时间戳

首页 > 解决方案 > 如何进行正确的 API 调用？

swift - 如何进行正确的 API 调用？

问题描述

我正在尝试通过调用 API 来访问 fixer.io。这是我第一次尝试这样做，但我没有得到想要的结果。我想从此 JSON 文件中获取“速率”和“结果”。

{
    "success": true,
    "query": {
        "from": "GBP",
        "to": "JPY",
        "amount": 25
    },
    "info": {
        "timestamp": 1519328414,
        "rate": 148.972231
    },
    "historical": ""
    "date": "2018-02-22"
    "result": 3724.305775
}

我实现的方法就是这个，但是在调用这个 API 时我不知道如何检索“rate”和“result”。

extension APIsRuler {
  func getExchangeRate(from: String, to: String, amount: String, callback: @escaping (Bool, ConversionResult?) -> Void) {
    var request = URLRequest(url: APIsRuler.exchangeURL)
    let body = "convert?access_key=\(APIsRuler.exchangeAPI)&from=\(from)&to=\(to)&amount=\(amount)"
    request.httpMethod = "GET"
    request.httpBody = body.data(using: .utf8)
    let session = URLSession(configuration: .default)

    task?.cancel()
    task = session.dataTask(with: request) { (data, response, error) in
      DispatchQueue.main.async {
        guard let data = data, error == nil else {
          return callback(false, nil)
        }
        guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
          return callback(false, nil)
        }
        guard let responseJSON = try? JSONDecoder().decode([String: Double].self, from: data),
          let rate = responseJSON["rate"],
          let result = responseJSON["result"] else {
            return callback(false, nil)
        }
        let conversionResult = ConversionResult(exchangeRate: rate, exchangeResult: result)
        callback(true, conversionResult)
      }
    }
    task?.resume()
  }
}

标签： swift

解决方案

使用真实的模型对象，如下所示：

struct Conversion: Codable {
    let success: Bool
    let query: Query
    let info: Info
    let historical, date: String
    let result: Double
}

struct Info: Codable {
    let timestamp: Int
    let rate: Double
}

struct Query: Codable {
    let from, to: String
    let amount: Int
}

并使用以下方法解析您的响应JSONDecoder：

do {
  let conversion = try JSONDecoder().decode(Conversion.self, from: data)
  let rate = conversion.info.rate
  let result = conversion.result
} catch { print(error) }

推荐阅读