In AngularJS - should $resource be used from controller or service?

Question

All the documentation, examples and tutorials I've found on $resource were using it directly in the controller. So far I'm just using $http from services and those services are further used in the controllers. I thought $resource should replace $http and not my whole service. Is my thinking wrong, or were the examples I've found just so trivial that nobody bothered creating a service?

I've heard once the quote

When you want to create a command line interface for your application and you need to copy code out of the controller, than the controller has too much logic and it should be in a service.

Now, obviously this depends on the complexity of a controller, let's assume a simple CRUD view with the corresponding controller. It seems like $resource would be all I need and I can take it also to create a console application without caring about anything else from the controller. But something inside me is just shouting when I want to access the data ($resource) directly in the controller.

Where is the line to be drawn between when a service is necessary when it's overkill?

Answer 1

This depends on the complexity and the long term goals of your app, but in my experience, your best bet is to wrap your $resource calls in a service since at some point in the future you'll find yourself pre/post processing the intput/output of your $resource calls and it's better to simply attach a new function (or parameter to an existing function) to the service that wraps your $resource calls rather than implement the processing code in every controller where you use the $resource. At first it may seem like it's pointless to add a wrapper that simply returns the $resource response immediately, but later on when the complexity grows, you'll be glad you did.

Answer 2

When you want to create a command line interface for your application and you need to copy code out of the controller, than the controller has too much logic and it should be in a service.

The reason this works is because your UI's are supposed to be independent of the service. A command line is a UI, and you shouldn't need a Controller to implement it, since you don't need Views, View Models or any of the other things that are part and parcel of an MVVM controller.