I am in process of creating Offline mode in an app. Whenever a http request is send, I would want an interceptor to detect the network state. If the state is no connectivity, I would want to create a mock response and make it feel like as if the response is coming from a server.
You could check if you are online or not by reading the status of the response in your interceptor, if its a 401 / 501/ etc:
var interceptor = ['$rootScope', '$q', function ($rootScope, $q) {
function success(response) {
return response;
}
function error(response) {
var status = response.status; // error code
if ((status >= 400) && (status < 500)) {
$rootScope.broadcast("AuthError", status);
return;
}
if ((status >= 500) && (status < 600)) {
$rootScope.broadcast("ServerError", status);
return;
}
// otherwise
return $q.reject(response);
}
return function (promise) {
return promise.then(success, error);
}
}]
There's another way, using html5, but I guess will not work on some browsers. This is done using navigator.onLine property, like:
if (navigator.onLine) {
//I'm online
} else {
I'm not online
}
(https://developer.mozilla.org/en-US/docs/Web/API/NavigatorOnLine/onLine)
If you throw an object inside your request interceptor this will trigger a call to the responseError interceptor, passing the throwed object as its argument.
You have to find a way notify responseError interceptor that this is not a real error and that it should return a custom response.
The responseError interceptor can choose to recover error returning a response object o fail returning a rejected promise (check angular's $http interceptor docs)
EDIT: If you throw an object from request interceptor you can't avoid an error message in console. It's better to return a rejected promise passing config object as value and put extra information in it for responseError detect the special situation.
Related
I have been looking at an application I made a while back and there is a particular page where the details are being loaded last. Because of this, it seems to be queuing the request (there are more than 6 others before it) and that is causing the page to be slow.
I figured I could find a solution to prioritize these requests and I found this:
How to prioritize requests in angular $http service?
So I created my version of it and added it to my interceptors:
// Add our auth interceptor to handle authenticated requests
$httpProvider.interceptors.push('authInterceptor');
$httpProvider.interceptors.push('httpPriorityInterceptor');
The interceptor looks like this:
function factory($injector, $q) {
var requestStack = [], // request stack
$http = null; // http service to be lazy loaded
return {
request: request,
responseError: responseError
};
//////////////////////////////////////////////////
function request(config) {
// Lazy load $http service
if (!$http) {
$http = $injector.get('$http');
}
if (!config.hasBeenRequested) {
config.hasBeenRequested = true;
config.priority = config.priority || 3;
console.log(config);
// add a copy of the configuration
// to prevent it from copying the timeout property
requestStack.push(angular.copy(config));
// sort each configuration by priority
requestStack = requestStack.sort(sort);
// cancel request by adding a resolved promise
config.timeout = $q.when();
}
// return config
return config;
}
function responseError(rejection) {
// check if there are requests to be processed
if (requestStack.length > 0) {
requestStack.reduceRight(function(promise, config) {
return promise.finally(function() {
return $http(config);
});
}, $q.when());
requestStack.length = 0;
}
// return rejected request
return $q.reject(rejection);
}
//////////////////////////////////////////////////
function sort(config1, config2) {
return config1.priority < config2.priority;
}
}
The problem is, it seems to be intercepting template requests too. I have no issue with that, but they are not resolving. Instead I get a lot of errors:
Error: [$templateRequest:tpload] Failed to load template: app/accounts/accounts.html (HTTP status: -1 )
Has anyone encountered this before? Is there something I can do to fix this?
you should know that every request such as html files , css file and ... comes into interceptor.
in your case you dont need to prioritize this files. so you can filter your request like:
if (config.url.toString().toLowerCase().includes("api")) {
//place your functionality
}
How do I reject or fail a successful $http.get() promise? When I receive the data, I run a validator against it and if the data doesn't have required properties I want to reject the request. I know I can do after the promise is resolved, but it seems like a good idea to intercept errors as soon as possible.
I'm familiar with the benefits of $q, but really want to continue using $http.
You can reject any promise by returning $q.reject("reason") to the next chained .then.
Same with $http, which returns a promise - this could be as follows:
return $http.get("data.json").then(function(response){
if (response.data === "something I don't like") {
return $q.reject("bad data");
}
return response.data;
}
This could simply be done within a service, which pre-handles the response with the .then as specified above, and returns some data - or a rejection.
If you want to do this at an app-level, you could use $http interceptors - this is just a service that provides functions to handle $http requests and responses, and allows you to intercept a response and return either a response - same or modified - or a promise of the response, including a rejection.
.factory("fooInterceptor", function($q){
return {
response: function(response){
if (response.data === "something I don't like") {
return $q.reject("bad data");
}
return response;
}
}
});
Same idea as above - except, at a different level.
Note, that to register an interceptor, you need to do this within a .config:
$httpProvider.interceptors.push("fooInterceptor");
You can use AngularJS interceptors. But you still need to use $q in them because $http uses $q.
Here is a useful article about interceptors.
