Awesome

Sample Swift Codable

Swift Codable Sample 입니다.

Codable

• Swift4에서 Codable이라는 프로토콜이 추가되었습니다.
  • Swift Standard Library
  • Xcode 9.0+
• https://developer.apple.com/documentation/swift/codable

Type Alias

Codable
A type that can convert itself into and out of an external representation.

Declaration
typealias Codable = Decodable & Encodable

Discussion
Codable is a type alias for the Encodable and Decodable protocols. When you use Codable as a type or a generic constraint, it matches any type that conforms to both protocols.

이라 설명이 되어있습니다.

Codable 은 Type Alias 입니다.

Codable
외부 표현으로 변환하거나 외부 표현으로 변환할 수 있는 유형입니다.

선언
typealias Codable = Decodable & Encodable

Discussion
Codable은 Encodable 및 Decodable 프로토콜의 typealias입니다.
Codable을 사용하면 두 프로토콜을 모두 준수해야 되지요.

통상 사용할 때는 디코딩을 할때 사용하는 것 같습니다.

설명이 잘 되어있는 링크

• 민소네님 블로그
  • Codable, 현실의 Codable 그리고 Extension
• 제드님 블로그
  • Swift ) 왕초보를 위한 Codable / JSON Encoding and Decoding

Sample Source

이해를 돕기위해 셈플 소스를 추가해 봤습니다.

• SampleData.swift

struct SampleStructData01: Codable {
    let id: String
    let code: String
    var order: Int?
    var test: Int?
}

struct SampleStructData02: Codable {
    let code: String
    let data: SampleStructData02SubData
    
    struct SampleStructData02SubData: Codable {
        let id : String
        let code : String
        let order : Int
    }
}

struct SampleStructData03 : Codable {
    let id : String
    var code : String?
    var order : Int
    enum CodingKeys : String, CodingKey{
        case id
        case code
        case order = "order_test"
    }
}

struct SampleStructData04 : Codable {
    let id : String
    let code : String
    let order : Int
}

/// https://github.com/yonaskolb/Codability
struct SampleAnyCodableData01 : Codable {
    let id : AnyCodable
    let code : String
}

• SampleResponse.swift

struct SampleResponse { }

/**
 {
     userId: 1,
     id: 1,
     title: "delectus aut autem",
     completed: false
 }
 */
extension SampleResponse {
    struct todos: Codable {
        let userId:Int
        let id:Int
        let title: String?
        let completed:Bool?
        
        let testTrash:String?
    }
}

• ViewController.swift

  • func sampleStructData01()

  func sampleStructData01() {
      print("===============================")
      print("== \(#function)")
      
      let dataJsonString = """
      {
          "id": "test@gmail.com",
          "code": "abcdefg1234",
          "order": 1
      }
      """.data(using: .utf8)!
      
      let sample = try! JSONDecoder().decode(SampleStructData01.self, from: dataJsonString)
      print(sample)
      print("===============================\n\n")
  }
  

  • func sampleStructData02()

  func sampleStructData02() {
      print("===============================")
      print("== \(#function)")
      
      let dataJsonString = """
      {
          "code": "poiuytrewq",
          "data": {
              "id": "test@gmail.com",
              "code": "abcdefg1234",
              "order": 1
          }
      }
      """.data(using: .utf8)!
      
      let sample = try! JSONDecoder().decode(SampleStructData02.self, from: dataJsonString)
      print(sample)
      print("===============================\n\n")
  }
  

  • func sampleStructData03()

  func sampleStructData02() {
      print("===============================")
      print("== \(#function)")
      
      let dataJsonString = """
      {
          "id": "test@gmail.com",
          "code": "abcdefg1234",
          "order_test": 1
      }
      """.data(using: .utf8)!
      
      let sample = try! JSONDecoder().decode(SampleStructData03.self, from: dataJsonString)
      print(sample)
      print("===============================\n\n")
  }
  

  • func sampleStructData04()

  func sampleStructData02() {
      print("===============================")
      print("== \(#function)")
      
      let dataJsonString = """
      [
          {
              "id": "aaaa@gmail.com",
              "code": "1234567890",
              "order": 1
          },
          {
              "id": "bbbb@gmail.com",
              "code": "abcdefghijklmn",
              "order": 2
          }
      ]
      """.data(using: .utf8)!
      
      do {
          let sample = try JSONDecoder().decode([SampleStructData04].self, from: dataJsonString)
          print(sample)
      } catch {
          print(error)
      }
      
      print("===============================\n\n")
  }
  

  • func sampleAnyCodableData01()
    • Codable을 사용하면서 Any 타입이 필요할 때.. 쉽지 않습니다. 그래서 라이브러리를 하나 사용해 봤습니다.
    • https://github.com/yonaskolb/Codability

  func sampleAnyCodableData01() {
      print("===============================")
      print("== \(#function)")
      
      let dataJsonString = """
      [
          {
              "id": "aaaa@gmail.com",
              "code": "1234567890",
          },
          {
              "id": 1234,
              "code": "abcdefghijklmn",
          }
      ]
      """.data(using: .utf8)!
      
      do {
          let samples = try JSONDecoder().decode([SampleAnyCodableData01].self, from: dataJsonString)
          //
          _ = samples.enumerated().map { sample -> String in
              if sample.element.id.value is String {
                  print("index \(sample.offset) : id.value is String")
              } else if sample.element.id.value is Int {
                  print("index \(sample.offset) : id.value is Int")
              } else {
                  print("index \(sample.offset) : id.value is ?")
              }
              return ""
          }
          print(samples)
      } catch {
          print(error)
      }
      
      print("===============================\n\n")
  }
  

  • func sampleRequest01()

  func sampleRequest01(){
      print("===============================")
      print("== \(#function)")
      
      let url = URL(string: "https://jsonplaceholder.typicode.com/todos/1")
      URLSession.shared.dataTask(with: url!, completionHandler: {
          (data, response, error) in
          if let error = error {
              print("== \(error)")
          } else {
              print("== success")
              
              guard let data = data else {
                  return
              }
              
              do {
                  let codableStruct = try JSONDecoder().decode(SampleResponse.todos.self, from: data)
                  print("\(codableStruct)")
                  print("== id : \(codableStruct.id)")
              } catch {
                  print("== err in codable")
              }
              
              print("===============================\n\n")
          }
      }).resume()
  }
  

Result Log

===============================
== sampleStructData01()
SampleStructData01(id: "test@gmail.com", code: "abcdefg1234", order: Optional(1), test: nil)
===============================


===============================
== sampleStructData02()
SampleStructData02(code: "poiuytrewq", data: JWSCodableSample.SampleStructData02.SampleStructData02SubData(id: "test@gmail.com", code: "abcdefg1234", order: 1))
===============================


===============================
== sampleStructData03()
SampleStructData03(id: "test@gmail.com", code: Optional("abcdefg1234"), order: 1)
===============================


===============================
== sampleStructData04()
[JWSCodableSample.SampleStructData04(id: "aaaa@gmail.com", code: "1234567890", order: 1), JWSCodableSample.SampleStructData04(id: "bbbb@gmail.com", code: "abcdefghijklmn", order: 2)]
===============================


===============================
== sampleRequest01()
== success
todos(userId: 1, id: 1, title: Optional("delectus aut autem"), completed: Optional(false), testTrash: nil)
== id : 1
===============================