在 Swift 4 中解析 NiceHash JSON

Question

我正在开发一个应用程序来从 NiceHash api 中获得平衡。我必须使用的 JSON 如下所示：

{
   "result":{
      "stats":[
         {
            "balance":"0.00000124",
            "rejected_speed":"0",
            "algo":5,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00000163",
            "rejected_speed":"0",
            "algo":7,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00114271",
            "rejected_speed":"0",
            "algo":8,
            "accepted_speed":"0.0002237"
         },
         {
            "balance":"0.00009395",
            "rejected_speed":"0",
            "algo":14,
            "accepted_speed":"0"
         },
         {
            "balance":"0.0000097",
            "rejected_speed":"0",
            "algo":20,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00000004",
            "rejected_speed":"0",
            "algo":21,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00128791",
            "rejected_speed":"0",
            "algo":22,
            "accepted_speed":"0"
         },
         {
            "balance":"0.0000005",
            "rejected_speed":"0",
            "algo":23,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00310707",
            "rejected_speed":"0",
            "algo":24,
            "accepted_speed":"0.0000002"
         },
         {
            "balance":"0.00002411",
            "rejected_speed":"0",
            "algo":26,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00000007",
            "rejected_speed":"0",
            "algo":27,
            "accepted_speed":"0"
         },
         {
            "balance":"0.0000047",
            "rejected_speed":"0",
            "algo":28,
            "accepted_speed":"0"
         },
         {
            "balance":"0.00001291",
            "rejected_speed":"0",
            "algo":29,
            "accepted_speed":"0"
         }
      ],
      "payments":[

      ],
      "addr":"some_bitcoin_adress"
   },
   "method":"stats.provider"
}

我想对“余额”的所有值求和，但我不知道如何访问它。我现在的代码如下所示：

struct stats: Codable {
    let balance: String
    let rejected_speed: String
    let algo: String
    let accepted_speed: String
}
struct result: stats {
    let stats: stats
}

以及获取 JSON 的函数：

func updateBalance() {
    let sampleDataAdress = "nicehash_link_here"
    let url URL(string: sampleDataAdress)!
    let jsonSata = try! Data(contentsOf: url)
    let jsonDecoder = JSONDecoder()
    let data = try? jsonDecoder.decode(Array<stats>.self, from jsonData)
    data?.count
    dump(data?.first)
}

我希望我至少能获得第一个统计数据，但我却得到了零。这是我第一次在 Swift 4 中做 JSON，我猜这段代码就是垃圾。

Answer 1

有很多问题。

首先要避免混淆名称结构总是大写的。但是，您的 stats 结构包含的不仅仅是命名更多的混乱。 ?

查看 JSON 结构。有

• 一个 root 字典，其中包含一个关键字字典 result

  struct Root : Decodable {
      let result : Result
  }
  

• result 字典，其中包含键 stats 的数组

  struct Result: Decodable {
      let stats: [Stats]
  
      var sumOfBalances : Double {
          return stats.flatMap{ Double($0.balance) }.reduce(0.0, +)
      }
  }
  

• 统计数据数组

  struct Stats: Decodable {
  
      private enum CodingKeys : String, CodingKey {
          case balance, rejectedSpeed = "rejected_speed", algo, acceptedSpeed = "accepted_speed"
      }
  
      let balance: String
      let rejectedSpeed: String
      let algo: Int
      let acceptedSpeed: String
  }
  

key 的值也是Int（没有双引号），而不是String

现在解码对象并获取余额总和

do {
    let root = try jsonDecoder.decode(Root.self, from jsonData)
    print(root.result.sumOfBalances)
} catch {
    print(error)
}

注意：

永远不要从带有Data(contentsOf 的远程 URL 同步加载数据。如果发生错误，您将阻塞当前线程，并且应用程序将可靠地崩溃。使用像 URLSession / URLSessionDataTask 这样的异步 API 并添加适当的错误处理。