swift - 为什么我的Weather Underground数据不能在Swift 3中打印？

我在打印地下气象数据时遇到问题。我的代码可以和其他数据源一起工作，只是不能在地下工作。我甚至尝试用实际数据替换URL（即https://api.wunderground.com/api/APIKEY/forecast/geolookup/forecast/q/94129.json”），但它不会打印。
有什么建议吗？

import Foundation
import UIKit

class APIManager {
    func weatherJSON(zip: String, completion: @escaping ([Weather]) -> Void) {
        let baseUrlString = "https://api.wunderground.com/api/APIKEY/forecast/geolookup/forecast/q/\(zip).json"

        guard let url = URL(string: baseUrlString) else { return }

        let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
            guard error == nil, let data = data else { return }

            do {
                guard let json = try JSONSerialization.jsonObject(with: data, options: []) as? [[String: Any]] else { return }

                // MARK: Print JSON
                print(json)

                var weatherList = [Weather]()
                for item in json {
                    if let weather = Weather.create(from: item) {
                        weatherList.append(weather)
                    }
                }
                completion(weatherList)
            } catch {
                print("Uh oh. You have an error with \(zip)!")
            }
        }
        task.resume()
    }
}

编辑：已解决
我使用了下面的代码，现在看到了错误。

最佳答案

我建议更改此项以报告错误：

enum WeatherError Error {
    case badURL
    case invalidJSON
}

func weatherJSON(zip: String, completion: @escaping ([Weather]?, Error?) -> Void) {
    let baseUrlString = "https://api.wunderground.com/api/APIKEY/forecast/geolookup/forecast/q/\(zip).json"

    guard let url = URL(string: baseUrlString) else {
        completion(nil, WeatherError.badURL)
        return
    }

    let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
        guard error == nil, let data = data else {
            completion(nil, error)
            return
        }

        do {
            guard let json = try JSONSerialization.jsonObject(with: data, options: []) as? [[String: Any]] else {
                completion(nil, WeatherError.invalidJSON)
                return
            }

            // MARK: Print JSON
            print(json)

            var weatherList = [Weather]()
            for item in json {
                if let weather = Weather.create(from: item) {
                    weatherList.append(weather)
                }
            }
            completion(weatherList, nil)
        } catch let parseError {
            print("Uh oh. You have an error with \(zip)!")
            if let responseString = String(data: data, encoding: .utf8) {
                print("responseString = \(responseString)")
            }
            completion(nil, parseError)
        }
    }
    task.resume()
}

然后，当你调用它时，你可以看到错误是什么

weatherJSON(zip: something) { weatherReports, error in
    guard let weatherReports = weatherReports, error == nil else {
        print(error)
        return
    }

    // use weatherReports here
}

这不会解决你的问题，但它会帮助你诊断出问题所在。