How to set a timeout to abort an $http.get() insid

问题:

I have the following method getData(url) in a my factory which uses $http.get(url) to get data from an URL

angular
  .module('az-app')
  .factory('WebServiceFactory', function ($http, $q) {

   var WebServiceFactory = this;


   WebServiceFactory.getData = function (url) {

      var deferred = $q.defer();

      $http.get(url)
        .then(
        function (response) {

          deferred.resolve({
            data: response
          });

        }, function (rejected) {

          deferred.reject({
            data: rejected
          });
        }
      );
      //Promise to be returned
      return deferred.promise;
    }

It works fine but I need to abort the http.get and/or reject the promise so I can display an error message from my controller which has this method:

var getSpecialties = function (type) {
  doctorsCtrl.showLoading();

  var url = "example.com";

  WebServiceFactory.getData(url)
    .then(
    function (result) {
      doctorsCtrl.hideLoading();


      var specialtiesArray = result.data.data;

      StorageFactory.specialties = specialtiesArray;
      doctorsCtrl.specialties = StorageFactory.specialties

      //I WANT TO TRIGGER THIS REJECTED FUNCTION when timeout time is finished
    }, function (rejected) {
      doctorsCtrl.hideLoading();
      doctorsCtrl.showAlert();
    }
  );
}

回答1:

The service $http accepts, in the config object, a timeout property that answers to what you need. Have a look at the documentation, especially the part about the config object:

timeout – {number|Promise} – timeout in milliseconds, or promise that should abort the request when resolved.

Also, notice that you're using promises in an inefficient way. The following is a promise antipattern:

WebServiceFactory.getData = function (url) {

 var deferred = $q.defer();

 $http.get(url)
   .then(
   function (response) {

     deferred.resolve(...);

   }, function (rejected) {

     deferred.reject(...);
   }
 );
 //Promise to be returned
 return deferred.promise;
}

You could have simply:

WebServiceFactory.getData = function (url) {
    return $http.get(url);
}

With a timeout of 3 seconds it would be:

Service:

WebServiceFactory.getData = function (url) {
    return $http.get(url, {timeout: 3000});  // <-- timeout applies ONLY for this call
}

Controller:

WebServiceFactory.getData(url).then(
    function (result) {
      doctorsCtrl.hideLoading();
      doctorsCtrl.specialties = StorageFactory.specialties = result.data;
    }, function (rejected) {
      doctorsCtrl.hideLoading();
      doctorsCtrl.showAlert();
    }
  );

Notice also that you're calling hideLoading both in case of success and error. You can call it once, in a chained finally handler:

// ...
.finally(function () {
    doctorsCtrl.hideLoading();
}