Develop Reference

Cancelling an angular service promise

I have a controller that performs a http request.
This request can take anywhere between 2 seconds to 4 minutes to return some data .
I have added a button, that users should click to cancel the request if searches take too long to complete.
Controller:
$scope.search = function() {
myFactory.getResults()
.then(function(data) {
// some logic
}, function(error) {
// some logic
});
}
Service:
var myFactory = function($http, $q) {
return {
getResults: function(data) {
var deffered = $q.dafer();
var content = $http.get('someURL', {
data: {},
responseType: json
)}
deffered.resolve(content);
returned deffered.promise;
}
}
}
Button click:
$scope.cancelGetResults = function() {
// some code to cancel myFactory.getResults() promise
}
How can I implement a button click to cancel the myFactory.getResults() promise?

The question uses deferred antipattern which usually should be avoided, but it fits the cancellation case:
getResults: function(data) {
var deffered = $q.defer();
$http.get('someURL', {
data: {},
responseType: json
}).then(deffered.resolve, deferred.reject);
deffered.promise.cancel = function () {
deferred.reject('CANCELLED')
};
returned deffered.promise;
}

getResult is a service in which we are implementing cancellation.
getResult = function(){
var deferred = $q.defer();
$http.get(url).success(function(result){
deffered.resolve(result);
}).error(function(){
deffered.reject('Error is occured!');
});
return deferred.promise;
};
where url variable is used in place of any Restful API url. You can use it with given code.
getResult().then(function (result) { console.log(result); };

You could use .resolve() method which should be available.
Pass the promise in the controller to the variable.
Create e.g. cancel method which takes the promise as an argument in you factory. Then call this method in the cancelGetResults() function in the controller.
In the cancel method you just call .resolve on the passed promise.
This should actually do.
https://www.bennadel.com/blog/2731-canceling-a-promise-in-angularjs.htm

How to cancel a promise in angularjs? [duplicate]

Given a Ajax request in AngularJS
$http.get("/backend/").success(callback);
what is the most effective way to cancel that request if another request is launched (same backend, different parameters for instance).

This feature was added to the 1.1.5 release via a timeout parameter:
var canceler = $q.defer();
$http.get('/someUrl', {timeout: canceler.promise}).success(successCallback);
// later...
canceler.resolve(); // Aborts the $http request if it isn't finished.

Cancelling Angular $http Ajax with the timeout property doesn't work in Angular 1.3.15.
For those that cannot wait for this to be fixed I'm sharing a jQuery Ajax solution wrapped in Angular.
The solution involves two services:
HttpService (a wrapper around the jQuery Ajax function);
PendingRequestsService (tracks the pending/open Ajax requests)
Here goes the PendingRequestsService service:
(function (angular) {
'use strict';
var app = angular.module('app');
app.service('PendingRequestsService', ["$log", function ($log) {
var $this = this;
var pending = [];
$this.add = function (request) {
pending.push(request);
};
$this.remove = function (request) {
pending = _.filter(pending, function (p) {
return p.url !== request;
});
};
$this.cancelAll = function () {
angular.forEach(pending, function (p) {
p.xhr.abort();
p.deferred.reject();
});
pending.length = 0;
};
}]);})(window.angular);
The HttpService service:
(function (angular) {
'use strict';
var app = angular.module('app');
app.service('HttpService', ['$http', '$q', "$log", 'PendingRequestsService', function ($http, $q, $log, pendingRequests) {
this.post = function (url, params) {
var deferred = $q.defer();
var xhr = $.ASI.callMethod({
url: url,
data: params,
error: function() {
$log.log("ajax error");
}
});
pendingRequests.add({
url: url,
xhr: xhr,
deferred: deferred
});
xhr.done(function (data, textStatus, jqXhr) {
deferred.resolve(data);
})
.fail(function (jqXhr, textStatus, errorThrown) {
deferred.reject(errorThrown);
}).always(function (dataOrjqXhr, textStatus, jqXhrErrorThrown) {
//Once a request has failed or succeeded, remove it from the pending list
pendingRequests.remove(url);
});
return deferred.promise;
}
}]);
})(window.angular);
Later in your service when you are loading data you would use the HttpService instead of $http:
(function (angular) {
angular.module('app').service('dataService', ["HttpService", function (httpService) {
this.getResources = function (params) {
return httpService.post('/serverMethod', { param: params });
};
}]);
})(window.angular);
Later in your code you would like to load the data:
(function (angular) {
var app = angular.module('app');
app.controller('YourController', ["DataService", "PendingRequestsService", function (httpService, pendingRequestsService) {
dataService
.getResources(params)
.then(function (data) {
// do stuff
});
...
// later that day cancel requests
pendingRequestsService.cancelAll();
}]);
})(window.angular);

