테이블보기를 다시로드하기 전에 두 개의 서버 요청이 완료되었습니다.

Question

테이블보기를 다시로드하기 전에이 두 가지 요청을 완료해야합니다 (테이블보기는 두 가지 모두에 따라 결정됩니다).

아래처럼 시도했지만 작동하지 않습니다.

요청 하나는 모든 것을하기 전에 테이블 뷰를 다시로드가 내가 진행하는 방법을 요청 2.

DispatchQueue.global(qos: DispatchQoS.QoSClass.default).async { 
     //1. request 1: 
     self.serverRequestAuth("/request1") 
     //2. request 2: 
     self.serverRequestAuth("/request2") 
      DispatchQueue.main.async{ 
       //3. reload the table view 
       self.tableView.reloadData() 
      } 
    } 

에서 수행되고, 완료됩니다?

언급 : serverRequestAuth에는 서버 요청, json의 구문 분석, 그 안에있는 사전 구문 분석이 포함되어 있습니다.

방법의 serverRequestAuth :

func serverRequestAuth(_ requestName: String, control:@escaping (_ check : Bool)-> Void){ 
    let requestNameEscaped = requestName.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)! 


    var request = NSMutableURLRequest() 
    request = NSMutableURLRequest(url: URL(string: "\(self.view.getServerPath())\(requestNameEscaped)")!, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 5) 

    request.httpMethod = "GET" 
    request.setValue(self.view.getAuth(), forHTTPHeaderField: "Authorization") 
    request.setValue("application/json", forHTTPHeaderField: "Content-Type") 

    let task = URLSession.shared.dataTask(with: request as URLRequest) {data, response, err in 
     if data != nil { 
      if let dictionary = self.parseJSONData(data!) { 
       self.parseDictionary(dictionary, typeOfRequest: requestName) 
       control(true) 
      }else{ 

       control(false) 
      } 
     } 
    } 
    task.resume() 
} 

그리고 당신은 그것을 호출 할 수 있습니다 :

func serverRequestAuth(_ requestName: String){ 
    let requestNameEscaped = requestName.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)! 


    var request = NSMutableURLRequest() 
    request = NSMutableURLRequest(url: URL(string: "\(self.view.getServerPath())\(requestNameEscaped)")!, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 5) 

    request.httpMethod = "GET" 
    request.setValue(self.view.getAuth(), forHTTPHeaderField: "Authorization") 
    request.setValue("application/json", forHTTPHeaderField: "Content-Type") 

    let task = URLSession.shared.dataTask(with: request as URLRequest) {data, response, err in 
     if data != nil { 
      if let dictionary = self.parseJSONData(data!) { 
       self.parseDictionary(dictionary, typeOfRequest: requestName) 
      } 
     } 
    } 
    task.resume() 
} 

Answer 1

시도가 DispatchSemaphore를 사용하는

func serverRequestAuth(_ requestName: String){ 
    let requestNameEscaped = requestName.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)! 

    let semaphore = DispatchSemaphore(value: 0); 
    var request = NSMutableURLRequest() 
    request = NSMutableURLRequest(url: URL(string: "\(self.view.getServerPath())\(requestNameEscaped)")!, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 5) 

    request.httpMethod = "GET" 
    request.setValue(self.view.getAuth(), forHTTPHeaderField: "Authorization") 
    request.setValue("application/json", forHTTPHeaderField: "Content-Type") 

    let task = URLSession.shared.dataTask(with: request as URLRequest) {data, response, err in 
     if data != nil { 
      if let dictionary = self.parseJSONData(data!) { 
       self.parseDictionary(dictionary, typeOfRequest: requestName) 
       semaphore.signal(); 
      } 
     } 
    } 
    task.resume() 
    semaphore.wait(timeout: .distantFuture) 
} 

Answer 2

이 시도

serverRequestAuth("myStringRequest1", control: {(check)in 

     if check { 
      self.serverRequestAuth("myStringRequest2", control: {(check) in 

       if check { 

        self.tableView.reloadData() 

       }else{ 

        print("error Request 2") 
       } 
      }) 


     }else { 

      print("error request 1") 

     } 
    }) 

Answer 3

한때 비슷한 문제가있었습니다. 간단한 솔루션을 제공하기 위해 나는이 작은 도서관을 썼다 :

당신은 그룹 작업에 요청을 할 수 있고 완료 후 테이블을 다시로드하는 모든 요청을 기다리는

https://github.com/prine/ROConcurrency

.

var taskRequest1 = TaskComplex { (finished) ->() in 
    self.serverRequestAuth("/request1", finished) 
} 

var taskRequest2 = TaskComplex { (finished) ->() in 
    self.serverRequestAuth("/request2", finished) 
} 

var reloadTable = TaskComplex { (finished) ->() in 
    DispatchQueue.main.async{ 
     // 3. reload the table view 
     self.tableView.reloadData() 
     finished() 
    } 
} 

var barrierComplex = BarrierComplex(tasks: [taskRequest1, taskRequest2], afterTask: reloadTable) 
barrierComplex.startTasks() 

귀하의 serverRequestAuth 방법은 비동기 완료되면 말할 필요가있다, 그래서 당신은 완성 된 콜백 추가해야합니다 언급과 함께, 이것은 나를 위해 일한 사람이었다,

func serverRequestAuth(_ requestName: String, _ finished:(Bool) ->()) { 
    let requestNameEscaped = requestName.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)! 


    var request = NSMutableURLRequest() 
    request = NSMutableURLRequest(url: URL(string: "\(self.view.getServerPath())\(requestNameEscaped)")!, cachePolicy: NSURLRequest.CachePolicy.reloadIgnoringLocalCacheData, timeoutInterval: 5) 

    request.httpMethod = "GET" 
    request.setValue(self.view.getAuth(), forHTTPHeaderField: "Authorization") 
    request.setValue("application/json", forHTTPHeaderField: "Content-Type") 

    let task = URLSession.shared.dataTask(with: request as URLRequest) {data, response, err in 
     if data != nil { 
      if let dictionary = self.parseJSONData(data!) { 
       self.parseDictionary(dictionary, typeOfRequest: requestName) 

       // Here you call finished to tell the Barrier that its finished 
       finished() 
      } 
     } 
    } 
    task.resume() 
}