I've been writing a service in AngularJS to save some data and, if it fails, alert the user. However, after I create my resource and call $save:
myResource.$save(function(success) {
console.log(success);
}, function(error) {
console.log(error);
});
I expect the error callback's argument to be an object with data, status, headers, etc., but all I get is an object with a "then" function. I tried to mock it up in JSFiddle:
http://jsfiddle.net/RichardBender/KeS7r/1/
However, this example works as I originally expected. I yanked this JSFiddle example and put it in my project and it has the same problem I originally described, despite that as far as I can tell everything else is equal. Does anyone have any idea why this might be? My project was created with Yeoman/Bower/Grunt but I can't see why those things would make a difference here.
Thanks,
Richard
I solved the problem. The error was in my HTTP interceptor, where upon an error code, I was accidentally returning $q.reject(promise) rather than $q.reject(response).
The bugged version:
.factory('httpInterceptor', function($q) {
return function(promise) {
return promise.then(
// On success, just forward the response along.
function(response) {
return response;
},
function(response) {
// ... where I process the error
return $q.reject(promise);
}
);
};
The fixed version:
.factory('httpInterceptor', function($q) {
return function(promise) {
return promise.then(
// On success, just forward the response along.
function(response) {
return response;
},
function(response) {
// ... where I process the error
return $q.reject(response);
}
);
};
-Richard
Related
I am using $http to make a call. Based on the successful result of the call I may decided to throw an error/reject and have it trickle down to the next call as an error. However if an error is thrown it just halt the process. How can I force the $http promise to reject without wrapping it in some $q code?
// A service
angular.module('app').factory('aService', function ($http, config) {
return {
subscribe: function (params) {
return $http({
url: '...'
method: 'JSONP'
}).then(function (res) {
// This is a successful http call but may be a failure as far as I am concerned so I want the calling code to treat it so.
if (res.data.result === 'error') throw new Error('Big Errror')
}, function (err) {
return err
})
}
}
})
// Controller
aService.subscribe({
'email': '...'
}).then(function (result) {
}, function (result) {
// I want this to be the Big Error message. How do I get here from the success call above?
})
In the above code I would like the Big Error message to end up as a rejected call. However in this case it just dies with the error. This is how I handle things in say Bluebird but it's a no go here.
Ti continue the Chain in a rejected state just return a rejected promise $q.reject('reason') from your $http result something like
$http.get(url).then(
function (response){
if(something){
return $q.reject('reason');
}
return response;
}
)
That way you'll get a a rejected promise and can react to it even when the api call is successful.
I am trying to use Breeze to get data from a server into an AngularJS app, and although the server is sending the JSON data, the client app is not getting it. The closest I've gotten to identifying the issue using the debugger is to see that the following function getRemoteEntities(), which is part of a Factory, should return a promise but instead returns an empty Object {} when called with a valid entityURL and jsonAdapter:
[...]
var manager = entityManagerFactory.newManager();
[...]
return {
getRemoteEntities: function (entityUrl, jsonAdapter) {
var query = breeze.EntityQuery
.from(entityUrl)
.using(jsonAdapter);
return manager.executeQuery(query)
.then(function (results) {
return results;
})
.catch(function (error) {
return $q.reject(error);
});
}
}
I have checked, and the code does use the Breeze Angular Service as described here. I do not understand what is not working.
EDIT: Removing the .using(jsonAdapter) means that I am able to get and resolve the promise, suggesting that it might be doing something that messes it up. Here is an example (they all follow this pattern):
.value('jsonProfileResultsAdapter', new breeze.JsonResultsAdapter({
name: "xyz", // mild obfuscation
extractResults: function (data) {
var results = data.results;
if (!results) throw new Error("Unable to resolve 'results' property");
return results;
},
visitNode: function (node, parseContext, nodeContext) {
if (node) {
if (node.person && node.assignments) {
return {entityType: "EmployeeModel"}
}
}
}
}))
What is the jsonAdapter doing? That's an unusual feature (not wrong, just unusual). Maybe you're doing something inside it that blows up the promise.
Take it away and see what you get. If you get a promise, even a failed promise, then you're on to something.
I am attempting to implement UI-router resolves which will return a result even if the API call fails. Our app has back-end permissions, and if the call fails, I still need to show nested pages (which won't load if a resolve calls fails normally, unless it is wrapped into a $q promise. I implement it like this with $http:
resolve: {
kittens: ["$q", "$timeout","$http", function ($q, $timeout, $http,) {
var url = "some api url"
return $http.get (url)
.then(function(result){ return {status:true , data: result} },
function(){ return {status:false} }); //on failure, return this
}],
}
The above works perfectly - it returns what I need on both call success and failure, however, it seems to fail if I try it with Restangular, the code below works fine:
kittens: function (Restangular) {
return Restangular
.one('stuff', 999999999999)
.all('stuffInStuff').getList()
.then(function (result) {
return result;
});
},
but if I try this with the above:
.then(function (result) {
return result;
}, function(error){return error})
the failure doesn't return anything and the controller isn't instantiated. I don't understand why this happens. I thought both $http.get() and Restangular.one().all().getList() (as an example) are both equivalent promises, that either return a result or fail. What's the difference? How do I provide a resolve value on call fail with Restangular?
