使用KeyedDecodingContainer用随机密钥解码对象

问题描述

我有一个要解码的对象数组

I have an array of objects that looks like this that I want to decode

let accountPending = """
{
    "blocks": {
        "F143CCC051927EEF59EEA78D16D80F855052BBF159EA6602843904C9445": {
            "amount": "10000000000000000000000000000000",
            "source": "6xswkroybxydyzaxybb1h531sx34omiu7an9t9jy19f9mca7a36s7by5e"
        },
    }
}
""".data(using: .utf8)!

所以我正在尝试以下方法

So I'm trying something along these lines

struct PendingBlock: Decodable {

let work: [String: PendingBlockData]

enum CodingKeys: String, CodingKey {
    case work = "???"
}

init(from decoder: Decoder) throws {
    let container = try decoder.container(keyedBy: CodingKeys.self)

    self.work = try container.decode(Dictionary.self, forKey: .work)
}

struct PendingBlockData: Decodable {
    let amount: String
    let source: String
}

显然，这是行不通的，因为 work 不是真正的价值。一位朋友建议使用 KeyedDecodingContainer 来获取密钥，但不确定从何处开始。希望在这里有所帮助。

Obviously this isn't going to work, since the string case for work isn't a real value. A friend recommended using KeyedDecodingContainer to get the keys but wasn't sure where to start with that. Would love some help here.

谢谢！

推荐答案

需要将字典值结构定义为可解码的，并使用String作为字典的键：

You just need to pass the define the dictionary value struct as decodable and use a String as the key for your dictionaries:

let json = """
{
  "blocks": {
    "F143CCC051927EEF59EEA78D16D80F855052BBF159EA6602843904C9445": {
      "amount": "10000000000000000000000000000000",
      "source": "6xswkroybxydyzaxybb1h531sx34omiu7an9t9jy19f9mca7a36s7by5e"
    }
  }
}
"""
let data = Data(json.utf8)

---

---

struct Root: Decodable {
    let blocks: [String:Block]
}
struct Block: Decodable {
    let amount: String
    let source: String
}

---

---

do {
    let blocks = try JSONDecoder().decode(Root.self, from: data).blocks
    for (key, value) in blocks {
        print(key, value)   // "F143CCC051927EEF59EEA78D16D80F855052BBF159EA6602843904C9445 Block(amount: "10000000000000000000000000000000", source: "6xswkroybxydyzaxybb1h531sx34omiu7an9t9jy19f9mca7a36s7by5e")\n"
    }
} catch {
    print(error)
}

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