Cancelation of requests issued with $http is not supported with the current version of AngularJS. There is a pull request opened to add this capability but this PR wasn't reviewed yet so it is not clear if its going to make it into AngularJS core.

If you want to cancel pending requests on stateChangeStart with ui-router, you can use something like this:
// in service
var deferred = $q.defer();
var scope = this;
$http.get(URL, {timeout : deferred.promise, cancel : deferred}).success(function(data){
//do something
deferred.resolve(dataUsage);
}).error(function(){
deferred.reject();
});
return deferred.promise;
// in UIrouter config
$rootScope.$on('$stateChangeStart', function (event, toState, toParams, fromState, fromParams) {
//To cancel pending request when change state
angular.forEach($http.pendingRequests, function(request) {
if (request.cancel && request.timeout) {
request.cancel.resolve();
}
});
});

For some reason config.timeout doesn't work for me. I used this approach:
let cancelRequest = $q.defer();
let cancelPromise = cancelRequest.promise;
let httpPromise = $http.get(...);
$q.race({ cancelPromise, httpPromise })
.then(function (result) {
...
});
And cancelRequest.resolve() to cancel. Actually it doesn't not cancel a request but you don't get unnecessary response at least.
Hope this helps.

This enhances the accepted answer by decorating the $http service with an abort method as follows ...
'use strict';
angular.module('admin')
.config(["$provide", function ($provide) {
$provide.decorator('$http', ["$delegate", "$q", function ($delegate, $q) {
var getFn = $delegate.get;
var cancelerMap = {};
function getCancelerKey(method, url) {
var formattedMethod = method.toLowerCase();
var formattedUrl = encodeURI(url).toLowerCase().split("?")[0];
return formattedMethod + "~" + formattedUrl;
}
$delegate.get = function () {
var cancelerKey, canceler, method;
var args = [].slice.call(arguments);
var url = args[0];
var config = args[1] || {};
if (config.timeout == null) {
method = "GET";
cancelerKey = getCancelerKey(method, url);
canceler = $q.defer();
cancelerMap[cancelerKey] = canceler;
config.timeout = canceler.promise;
args[1] = config;
}
return getFn.apply(null, args);
};
$delegate.abort = function (request) {
console.log("aborting");
var cancelerKey, canceler;
cancelerKey = getCancelerKey(request.method, request.url);
canceler = cancelerMap[cancelerKey];
if (canceler != null) {
console.log("aborting", cancelerKey);
if (request.timeout != null && typeof request.timeout !== "number") {
canceler.resolve();
delete cancelerMap[cancelerKey];
}
}
};
return $delegate;
}]);
}]);
WHAT IS THIS CODE DOING?
To cancel a request a "promise" timeout must be set.
If no timeout is set on the HTTP request then the code adds a "promise" timeout.
(If a timeout is set already then nothing is changed).
However, to resolve the promise we need a handle on the "deferred".
We thus use a map so we can retrieve the "deferred" later.
When we call the abort method, the "deferred" is retrieved from the map and then we call the resolve method to cancel the http request.
Hope this helps someone.
LIMITATIONS
Currently this only works for $http.get but you can add code for $http.post and so on
HOW TO USE ...
You can then use it, for example, on state change, as follows ...
rootScope.$on('$stateChangeStart', function (event, toState, toParams) {
angular.forEach($http.pendingRequests, function (request) {
$http.abort(request);
});
});

