How to cancel request [duplicate] - javascript

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;
});

Related

How to reload a http.get request after performing a function

I am trying to delete a post from a list. The delete function is performing by passing serially to a delete function showed below.
$scope.go = function(ref) {
$http.get("api/phone_recev.php?id="+ref)
.success(function (data) { });
}
After performing the function, I need to reload the http.get request which used for listing the list.
$http.get("api/phone_accept.php")
.then(function (response) { });
Once the function performed. The entire list will reload with new updated list. Is there any way to do this thing.
Try this
$scope.go = function(ref) {
$http.get("api/phone_recev.php?id="+ref)
.success(function (data) {
//on success of first function it will call
$http.get("api/phone_accept.php")
.then(function (response) {
});
});
}
function list_data() {
$http.get("api/phone_accept.php")
.then(function (response) {
console.log('listing');
});
}
$scope.go = function(ref) {
$http.get("api/phone_recev.php?id="+ref)
.success(function (data) {
// call function to do listing
list_data();
});
}
Like what #sudheesh Singanamalla says by calling the same http.get request again inside function resolved my problem.
$scope.go = function(ref) {
$http.get("api/phone_recev.php?id="+ref).success(function (data) {
//same function goes here will solve the problem.
});}
});
You can use $q - A service that helps you run functions asynchronously, and use their return values (or exceptions) when they are done processing.
https://docs.angularjs.org/api/ng/service/$q
Inside some service.
app.factory('SomeService', function ($http, $q) {
return {
getData : function() {
// the $http API is based on the deferred/promise APIs exposed by the $q service
// so it returns a promise for us by default
return $http.get("api/phone_recev.php?id="+ref)
.then(function(response) {
if (typeof response.data === 'object') {
return response.data;
} else {
// invalid response
return $q.reject(response.data);
}
}, function(response) {
// something went wrong
return $q.reject(response.data);
});
}
};
});
function somewhere in controller
var makePromiseWithData = function() {
// This service's function returns a promise, but we'll deal with that shortly
SomeService.getData()
// then() called when gets back
.then(function(data) {
// promise fulfilled
// something
}, function(error) {
// promise rejected, could log the error with: console.log('error', error);
//some code
});
};

Asynchronously function returns undefined with $q deferred

I am calling my data from my api through a factory that looks like this:
app.factory('Service', ['$http', function ($http) {
var urlBase = 'http://localhost:50476/api';
var Service = {};
Service.getComp = function () {
return $http.get(urlBase + '/complaints')
};
return Service;
}]);
Then I use my controller to use the directive:
getComp();
$scope.comp = [];
function getComp() {
var deferred = $q.defer();
Service.getComp()
.success(function (comp) {
console.log('comp', comp); //returns array data
$scope.comp = comp.data;
deferred.resolve(comp);
})
.error(function (error) {
$scope.error = 'error' + error.message;
});
return deferred.promise;
}
$scope.index = 0;
$scope.complaints = $scope.comp[0];
console.log($scope.complaints); //undefined
console.log($scope.comp); //array of 0
When I try to access the items outside of the function it is undefined. I tried to look for resolutions like using $q but it is still not displaying data. When I added the deferred part my ng-repeat stops working as well.
Try this:
getComp();
$scope.comp = [];
function getComp() {
return Service.getComp()
.success(function (comp) {
$scope.comp = comp.data;
$scope.complaints = $scope.comp[0];
})
.error(function (error) {
$scope.error = 'error' + error.message;
});
}
The values are undefined when you do your logs because those lines run before your request comes back from the server. That's why setting $scope.complaints has to go into the success callback.
if you want to make sure complaints are loaded on certain states before you start your logic you can use ui-routers resolve keyword (i suppose you are using ui-router with ionic - standard package)
In you main.js
$stateProvider.state('yourState', {
resolve: {
complaints: function(Service) {
return Service.getComp();
}
}
});
in your controller you can then inject complaints
.controller('myController', function(complaints) {
$scope.complaints = complaints;
})
resolve at $stateProvider will block and wait for the promise to resolve...

AngularJS: how to stay in 'run' method until it finishes

I have a simple scenario - I wish to init my http calls with interceptor that will add a value in headers (a token of some kind).
The problem is that the token is received via http as well (it should be the first call) but I don't know how to make all other calls to wait for it to finish before issuing their own calls...
.factory('sessionData', function () {
var currentToken = '[uninitialized-token]';
return {
getToken: function () {
return currentToken;
},
setAuthData: function (token) {
currentToken = token;
}
}
})
.factory('sessionInjector', ['sessionData', function (sessionData) {
var sessionInjector = {
request: function (config) {
console.log("sending with token: " + sessionData.getToken());
config.headers['x-header-sessionID'] = sessionData.getToken();
}
};
return sessionInjector;
}])
.config(['$httpProvider', function ($httpProvider) {
$httpProvider.interceptors.push('sessionInjector');
}])
.run(['$http', 'configs', 'sessionData', function ($http, configs, sessionData) {
$http.get(configs.authApiUrl + 'login').then(function (ret) {
sessionData.setAuthData(ret);
console.log("successfully authenticated with token " + sessionData.getToken());
});
}])
.controller('TestCtrl', function($http){
$scope.p1 = 'Uninitialized';
$http.get('http://localhost/api/getData').then(function(ret){
$scope.p1 = ret;
});
});
The problem is that the TestCtrl issues an http call before the run method finished getting the token (resulting in header value having the [uninitialized-token] in it's value).
How to make the controllers wait for the 'run' async methods to finish?
$http interceptors can be used to return promises in their callbacks. You can use this to intercept each call and delay it until the promise is resolved.
You should understand how promises work for this.
Example:
myModule.factory('tokenPromise', function($http) {
return $http.get({url: 'myurl/token', bypassToken: true}).then(function(data) {
// This is when your token webservice return, deal with the response here
return data.token;
});
});
myModule.factory('myHttpInterceptor', function($q, tokenPromise) {
return {
'request': function(config) {
if (config.bypassToken) return config;
// This ensures the token promise is resolved before proceeding with the request.
return tokenPromise.then(function(token) {
config.headers['x-header-sessionID'] = token;
return config;
});
},
};
});
myModule.config(function($httpProvider) {
//wire the interceptor here
$httpProvider.interceptors.push('myHttpInterceptor');
})
reference: http service on angular official docs

