Coinbase API解析到Swift App返回不正确的格式

Question

我正在使用coinmarketcap api来获取硬币价格，使用下面的代码。数据模型Coin也在下面的代码和JSON响应之后给出。我得到一个错误：“数据无法读取，因为它的格式不正确。”正确的格式应该是什么样子的？

“”“

import Foundation
import SwiftUI
import Alamofire

class CryptoViewModel: ObservableObject {
    
    func fetchData() {
        let headers: HTTPHeaders = [
            "Accepts": "application/json",
              "X-CMC_PRO_API_KEY": "5dd693fc-6446-44c4-8aaa-75b1bfa4376f"
        ]
        
        AF.request("https://pro-api.coinmarketcap.com/v1/cryptocurrency/listings/latest", headers: headers).response { response in
            guard let data = response.data else { return }
            
            do {
                let coins = try JSONDecoder().decode([Coin].self, from: data)
                print(coins)
            }
            catch {
                print(error.localizedDescription)
            }
            
        }
        
    }
    
}

“”“

“”“

import SwiftUI

struct Coin: Decodable {
    
    var slug: String?
    var symbol: String?
    
    enum CodingKeys: String, CodingKey {
        case slug = "slug"
        case symbol = "symbol"
    }
}

“”“

“”“

success({
    data =     (
                {
            "circulating_supply" = 18697137;
            "cmc_rank" = 1;
            "date_added" = "2013-04-28T00:00:00.000Z";
            id = 1;
            "last_updated" = "2021-05-02T14:22:02.000Z";
            "max_supply" = 21000000;
            name = Bitcoin;
            "num_market_pairs" = 9549;
            platform = "<null>";
            quote =             {
                USD =                 {
                    "last_updated" = "2021-05-02T14:22:02.000Z";
                    "market_cap" = "1063000586851.752";
                    "percent_change_1h" = "0.09591311";
                    "percent_change_24h" = "-1.05109813";
                    "percent_change_30d" = "-4.45794679";
                    "percent_change_60d" = "11.80459387";
                    "percent_change_7d" = "14.06195861";
                    "percent_change_90d" = "69.54985569999999";
                    price = "56853.65555441735";
                    "volume_24h" = "40969975368.50657";
                };
            };
            slug = bitcoin;
            symbol = BTC;
            tags =             (
                mineable,
                pow,
                "sha-256",
                "store-of-value",
                "state-channels",
                "coinbase-ventures-portfolio",
                "three-arrows-capital-portfolio",
                "polychain-capital-portfolio",
                "binance-labs-portfolio",
                "arrington-xrp-capital",
                "blockchain-capital-portfolio",
                "boostvc-portfolio",
                "cms-holdings-portfolio",
                "dcg-portfolio",
                "dragonfly-capital-portfolio",
                "electric-capital-portfolio",
                "fabric-ventures-portfolio",
                "framework-ventures",
                "galaxy-digital-portfolio",
                "huobi-capital",
                "alameda-research-portfolio",
                "a16z-portfolio",
                "1confirmation-portfolio",
                "winklevoss-capital",
                "usv-portfolio",
                "placeholder-ventures-portfolio",
                "pantera-capital-portfolio",
                "multicoin-capital-portfolio",
                "paradigm-xzy-screener"
            );
            "total_supply" = 18697137;
        }, ...

“”“

Answer 1

首先，我认为您可能希望删除示例中的API密钥并重置它。

关于你的问题。您的响应以data属性开始。为了解析它，你也需要从那里开始你的struct。

所以像这样的东西应该是可行的；

struct Coins: Decodable {
    let data: [Coin]

    struct Coin: Decodable {
        let symbol: String
        let slug: String
        let quote: [String: Quote]
    }

    struct Quote: Decodable {
        let price: Double
    }
}

我嵌套了结构以保留名称空间。每件事都是非常相关的。如果你需要单独访问它们中的一个，你可以把它们拉出来。

此外，您可以省略CodingKeys，因为该键与您的变量名相同。此外，我认为你不需要选项，但我对API并不完全熟悉。

此外，我认为你只能得到一组数据，而不是一组硬币。因此，我将在这里执行以下操作；

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

Answer 2

您将整个响应解析为coins数组，但是您感兴趣的实际数据位于data key下，因此您需要添加一个附加层

struct Coins: Decodable {
    let coins: [Coin]
}

并解码它，而不是Coin

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