JSON

gistfile1.swift

import Foundation

enum JSON {
	case JString(String)
	case JNumber(Double)
	case JBool(Bool)
	case JArray([JSON])
	case JObject([String: JSON])
	case Null
}

extension JSON {
	static func from(obj: AnyObject) -> JSON {
		if let str = obj as? String {
			return .JString(str)
		} else if let n = obj as? Double {
			return .JNumber(n)
		} else if let b = obj as? Bool {
			return .JBool(b)
		} else if let arr = obj as? [AnyObject] {
			return .JArray(arr.map(from))
		} else if let dict = obj as? [String: AnyObject] {
			var newDict = [String: JSON]()
			for (k,v) in dict {
				newDict[k] = from(v)
			}
			return .JObject(newDict)
		} else {
			return .Null
		}
	}
}

extension JSON: NilLiteralConvertible {
	static func convertFromNilLiteral() -> JSON {
		return .Null
	}
}

extension JSON {
	subscript (str: String) -> JSON {
		get {
			switch self {
			case .JObject(let dict):
				return dict[str] ?? .Null
			default:
				return .Null
			}
		}
	}
	subscript (i: Int) -> JSON {
		get {
			switch self {
			case .JArray(let arr):
				return arr[i]
			default:
				return .Null
			}
		}
	}
}

extension JSON {
    var string: String? {
        get {
            switch self {
            case .JString(let str):
                return str
            default:
                return nil
            }
        }
	}
    var number: Double? {
        get {
            switch self {
            case .JNumber(let n):
                return n
            default:
                return nil
            }
        }
	}
    var bool: Bool? {
        get {
            switch self {
            case .JBool(let b):
                return b
            default:
                return nil
            }
        }
	}
}

protocol JSONModel {
    class func createFromJSON(json: JSON) -> Self?
}

extension JSON {
    static func model<M: JSONModel>(data: NSData) -> M? {
    	var error: NSError?
		let object: AnyObject! = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &error)
		assert(error == nil)
	    return M.createFromJSON(JSON.from(object))
    }
}

class ExampleModel: JSONModel {
    let name: String
    var email: String?
    
    required init(name: String, email: String?) {
        self.name = name
        self.email = email
    }
    
    class func createFromJSON(json: JSON) -> Self? {
        return self(name: json["name"].string!, email: json["email"].string)
    }
}

let jsonData = ("{\"name\":\"John\", \"email\":\"hey@mail.com\"}" as NSString).dataUsingEncoding(NSUTF8StringEncoding)!


let model: MyModel? = JSON.model(jsonData)