;
}
}).error(function(data,status){
return error;
});
}
newObject.getChart = _getChart;
return newObject;
});
app.controller("chartController",function($scope,$http,factoryServices){
factoryServices.getChart($scope.chartServicesCompleted);
$scope.chartServicesCompleted = function(data){
$scope.serviceResponse = data;
}
})
If you rewrite your code like this, it should work as expected:
var app = angular.module("app",[]);
app.factory('factoryServices',function($http){
var newObject = {};
var _getChart= function(){
return $http.get("http://citibikenyc.com/stations/json")
.then(function(response){
if(response.data) {
return response.data;
}
}, function(response){
console.error("getChart failed with ",response);
});
}
newObject.getChart = _getChart;
return newObject;
});
and your controller
app.controller("chartController",function($scope,$http,factoryServices){
factoryServices.getChart().then(chartServicesCompleted);
function chartServicesCompleted(data){
$scope.serviceResponse = data;
}
})
The reason your initial code doesn't work, is because your getChart doesn't actually take an argument. So passing your callback like this: getChart($scope.chartServicesCompleted) doesn't do anything. In the rewritten code, I've made it so the getChart function returns the promise created by $http.get(..) which then allows you to use .then([callback]) in your controller.
you are passing a callback function but not handling inside the service method.
do change as
var _getChart= function(callback){
$http.get("http://citibikenyc.com/stations/json")
.success(function(data, status){
callback(data);
}).error(function(data,status){
callback(data);
});
}
now factoryServices.getChart($scope.chartServicesCompleted); will work
you can make more generic by handling success and error callback separately.
or one more way is to implement the success and error logic inside your controller.
but do not forget to check the function type i.e
if(typeof callback == 'function'){
callback(data);
}
Edit: as per advanced you call implement promises.
if you are using angular version 1.6, the success and error methods have been depreciated.
secondly you can do inside service return the http object
var _getChart= function(){
return $http.get("http://citibikenyc.com/stations/json");
}
and then handle the promise in the controller like
factoryServices.getChart().then(successMethod, error method);
Let the service return the promise to the controller. ex:
var _getChart= function(){
return $http.get("http://citibikenyc.com/stations/json");
}
and in the controller handle the promise. Use 'then' instead
factoryServices.getChart().then(function(response){var theDate = response.data},function(error){});
you can declare methods instead in the controller for handling the success and error
factoryServices.getChart).then(onSuccess,onError);
Don use the .success method and .error method. They dont't behave as other promises. So get used to 'then'
You really don't need to handle errors in the service method.I use angular interceptors in most of the cases. Check em out. But sometimes you need to handle the error in the controller. So its good to get the callback in the controller

Angular - set controller variable after service $http call

I'm finding it difficult making sense of all the differing blogs and examples out there on how to use a promise correctly in angular, so would appreciate some clarification from someone please.
Is using a callback passed in to the service get method to set the controller variable like this wrong?
In the Session service:
self.getSessions = function(callback) {
$http.get(self.urls.sessionsList).then(
function (response) {
callback(response.data);
},
function (response) {
// failure
}
);
};
from this controller:
.controller('SessionsController', ['Session', function(Session) {
var self = this;
self.sessions = [];
Session.getSessions(function(data) {
self.sessions = data;
});
}])
Q) Is using a callback passed in to the service get method to set the controller >>variable like this wrong?.
No, it is not wrong, but you can use the power of the promise and change your code to be something like below, where you can chain to the "then" method :
self.getSessions = function() {
return $http.get(self.urls.sessionsList);
}
and change your controller code to be:
.controller('SessionsController', ['Session', function(Session) {
var self = this;
self.sessions = [];
Session.getSessions().then(function(response) {
self.sessions = response.data;
});
}]);
Then, you can see that the caller can chain the to "then" and do more and more functionality,...
hope that helps.
Use Deffered promise is bad thing since es6 promise is released

