swift-json-class.swift

/*

    Converts A class to a dictionary, used for serializing dictionaries to JSON

    Supported objects:
    - Serializable derived classes
    - Arrays of Serializable
    - NSData
    - String, Numeric, and all other NSJSONSerialization supported objects

*/

import Foundation

public class Serializable : NSObject{
    
    public func toDictionary() -> NSDictionary {
        var aClass : AnyClass? = self.dynamicType
        var propertiesCount : CUnsignedInt = 0
        let propertiesInAClass : UnsafeMutablePointer<objc_property_t> = class_copyPropertyList(aClass, &propertiesCount)
        var propertiesDictionary : NSMutableDictionary = NSMutableDictionary()
   
        for var i = 0; i < Int(propertiesCount); i++ {
            var property = propertiesInAClass[i]
            var propName = NSString(CString: property_getName(property), encoding: NSUTF8StringEncoding)!
            var propType = property_getAttributes(property)
            var propValue : AnyObject! = self.valueForKey(propName);
            
            if propValue is Serializable {
                propertiesDictionary.setValue((propValue as Serializable).toDictionary(), forKey: propName)
            } else if propValue is Array<Serializable> {
                var subArray = Array<NSDictionary>()
                for item in (propValue as Array<Serializable>) {
                    subArray.append(item.toDictionary())
                }
                propertiesDictionary.setValue(subArray, forKey: propName)
            } else if propValue is NSData {
                propertiesDictionary.setValue((propValue as NSData).base64EncodedStringWithOptions(nil), forKey: propName)
            } else if propValue is Bool {
                propertiesDictionary.setValue((propValue as Bool).boolValue, forKey: propName)
            } else {
                propertiesDictionary.setValue(propValue, forKey: propName)
            }
        }
        
        // class_copyPropertyList retaints all the 
        propertiesInAClass.dealloc(Int(propertiesCount))
        
        return propertiesDictionary
    }
    
    public func toJson() -> NSData! {
        var dictionary = self.toDictionary()
        //println(dictionary)
        var err: NSError?
        return NSJSONSerialization.dataWithJSONObject(dictionary, options:NSJSONWritingOptions(0), error: &err)
    }
    
    public func toJsonString() -> NSString! {
        return NSString(data: self.toJson(), encoding: NSUTF8StringEncoding)
    }

}

swift-json-usage.swift

import XCTest

class Person:Serializable{
    var Name : String
    var Surname : String
    var Animals : Array<Animal>
    
    init(Name:String, Surname:String) {
        self.Name = Name
        self.Surname = Surname
        self.Animals = Array<Animal>()
    }
}

class Animal:Serializable {
    var Nickname : String
    var Kind : String
    
    init(Nickname : String, Kind : String) {
        self.Nickname = Nickname
        self.Kind = Kind
    }
}

class SerializationTests: XCTestCase {
    func test_serialization_works() {
        var john = Person(Name: "John", Surname: "Doe")
    
        john.Animals.append(Animal(Nickname: "Fluffy", Kind: "Dog"))
        john.Animals.append(Animal(Nickname: "Purry", Kind: "Cat"))
        
        println(john.toJson()) //will give binary data to include in HTTP Body
        println(john.toJsonString()) //will give the exact string in JSON
        
        //{"Surname":"Doe","Name":"John","Animals":[{"Kind":"Dog","Nickname":"Fluffy"},{"Kind":"Cat","Nickname":"Purry"}]}
        
        var expected = "{\"Surname\":\"Doe\",\"Name\":\"John\",\"Animals\":[{\"Kind\":\"Dog\",\"Nickname\":\"Fluffy\"},{\"Kind\":\"Cat\",\"Nickname\":\"Purry\"}]}";
        
        XCTAssertEqual(john.toJsonString(), expected,"")
    }
}