Edit: Btw, I did read this post, and I understand that if a UI-router resolve isn't wrapped, it fails if the promise is rejected, but I don't seem to fully get how to approach it with Restanagular...
edit 3: This fails as well:
.then(function (result) {
return result;
})
.catch(function (error) {
return error;
})
I think you have two ways ,
1.) Dont return restangular instance inside resolve of ui router, because you are returning promise which is rejected. you cant bypass this rejection natively. When you return Restangular.one().get() and it fails, your resolve fails. if you dont return instance, resolve will get resolved even when your request is still loading(which i think you dont want and you want wait for success/error)
second , for me correct way is this.
resolve: {
kittens: ["$q", "Restangular", function ($q, Restangular) {
var deferred = $q.defer();
Restangular.one('some-api').get().then(function(data) {
deferred.resolve(data);
}, function(err) {
deferred.resolve(err);
});
return deferred.promise;
}],
}
in this case, resolve will be resolved everytime and you will get transition even when rest call will fail
I'd like to know if it's possible to handle the $promise returned by ngResource on multiple levels so that the code is DRY
here is a simple example
aService = function(aResource) {
var error, success;
success = function(response) {
console.log('Service Success');
};
error = function(response) {
console.log('Service Error');
};
this.servicePostReq = function() {
return aResource.save().$promise.then(success, error);
};
return this;
angular.module('app.service').factory('aService', ['aResource', aService]);
this works fine so far... it Service Success when response is OK and it Service Error when response is not OK
but when I add a controller that use this aService like following
aController = function(aService) {
var error, success;
success = function(response) {
console.log('Controller Success');
};
error = function(response) {
console.log('Controller Error');
};
this.controllerPostReq = function() {
aService.servicePostReq().then(success, error);
};
return this;
};
angular.module('app.controller').controller('aController', ['aService', aController]);
the controller always success...
so if the request return success the output is
Service Success
Controller Success
and if the request fails the output is
Service Error
Controller Success
how do I chain the promise so that I don't have to add the code handled in the service for every controller that use the service ?
The problem is your service. Change this:
this.servicePostReq = function() {
return aResource.save().$promise.then(success, error);
};
To this:
this.servicePostReq = function() {
return aResource.save().$promise.then(success);
};
Explanation:
Since your service returns aResource.save().$promise.then(success, error), it's returning a new promise with an error handler included. Later, in your controller, you add onto the chain like this.
aService.servicePostReq().then(success, error);
The complete promise chain at this point looks if you expand it out:
return aResource.save().$promise
.then(successFnFromService, errorFnFromService)
.then(successFnFromController, errorFnFromController);
Since you catch the error from aResource.save() with errorFnFromService, the promise chain is basically "clean" at this point and it will just continue with the next then.
By removing the first error handler, you allow the error to be caught later on.
A better way (in general) to handle errors in promise chains would be to use a single .catch() at the end of the chain.
Consider this bad code (try running on your browser console):
new Promise(
function(resolve, reject){
reject('first');
}).then(
function(result) {
console.log('1st success!', result);
return result;
},
function(err) {
console.log('1st error!', err);
return err;
}
).then(
function(result){
console.log('2nd success!', result);
},
function(err){
console.log("2nd error!", err);
}
);
Output:
1st error! first
2nd success! first
Better way:
new Promise(
function(resolve, reject){
reject('first');
}).then(function(result) {
console.log('1st success!', result);
return result;
}).then(function(result){
console.log('2nd success!', result);
// catch error once at the end
}).catch(function(err){
console.log("error!", err);
});
Output:
error! first
Try both of those in browser console, and change reject to resolve to see how it affects the output.
add a dependency on the $q and use $q.reject to control the execution...
in your example you need a $q.reject in the aService.error method
as mentioned here in the $q docs
reject(reason);
Creates a promise that is resolved as rejected with the specified reason. This api should be used to forward rejection in a chain of promises. If you are dealing with the last promise in a promise chain, you don't need to worry about it.
When comparing deferreds/promises to the familiar behavior of try/catch/throw, think of reject as the throw keyword in JavaScript. This also means that if you "catch" an error via a promise error callback and you want to forward the error to the promise derived from the current promise, you have to "rethrow" the error by returning a rejection constructed via reject.
To properly chain promises, both success and error handlers should return some value. The return values are automatically wrapped in a new promise for you. This means that in the case of errors, you must return a rejected promise using $q.reject.
So your service should look like this:
aService = function($q, aResource) {
var error, success;
success = function(response) {
// important! return a value, handlers down the chain will
// execute their success handlers and receive this value
return 'Service Success';
};
error = function(response) {
// important! return a REJECTION, handlers down the chain will
// execute their error handlers and receive this value
return $q.reject('Service Error');
};
this.servicePostReq = function() {
return aResource.save().$promise.then(success, error);
};
return this;
angular.module('app.service').factory('aService', ['$q', 'aResource', aService]);
Hello I am using ngResource $save method and I get two different behaviours, I don't understand why
First I'm using it in this way:
$scope.user = new User($scope.user);
$scope.user.$save(function () {
$window.location.href = //redirection here;
}, function (response) {
$scope.form.addErrors(response.data.errors);
});
Then I have another controller when I'm doing a similar operation, but even getting 404 or 422 errors from the server the first callback is executed and the errors callback is ignored.
Does anyone have any idea of this? I've been searching in Google for hours trying to find more documentation about $save but I'm still stuck with this problem.
Thank you.
Well, the problem was on an interceptor I am using to detect 401 (unauthorized errors)
here is the interceptor, notice that you must return $q.reject(response) otherwise the other callbacks are not called (in my case the error callback in ngResource.$save)
MyApp.config(function ($httpProvider) {
$httpProvider.interceptors.push(function($window, $q) {
return {
'responseError': function(response) {
if (response.status == 401) { // Unathorized
$window.location.href = 'index.html';
}
// return response; <-- I was doing this before cancelling all errors
return $q.reject(response);
}
};
});
});