Encoding to dictionary

Question

I'm completely lost in encoding classes to Dictionary

I have for instance the following class

class AdjectifsModel: BaseModel {
    var id: Int = 0
    var idmot: Int = 0
    var idtypemot: Int = 0
    var idracine: Int = 0
    var racine: String = ""
    var francais: String = ""
    var msingulier: String = ""
    var fsingulier: String = ""
    var mpluriel: String = ""
    var fpluriel: String = ""
    var commentaire: String = ""
    var erreur: Int = 0
    var nbliens: Int = 0

    enum CodingKeys: String, CodingKey {
        case id
        case idmot
        case idtypemot
        case idracine
        case racine
        case francais
        case msingulier
        case fsingulier
        case mpluriel
        case fpluriel
        case commentaire
        case erreur
        case nbliens
    }
}

No problem to encode it with the following code:

required convenience init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        self.init()
        self.id          = try container.decoder(Int.self, forKey: .id)
        self.idmot       = try container.decoder(Int.self, forKey: .idmot)
        self.idtypemot   = try container.decoder(Int.self, forKey: .idtypemot)
        self.idracine    = try container.decoder(Int.self, forKey: .idracine)
        self.racine      = try container.decoder(String.self, forKey: .racine)
        self.francais    = try container.decoder(String.self, forKey: .francais)
        self.msingulier  = try container.decoder(String.self, forKey: .msingulier)
        self.fsingulier  = try container.decoder(String.self, forKey: .fsingulier)
        self.mpluriel    = try container.decoder(String.self, forKey: .mpluriel)
        self.fpluriel    = try container.decoder(String.self, forKey: .fpluriel)
        self.commentaire = try container.decoder(String.self, forKey: .commentaire)
        self.erreur      = try container.decoder(Int.self, forKey: .erreur, defaut: 0)
        self.nbliens     = try container.decoder(Int.self, forKey: .nbliens, defaut: 0)
    }

But in order to save my class, I need to transform it in a Dictionary [String: String] and I don't kown how to do it

I found on the internet the following code:

class DictionaryEncoder {
    private let encoder = JSONEncoder()

    var dateEncodingStrategy: JSONEncoder.DateEncodingStrategy {
        set { encoder.dateEncodingStrategy = newValue }
        get { return encoder.dateEncodingStrategy }
    }

    var dataEncodingStrategy: JSONEncoder.DataEncodingStrategy {
        set { encoder.dataEncodingStrategy = newValue }
        get { return encoder.dataEncodingStrategy }
    }

    var nonConformingFloatEncodingStrategy: JSONEncoder.NonConformingFloatEncodingStrategy {
        set { encoder.nonConformingFloatEncodingStrategy = newValue }
        get { return encoder.nonConformingFloatEncodingStrategy }
    }

    var keyEncodingStrategy: JSONEncoder.KeyEncodingStrategy {
        set { encoder.keyEncodingStrategy = newValue }
        get { return encoder.keyEncodingStrategy }
    }

    func encode(_ value: T) throws -> [String: Any] where T : Encodable {
        let data = try encoder.encode(value)
        return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
    }
}

I copy it (and I must admit that I don't undestand how it works).

If my class contains only strings property, the following Code works:

var params = try DictionaryEncoder().encode(self)

but if the properties are mixed (Strings and Int) it doesn't work

Swift

900

Posted by

PatriceRapaport

Reply

Add a Comment

Answer 1

This is working for me. Here’s a cut down version of your code:

import Foundation

class AdjectifsModel: Codable {
    var id: Int = 0
    var racine: String = ""

    enum CodingKeys: String, CodingKey {
        case id
        case racine
    }
}

class DictionaryEncoder {
    private let encoder = JSONEncoder()

    func encode<T>(_ value: T) throws -> [String: Any] where T : Encodable {
        let data = try encoder.encode(value)
        return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
    }
}

let obj = AdjectifsModel()
let params = try DictionaryEncoder().encode(obj)
print(params)
// ["racine": , "id": 0]

