快速解码JSON数据，并从服务器向两个不同的结构发送两个不同的json响应

Question

[当我通过urlSession向服务器发出api请求时，可能会收到json之类的信息

{
    "movie": "Avengers",
    "director": "Joss Whedon",
}

或这样

{
    "apiKey": "invalid"
}

我有两个要像这样保存的结构

struct Movie: Codable {
    let request: String
    let director: String

    init(movie:String, director:Sring) {
        self.movie = movie
        self.director = director
    }
}

struct Valid: Codable {
    let apiKey: String

    init(apiKey:String) {
        self.apiKey = apiKey
    }
}

基于响应，我想解码为第一个结构或第二个结构。怎么做。

Answer 1

if let url = URL(string: "myurl.com") {
   URLSession.shared.dataTask(with: url) { data, response, error in
      if let data = data {
        guard let json = data as? [String:AnyObject] else {
              return
        }
          do {
            if let movie =  json["movie"]{
              //moview is there. so you can decode to your movie struct
              let res = try JSONDecoder().decode(Movie.self, from: data)
            }else{
              //move is not there.it means error
              let res = try JSONDecoder().decode(Valid.self, from: data)
            }
          } catch let error {
             print(error)
          }
       }
   }.resume()
}

Answer 2

首先，解析上述2个[[JSON响应的Codable类型应该看起来像，

struct Movie: Decodable {
    let movie: String
    let director: String
}

struct Valid: Decodable {
    let apiKey: String
}

无需显式创建init()。 Codable将自动处理。
下一步，您需要创建另一个可以处理两个响应的Codable类型，即
enum Response: Decodable {
    case movie(Movie)
    case valid(Valid)

    init(from decoder: Decoder) throws {
        let container = try decoder.singleValueContainer()
        do {
            let data = try container.decode(Movie.self)
            self = .movie(data)
        } catch  {
            let data = try container.decode(Valid.self)
            self = .valid(data)
        }
    }
}

现在，您可以像这样解析
JSON

data，

do {
    let response = try JSONDecoder().decode(Response.self, from: data)
    print(response)
} catch {
    print(error)
}