MVC-N: Isolating Network Calls From View Controllers
We have a network controller: it talks to the internet, your local network, or even be a flat file system. It then pushes data into your cache, into your persistence engine. Here comes the exciting part: your entire view layer talks to the cache only. It does not get data from the internet directly. The ViewController’s job is to display or update that data, not to do networking code. This design will serve you forever, and it has so many benefits that you’ll never want to use the anti-pattern ever again.
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We can use the concurrent design of the NSOperation to do our network requests. In Swift, because we cannot access the property directly for
finished, we have to do hacking (which I do have a radar for, and I am hoping they will fix this). The idea behind this overridedvaris that we need to tell the queue that we are done. To do that, the queue is listening for “isFinished”. In Objective-C,isFinishedtranslates into the variableFinishedfine; in Swift, it only listens for “isFinished”, it does not listen for the actual property ofFinish, you cannot change it.