Most of the stuff I elided for simplicity, but there’s one potentially significant change that I had to make because your post is missing some details, namely the declaration of

BaseObject

. Implementing

Codable

in a class hierarchy is a little tricky. Here’s an example of how you might do that:

class BaseObject: Codable {
    var uuid: UUID
    init() {
        self.uuid = UUID()
    }
}

class AdjectifsModel: BaseObject {
    var id: Int
    var racine: String

    override init() {
        self.id = 0
        self.racine = ""
        super.init()
    }

    required init(from decoder: Decoder) throws {
        fatalError()
    }

    override func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try super.encode(to: container.superEncoder())
        try container.encode(self.id, forKey: .id)
        try container.encode(self.racine, forKey: .racine)
    }

    enum CodingKeys: String, CodingKey {
        case id
        case racine
    }
}

class DictionaryEncoder {
    private let encoder = JSONEncoder()

    func encode<T>(_ value: T) throws -> [String: Any] where T : Encodable {
        let data = try encoder.encode(value)
        return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
    }
}

let obj = AdjectifsModel()
let params = try DictionaryEncoder().encode(obj)
print(params)
// ["super": {
//     uuid = "E328BB0B-B892-458B-B7E7-ED7C00A3F2D6";
// }, "id": 0, "racine": ]

Note the nested dictionary here. The encoding architecture uses this to prevent key clashes between the properties in the class and the properties in the superclass.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Posted by

eskimo

Add a Comment

Answer 2

This is working for me. Here’s a cut down version of your code:

import Foundation

class AdjectifsModel: Codable {
    var id: Int = 0
    var racine: String = ""

    enum CodingKeys: String, CodingKey {
        case id
        case racine
    }
}

class DictionaryEncoder {
    private let encoder = JSONEncoder()

    func encode<T>(_ value: T) throws -> [String: Any] where T : Encodable {
        let data = try encoder.encode(value)
        return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
    }
}

let obj = AdjectifsModel()
let params = try DictionaryEncoder().encode(obj)
print(params)
// ["racine": , "id": 0]

Most of the stuff I elided for simplicity, but there’s one potentially significant change that I had to make because your post is missing some details, namely the declaration of

BaseObject

. Implementing

Codable

in a class hierarchy is a little tricky. Here’s an example of how you might do that:

class BaseObject: Codable {
    var uuid: UUID
    init() {
        self.uuid = UUID()
    }
}

class AdjectifsModel: BaseObject {
    var id: Int
    var racine: String

    override init() {
        self.id = 0
        self.racine = ""
        super.init()
    }

    required init(from decoder: Decoder) throws {
        fatalError()
    }

    override func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        try super.encode(to: container.superEncoder())
        try container.encode(self.id, forKey: .id)
        try container.encode(self.racine, forKey: .racine)
    }

    enum CodingKeys: String, CodingKey {
        case id
        case racine
    }
}

class DictionaryEncoder {
    private let encoder = JSONEncoder()

    func encode<T>(_ value: T) throws -> [String: Any] where T : Encodable {
        let data = try encoder.encode(value)
        return try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String: Any]
    }
}

let obj = AdjectifsModel()
let params = try DictionaryEncoder().encode(obj)
print(params)
// ["super": {
//     uuid = "E328BB0B-B892-458B-B7E7-ED7C00A3F2D6";
// }, "id": 0, "racine": ]

Note the nested dictionary here. The encoding architecture uses this to prevent key clashes between the properties in the class and the properties in the superclass.

Share and Enjoy
—
Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware

let myEmail = "eskimo" + "1" + "@apple.com"

Posted by

eskimo

Add a Comment

Answer 3

Thank you Claude

In fact what was missing was the encode function, as my Class is derived not from Codable but from another class

Posted by

PatriceRapaport

Add a Comment

Answer 4

You should thank Quinn, I did nothing but learn from his answer 😁

Posted by

Claude31

Add a Comment

Answer 5

Ho yes, sorry my mistake

So thank you Quinn

Posted by

PatriceRapaport

Add a Comment

Encoding to dictionary

Accepted Reply

Replies