Best architectural approaches for building iOS networking applications (REST clients)

Question

I\'m an iOS developer with some experience and this question is really interesting to me. I saw a lot of different resources and materials on this topic, but nevertheless I\

Answer 1

From a purely class design perspective, you will usually have something like this:

• Your view controllers controlling one or more views

• Data model class - It really depends upon how many real distinct entities you are dealing with, and how they are related.

  For example, if you have an array of items to be displayed in four different representations (list, chart, graph etc), you will have one data model class for list of items, one more for an item. The list of item class will be shared by four view controllers - all children of a tab bar controller or a nav controller.

  Data model classes will come handy in not only displaying data, but also serializing them wherein each of them can expose their own serialization format through JSON / XML / CSV (or anything else) export methods.

• It is important to understand that you also need API request builder classes that map directly with your REST API endpoints. Let's say you have an API that logs the user in - so your Login API builder class will create POST JSON payload for login api. In another example, an API request builder class for list of catalog items API will create GET query string for corresponding api and fire the REST GET query.

  These API request builder classes will usually receive data from view controllers and also pass the same data back to view controllers for UI update / other operations. View controllers will then decide how to update Data Model objects with that data.

• Finally, the heart of the REST client - API data fetcher class which is oblivious to all sorts of API requests your app makes. This class will more likely be a singleton, but as others pointed out, it doesn't have to be a singleton.

  Note that the link is just a typical implementation and does not take into consideration scenarios like session, cookies etc, but it is enough to get you going without using any 3rd party frameworks.