Angular $HTTP Error Handler - angularjs

Below is an example of a pretty crude way i'm currently handling a a HTTP call which is taking too long.
If it takes more than 3 seconds, re-fire, and if this fails 4 times than exit.
While it works, I don't wish to create every HTTP request like this as it is too much code for one call.
Is there a way of applying this globally?
I'm not sure if an interceptor is suitable for this case, as I need the error handle to kick in after the HTTP call takes too long, rather than when it receives a bad response from the server.
I would also need this to apply to requests for partial views.
Code:
var errorCount = 0;
function someFunction() {
var startTime = new Date().getTime();
var deferred = $q.defer();
var url = 'some url';
$http.get(url, {cache: true, timeout: 3000}).success(function(response) {
deferred.resolve(response);
}).error(function(result, status, header, config) {
var respTime = new Date().getTime() - startTime;
if( respTime >= config.timeout ){
errorCount +=1;
if ( errorCount > 3) {
errorCount = 0;
deferred.reject(result);
} else {
getCountries();
};
} else{
deferred.reject(error);
};
});
return deferred.promise;
};

Ok so this is what I ended up doing.
Probably not the best way but maybe someone will find it useful too!
So using an interceptor I configure all outgoing HTTP requests to abort after 3 seconds, and configure any responses which have a status of 'abort' (which is a status of '-1' I think) to retry 3 times.
Code:
(function() {
'use strict';
angular
.module('InterceptModule', []);
angular
.module('InterceptModule')
.factory('myInterceptor', myInterceptor);
myInterceptor.$inject = ['$q', '$injector','$cookies']
function myInterceptor($q,$injector,$cookies) {
var errorCount = 0;
var service = {
responseError: responseError,
request : request
};
return service;
//////////
/* this function is where tell the request to re-fire if it
* has been aborted.
*
*/
function responseError(response) {
if ( response.status == -1 ) {
var deferred = $q.defer();
var firstResponse = response;
var url = response.config.url;
var $http = $injector.get('$http');
$http.get(url, {cache: true}).then(function(response) {
deferred.resolve(response);
}, function(result, status, header, config) {
if ( status == -1 ) {
errorCount += 1;
if ( errorCount > 3 ) {
errorCount = 0;
deferred.reject(result);
} else {
responseError(firstResponse);
}
};
deferred.reject(result);
});
return deferred.promise;
};/* if */
return $q.reject(response);
};
/**
* this function is where we configure our outgoing http requests
* to abort if they take longer than 3 seconds.
*
*/
function request(config) {
config.timeout = 3000;
return config;
};
}/* service */
})();
Inject our intercept module
angular
.module('myApp', ['InterceptModule']);
Then push our interceptor in our config
$httpProvider.interceptors.push('myInterceptor');

