How to create JSON from Model in ios Swift 3

Question

I have created model class for the user as below.

public class SignUpUser {
    public var fullName : String?
    public var id : Int?
    public var city : String?
    public var email : String?
    public var address : String?
    public var lastName : String?
    public var countryCode : String?
    public var firstName : String?
    public var zipCode : Int?
    public var contactNumber : Int?
    public var sex : String?
    public var dob : String?
    public var signupType : String?
    public var verified : String?
    public var emailTokenExpiration : String?
    public var updatedAt : String?
    public var createdAt : String?

/**
    Returns an array of models based on given dictionary.

    Sample usage:
    let user_list = User.modelsFromDictionaryArray(someDictionaryArrayFromJSON)

    - parameter array:  NSArray from JSON dictionary.

    - returns: Array of User Instances.
*/
    public class func modelsFromDictionaryArray(array:NSArray) -> [SignUpUser]
    {
        var models:[SignUpUser] = []
        for item in array
        {
            models.append(SignUpUser(dictionary: item as! NSDictionary)!)
        }
        return models
    }

/**
    Constructs the object based on the given dictionary.

    Sample usage:
    let user = User(someDictionaryFromJSON)

    - parameter dictionary:  NSDictionary from JSON.

    - returns: User Instance.

*/

    init?() {}


    required public init?(dictionary: NSDictionary) {
        fullName = dictionary["fullName"] as? String
        id = dictionary["id"] as? Int
        city = dictionary["city"] as? String
        email = dictionary["email"] as? String
        address = dictionary["address"] as? String
        lastName = dictionary["lastName"] as? String
        countryCode = dictionary["countryCode"] as? String
        firstName = dictionary["firstName"] as? String
        zipCode = dictionary["zipCode"] as? Int
        contactNumber = dictionary["contactNumber"] as? Int
        sex = dictionary["sex"] as? String
        dob = dictionary["dob"] as? String
        signupType = dictionary["signupType"] as? String
        verified = dictionary["verified"] as? String
        emailTokenExpiration = dictionary["emailTokenExpiration"] as? String
        updatedAt = dictionary["updatedAt"] as? String
        createdAt = dictionary["createdAt"] as? String
    }


/**
    Returns the dictionary representation for the current instance.

    - returns: NSDictionary.
*/
    public func dictionaryRepresentation() -> NSDictionary {

        let dictionary = NSMutableDictionary()

        dictionary.setValue(self.fullName, forKey: "fullName")
        dictionary.setValue(self.id, forKey: "id")
        dictionary.setValue(self.city, forKey: "city")
        dictionary.setValue(self.email, forKey: "email")
        dictionary.setValue(self.address, forKey: "address")
        dictionary.setValue(self.lastName, forKey: "lastName")
        dictionary.setValue(self.countryCode, forKey: "countryCode")
        dictionary.setValue(self.firstName, forKey: "firstName")
        dictionary.setValue(self.zipCode, forKey: "zipCode")
        dictionary.setValue(self.contactNumber, forKey: "contactNumber")
        dictionary.setValue(self.sex, forKey: "sex")
        dictionary.setValue(self.dob, forKey: "dob")
        dictionary.setValue(self.signupType, forKey: "signupType")
        dictionary.setValue(self.verified, forKey: "verified")
        dictionary.setValue(self.emailTokenExpiration, forKey: "emailTokenExpiration")
        dictionary.setValue(self.updatedAt, forKey: "updatedAt")
        dictionary.setValue(self.createdAt, forKey: "createdAt")

        return dictionary
    }

}

I am trying to conver the object to JSON with following way but getting error saying "invalid top-level type in json write"

let signUpuser =  SignUpUser()
        signUpuser?.fullName = "Teswt"
        signUpuser?.id = 1
        signUpuser?.city = "Test"
        signUpuser?.email = "Test"
        signUpuser?.address = "Test"
        signUpuser?.lastName = "Test"
        signUpuser?.countryCode = "Test"
        signUpuser?.firstName = "Test"
        signUpuser?.zipCode = 380004
        signUpuser?.contactNumber = 12345
        signUpuser?.sex = "Test"
        signUpuser?.dob = "Test"
        signUpuser?.signupType = "Test"
        signUpuser?.verified = "Test"
        signUpuser?.emailTokenExpiration = "Test"
        signUpuser?.updatedAt = "Test"
        signUpuser?.createdAt = "Test"

if let jsonData = try? JSONSerialization.data(withJSONObject: signUpuser, options: []) {
            let theJSONText = String(data: jsonData, encoding: .utf8)
            AppLog.debug(tag: TAG, msg: theJSONText!)
        }

In Android using Google's gson library we can easily convert JSON to Object and vice versa but in iOS it seems bit difficult.

I also tried to wrap the SignupUser object inside other class object but no luck.

"Wrapping inside other class..."

let wrapperObject = JSONServerRequest(data: signUpuser)
        if let jsonData = try? JSONSerialization.data(withJSONObject: wrapperObject, options: []) {
            let theJSONText = String(data: jsonData, encoding: .utf8)
            AppLog.debug(tag: TAG, msg: theJSONText!)
        }

I don't wish to do this with Dictionary as I have to write the keys every time, I prefer to work with objects so If anyone has any clue please kindly guide me.

Answer 1

Add this method in your model class

func toDictionary() -> [String : Any] {

    var dictionary = [String:Any]()
    let otherSelf = Mirror(reflecting: self)

    for child in otherSelf.children {

        if let key = child.label {
            dictionary[key] = child.value
        }
    }

    print("USER_DICTIONARY :: \(dictionary.description)")

    return dictionary
}

This will give the dictionary representation of your model class so you can access like youclassObj.toDictionary()

and follow as per requirement : Convert Dictionary to JSON in Swift