here is a version that handles multiple requests, also checks for cancelled status in callback to suppress errors in error block. (in Typescript)
controller level:
requests = new Map<string, ng.IDeferred<{}>>();
in my http get:
getSomething(): void {
let url = '/api/someaction';
this.cancel(url); // cancel if this url is in progress
var req = this.$q.defer();
this.requests.set(url, req);
let config: ng.IRequestShortcutConfig = {
params: { id: someId}
, timeout: req.promise // <--- promise to trigger cancellation
};
this.$http.post(url, this.getPayload(), config).then(
promiseValue => this.updateEditor(promiseValue.data as IEditor),
reason => {
// if legitimate exception, show error in UI
if (!this.isCancelled(req)) {
this.showError(url, reason)
}
},
).finally(() => { });
}
helper methods
cancel(url: string) {
this.requests.forEach((req,key) => {
if (key == url)
req.resolve('cancelled');
});
this.requests.delete(url);
}
isCancelled(req: ng.IDeferred<{}>) {
var p = req.promise as any; // as any because typings are missing $$state
return p.$$state && p.$$state.value == 'cancelled';
}
now looking at the network tab, i see that it works beatuifully. i called the method 4 times and only the last one went through.

You can add a custom function to the $http service using a "decorator" that would add the abort() function to your promises.
Here's some working code:
app.config(function($provide) {
$provide.decorator('$http', function $logDecorator($delegate, $q) {
$delegate.with_abort = function(options) {
let abort_defer = $q.defer();
let new_options = angular.copy(options);
new_options.timeout = abort_defer.promise;
let do_throw_error = false;
let http_promise = $delegate(new_options).then(
response => response,
error => {
if(do_throw_error) return $q.reject(error);
return $q(() => null); // prevent promise chain propagation
});
let real_then = http_promise.then;
let then_function = function () {
return mod_promise(real_then.apply(this, arguments));
};
function mod_promise(promise) {
promise.then = then_function;
promise.abort = (do_throw_error_param = false) => {
do_throw_error = do_throw_error_param;
abort_defer.resolve();
};
return promise;
}
return mod_promise(http_promise);
}
return $delegate;
});
});
This code uses angularjs's decorator functionality to add a with_abort() function to the $http service.
with_abort() uses $http timeout option that allows you to abort an http request.
The returned promise is modified to include an abort() function. It also has code to make sure that the abort() works even if you chain promises.
Here is an example of how you would use it:
// your original code
$http({ method: 'GET', url: '/names' }).then(names => {
do_something(names));
});
// new code with ability to abort
var promise = $http.with_abort({ method: 'GET', url: '/names' }).then(
function(names) {
do_something(names));
});
promise.abort(); // if you want to abort
By default when you call abort() the request gets canceled and none of the promise handlers run.
If you want your error handlers to be called pass true to abort(true).
In your error handler you can check if the "error" was due to an "abort" by checking the xhrStatus property. Here's an example:
var promise = $http.with_abort({ method: 'GET', url: '/names' }).then(
function(names) {
do_something(names));
},
function(error) {
if (er.xhrStatus === "abort") return;
});

AngularJS not waiting for HTTP request to be done

Hello guys I have the following code here :
angular.module('todomvc')
.factory('todoStorage', function ($http) {
'use strict';
var STORAGE_ID = 'todos-angularjs';
return {
get: function () {
$http({method: 'GET', url: '/api/todo.php'}).
success(function(data, status, headers, config) {
// this callback will be called asynchronously
// when the response is available
return JSON.stringify(data);
}).
error(function(data, status, headers, config) {
// called asynchronously if an error occurs
// or server returns response with an error status.
});
},
put: function (todos) {
debugger;
localStorage.setItem(STORAGE_ID, JSON.stringify(todos));
}
};
});
as well as
angular.module('todomvc')
.controller('TodoCtrl', function TodoCtrl($scope, $routeParams, $filter, todoStorage, $http) {
'use strict';
var todos = $scope.todos = todoStorage.get();
$scope.newTodo = '';
$scope.editedTodo = null;
$scope.$watch('todos', function (newValue, oldValue) {
$scope.remainingCount = $filter('filter')(todos, { completed: false }).length;
$scope.completedCount = todos.length - $scope.remainingCount;
$scope.allChecked = !$scope.remainingCount;
if (newValue !== oldValue) { // This prevents unneeded calls to the local storage
todoStorage.put(todos);
}
}, true);
The issue i have is that the HTTP request is not completing before the code at $scope.$watch is being executed therefore it is calling .length on undefined. I am a total n00b to Angular and wanted to use this TodoMVC to get it working however im not sure what i can do to halt the whole process instead of wrapping the rest of the code within the success callback from the http request.
Thanks in advance