How to write a unit test with Jest for code with Promise

I am trying to write a unit test with Jest and Jasmine-pit for the below code and am totally stumped with it. The code is an ajax call which retrieves some data from resource and saves it in the variable.
init = function() {
var deferred = Q.defer();
$.ajax({
type: 'GET',
datatype: 'json',
url: window.location.origin + name,
success: function (data) {
userId = data.userId;
apiKey = data.apiKey;
deferred.resolve();
}
});
return deferred.promise;
},
This frustrated me most of the day today. Here is what I ended up with (testing my ActionCreator (Flux) which uses an API that returns promises and dispatches stuff based on the promise). Basically I mock out the API method that returns the promise and resolve it right away. You'd think that this would be enough to get the .then(...) methods to fire, but the pit code was required to have my ActionCreator actually do work based on the resolved promise.
jest.dontMock('../LoginActionCreators.js');
jest.dontMock('rsvp'); //has to be above the require statement
var RSVP = require('rsvp'); //could be other promise library
describe('LoginActionCreator', function() {
pit('login: should call the login API', function() {
var loginActionCreator = require('../LoginActionCreators');
var Dispatcher = require('../../dispatcher/Dispatcher');
var userAPI = require('../../api/User');
var Constants = require('../../constants/Constants');
//my api method needs to return this
var successResponse = { body: {"auth_token":"Ve25Mk3JzZwep6AF7EBw=="} };
//mock out the API method and resolve the promise right away
var apiMock = jest.genMockFunction().mockImplementation(function() {
var promise = new RSVP.Promise(function(resolve, reject) {
resolve(successResponse);
});
return promise;
});
//my action creator will dispatch stuff based on the promise resolution, so let's mock that out too
var dispatcherMock = jest.genMockFunction();
userAPI.login = apiMock;
Dispatcher.dispatch = dispatcherMock;
var creds = {
username: 'username',
password: 'password'
};
//call the ActionCreator
loginActionCreator.login(creds.username, creds.password);
//the pit code seems to manage promises at a slightly higher level than I could get to on my
// own, the whole pit() and the below return statement seem like they shouldnt be necessary
// since the promise is already resolved in the mock when it is returned, but
// I could not get this to work without pit.
return (new RSVP.Promise(function(resolve) { resolve(); })).then(function() {
expect(apiMock).toBeCalledWith(creds);
expect(dispatcherMock.mock.calls.length).toBe(2);
expect(dispatcherMock.mock.calls[0][0]).toEqual({ actionType: Constants.api.user.LOGIN, queryParams: creds, response: Constants.request.PENDING});
expect(dispatcherMock.mock.calls[1][0]).toEqual({ actionType: Constants.api.user.LOGIN, queryParams: creds, response: successResponse});
});
});
});
Here is the ActionCreator which ties the API to the Dispatcher:
'use strict';
var Dispatcher = require('../dispatcher/Dispatcher');
var Constants = require('../constants/Constants');
var UserAPI = require('../api/User');
function dispatch(key, response, params) {
var payload = {actionType: key, response: response};
if (params) {
payload.queryParams = params;
}
Dispatcher.dispatch(payload);
}
var LoginActionCreators = {
login: function(username, password) {
var params = {
username: username,
password: password
};
dispatch(Constants.api.user.LOGIN, Constants.request.PENDING, params);
var promise = UserAPI.login(params);
promise.then(function(res) {
dispatch(Constants.api.user.LOGIN, res, params);
}, function(err) {
dispatch(Constants.api.user.LOGIN, Constants.request.ERROR, params);
});
}
};
module.exports = LoginActionCreators;
This tutorial on the website of Jest doesn't answer the question directly, but has the gist of how to unit test promise.
https://facebook.github.io/jest/docs/tutorial-async.html

How to abort a request in a http-interceptor?

In an app I have the following url structure for the api:
// public
public/url-xyz
// private
dashboard/url-xyz
Knowing that, and trying to save unnecessary requests: What would be the best way to cancel a request? What I've tried so far is:
angular.module('mymod').factory('httpInterceptors', function ($injector, $q, httpBuffer)
{
return {
request: function (config)
{
var url = config.url;
if (url.match('/dashboard/')) {
// immediately cancel request
var canceler = $q.defer();
config.timeout = canceler.promise;
canceler.reject(config);
// logout and go to login-page immediately
// ...
}
// request config or an empty promise
return config || $q.when(config);
}
};
});
But this can lead to problems with $ressource as it expects an array and gets an object as a response, if its request is canceled like that.
You should be able to return $q.reject([reason])
angular.module('mymod').factory('httpInterceptors', function ($injector, $q, httpBuffer)
{
return {
request: function (config)
{
var url = config.url;
if (url.match('/dashboard/')) {
// immediately cancel request
return $q.reject(config);
// logout and go to login-page immediately
// ...
}
// request config or an empty promise
return config || $q.when(config);
}
};
});

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