How can I create a service that returns the value promise

I want to create a service that returns a json
Or by request to to the server, or by checking if it exists already in: Window.content
But I don't want to get a promise from my Controller !
I want to get the json ready !
I have tried several times in several ways
I tried to use with then method to do the test in my Service
but I still get a promise
( Whether with $http only, and whether with $q )
I could not get the value without getting promise from my Controller
My Service :
app.service('getContent',['$http', function( $http ){
return function(url){ // Getting utl
if(window.content){ // if it's the first loading, then there is a content here
var temp = window.content;
window.content = undefined;
return temp;
}
return $http.get(url);
};
}]);
My Controller:
.state('pages', {
url: '/:page',
templateProvider:['$templateRequest',
function($templateRequest){
return $templateRequest(BASE_URL + 'assets/angularTemplates/pages.html');
}],
controller: function($scope, $stateParams, getContent){
// Here I want to to get a json ready :
$scope.contentPage = getContent(BASE_URL + $stateParams.page + '?angular=pageName');
}
});
If the data exists, just resolve it in a promise.
While this process is still asynchronous it won't require a network call and returns quickly.
app.service('getContent',['$http', '$q', function( $http, $q ){
return function(url){
// create a deferred
var deferred = $q.defer();
if(window.content){ // if it's the first loading, then there is a content here
var temp = window.content;
window.content = undefined;
deferred.resolve(temp); // resolve the data
return deferred.promise; // return a promise
}
// if not, make a network call
return $http.get(url);
};
}]);
Just to reiterate, this asynchronous, but it won't require a network call.
This is not possible. If the code responsible to calculate or retrieve the value relies on a promise, you will not be able to return the value extracted from the promise by your function.
Explanation: This can easily be seen from the control flow. A promise is evaluated asynchronously. It may take several seconds to retrieve json from a server, but the caller of your function should not wait so long because your whole runtime environment would block. This is why you use promises in the first place. Promises are just a nice way to organize callbacks. So when your promise returns, the event that caused the function call will have already terminated. In fact it must have, otherwise your promise could not be evaluated.
You're thinking about this wrong. A service always returns a promise, because there is no synchronous way of getting JSON from an API:
app.factory('myService', ['$http', function($http) {
return $http('http://my_api.com/json', function(resp) {
return resp.data;
});
}]);
You would then call this within your controller like so:
app.controller('myController', ['$scope', 'myService', function($scope, myService) {
myService.then(function(data) {
$scope.contentPage = data; // here is your JSON
}, function(error) {
// Handle errors
});
}]);
Your service is returning a promise as it's written at the moment. A promise is always a promise, because you don't really know when it will be finished. However with Angular's 2 way data binding this isn't an issue. See my edits bellow as well as the example on $HTTP in the docs
In your controller
controller: function($scope, $stateParams, getContent){
getContent(BASE_URL + $stateParams.page + '?angular=pageName')
.then(aSuccessFn, aFailedFn);
function aSuccessFn(response) {
// work with data object, if the need to be accessed in your template, set you scope in the aSuccessFn.
$scope.contentPage = response.data;
}
function aFailedFn(data) {
// foo bar error handling.
}
}

How to use an angular scope variable outside the scope it is defined in

I have a service like below, which fetches the id of a student from a RESTful (Laravel) API and returns it.
.factory('Student', function($http)
{
return {
getId: function(adm_no) {
return $http.post('/api/student/getId',{adm_no:adm_no})
.then(function(response)
{
return response.data;
},
function(httpError)
{
Notifier.error(httpError.data.error.message,'Error ' + httpError.status + " Encountered");
});
}
}
}
)
Then i use it as follows in a controller.
$scope.adm_no = 98;
Student.getId($scope.adm_no)
.then(function(response)
{
$scope.id = response;
});
// probably i want to use the `$scope.id` when a particular event takes place (or even in another query to the server alltogether), but outside the above function scope e.g.
$scope.showId = function()
{
alert($scope.id);
};
Now, the question is how I can use the a scope variable declared in a 'local scope' outside the scope, for the usage above shows that $scope.id is undefined?
Your $scope.id is undefined in function $scope.showId() because when you call an alert function, your post request hasn't finished yet and so $scope.id hasn't been initialized (it is beeing executed asynchronously). Try this:
$scope.showId = function() {
if ($scope.id) {
alert($scope.id);
}
};
Anyway you don't have to use $rootScope in this case. Your property id from $scope is accesible from your whole controller. You have to wait for the ajax post request and than it is initialized.
In place of $scope you have to use $routescope variable to get id in other place as-
Student.getId($scope.adm_no)
.then(function(response)
{
$routescope.id = response;
});

