成功时拒绝$ http承诺

Question

I have a function that that returns a promise of an $http GET (the promise success/error is handled by the invoker). What I need is, given certain conditions and even though the $http is successful, to return an error (the invoker would catch this condition as a rejected promise).

In this plunk, I tried to return $q.reject() but this doesn't work.

http://plnkr.co/edit/iC3Wb1PBUFrXgPbTJyU0?p=preview

This is the JavaScript:

app.controller("ctrl", function($scope, $http) {
  var getUrl = function() {
    var config = {
      method: 'GET',
      url: 'some.txt'
    };
    var x = 1; // if x == 1 the http should fail
    return $http(config).success(function(response, status, headers, config) {
      console.log(response);
      if (x == 1) return $q.reject('error');
    }).error(function(data, status, headers, config) {});
  };
  var init = function() {
    var promise = getUrl();
    promise.then(function() {
      alert('OK');
    }, function() {
      alert('error');
    });
  };
  init();
});

Any ideas?

Answer 1

$http.success() and error() are convenience shortcuts that are not 100% compliant with promises. Use vanilla promise then instead:

$http(config).then(function(response){return $q.reject}, function onError(reason){})

updated plunker

Answer 2

Try this: http://plnkr.co/edit/hTNFjXXDfqQ7e7jvNMtg?p=preview

You return a deferred promise of your own and resolve/reject is on will

 var defer = $q.defer();


          $http(config)
              .success(function (response, status, headers, config) {
                  console.log(response);

                  if (x == 1)
                       defer.reject('error');
                 else
                  defer.resolve(response);

              })
                .error(function (data, status, headers, config) {
              });

              return defer.promise;