I recently posted a detailed description of the issue I am facing here at SO. As I couldn't send an actual $http request, I used timeout to simulate asynchronous behavior. Data binding from my model to view is working correct, with the help of @Gloopy
Now, when I use $http instead of $timeout (tested locally), I could see the asynchronous request was successful and data is filled with json response in my service. But, my view is not updating.
updated Plunkr here
Here is a Plunk that does what you want: http://plnkr.co/edit/TTlbSv?p=preview
The idea is that you work with promises directly and their "then" functions to manipulate and access the asynchronously returned responses.
app.factory('myService', function($http) {
var myService = {
async: function() {
// $http returns a promise, which has a then function, which also returns a promise
var promise = $http.get('test.json').then(function (response) {
// The then function here is an opportunity to modify the response
console.log(response);
// The return value gets picked up by the then in the controller.
return response.data;
});
// Return the promise to the controller
return promise;
}
};
return myService;
});
app.controller('MainCtrl', function( myService,$scope) {
// Call the async method and then do stuff with what is returned inside our own then function
myService.async().then(function(d) {
$scope.data = d;
});
});
Here is a slightly more complicated version that caches the request so you only make it first time (http://plnkr.co/edit/2yH1F4IMZlMS8QsV9rHv?p=preview):
app.factory('myService', function($http) {
var promise;
var myService = {
async: function() {
if ( !promise ) {
// $http returns a promise, which has a then function, which also returns a promise
promise = $http.get('test.json').then(function (response) {
// The then function here is an opportunity to modify the response
console.log(response);
// The return value gets picked up by the then in the controller.
return response.data;
});
}
// Return the promise to the controller
return promise;
}
};
return myService;
});
app.controller('MainCtrl', function( myService,$scope) {
$scope.clearData = function() {
$scope.data = {};
};
$scope.getData = function() {
// Call the async method and then do stuff with what is returned inside our own then function
myService.async().then(function(d) {
$scope.data = d;
});
};
});
then? –
Murat myService.async() multiple times from various controllers, how would you organise the service so that is only does the $http.get() for the first request, and all subsequent requests just return a local object array that gets set at the first call to myService.async(). In other words, I want to avoid multiple, needless requests to the JSON service, when really I only need to make one. –
Outbound $scope.data = myService.async() directly in the controller. –
Thief 'myConfigService.getConfig().then(function(config) { doSomething(config); });. Is there a neat way? –
Alanalana Let it be simple. It's as simple as
promise in your service(no need to use then in service)then in your controllerDemo. http://plnkr.co/edit/cbdG5p?p=preview
var app = angular.module('plunker', []);
app.factory('myService', function($http) {
return {
async: function() {
return $http.get('test.json'); //1. this returns promise
}
};
});
app.controller('MainCtrl', function( myService,$scope) {
myService.async().then(function(d) { //2. so you can use .then()
$scope.data = d;
});
});
app.factory, and in your code it's app.service. It's supposed app.factory in this case. –
Convenient Because it is asynchronous, the $scope is getting the data before the ajax call is complete.
You could use $q in your service to create promise and give it back to
controller, and controller obtain the result within then() call against promise.
In your service,
app.factory('myService', function($http, $q) {
var deffered = $q.defer();
var data = [];
var myService = {};
myService.async = function() {
$http.get('test.json')
.success(function (d) {
data = d;
console.log(d);
deffered.resolve();
});
return deffered.promise;
};
myService.data = function() { return data; };
return myService;
});
Then, in your controller:
app.controller('MainCtrl', function( myService,$scope) {
myService.async().then(function() {
$scope.data = myService.data();
});
});
this.async = function() { and this.getData = function() {return data} ? I hope you get what i mean –
Stormi deffered = $q.defer() inside the myService.async if I want to call myService.async() two or more time –
Beforetime $q.defer as the $http service already returns a promise. The promise returned will hang if the $http returns an error. In addition the .success and .error methods are deprecated and have been removed from AngularJS 1.6. –
Isoniazid tosh shimayama have a solution but you can simplify a lot if you use the fact that $http returns promises and that promises can return a value:
app.factory('myService', function($http, $q) {
myService.async = function() {
return $http.get('test.json')
.then(function (response) {
var data = reponse.data;
console.log(data);
return data;
});
};
return myService;
});
app.controller('MainCtrl', function( myService,$scope) {
$scope.asyncData = myService.async();
$scope.$watch('asyncData', function(asyncData) {
if(angular.isDefined(asyncData)) {
// Do something with the returned data, angular handle promises fine, you don't have to reassign the value to the scope if you just want to use it with angular directives
}
});
});
A little demonstration in coffeescript: http://plunker.no.de/edit/ksnErx?live=preview
Your plunker updated with my method: http://plnkr.co/edit/mwSZGK?p=preview
A much better way I think would be something like this:
Service:
app.service('FruitsManager',function($q){
function getAllFruits(){
var deferred = $q.defer();
...
// somewhere here use: deferred.resolve(awesomeFruits);
...
return deferred.promise;
}
return{
getAllFruits:getAllFruits
}
});
And in the controller you can simply use:
$scope.fruits = FruitsManager.getAllFruits();
Angular will automatically put the resolved awesomeFruits into the $scope.fruits.
I had the same problem, but when I was surfing on the internet I understood that $http return back by default a promise, then I could use it with "then" after return the "data". look at the code:
app.service('myService', function($http) {
this.getData = function(){
var myResponseData = $http.get('test.json').then(function (response) {
console.log(response);.
return response.data;
});
return myResponseData;
}
});
app.controller('MainCtrl', function( myService, $scope) {
// Call the getData and set the response "data" in your scope.
myService.getData.then(function(myReponseData) {
$scope.data = myReponseData;
});
});
When binding the UI to your array you'll want to make sure you update that same array directly by setting the length to 0 and pushing the data into the array.