How to use data from $http in other controller

How can I use the totalResults outside of the function that Im setting it? I just cant wrap my head around how to do it, I need to use the totalResults that I gather from my database and use in another function to calculate the amount of pages. I do this so I dont load all the data to the client but I still need to know the total count of rows in the database table.
My json looks like:
Object {total: 778, animals: Array[20]}
Angular:
var app = angular.module('app', []);
app.controller('AnimalController', ['$scope', 'animalSrc', function($scope, animalSrc)
{
$scope.animals = [];
var skip = 0;
var take = 20;
var totalResults = null;
//$scope.totalResults = null;
$scope.list = function()
{
animalSrc.getAll(skip, take, function(data) {
$scope.animals = $scope.animals.concat(data.animals);
// I need to be able to use this outside of function ($scope.list)
totalResults = data.total;
//$scope.totalResults = data.total;
});
};
$scope.showMore = function()
{
skip += 20;
$scope.list();
};
$scope.hasMore = function()
{
//
};
// Outputs null, should be the total rows from the $http request
console.log(totalResults);
}]);
app.factory('animalSrc', ['$http', function($http)
{
// Private //
return {
getAll: function(skip, take, callback)
{
$http({
method: 'GET',
url: 'url' + skip + '/' + take
}).
success(function(data) {
callback(data);
}).
error(function(data) {
console.log('error: ' + data);
});
}
};
}]);
You need to start thinking asynchronously. Your console.log is called before the $http has returned and totalResults has been set. Therefore, totalResults will always be null.
You need to find some way to delay the call to console.log so that the $http call can finish before you run console.log. One way to do this would be to put the console.log call inside your callback function so that it is definitely called after $http's success.
A more elegant way to do this is to use promises. angular.js implements $q, which is similar to Q, a promise library.
http://docs.angularjs.org/api/ng.$q
Instead of creating a callback function in getAll, you return a promise. Inside $http success, you resolve the promise with the data. Then, in your controller, you have a function that is called when the promise is resolved. Promises are nice because they can be passed around and they allow you to control the flow of your asynchronous code without blocking.
Here's a boilerplate I was just working on for myself for similar setup where data is an object that needs to be split into more than one scope item. Issue you weren't grasping is storing the data within the service, not just using service to retrieve data. Then the data items are available across multple controllers and directives by injecting service
app.run(function(MyDataService){
MyDataService.init();
})
app.factory('MyDataService',function($http,$q){
var myData = {
deferreds:{},
mainDataSchema:['count','items'],
init:function(){
angular.forEach(myData.mainDataSchema,function(val,idx){
/* create deferreds and promises*/
myData.deferreds[val]=$q.defer();
myData[val]= myData.deferreds[val].promise
});
/* load the data*/
myData.loadData();
},
loadData:function(){
$http.get('data.json').success(function(response){
/* create resolves for promises*/
angular.forEach(myData.mainDataSchema,function(val,idx){
myData.deferreds[val].resolve(response[val]);
});
/* TODO -create rejects*/
})
}
}
return myData;
})
app.controller('Ctrl_1', function($scope,MyDataService ) {
$scope.count = MyDataService.count;
$scope.items =MyDataService.items;
});
app.controller('Ctrl_2', function($scope,MyDataService ) {
$scope.items =MyDataService.items;
$scope.count = MyDataService.count;
});
Plunker demo

Resources