Swift -使用jsonDecoder解码特定密钥

Question

我不确定如何表达我的问题，但我正在尝试找到如何在不创建多个模型的情况下解码整个json，而只解码一个特定的键。

JSON示例：

{
  "page": 1,
  "results": [
    {
      "poster_path": "/e1mjopzAS2KNsvpbpahQ1a6SkSn.jpg",
      "adult": false,
      "overview": "From DC Comics comes the Suicide Squad, an antihero team of incarcerated supervillains who act as deniable assets for the United States government, undertaking high-risk black ops missions in exchange for commuted prison sentences.",
      "release_date": "2016-08-03",
      "genre_ids": [
        14,
        28,
        80
      ],
      "id": 297761,
      "original_title": "Suicide Squad",
      "original_language": "en",
      "title": "Suicide Squad",
      "backdrop_path": "/ndlQ2Cuc3cjTL7lTynw6I4boP4S.jpg",
      "popularity": 48.261451,
      "vote_count": 1466,
      "video": false,
      "vote_average": 5.91
    },
    ...
  ]
}

我只需要拿到results。现在我有两个模型：

struct Movies: Codable {
    let results: [MovieResult]?
}

struct MovieResult: Codable {
    let popularity: Double?
    let poster_path: String?
    let backdrop_path: String?
    let title: String?
    let vote_average: Double?
    let overview: String?
    let release_date: String?
}

并获得解码：

        RESTful.request(path: path, method: "GET", parameters: parameters, headers: nil) { (result) in
            switch result {
            case .failure(let error):
                completion(.failure(.networkingError))
            case .success(let data):
                let jsonDecoder = JSONDecoder()
                do{
                    let popularMovies = try jsonDecoder.decode(Movies.self, from: data)
                    completion(.success(popularMovies))
                } catch (let error) {
                    completion(.failure(.errorDecoding))
                }
            }
        }

由于我只需要results，有没有办法(使用jsonDecoder)将其解码为单个模型

Answer 1

JSON必须始终从根对象中解码。

但是有一个非常简单的解决方案，声明Result类型

Result<MovieResult,Error>

并在成功时调用completion

completion(.success(popularMovies.results))