代码未进入数据任务的完成处理程序

Question

完成处理程序代码未得到执行。当我调试代码时，它的到来直到 session.datatask 并且之后它没有进入完成处理程序。我们实际上正在将这个项目从objectivec迁移到swift。我不确定生成的请求是否击中 django。如何进一步调试。在 datatask 之后，控件退出 if 请求循环，并且执行顺利，没有任何错误。但数据不是从数据库中获取的。

func makeRequest(_ url: String?, path: String?, httpMethod: String?, httpBody httpBoday: Data?, completion: @escaping (_ result: [AnyHashable : Any]?, _ error: Error?) -> Void) {
        let headers = [
            "cache-control": "no-cache",
            "Authorization": "Token f491fbe3ec54034d51e141e28aaee87d47bb7e74"
        ]
        var request: URLRequest? = nil
        if let url = URL(string: "\(url ?? "")\(path ?? "")") {
            request = URLRequest(url: url, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)
        }
        request?.httpMethod = httpMethod ?? ""
        request?.allHTTPHeaderFields = headers
        let configuration = URLSessionConfiguration.default
        configuration.httpCookieStorage = nil
        configuration.requestCachePolicy = NSURLRequest.CachePolicy.reloadIgnoringLocalAndRemoteCacheData
        if #available(iOS 11.0, *) {
            configuration.waitsForConnectivity = false
        }
        let session = URLSession(configuration: configuration)
        //        let session = URLSession.shared
        var task: URLSessionDataTask? = nil
        print ("Request =======>",request)
        if let request = request {
            task = session.dataTask(with: request , completionHandler: { data, response, error in
                            //.dataTask(with: request, completionHandler: { data, response, error in
               print ("testing******************")
                var result: Any? = nil
                if error != nil {
                    if let error = error {
                        print("\(error)")
                    }
                    if completion != nil {
                        completion(nil, error)
                    }
                } else
                {
                    var string: String? = nil
                    if let data = data {
                        string = String(data: data, encoding: .utf8)
                    }
                    string = self.string(byRemovingControlCharacters: string)

                    do {
                        if let data = string?.data(using: .utf8) {
                            result = try JSONSerialization.jsonObject(with: data, options: []) as!  [AnyHashable : Any]
                             print ("Result ===============>",result)
                        }
                    } catch {
                        print("Error while getting the data from json object")
                    }
                    DispatchQueue.main.async() {
                        if completion != nil {
                            completion(result as! [AnyHashable : Any], error)
                        }
                    }
                }
            })
        }
        else
        {
            print("Inside the else block of request")
        }
        task?.resume()
    }

Answer 1

这一行是你的问题：

if let url = URL(string: "\(url ?? "")\(path ?? "")") {
   request = URLRequest(url: url, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)
}

应该是这样的：

guard let urlString = url else { return }
guard let path = path else { return }
if let requestURL = URL(string: "\(urlString)\(path)" {
   request = URLRequest(url: requestURL, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)
}

另外，应该没什么区别，但你有 2 个不同的缓存策略。 此外，您没有在任何地方使用 httpBody。我想你的请求不需要它，但我想我会提醒你看看。