angularjs handling $resource $promise errors

问题

Could somebody help me figure out how to return hard-coded data in my AngularJS factory if there is an error connecting to my API. My hard-coded data are located in another factory called "dataFactory". Appreciate the assistance.

service.factory("ScheduleFactory", ['$http', '$resource', '$q', 'dataFactory', function($http, $resource, $q, dataFactory) {
        var objFactory = {};

        objFactory.getDaysOfWeek = function(includeWeekends) {
            var days = [];
            var API  = $resource(restURL + '/daysOfWeek/');

            API.query()
                .$promise
                    .then(function(data) {
                        isEmpty = (data.length === 0);

                        if (!isEmpty) {
                            days    = data;
                        };
                    })
                    .catch(function(error) {
                        console.log("rejected " + JSON.stringify(error));

                        var data    = null;
                        days    = dataFactory.daysOfWeek;

                        console.log(days.length); // returns 5
                    });


            console.log("after promise " + days.length);  // returns 'after promise 0'

            return days;
        };

My dataFactory is defined as follows:

dataApp.factory("dataFactory", function() {
    objDataFactory  = {};

    objDataFactory.daysOfWeek = [
        {   dayName:        'Monday'
            , dayAbbrev:    'Mon'
            , index:        1
            , isSelected:   false
            , isWeekday:    true    }
        , { dayName:        'Tuesday'
             , dayAbbrev:   'Tue'
             , index:       2
             , isSelected:  false
             , isWeekday:   true    }
        , { dayName:        'Wednesday'
             , dayAbbrev:   'Wed'
             , index:       3
             , isSelected:  false
             , isWeekday:   true    }
        , { dayName:        'Thursday'
             , dayAbbrev:   'Thu'
             , index:       4
             , isSelected:  false
             , isWeekday:   true    }
        , { dayName:        'Friday'
             , dayAbbrev:   'Fri'
             , index:       5
             , isSelected:  false
             , isWeekday:   true    }
    ];

    return objDataFactory;
});

回答1:

I'd like to think this is what you are looking for:

service.factory("ScheduleFactory", ['$http', '$resource', '$q', 'dataFactory', function($http, $resource, $q, dataFactory) {
     var objFactory = {};

     objFactory.getDaysOfWeek = function(includeWeekends) {
          var API  = $resource(restURL + '/daysOfWeek/'), defObj = $q.defer();

          var daysQuery = API.query();
          daysQuery.$promise.then(function(data) {
                    //you can add anything else you want inside this function
                    defObj.resolve(data);
               }, function(error) {
                    //you can add anything else you want inside this function
                    defObj.resolve(dataFactory.daysOfWeek);
               });

            return defObj.promise;
        };

I've skipped any data formatting and assignment details because you're liable to change them anyway. By wrapping your API query in an extra promise you gain the ability to manipulate what is returned. If your API can be reached, you return the data from it in the resolution of your outer promise. Otherwise, you return your hard-coded data from your other service in the resolution of your outer promise.

回答2:

No catch block, use a regular error callback function:

   API.query()
        .$promise
            .then(function(data) {
                    isEmpty = (data.length === 0);

                    if (!isEmpty) {
                        days    = data;
                 },
                 function(error) { // removed catch here
                    console.log("rejected " + JSON.stringify(error));

                    var data    = null;
                    days    = dataFactory.daysOfWeek;

                    console.log(days.length); // returns 5
                ...

See in the docs:

then(successCallback, errorCallback, notifyCallback) – regardless of when the promise was or will be resolved or rejected, then calls one of the success or error callbacks asynchronously as soon as the result is available. The callbacks are called with a single argument: the result or rejection reason. Additionally, the notify callback may be called zero or more times to provide a progress indication, before the promise is resolved or rejected.

来源：https://stackoverflow.com/questions/25070690/angularjs-handling-resource-promise-errors