Author: Bart Jacobs
Many developers new to Swift seem to be struggling with JSON. Despite the speed of Foundation's JSONSerialization class, it hands you an object of type Any, leaving it up to you to unwrap the object you received.
In Objective-C, that's less of a problem. But Swift's inherent safety measures make this less trivial. This is what you end up with if you decide to choose for JSONSerialization.
if let JSON = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: AnyObject],
let currently = JSON?["currently"] as? [String: AnyObject],
let summary = currently["summary"] {
print(summary)
}
That doesn't look pretty. It looked even worse in earlier versions of Swift. Once the Swift Core Libraries project starts to take shape, this becomes much easier. The goal of this project is to add functionality to the Swift programming language on top of the Swift standard library.
Fortunately, there are a bunch of open source libraries available for handling JSON in Swift. One of the most popular solutions is SwiftyJSON. SwiftyJSON is quickly gaining in popularity for the same reasons AFNetworking was a few years ago, a lack of a robust, native solution.
Another popular solution is, Argo, created and maintained by none other than ThoughtBot.
For many years, I've been using JSONModel. I love JSONModel because it makes consuming APIs so much easier. The most important downside of JSONModel is that every model class needs to inherit from JSONModel. That's a trade-off many developers are not willing to make.
I've been looking for a nice solution to replace JSONModel in Swift. Ideally, it's a solution that doesn't rely on inheritance but that still gives me access to a nice API for parsing JSON and pouring raw data into model objects. Unbox, created by John Sundell, looks very promising to me.
Unbox doesn't rely on inheritance. It defines a protocol that any class or structure can conform to. It provides support for:
- key paths
- nested models
- failable initializers
- native error handling
- custom transformations
I'd like to show you how Unbox works by consuming the Dark Sky API. Dark Sky's API returns a large blob of data that would be a pain to consume if all you had was the JSONSerialization class. Unbox makes this much, much easier.
Read this article on the blog.