This is my attempt to implement some Sourcery templates which automatically generates JSON bindings for your structs and classes.

My objective here is to provide a fully tested code generation template that will let you skip the pain of writing this code:

extension Contact: JSONDeserializable {
    enum Fields: String {
        case identifier = "id"
        case firstName = "first_name"
        case lastName = "last_name"
        case age = "age"
    }

    init?(JSONObject: [String : Any]) {
        guard let id = JSONObject[Fields.identifier.rawValue] as? String,
            let firstName = JSONObject[Fields.firstName.rawValue] as? String,
            let lastName = JSONObject[Fields.lastName.rawValue] as? String,
            let age = JSONObject[Fields.age.rawValue] as? Int
            else {
                return nil
        }
        self.id = id
        self.firstName = firstName
        self.lastName = lastName
        self.age = age
    }
}

The JSON serialization/deserialization is based on two protocols.

protocol JSONDeserializable {
    init?(JSONObject: [String: Any])
}

protocol JSONSerializable {
    func toJSONObject() -> [String: Any]
}

With this tool, you do not need to implement these protocols, the Sourcery templates will do the boiler plate code for you.
To do this, all you need to do is conform to one (or both) of these protocols:

protocol AutoJSONDeserializable {}

protocol AutoJSONSerializable {}

And then run Sourcery using the templates found in the Templates/ folder of this repository.

Let say you have a model struct like this one:

struct Contact {
    let id: String
    let firstName: String
    let lastName: String
    let age: Int
}

Making it conform to AutoJSONDeserializable would result make it support this JSON:

{
  "id": "SomeID",
  "firstName": "John",
  "lastName": "Doe'"
}

• primitive JSON types (String, Int, Double)
• ISO8601 formatted dates
• optionals
• nested structures
• JSONKey annotation

When mapping your JSON to your model structure, you may sometimes want to use a different attribute name as the one in the JSON file.
Let's say you have this JSON:

{
  "id": "SomeID",
  "first_name": "John",
  "last_name": "Doe'"
}

As you can see, the naming convention does not follow camel case. To fix this you can use Sourcery annotations.
On a property, you can define the JSONKey attribute with the JSON name you want to bind the property to:

struct Contact {
    let id: String
    // sourcery: JSONKey = "first_name"
    let firstName: String
    // sourcery: JSONKey = "last_name"
    let lastName: String
}

The current installation process is pretty basic and does not support any dependency managers yet.
To install just copy the following source files in your project:

• Sources/AutoJSONSerialization/AutoJSONSerializable.swift
• Sources/AutoJSONSerialization/AutoJSONDeserializable.swift
• Sources/AutoJSONSerialization/JSONDateFormatter.swift

And then copy the Templates files and configure Sourcery.