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.
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Under what circumstances will the server send you back invalid data?Explosion Pills– Explosion Pills2015-03-21 02:17:30 +00:00Commented Mar 21, 2015 at 2:17
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When it's missing properties that my application needs.user56512– user565122015-03-21 02:53:51 +00:00Commented Mar 21, 2015 at 2:53
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2 Answers
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");
Comments
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.