Related

Retry failed requests with $http interceptor

The API my webapp is talking to sometimes overloads and is sending 500 Internal Server Error if it cannot handle request.
There are 100+ different requests my web application can send, so if I implement retry on each individually, it will cost me hours of typing.
I'm already using $httpProvider interceptor, here it is (simplified)
$httpProvider.interceptors.push(function ($q) {
return {
responseError: function (response) {
switch (response.status) {
case 401 :
window.location = "/";
alert('Session has expired. Redirecting to login page');
break;
case 500 :
// TODO: retry the request
break;
}
return $q.reject(response);
}
};
});
How could I resend a request after getting 500 response code from the server?
Angular provides reference to the config object which was used by $http service for doing the request in the response (response.config). That means if we can inject $http service in the interceptor we can easily resend the request. Simple injecting of $http service in the interceptor is not possible because of the circular dependency but luckily there is a workaround for that.
This is an example how the implementation of a such interceptor can be done.
$httpProvider.interceptors.push(function ($q, $injector) {
var incrementalTimeout = 1000;
function retryRequest (httpConfig) {
var $timeout = $injector.get('$timeout');
var thisTimeout = incrementalTimeout;
incrementalTimeout *= 2;
return $timeout(function() {
var $http = $injector.get('$http');
return $http(httpConfig);
}, thisTimeout);
};
return {
responseError: function (response) {
if (response.status === 500) {
if (incrementalTimeout < 5000) {
return retryRequest(response.config);
}
else {
alert('The remote server seems to be busy at the moment. Please try again in 5 minutes');
}
}
else {
incrementalTimeout = 1000;
}
return $q.reject(response);
}
};
});
Note: In this example implementation the interceptor will retry the request until you receive a response with status that is different than 500. Improvement to this can be adding some timeout before retrying and retrying only once.
You can check for any possible server side errors by expanding the status code check a little more. This interceptor will attempt to retry the request multiple times and will do so on any response code 500 or higher. It will wait 1 second before retrying, and give up after 3 tries.
$httpProvider.interceptors.push(function ($q, $injector) {
var retries = 0,
waitBetweenErrors = 1000,
maxRetries = 3;
function onResponseError(httpConfig) {
var $http = $injector.get('$http');
setTimeout(function () {
return $http(httpConfig);
}, waitBetweenErrors);
}
return {
responseError: function (response) {
if (response.status >= 500 && retries < maxRetries) {
retries++;
return onResponseError(response.config);
}
retries = 0;
return $q.reject(response);
}
};
});
I wanted to retry requests in my response block also, so combining multiple answers from different posts from SO, I've written my interceptor as follows -
app.config(['$httpProvider', function ($httpProvider) {
$httpProvider.interceptors.push(['$rootScope', '$cookies', '$q', '$injector', function ($rootScope, $cookies, $q, $injector) {
var retries = 0, maxRetries = 3;
return {
request: function (config) {
var csrf = $cookies.get("CSRF-Token");
config.headers['X-CSRF-Token'] = csrf;
if (config.data) config.data['CSRF-Token'] = csrf;
return config;
},
response: function (r) {
if (r.data.rCode == "000") {
$rootScope.serviceError = true;
if (retries < maxRetries) {
retries++;
var $http = $injector.get('$http');
return $http(r.config);
} else {
console.log('The remote server seems to be busy at the moment. Please try again in 5 minutes');
}
}
return r;
},
responseError: function (r) {
if (r.status === 500) {
if (retries < maxRetries) {
retries++;
var $http = $injector.get('$http');
return $http(r.config);
} else {
console.log('The remote server seems to be busy at the moment. Please try again in 5 minutes');
}
}
retries = 0;
return $q.reject(r);
}
}
}]);
}])
credits to #S.Klechkovski, #Cameron & https://stackoverflow.com/a/20915196/5729813

AngularJs cancel http request: application still waiting for response after cancel

In my application, I have a service called 'pendingRequests' that keeps track of my http requests. I configured my $httpProvider to use this service.
The purpose of this service is to give me the ability to cancel ALL pending http requests occurring in ANY controller.
Here is the code:
app.service('pendingRequests', function($rootScope, $q) {
var pending = [];
this.get = function() {
return pending;
};
this.add = function(request) {
pending.push(request);
//console.log("Pending Requests(before):" + pending);
};
this.remove = function(request) {
angular.forEach(pending, function(p , key) {
if(p.url == request.url) pending.splice(key, 1);
});
// console.log("Pending Requests(after):" + pending);
};
this.cancelAll = function() {
if(typeof pending !='undefined'){
angular.forEach(pending, function(p) {
p.canceller.resolve();
});
pending.length = 0;
}
};
});
app.config(function($httpProvider){
$httpProvider.interceptors.push(function($q, pendingRequests){
return {
'request': function (config){
var canceller = $q.defer();
pendingRequests.add({
url: config.url,
canceller: canceller
});
config.timeout = canceller.promise;
return config || $q.when(config);
},
'response': function (response){
pendingRequests.remove(response.config);
//pendingRequests remove request
return response;
}
}
});
});
The service is canceling the requests as intended. However, the next request submitted is delayed as if it is still waiting for another request to complete.
What is causing this delay?