Issue
#1 you need to return promise from your get method of your factory, and use $http.then instead of http's custom promise method success.
#2 you need to chain it though to assign value to the scope property.
#3 when you watch asyncronously assigned properties you need to have a null check because the watch is going to run when the controller is set up.
#4 I am not sure if you should do JSON.stringify the response because looks like you are in need of an array data?
In your factory
return {
get: function () {
return $http({method: 'GET', url: '/api/todo.php'}). //Return here
then(function(response) { //
return response.data;
}, function(response) {
// called asynchronously if an error occurs
// or server returns response with an error status.
});
},
In your controller:-
var todos;
todoStorage.get().then(function(data) {
todos = $scope.todos = data
});
and
$scope.$watch('todos', function (newValue, oldValue) {
if(!newValue) return;
$scope.remainingCount = $filter('filter')(todos, { completed: false }).length;
$scope.completedCount = todos.length - $scope.remainingCount;
$scope.allChecked = !$scope.remainingCount;
if (newValue !== oldValue) { // This prevents unneeded calls to the local storage
todoStorage.put(todos);
}
}, true);

use this code:
angular.module('todomvc')
.factory('todoStorage', function ($http) {
'use strict';
var STORAGE_ID = 'todos-angularjs';
return {
get: function () {
return $http({method: 'GET', url: '/api/todo.php'})
},
put: function (todos) {
debugger;
localStorage.setItem(STORAGE_ID, JSON.stringify(todos));
}
};
});
angular.module('todomvc')
.controller('TodoCtrl', function TodoCtrl($scope, $routeParams, $filter, todoStorage, $http) {
'use strict';
$scope.newTodo = '';
$scope.editedTodo = null;
todoStorage.get()
.then(function(d){
$scope.todos=d;
})
.catch(function(e){
console.error(e);
})
$scope.$watch('todos', function (newValue, oldValue) {
$scope.remainingCount = $filter('filter')(todos, { completed: false }).length;
$scope.completedCount = todos.length - $scope.remainingCount;
$scope.allChecked = !$scope.remainingCount;
if (newValue !== oldValue) { // This prevents unneeded calls to the local storage
todoStorage.put(todos);
}
}, true);

$http is wrapped in a promise. You could return the promise from the service:
return $http({method: 'GET', url: '/api/todo.php'})
In the controller you can use then method to specify the behaviour when the request is completed:
$scope.newTodo = '';
$scope.editedTodo = null;
todoStorage.get().then(function(result) {
$scope.todos = result.data;
$scope.$watch('todos', function (newValue, oldValue) {
$scope.remainingCount = $filter('filter')($scope.todos, { completed: false }).length;
$scope.completedCount = todos.length - $scope.remainingCount;
$scope.allChecked = !$scope.remainingCount;
if (newValue !== oldValue) { // This prevents unneeded calls to the local storage
todoStorage.put($scope.todos);
}
}, true);
});
A good example about how to chain promises:
http://codepen.io/willh/pen/fCtuw

AngularJS how to set variable in $http success function of dependency provider

I'm newbie in angularjs and I'm trying to create new provider. This is my code:
myApp.provider('$Data', function() {
this.URL = 'http://maps.googleapis.com/maps/api/geocode/json?address=Singapore, SG, Singapore, 153 Bukit Batok Street 1&sensor=true';
this.$get = $get;
$get.$inject = ['$http', '$q'];
function $get($http, $q) {
var that = this;
return {
isConnected: function() {
var bIsConnected = 'Default';
$http({method: 'GET', url:that.URL}).then(function (data) {
bIsConnected = 'Yes';
alert('Run this code!');
}, function (data) {
bIsConnected = 'No';
});
return bIsConnected;
}
}
}
});
Jsfiddle demo:
http://jsfiddle.net/0udm9/9dPsb/6/
After I run $Data.isConnected(), the result is always 'Default' although browser show the alert box. I think it's from success function is not of $get. And I have to use provider, not service or factory for this case. Can I do anything to fix this issue?
Thanks,