Instead of this (which set a different array reference to data which your UI won't know about):
myService.async = function() {
$http.get('test.json')
.success(function (d) {
data = d;
});
};
try this:
myService.async = function() {
$http.get('test.json')
.success(function (d) {
data.length = 0;
for(var i = 0; i < d.length; i++){
data.push(d[i]);
}
});
};
Here is a fiddle that shows the difference between setting a new array vs emptying and adding to an existing one. I couldn't get your plnkr working but hopefully this works for you!
angular.copy(d, data) will also work. When a destination is supplied to the copy() method, it will first delete the destination's elements, and then copy in the new ones from the source. –
Jessee Related to this I went through a similar problem, but not with get or post made by Angular but with an extension made by a 3rd party (in my case Chrome Extension).
The problem that I faced is that the Chrome Extension won't return then() so I was unable to do it the way in the solution above but the result is still Asynchronous.
So my solution is to create a service and to proceed to a callback
app.service('cookieInfoService', function() {
this.getInfo = function(callback) {
var model = {};
chrome.cookies.get({url:serverUrl, name:'userId'}, function (response) {
model.response= response;
callback(model);
});
};
});
Then in my controller
app.controller("MyCtrl", function ($scope, cookieInfoService) {
cookieInfoService.getInfo(function (info) {
console.log(info);
});
});
Hope this can help others getting the same issue.
I've read http://markdalgleish.com/2013/06/using-promises-in-angularjs-views/ [AngularJS allows us to streamline our controller logic by placing a promise directly on the scope, rather than manually handing the resolved value in a success callback.]
so simply and handy :)
var app = angular.module('myApp', []);
app.factory('Data', function($http,$q) {
return {
getData : function(){
var deferred = $q.defer();
var promise = $http.get('./largeLoad').success(function (response) {
deferred.resolve(response);
});
// Return the promise to the controller
return deferred.promise;
}
}
});
app.controller('FetchCtrl',function($scope,Data){
$scope.items = Data.getData();
});
Hope this help
defrred.promise is not a function. –
Dumont $scope.items = Data.getData(); is deprecated in Anglular –
Alanalana I really don't like the fact that, because of the "promise" way of doing things, the consumer of the service that uses $http has to "know" about how to unpack the response.
I just want to call something and get the data out, similar to the old $scope.items = Data.getData(); way, which is now deprecated.
I tried for a while and didn't come up with a perfect solution, but here's my best shot (Plunker). It may be useful to someone.
app.factory('myService', function($http) {
var _data; // cache data rather than promise
var myService = {};
myService.getData = function(obj) {
if(!_data) {
$http.get('test.json').then(function(result){
_data = result.data;
console.log(_data); // prove that it executes once
angular.extend(obj, _data);
});
} else {
angular.extend(obj, _data);
}
};
return myService;
});
Then controller:
app.controller('MainCtrl', function( myService,$scope) {
$scope.clearData = function() {
$scope.data = Object.create(null);
};
$scope.getData = function() {
$scope.clearData(); // also important: need to prepare input to getData as an object
myService.getData($scope.data); // **important bit** pass in object you want to augment
};
});
Flaws I can already spot are
getData can only accept the obj parameter in the form of an object (although it could also accept an array), which won't be a problem for many applications, but it's a sore limitation$scope.data with = {} to make it an object (essentially what $scope.clearData() does above), or = [] for an array, or it won't work (we're already having to assume something about what data is coming). I tried to do this preparation step IN getData, but no luck.Nevertheless, it provides a pattern which removes controller "promise unwrap" boilerplate, and might be useful in cases when you want to use certain data obtained from $http in more than one place while keeping it DRY.
As far as caching the response in service is concerned , here's another version that seems more straight forward than what I've seen so far:
App.factory('dataStorage', function($http) {
var dataStorage;//storage for cache
return (function() {
// if dataStorage exists returned cached version
return dataStorage = dataStorage || $http({
url: 'your.json',
method: 'GET',
cache: true
}).then(function (response) {
console.log('if storage don\'t exist : ' + response);
return response;
});
})();
});
this service will return either the cached data or $http.get;
dataStorage.then(function(data) {
$scope.data = data;
},function(e){
console.log('err: ' + e);
});
Please try the below Code
You can split the controller (PageCtrl) and service (dataService)
'use strict';
(function () {
angular.module('myApp')
.controller('pageContl', ['$scope', 'dataService', PageContl])
.service('dataService', ['$q', '$http', DataService]);
function DataService($q, $http){
this.$q = $q;
this.$http = $http;
//... blob blob
}
DataService.prototype = {
getSearchData: function () {
var deferred = this.$q.defer(); //initiating promise
this.$http({
method: 'POST',//GET
url: 'test.json',
headers: { 'Content-Type': 'application/json' }
}).then(function(result) {
deferred.resolve(result.data);
},function (error) {
deferred.reject(error);
});
return deferred.promise;
},
getABCDATA: function () {
}
};
function PageContl($scope, dataService) {
this.$scope = $scope;
this.dataService = dataService; //injecting service Dependency in ctrl
this.pageData = {}; //or [];
}
PageContl.prototype = {
searchData: function () {
var self = this; //we can't access 'this' of parent fn from callback or inner function, that's why assigning in temp variable
this.dataService.getSearchData().then(function (data) {
self.searchData = data;
});
}
}
}());© 2022 - 2024 — McMap. All rights reserved.