使用Swift处理递增的JSON名称 [英] Handling incrementing JSON name using Swift

问题描述

我有一个名称递增的JSON对象以进行解析，我想将输出存储到具有名称字段和pet字段列表的对象中。我通常使用JSONDecoder，因为它非常方便且易于使用，但是我不想对CodingKey进行硬编码，因为我认为这是非常不好的做法。

I have a JSON object with incrementing names to parse and I want to store the output into an object with a name field and a list of pet field. I normally use JSONDecoder as its pretty handy and easy to use, but I don't want to hard-code the CodingKey as I think it is very bad practice.

输入：

{"shopName":"KindHeartVet", "pet1":"dog","pet2":"hamster","pet3":"cat",  ...... "pet20":"dragon"}

我要存储结果的对象如下所示。

The object that I want to store the result in is something like the following.

class VetShop: NSObject, Decodable {
var shopName: String?
var petList: [String]?

private enum VetKey: String, CodingKey {
    case shopName
    case petList
}

required init(from decoder: Decoder) throws {
    let container = try decoder.container(keyedBy: VetKey.self)
    shopName = try? container.decode(String.self, forKey: .shopName)

    // implement storing of petList here.
}

}

我一直在苦苦挣扎的是，因为CodingKey是枚举，它是一个let常量，所以我不能修改（也不应该修改）常量，但是我需要将petList映射到 petN字段，

What I'm struggling a lot on is, as CodingKey is enum, its a let constants, so I can't modify (and shouldn't modify) a constant, but I need to map the petList to the "petN" field, where N is the incrementing number.

编辑：

我绝对不能改变API响应结构，因为它是一个公共API，而不是我开发的东西，我只是想解析并从此API获取值，希望这能消除混乱！

I definitely cannot change the API response structure because it is a public API, not something I developed, I'm just trying to parse and get the value from this API, hope this clear the confusion!

推荐答案

Codable 具有动态密钥的规定。如果您绝对无法更改获取的JSON的结构，则可以为它实现一个解码器，如下所示：

Codable has provisions for dynamic keys. If you absolutely can't change the structure of the JSON you're getting, you could implement a decoder for it like this:

struct VetShop: Decodable {
    let shopName: String
    let pets: [String]

    struct VetKeys: CodingKey {
        var stringValue: String
        var intValue: Int?
        init?(stringValue: String) {
            self.stringValue = stringValue
        }
        init?(intValue: Int) {
            self.stringValue = "\(intValue)";
            self.intValue = intValue
        }
    }

    init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: VetKeys.self)
        var pets = [String]()
        var shopName = ""
        for key in container.allKeys {
            let str = try container.decode(String.self, forKey: key)
            if key.stringValue.hasPrefix("pet") {
                pets.append(str)
            } else {
                shopName = str
            }
        }
        self.shopName = shopName
        self.pets = pets
    }
}

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