如何解码具有不同类型的JSON属性？ [英] How to decode a JSON property with different types?

问题描述

我有JSON

{
"tvShow": {
    "id": 5348,
    "name": "Supernatural",
    "permalink": "supernatural",
    "url": "http://www.episodate.com/tv-show/supernatural",
    "description": "Supernatural is an American fantasy horror television series created by Eric Kripke. It was first broadcast on September 13, 2005, on The WB and subsequently became part of successor The CW's lineup. Starring Jared Padalecki as Sam Winchester and Jensen Ackles as Dean Winchester, the series follows the two brothers as they hunt demons, ghosts, monsters, and other supernatural beings in the world. The series is produced by Warner Bros. Television, in association with Wonderland Sound and Vision. Along with Kripke, executive producers have been McG, Robert Singer, Phil Sgriccia, Sera Gamble, Jeremy Carver, John Shiban, Ben Edlund and Adam Glass. Former executive producer and director Kim Manners died of lung cancer during production of the fourth season.<br>The series is filmed in Vancouver, British Columbia and surrounding areas and was in development for nearly ten years, as creator Kripke spent several years unsuccessfully pitching it. The pilot was viewed by an estimated 5.69 million viewers, and the ratings of the first four episodes prompted The WB to pick up the series for a full season. Originally, Kripke planned the series for three seasons but later expanded it to five. The fifth season concluded the series' main storyline, and Kripke departed the series as showrunner. The series has continued on for several more seasons with Sera Gamble and Jeremy Carver assuming the role of showrunner.",
    "description_source": "http://en.wikipedia.org/wiki/Supernatural_(U.S._TV_series)#Spin-off_series",
    "start_date": "2005-09-13",
    "end_date": null,
    "country": "US",
    "status": "Running",
    "runtime": 60,
    "network": "The CW",
    "youtube_link": "6ZlnmAWL59I",
    "image_path": "https://static.episodate.com/images/tv-show/full/5348.jpg",
    "image_thumbnail_path": "https://static.episodate.com/images/tv-show/thumbnail/5348.jpg",
    "rating": "9.6747",
    "rating_count": "249",
    "countdown": null
}
}

在不同序列中 rating 的值是 Int （ rating：0）或 String （ rating： 9.6747）。

The value of rating in different serials is Int ("rating": 0) or String ("rating": "9.6747").

我正在使用可编码/可解码协议解析JSON：

I am parsing JSON with Codable/Decodable protocols:

struct DetailModel : Decodable {

var id : Int?
var name : String?
var permalink : String?
var url : String?
var description : String
var description_source : String?
var start_date : String?
var end_date : String?
var country : String?
var status : String?
var runtime : Int?
var network : String?
var youtube_link : String?
var image_path : String?
var image_thumbnail_path : String?
var rating: String
var rating_count : String?
var countdown : String?
var genres : [String]?
var pictures : [String]?
var episodes : [EpisodesModel]?
}

如果rating == String，则我的代码有效，并且我拥有所有变量JSON，但如果rating == Int，则全部为 nil 。我应该怎么解析所有类型的变量 rating 一次 Int 和 String ？

If rating == String, my code work and I have all the variables from JSON, but if rating == Int, all is nil. What should I do to parse all the types of variable rating at once Int and String?

我可解码的函数：

    func searchSerialDetail(id: Int, completion: @escaping (DetailModel?) -> Void){

    let parameters: [String: Any] = ["q": id]

    Alamofire.request(DetailNetworkLayer.url, method: .get, parameters: parameters).response { (jsonResponse) in

        if let jsonValue =  jsonResponse.data {
            let jsonDecoder = JSONDecoder()
                let detail = try? jsonDecoder.decode(DetailModel.self, from: jsonValue)
                completion(detail)
        }
    }
}

谢谢。

推荐答案

您将必须实现自己的 func encoding（转至编码器：Encoder）抛出和 init（来自解码器：Decoder）抛出都是 Codable 协议。然后将您的 rating 变量更改为枚举

You will have to implement your own func encode(to encoder: Encoder) throws and init(from decoder: Decoder) throws which are both properties of the Codable protocol. Then change your rating variable into an enum

看起来像这样：

enum Rating: Codable {
    case int(Int)
    case string(String)

    func encode(to encoder: Encoder) throws {
        var container = encoder.singleValueContainer()
        switch self {
        case .int(let v): try container.encode(v)
        case .string(let v): try container.encode(v)
        }
    }

    init(from decoder: Decoder) throws {
        let value = try decoder.singleValueContainer()

        if let v = try? value.decode(Int.self) {
            self = .int(v)
            return
        } else if let v = try? value.decode(String.self) {
            self = .string(v)
            return
        }

        throw Rating.ParseError.notRecognizedType(value)
    }

    enum ParseError: Error {
        case notRecognizedType(Any)
    }
}

然后在 DetailModel 上，只需将 rating：String 更改为 rating：评级

Then on your DetailModel just change rating: String to rating: Rating

此方法有效，我已经用这些JSON字符串进行了测试。

This works, I have tested with these JSON strings.

// int rating
{   
    "rating": 200,
    "bro": "Success"
}

// string rating
{
    "rating": "200",
    "bro": "Success"
}

编辑：我发现了一种更快的实现 init的方法（来自解码器：解码器）抛出，它会产生更好的错误消息，使用此方法，您现在可以省略 ParseError 枚举。

Edit: I've found a better swiftier way of implementing init(from decoder: Decoder) throws, which produces a better error message, by using this you can now omit the ParseError enum.

init(from decoder: Decoder) throws {
    let value = try decoder.singleValueContainer()
    do {
        self = .int(try value.decode(Int.self))
    } catch DecodingError.typeMismatch {
        self = .string(try value.decode(String.self))
    }
}

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