What $httpProvider.interceptors.push does

Question

i am new in angular when reading this article https://www.c-sharpcorner.com/UploadFile/ff2f08/token-based-authentication-using-Asp-Net-web-api-in-angularj/

i found few line of code which is not clear to me. those lines are

.config(['$httpProvider', function ($httpProvider) {
$httpProvider.interceptors.push(function ($q, $rootScope, $window, $location) {
return {
request: function (config) {
return config;
},
requestError: function (rejection) {
return $q.reject(rejection);
},
response: function (response) {
if (response.status == "401") {
$location.path('/login');
}
//the same response/modified/or a new one need to be returned.
return response;
},
responseError: function (rejection) {
if (rejection.status == "401") {
$location.path('/login');
}
return $q.reject(rejection);
}
};
});

please some one help me to understand the above few lines of code and their objective.

Debasis Saha · Answer

AngularJS interceptors offer a convenient way to modify request made by the $http service both before they are sent and after they return. An interceptor is simply a factory()service that returns an object with 4 properties that map to functions: request : called before a request is sent, capable of mutating the request object response : called with an $http request succeeds, is passed the results object, responseError : Called if $http method fails to execute This object is then registered as an interceptor with the $httpproviderin a config() block. It's perfectly fine to include all or only a subset of the properties that are needed. The way to think about interceptor functions is as promise callback functions that are called for all HTTP requests.

Tridip Bhattacharjee · Answer

thanks a lot for nice explanation.