It contains our project and a reference to a new project called Pods. Select XCode path sudo xcode-select -switch /Applications/Xcode.appĪdd ObjectMapper repository pod repo add ObjectMapper Ĭlose XCode and open the created file *.xcworkspace. To reference ObjectMapper add this content to the PodFile Install cocoapods sudo gem install cocoapodsĬreate Podfile in our project root touch Podfile To add ObjectMapper to our project we need to execute the following commands: Check the project in GitHub for more information) (If would also be possible to add it as a submodule. We will use it to reference ObjectMapper in our project. Reference ObjectMapper using CocoaPodsĬocoaPods is a dependency manager for Swift and Objective-C Cocoa projects. ObjectMapper is an open source project to make JSON Object mapping written in Swift. In this example we will see how to serialize and deserialize objects to/from JSON using ObjectMapper in our iOS application.įor example, this would be the JSON representation of an object with two properties JSON (JavaScript Object Notation) is a lightweight, human readable, open source, data-interchange format. In this case, the CodingKeys value tells us that we're trying to extract a value for the missingObject key but that key does not exist in the JSON as noted by the debugDescription.This post is part of my collection: Swift 2 – For Beginners. We can find out which key wasn't found by reading the CodingKeys declaration that comes after the error case. We can see that we're dealing with a keyNotFound error. For example, if our struct would contain a type that is not present in the JSON data we would see an error that looks like this: keyNotFound(CodingKeys(stringValue: "missingObject", intValue: nil), (codingPath:, debugDescription: "No value associated with key CodingKeys(stringValue: \"missingObject\", intValue: nil) (\"missingObject\").", underlyingError: nil)) The error messages that are surfaced by JSONDecoder are generally very helpful. If something goes wrong we print the error so we can see what went wrong. A dictionary that's defined as Dictionary is Codable too.Īrrays and dictionaries both play important roles in JSON because everything in JSON is defined using the equivalent of Swift's arrays and dictionaries.įor example, the following is valid JSON for an array of strings: Īnd the following is an example of a dictionary in JSON: block. This means that an array defined as Array conforms to Codable already. For example, Int, String, and Bool are Codable out of the box.Įven dictionaries and arrays are Codable by default as long as the objects that you store in them conform to Codable. If you only want to transform instances of your struct into Data, you can conform your object to Encodable, and if you want to do both you can conform to Codable.Ī lot of Swift's built-in types already conform to Codable by default. When you only want to convert JSON data into a struct, you can conform your object to Decodable. These two protocols are used to indicate whether a certain struct, enum, or class, can be encoded into JSON data, or materialized from JSON data. The Codable protocol in Swift is really a union of two protocols: Encodable and Decodable.
After that, I'll show you how to define a struct that implements the Codable protocol, and I'll explain the basics of encoding and decoding JSON data. I'll start by explaining what Swift's Codable is. It's good to understand that the principles in this series can be applied to both JSON data, as well as. I will focus on showing you how to work with JSON and Codable in Swift. The post you're looking at is intended to provide an introduction into Swift's Codable protocol, and it's part of a series of posts on this topic. plist file into Swift structs, or to convert Swift structs into data for a. Out of the box, Codable can also be used to decode a. What's nice about Codable is that it was designed to not be limited to JSON. And Swift's Codable protocol was designed to provide a powerful and useful mechanism to convert JSON data into Swift structs.
Well, JSON is arguably the most common data format that we use to exchange data on the web. In this post, I want to take a look at Swift's Codable protocol. But that's way beyond what I want to cover in this post. Objects in Javascript are very comparable to dictionaries in Swift, except they aren't strongly typed and they have a couple of extra features. Javascript doesn't have strong typing, so a JSON object in Javascript is really just a JavaScript Object. When you're working with Javascript, this JSON data can be easily decoded into a Javascript object.
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