I have created http interceptors and attached to my main app as below:
angular.module('app',['ui.router'])
.factory('AuthInterceptor',function($window,$q){
return{
request: function(config){
console.log("config object is");
console.log(config);
if($window.sessionStorage.getItem('token')){
config.headers['x-access-token']= $window.sessionStorage.getItem('token');
}
return config || $q.when(config);
},
response: function(response){
console.log("response object is:");
console.log(response);
if (response['status'] >= 400) {
console.log("Not Authorized.kindly login first");
$state.transitionTo('login');
}
return response || $q.when(response);
}
};
})
.config(function($httpProvider){
$httpProvider.interceptors.push('AuthInterceptor');
});
On the server-side (some express code) I am checking if the user is authorized or not and if not I respond with the following code (only displaying a subset of code to keep things concise):
if(!req.user){
res.send('Not authorized',400);
}
The server code works fine (i can see it in the network tab of the chrome developer tools)
However AuthInterceptor.response() does nto get called.
However do note that the AuthInterceptor.response() does get executed when the response status is 200
So I am confused.. why is it not intercepting 400 statuses ?
If the response status code is outside of the range [200-299], then the responseError interceptor is called.
You need to provide a responseError interceptor:
return {
request: function (config) {...},
responseError: function (rejection) {...}
};
So I have a bunch of controllers that do $http requests
but in every $http request i have a .error(function(data...){//always the same})
How could I build an.. "abstract class" for $http?
This here would be the always repeating code
.error(function(){
$scope.flashes = {
server: {
type: "danger",
message: "There was a server error processing your request. Please try again later."
}
};
})
I add the same concern few weeks ago and i came up with this solution :
I first created a custom service intercepting every http requests made :
.factory('HttpInterceptor', ['$q', '$rootScope', function($q, $rootScope) {
return {
// On request success
request : function(config) {
// Return the config or wrap it in a promise if blank.
return config || $q.when(config);
},
// On request failure
requestError : function(rejection) {
//console.log(rejection); // Contains the data about the error on the request.
// Return the promise rejection.
return $q.reject(rejection);
},
// On response success
response : function(response) {
//console.log(response); // Contains the data from the response.
// Return the response or promise.
return response || $q.when(response);
},
// On response failure
responseError : function(rejection) {
//console.log(rejection); // Contains the data about the error.
//Check whether the intercept param is set in the config array. If the intercept param is missing or set to true, we display a modal containing the error
if (rejection.config && typeof rejection.config.intercept === 'undefined' || rejection.config.intercept)
{
//emitting an event to draw a modal using angular bootstrap
$rootScope.$emit('errorModal', rejection.data);
}
// Return the promise rejection.
return $q.reject(rejection);
}
};
}]);
I also defined a custom config property 'intercept' that i can add to the $http config object. It is useful when I don't want to apply this behavior on a particular request.
E.g :
var registerResource = $resource('/registration/candidate/register', {}, {query:
{method:'POST', isArray: false, intercept: false }
});
In order the have a flexible solution, it is also important to not forget to do :
return $q.reject(rejection);
So you can still use the error callback on your promise in your controller if you want to combine both ways (interception + manual handling)
Finally, I added this service to my application :
app.config(['$httpProvider', function($httpProvider) {
// Add the interceptor to the $httpProvider to intercept http calls
$httpProvider.interceptors.push('HttpInterceptor');
}]);
I simplified the service but you can also use it for many things. Personally, I also use it to :
Make sure to not fire duplicate http requests (if the user click a lot on a submit button).
Draw an alert at the beginning of an http call and close it at the end to inform the user that is treatment is processing (export of data for instance).
PS: The official documentation mention this interceptor
You could do something like this:
app.service('myHttp', function($http){
return function($scope, httpParameters){
var httpPromise = $http(httpParameters);
httpPromise.error(function(){
$scope.flashes = {
server: {
type: "danger",
message: "There was a server error"
}
}
});
};
});
app.controller('MainCtrl', function($scope, myHttp) {
myHttp($scope, {method: 'GET', url: 'www.google.com'});
});
I have an issue with angularjs app communicating with a REST API. The problem is the api returnes a status code and also adds a status description like HTTP/1.1 417 Invalid quantity.
With jquery ajax the jqXHR object had a statusText property but with angularjs I can't seem to find how can I access this in my error handler. Needless to say I can't modify the API which for a 417 status code for example can return different status descriptions.
I have found that I would need to change the angularjs library but in case of an update this would not be handy. I would have to change xhr.responseText to xhr.statusText. Can I somehow overwrite this function from my code and don't modify angular library?
xhr.onreadystatechange = function() {
if (xhr.readyState == 4) {
completeRequest(
callback, status || xhr.status, xhr.responseText, xhr.getAllResponseHeaders());
}
};
Here's the work around to get StatusText (as pointed out that some mobile browsers strip out DATA from successfull responses: https://stackoverflow.com/a/28470163/1586498
I have also discovered that .success and .error on $http in Angular does not pass the StatusText, you have to use .then(response)
You need to create an httpInterceptor as outlined here during your module config.
// register the interceptor as a service
$provide.factory('myHttpInterceptor', function($q) {
return function(promise) {
return promise.then(function(response) {
// do something on success
}, function(response) {
//do something for your 417 error
if(response.status == 417) {
alert("We've got a 417!");
return $q.reject(response);
}
//some other error
return $q.reject(response);
});
}
});
$httpProvider.responseInterceptors.push('myHttpInterceptor');
The support for statusText was added in AngularJS 1.2.16.