Reject from 'response' into 'responseError'

Question

Sometimes, the API I'm using will return 200 ok even though there has been an error. The response JSON object will look something like:

{
    error: true
}

I've built a $http response interceptor that simply checks for this error and rejects it. I want it to then jump into my responseError function:

$httpProvider.interceptors.push(function($q) {
    return {

        response: function (response) {

            if (response.data.error) {

                // There has been an error, reject this response
                return $q.reject(response);
            }

            return response;
        },

        responseError: function(rejection) {

            // Display an error message to the user
            ...

            return $q.reject(rejection);
        }
    }
});

Problem is, even after rejecting the response, my responseError function isn't called. It is called on 500 errors etc so I know it's working. I'd expect a rejection to do the same thing.

From the docs:

responseError: interceptor gets called when a previous interceptor threw an error or resolved with a rejection.

Any ideas on what's missing?

Answer 1

Looks like this isn't possible to do. To cut down on duplicate code, simply declare the error handling function separately and reuse it inside the response and responseError functions.

$httpProvider.interceptors.push(function($q) {

    var handleError = function (rejection) { ... }

    return {

        response: function (response) {

            if (response.data.error) {
                return handleError(response);
            }

            return response;
        },

        responseError: handleError
    }
});

Answer 2

To add to this answer: rejecting the promise in the response interceptor DOES do something.

Although one would expect it to call the responseError in first glance, this would not make a lot of sense: the request is fulfilled with succes. But rejecting it in the response interceptor will make the caller of the promise go into error handling. So when doing this

$http.get('some_url')
.then(succes)
.catch(err)

Rejecting the promise will call the catch function. So you don't have you proper generic error handling, but your promise IS rejected, and that's useful :-)

Answer 3

Should you want to pass the http response to the responseError handler, you could do it like this:

$httpProvider.interceptors.push(function($q) {

    var self = {

        response: function (response) {

            if (response.data.error) {
                return self.responseError(response);
            }

            return response;
        },

        responseError: function(response) {
            // ... do things with the response
        }
    }
    return self;
});