Xcode - 当搜索大小大于 14 时 API 失败

Question

从 iTunes API https://itunes.apple.com/search?term=\(search)&entity=software&limit=14 获取数据时，如果限制为较大的数字（例如 30、40、50 等），则获取失败。该限制由 URL 末尾的limit=14 表示。 14 是返回的结果数。这可以更改为任何数字。

在 Postman 中拨打电话时，我可以输入任何数字的限制，它可以正常工作。此外，在 XCtest 中运行大量 api 时，测试通过。似乎只有在应用中进行通话时才会失败。

失败发生在guard let 语句中。在下面的代码中，如果数字太大（例如 50），它会打印“failed to fetch data”——表明存在 URL 问题。当使用较小的数字（例如 10）时，获取成功并且数据在我的表视图中返回。您还可以更改搜索词。目前我将其设置为“Apple”。

以下是 API 的代码：

 import Foundation
import UIKit

struct Response: Codable {
  var resultCount: Int
  var results: [Result]
}

struct Result: Codable {
  var screenshotUrls, ipadScreenshotUrls, appletvScreenshotUrls: [String]
  var artworkUrl60, artworkUrl512, artworkUrl100, artistViewUrl: String
  var supportedDevices, advisories: [String]
  var isGameCenterEnabled: Bool
  var features: [String]
  var kind, minimumOsVersion, trackCensoredName, fileSizeBytes: String
  var contentAdvisoryRating: String
  var genreIds: [String]
  var primaryGenreName, artistName, trackContentRating, trackName, releaseDate, sellerName, currentVersionReleaseDate, releaseNotes, version: String
  var primaryGenreId: Int
  var currency, description: String
  var price: Double
  var averageUserRating: Double
}

    class API {
  var storedData = Response(resultCount: Int.init(), results: [])
  func loadData(search: String, completionHandler: @escaping (Response) -> Void) {
    guard let url = URL(string:"https://itunes.apple.com/search?term=\(search)&entity=software&limit=40") else {
      print("failed to fetch data")
      return
    }
    let request = URLRequest(url: url)
    URLSession.shared.dataTask(with: request) { data, response, error in
      if let data = data {
        if let response = try? JSONDecoder().decode(Response.self, from: data) {
          DispatchQueue.main.async {
            self.storedData.resultCount = response.resultCount
            self.storedData.results = response.results
            completionHandler(self.storedData)
          }
          return
        }
      }
      print("failed \(error?.localizedDescription ?? "unknown error")")
    }
    .resume()
  }
  func reloadTableData() {
    DataManager.shared.viewController.tableView.reloadData()
  }
}

对于为什么较大的数字会导致在运行应用程序时让守卫失败，但在我的测试或邮递员中没有失败的任何想法？

编辑

以下是我如何调用该函数。我在 viewdidload 中调用它。它使用完成处理程序，因此如下所示：

api.loadData(search: "ibm") { Results in
  self.filteredResults = self.api.storedData.results //stores value in filtered results array
  
  self.tableView.reloadData() //refreshes table view - table view is referencing the filteredResults array
}

Answer 1

当您设置的限制超过 20 个时，JSON 中缺少许多键：

• 解码 JSON 时始终使用 doCatch 并打印 error，它会告诉您出了什么问题，由于以下错误，您的源解码失败：refer

    keyNotFound(CodingKeys(stringValue: "releaseNotes", intValue: nil), Swift.DecodingError.Context(codingPath: [CodingKeys(stringValue: "results", intValue: nil), _JSONKey(stringValue: "Index 15", intValue: 15)], debugDescription: "No value associated with key CodingKeys(stringValue: \"releaseNotes\", intValue: nil) (\"releaseNotes\").", underlyingError: nil))

• 现在尝试在结构体Optional 中设置所有变量来修复解码问题。

---

使属性可选

struct Response: Codable {
  var resultCount: Int?
  var results: [Result]?
}

struct Result: Codable {
  var screenshotUrls, ipadScreenshotUrls, appletvScreenshotUrls: [String]?
  var artworkUrl60, artworkUrl512, artworkUrl100, artistViewUrl: String?
  var supportedDevices, advisories: [String]?
  var isGameCenterEnabled: Bool?
  var features: [String]?
  var kind, minimumOsVersion, trackCensoredName, fileSizeBytes: String?
  var contentAdvisoryRating: String?
  var genreIds: [String]?
  var primaryGenreName, artistName, trackContentRating, trackName, releaseDate, sellerName, currentVersionReleaseDate, releaseNotes, version: String?
  var primaryGenreId: Int?
  var currency, description: String?
  var price: Double?
  var averageUserRating: Double?
}

把这个放在if-let数据块里面：

        do {
            let response =  try JSONDecoder().decode(Response.self, from: data)
            DispatchQueue.main.async {
                self.storedData.resultCount = response.resultCount
                self.storedData.results = response.results
                completionHandler(self.storedData)
            }
            
        } catch let error {
            print(error)
        }