ngResource custom model actions - angularjs

Question

I'm using ngResource to handle my models in my Ionic/Angular app and I'm having trouble figuring out how/if I can make custom actions on the resource.
I'm storing my model instances in local storage and when I update a record, I want to update the local storage as well. I have this working, but I'm having to copy and paste code for multiple instances and would like to keep it DRY.
LogEntry.update($scope.timeLog, function(data) {
// update local storage
for ( var i = 0; i < logEntries.length; i++) {
if(logEntries[i].id == $scope.timeLog.id){
logEntries[i] = $scope.timeLog;
}
};
localStorageService.set('LogEntries', logEntries);
});
Here is a situation where I update a record, and after the promise returns I update local storage. I would like to make this repeatable, how I envision it being possible (based on other things I've seen in other frameworks and other languages) is something like:
LogEntry.update($scope.timeLog, function(data) {
// update local storage
LogEntry.updateLocalStorage($scope.timeLog);
});
My resource looks like:
.factory('LogEntry', function(config, $resource) {
return $resource(config.apiUrl + 'logentries/:id/', {}, {
'update': {
method:'PUT',
params: { id: '#id' }
}
});
})
Maybe I'm missing something in the docs, but it's pretty short and I'm not seeing a way to do this. Is something like LogEntry.updateLocalStorage($scope.timeLog); possible to store with ngResource, or do custom actions like that need to come from somewhere else? I'd like to keep my model-related actions together if possible.

Answer 1

You could use the transformResponse method in your resource definition. It's kind of a hack since you don't actually need to alter the response, but it allows you to preform actions with the returned data:
{function(data, headersGetter)|Array.<function(data, headersGetter)>}
transform function or an array of such functions. The transform function takes the http response body and headers and returns its transformed (typically deserialized) version. By default, transformResponse will contain one function that checks if the response looks like a JSON string and deserializes it using angular.fromJson. To prevent this behavior, set transformResponse to an empty array: transformResponse: []
https://docs.angularjs.org/api/ngResource/service/$resource
.factory('LogEntry', function (config, $resource) {
return $resource(config.apiUrl + 'logentries/:id/', {}, {
'update': {
'method': 'PUT',
'params': {
'id': '#id'
},
'transformResponse': function (data, header) {
// do stuff with data
return data;
}
}
});
})
That way it will always execute when you get a response but you could also use the transformRequest method, which will always fire on request regardless if you're getting a response.
{function(data, headersGetter)|Array.<function(data, headersGetter)>}
transform function or an array of such functions. The transform function takes the http request body and headers and returns its transformed (typically serialized) version. By default, transformRequest will contain one function that checks if the request data is an object and serializes to using angular.toJson. To prevent this behavior, set transformRequest to an empty array: transformRequest: []
https://docs.angularjs.org/api/ngResource/service/$resource
Which you choose depends on your usecase. Using transformRequest you could always save to localstorage, even when remote is down.