Angular - abort ajax request when using Restangular

I have a method that calls an angular service and consequently makes an ajax request via the service. I need to make sure that if this is called several times, the previous request in aborted (if it hasn't already been resolved that is).
This method can get called multiple times. This method is actually from ngTable on ngTableParams:
getData = function($defer, params) {
myService.getRecord(params).then(function(res){
...
$defer.resolve(res.Records);
});
}
Here's the method on the service:
this.getRecords = function(params) {
...
return Restangular
.all('/api/records')
.post(filters);
};
If ngTable makes 3 calls I want the first 2 to be aborted (unless of course they returned so fast that it got resolved)
You can abort $http calls via the timeout config property, which can be a Promise, that aborts the request when resolved.
So in restangular, you can do this like
var abort = $q.defer();
Restangular.one('foos', 12345).withHttpConfig({timeout: abort.promise}).get();
abort.resolve();
To integrate it with your usecase, for example, you could have this in your service:
var abortGet;
this.getRecords = function(params) {
...
if (abortGet) abortGet.resolve();
abortGet = $q.defer();
return Restangular
.all('/api/records')
.withHttpConfig({timeout: abortGet.promise})
.post(filters);
}
This way calling getRecords always aborts the previous call if has not been resolved yet!
This is another approach if you want to abort all http requests when change the state for UI-router:
angular
.run(function(HttpHandlerSrv) {
HttpHandlerSrv.abortAllRequestsOn('$stateChangeSuccess');
HttpHandlerSrv.R.setFullRequestInterceptor(function(element, operation, route, url, headers, params, httpConfig) {
httpConfig = httpConfig || {};
if(httpConfig.timeout === undefined) {
httpConfig.timeout = HttpHandlerSrv.newTimeout();
}
return { element: element, params: params, headers: headers, httpConfig: httpConfig };
});
})
.factory('HttpHandlerSrv', HttpHandlerSrv);
/** ngInject */
function HttpHandlerSrv($q, $rootScope, Restangular) {
var requests = [];
return {
R: Restangular,
newTimeout: newTimeout,
abortAllRequests: abortAllRequests,
abortAllRequestsOn: abortAllRequestsOn
};
function newTimeout() {
var request = $q.defer();
requests.push(request);
return request.promise;
}
function abortAllRequests() {
angular.forEach(requests, function(request) {
request.resolve();
});
requests = [];
}
function abortAllRequestsOn(event) {
$rootScope.$on(event, function(event, newUrl, oldUrl) {
if(newUrl !== oldUrl) { abortAllRequests(); }
});
}
}

Why isn't my $resource error handler called when I have a responseError interceptor?

I'm building my first Angular app, and I've run into a problem. I have an AngularJS resource whose .get I call with both a success and error callback, like so:
var new_uptime = Uptime.get({}, function(){
console.log("new_uptime", new_uptime, "$scope.uptime", $scope.uptime);
console.log("new_uptime.uptime", new_uptime.uptime);
if ($scope.uptime && new_uptime.uptime < $scope.uptime.uptime) {
console.log("Reboot detected");
location.reload(true);
}
$scope.uptime = new_uptime;
$timeout(reload_uptime, 5000);
}, function(response){
console.log("Failed to read uptime", response);
console.log("Retrying in 10s");
$scope.uptime = "[unknown]";
$timeout(reload_uptime, 10000);
});
I've tested this with various error statuses from the server, and it works fine. Now I'd like to add app-wide retrying on 503s. I've added a module for that, which looks like this:
retry_module = angular.module('service.retry', []);
retry_module.factory("retry", ["$q", "$injector", "$timeout", function($q, $injector, $timeout) {
return {
"responseError": function(rejection) {
console.log("Request failed", rejection);
if (rejection.status != 503) {
console.log("Unhandled status");
return $q.reject(rejection);
}
var delay = Math.floor(Math.random() * 1000);
console.log("Was 503, retrying in " + delay + "ms");
var deferred = $q.defer();
$timeout(function() {
var $http = $http || $injector.get("$http");
deferred.resolve($http(rejection.config));
}, delay);
return deferred;
}
};
}]);
retry_module.config(["$httpProvider", function ($httpProvider) {
$httpProvider.interceptors.push("retry");
}]);
This works well for retrying on 503s, and successful attempts are handled by the success callback in the Uptime.get caller, as intended. However, if the server returns some other error, then I get the "Unhandled status" printout, but then neither "new_uptime" nor "Failed to read uptime". Where did my rejection go, and how do I go about trouble-shooting issues like this?
You need to return the promise, not the deferred. So the end of your responseError handler should be:
var deferred = $q.defer();
$timeout(function() {
var $http = $http || $injector.get("$http");
deferred.resolve($http(rejection.config));
}, delay);
return deferred.promise;

How to cancel an $http request in AngularJS?

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;
});

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