Bittrex API - Swift 中的 JSON 结构

Question

我正在尝试在我的示例 iOS 应用程序中调用 Bittrex api。

我正在尝试从这里读取 JSON。 https://bittrex.com/api/v1.1/public/getmarketsummaries

但我收到此错误：应解码 Array 但找到了字典。”，underlyingError: nil)

根据谷歌搜索结果，JSON Struct 不正确。

我可能在哪里犯了错误？

这是我的 JSON 结构；

struct MarketSummaries : Decodable{
    let success : Bool?
    let message : String?
    let result : [SummaryResult]?
}

struct SummaryResult : Decodable{
    let marketName : String?
    let high : Double?
    let low : Double?
    let volume : Double?
    let last : Double?
    let baseVolume : Double?
    let timeStamp : String?
    let bid : Double?
    let ask : Double?
    let openBuyOrders : Int?
    let openSellOrders : Int?
    let prevDay : Double?
    let created : String?

    private enum CodingKeys : String, CodingKey {
        case marketName = "MarketName", high = "High", low = "Low", volume = "Volume",
        last = "Last", baseVolume = "BaseVolume", timeStamp = "TimeStamp", bid = "Bid",
        ask = "Ask", openBuyOrders = "OpenBuyOrders", openSellOrders = "OpenSellOrders",
        prevDay = "PrevDay", created = "Created"
    }
}

这是我的 JSON 结构；

let url = URL(string: "https://bittrex.com/api/v1.1/public/getmarketsummaries")
let session = URLSession.shared
let task = session.dataTask(with: url!) { (data, response, error) in
    if error != nil {}
    else
    {
        if (data != nil)
        {
            do
            {
                let coins = try JSONDecoder().decode([MarketSummaries].self, from: data!)

                DispatchQueue.main.async {
                    self.market = coins
                    self.table.reloadData()
                }
            }
            catch
            {
                print(error)
            }
        }
    }
}
task.resume()

Answer 1

我发现了自己的错误。从 JSON 读取数据时，我像数组一样读取 MarketSummaries。但它不是一个数组。

坏线：

 let coins = try JSONDecoder().decode([MarketSummaries].self, from: data!)

修正线

 let coins = try JSONDecoder().decode(MarketSummaries.self, from: data!)

Answer 2

您可以使用这个 Result 类来检索您的 Json 数据...我认为这会对您有所帮助。

import foundation

public class Result {
public var marketName : String?
public var high : Double?
public var low : Double?
public var volume : Double?
public var last : Double?
public var baseVolume : Double?
public var timeStamp : String?
public var bid : Double?
public var ask : Double?
public var openBuyOrders : Int?
public var openSellOrders : Int?
public var prevDay : Double?
public var created : String?

/** Returns an array of models based on given dictionary.

Sample usage:
let result_list = Result.modelsFromDictionaryArray(someDictionaryArrayFromJSON)

- parameter array:  NSArray from JSON dictionary.

- returns: Array of Result Instances.
 */
public class func modelsFromDictionaryArray(array:NSArray) -> [Result]
{
    var models:[Result] = []
    for item in array
    {
        models.append(Result(dictionary: item as! NSDictionary)!)
    }
    return models
}

 /**
 Constructs the object based on the given dictionary.

Sample usage:
let result = Result(someDictionaryFromJSON)

- parameter dictionary:  NSDictionary from JSON.

- returns: Result Instance.
*/
  required public init?(dictionary: NSDictionary) {

    marketName = dictionary["MarketName"] as? String
    high = dictionary["High"] as? Double
    low = dictionary["Low"] as? Double
    volume = dictionary["Volume"] as? Double
    last = dictionary["Last"] as? Double
    baseVolume = dictionary["BaseVolume"] as? Double
    timeStamp = dictionary["TimeStamp"] as? String
    bid = dictionary["Bid"] as? Double
    ask = dictionary["Ask"] as? Double
    openBuyOrders = dictionary["OpenBuyOrders"] as? Int
    openSellOrders = dictionary["OpenSellOrders"] as? Int
    prevDay = dictionary["PrevDay"] as? Double
    created = dictionary["Created"] as? String
}


/**
Returns the dictionary representation for the current instance.

- returns: NSDictionary.
 */
   public func dictionaryRepresentation() -> NSDictionary {

    let dictionary = NSMutableDictionary()

    dictionary.setValue(self.marketName, forKey: "MarketName")
    dictionary.setValue(self.high, forKey: "High")
    dictionary.setValue(self.low, forKey: "Low")
    dictionary.setValue(self.volume, forKey: "Volume")
    dictionary.setValue(self.last, forKey: "Last")
    dictionary.setValue(self.baseVolume, forKey: "BaseVolume")
    dictionary.setValue(self.timeStamp, forKey: "TimeStamp")
    dictionary.setValue(self.bid, forKey: "Bid")
    dictionary.setValue(self.ask, forKey: "Ask")
    dictionary.setValue(self.openBuyOrders, forKey: "OpenBuyOrders")
    dictionary.setValue(self.openSellOrders, forKey: "OpenSellOrders")
    dictionary.setValue(self.prevDay, forKey: "PrevDay")
    dictionary.setValue(self.created, forKey: "Created")

    return dictionary
}

}