You have to use promise in your code.
DEMO
Provider:
isConnected: function() {
var deferred = $q.defer();
$http.get(that.url).then(function(res) {
deferred.resolve('Yes');
console.log('example:success', res);
}, function(err) {
deferred.resolve('No');
console.log('example:error', err);
});
return deferred.promise;
}
Controller:
$Data.isConnected().then(function(data) {
$scope.data = data;
});
// UPD
You must use objects if you need to use return values with async code.
DEMO
// UPD 2
FRESH DEMO LINK

Why im not getting the response back from this factory function in angularJS [duplicate]

This question already has answers here:
How do I return the response from an asynchronous call?
(41 answers)
Closed 8 years ago.
I got this angular factory:
var productApp = angular.module('productApp', ['ngRoute', 'LocalStorageModule', 'angularSlideables', 'ui.bootstrap']);
productApp.factory('productFactory', function($http, localStorageService, $q) {
var factory = {};
factory.getProductById = function(prod_id) {
if(prod_id !== '') {
$http({
url: 'rest/message/getProductById/' + prod_id,
method: 'GET'
}).success(function(data, status) {
return data;
}).error(function(data, status){
// do nothing
});
}else {
alert("There was an error while passing the ID. Please refresh the page and try again");
}
}
return factory;
});
Injecting the factory in a controller and calling to the "getProductById" function:
productApp.controller('ModalInstanceCtrl', function ($scope, $modalInstance, productFactory, prodId) {
console.log("this is the prod id " + prodId);
// search product in the database
$scope.prod = productFactory.getProductById(prodId);
console.log($scope.prod);
$scope.ok = function () {
console.log($scope.prodData);
};
$scope.cancel = function () {
$modalInstance.dismiss('cancel');
};
});
Now, don't know what's wrong with it... the function RETURNS the data because i did a console.log(data) and saw all the response, but in the controller if i inspect the $scope.prod, it's undefined. It's not returning the data back from the function.
(Just in case you guys ask, the "prodId" in the controller parameter is fine, and retrieving that from another controller)
How can i solve this? :(
Thanks in advance.

The pattern I have used to solve this problem is to pass in the success & error callback functions to the factory... like this:
var productApp = angular.module('productApp', ['ngRoute', 'LocalStorageModule', 'angularSlideables', 'ui.bootstrap']);
productApp.factory('productFactory', function($http, localStorageService, $q) {
var factory = {};
factory.getProductById = function(prod_id, successCallback, errorCallback) {
if(prod_id !== '') {
$http({
url: 'rest/message/getProductById/' + prod_id,
method: 'GET'
})
.success(successCallback)
.error(errroCallback);
} else {
alert("There was an error while passing the ID. Please refresh the page and try again");
}
}
return factory;
});
and then:
productApp.controller('ModalInstanceCtrl', function ($scope, $modalInstance, productFactory, prodId) {
console.log("this is the prod id " + prodId);
// search product in the database
productFactory.getProductById(prodId, function successCallback(data) {
$scope.prod = data;
}, function errorCallback(data, status) {
alert("An error occurred retrieving product. Please refresh the page & try again.");
});
console.log($scope.prod);
$scope.ok = function () {
console.log($scope.prodData);
};
$scope.cancel = function () {
$modalInstance.dismiss('cancel');
};
});
By doing it this way instead, you have access to the scope in the controller & can do whatever you need to with the returned data.

Here's what I do. I'm using $resournce instead of $http, but it should be enough to get you going. You may even want to use the $resource since it has the built in fns.
My factory:
.factory('WorkOrder', function($resource){
// $resource Usage: $resource(url[, paramDefaults][, actions]);
return $resource('/controller/get/:id.json', {}, {
/*
* By default, the following actions are returned; modify or add as needed
* { 'get': {method:'GET'},
* 'save': {method:'POST'},
* 'query': {method:'GET', isArray:true},
* 'delete': {method:'DELETE'} };
*/
});
})
My controller:
// get the work order data using the work order id from the tag attribute
var getWO = function() {
WorkOrder.get({woId:$attrs.id},
// success callback
function(response) {
// Assign the work order data to the scope
$scope.WorkOrder = response.WorkOrder;
},
// fail callback
function(response) {
// whatever...
}
);
};
getWO();
I put my success and fail fns in my controller because that's where I most likely know how I want to respond to success or failed calls. I also assign the function to a variable and then call it right after in case I want to include the fn call inside a $timeout or call it elsewhere.
Hope this answers your question.