Swift 2 JSON Appel peut lancer, mais il n'est pas marqué avec 'try' et l'erreur n'est pas traitée

Question

J'ai une fonction appelée recognDropoff et cela a bien fonctionné avec Swift 1.2 dans Xcode 6.4. Cependant, maintenant j'utilise Xcode 7.1 avec Swift 2 et j'obtiens cette erreur: Call can throw, but it is not marked with 'try' and the error is not handled

func recognizeDropoff() { 
     let currentUsername = PFUser.currentUser()!.username 

     let url = NSURL(string: "http://test.informatica-corlaer.nl/dropoffRecognizer.php?user=\(currentUsername!)&unique=3456364567") 
     let request = NSMutableURLRequest(URL: url!) 

     let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { 
      data, response, error in 

      if data == nil { 
       print("request failed \(error)") 
       return 
      } 

      let parseError: NSError? 

      if let json = NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String] { 

       let dropoffIndicator = json["dropoffIndicator"] 

       if (dropoffIndicator == "TRUE") { 
        dispatch_async(dispatch_get_main_queue()){ 
         let Storyboard = UIStoryboard(name: "Main", bundle: nil) 
         let MainVC : UIViewController = Storyboard.instantiateViewControllerWithIdentifier("dropoffSuccess") 

         self.presentViewController(MainVC, animated: true, completion: nil) 

        } 
       } 

      } else { 
       print("parsing error: \(parseError)") 
       let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding) 
       print("raw response: \(responseString)") 
      } 
     } 
     task.resume() 
    } 

Le problème est dans la ligne if let json = NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String]. Cependant, je suis assez confus parce que je viens de faire fonctionner mon code avec Swift 1.2. Je ne peux vraiment pas comprendre comment résoudre ce problème. Que devrais-je changer?

J'ai essayé toutes les autres solutions à partir d'autres questions similaires, mais je n'arrive tout simplement pas à le faire fonctionner. J'ai essayé de faire une combinaison do-catch, mais cela m'a seulement donné plus d'erreurs.

EDIT: Nouveau code que je ne peux pas comprendre

@IBAction func editingCodeChanged(sender: AnyObject) { 
     checkMaxLength(sender as! UITextField, maxLength: 4) 

     let currentUsername = PFUser.currentUser()!.username 

     if ((UnlockCodeField.text!).characters.count == 4) { 
      let url = NSURL(string: "http://test.informatica-corlaer.nl/unlockCodeTransmitter.php?user=\(currentUsername!)&unique=5782338593203") 
      let request = NSMutableURLRequest(URL: url!) 

      // modify the request as necessary, if necessary 

      let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { 
       data, response, error in 

       if data == nil { 
        print("request failed \(error)") 
        return 
       } 

       let parseError: NSError? 
       if let json = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String] { 

        let databaseUnlockCode = json["unlockCode"] 

        let enteredUnlockCode = self.UnlockCodeField.text! 

        if (databaseUnlockCode == enteredUnlockCode) { 
         dispatch_async(dispatch_get_main_queue()){ 
          let Storyboard = UIStoryboard(name: "Main", bundle: nil) 
          let MainVC : UIViewController = Storyboard.instantiateViewControllerWithIdentifier("VehiclePurchaseStatus") 

          self.presentViewController(MainVC, animated: true, completion: nil) 

          let myUrl = NSURL(string: "http://test.informatica-corlaer.nl/VEPunlockExecuter.php?user=\(currentUsername!)&unique=8648604386910"); 
          let request = NSMutableURLRequest(URL:myUrl!); 
          request.HTTPMethod = "POST"; 

          NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) 
           { 
            (response, data, error) in 
            print(response) 

          } 

         } 
        } else { 
         dispatch_async(dispatch_get_main_queue()){ 

          let alert = UIAlertView() 
          alert.title = "Whoops!" 
          alert.message = "You entered the wrong code. Please enter the code displayed on the VEP screen." 
          alert.addButtonWithTitle("OK") 
          alert.show() 

         } 
        } 

       } else { 
        print("parsing error: \(parseError)") 
        let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding) 
        print("raw response: \(responseString)") 
       } 
      } 
      task.resume() 

     } 
    } 

Answer 1

Essayez de remplacer

if let json = NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String] { 
    let dropoffIndicator = json["dropoffIndicator"] 

    if (dropoffIndicator == "TRUE") { 
     dispatch_async(dispatch_get_main_queue()){ 
      let Storyboard = UIStoryboard(name: "Main", bundle: nil) 
      let MainVC : UIViewController = Storyboard.instantiateViewControllerWithIdentifier("dropoffSuccess") 

      self.presentViewController(MainVC, animated: true, completion: nil) 

      } 
     } 
    } else { 
     print("parsing error: \(parseError)") 
     let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding) 
     print("raw response: \(responseString)") 
    } 
} 

à

do { 
    if let json = try NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String] { 
     let dropoffIndicator = json["dropoffIndicator"] 

     if (dropoffIndicator == "TRUE") { 
      dispatch_async(dispatch_get_main_queue()){ 
       let Storyboard = UIStoryboard(name: "Main", bundle: nil) 
       let MainVC : UIViewController = Storyboard.instantiateViewControllerWithIdentifier("dropoffSuccess") 

       self.presentViewController(MainVC, animated: true, completion: nil) 

       } 
      } 
     } else { 
      print("parsing error: \(parseError)") 
      let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding) 
      print("raw response: \(responseString)") 
     } 
    } 
} catch (_) { 
    print("...") 
} 

UPD: complet Code:

func recognizeDropoff() { 
    let currentUsername = PFUser.currentUser()!.username 

    let url = NSURL(string: "http://test.informatica-corlaer.nl/dropoffRecognizer.php?user=\(currentUsername!)&unique=3456364567") 
    let request = NSMutableURLRequest(URL: url!) 

    let task = NSURLSession.sharedSession().dataTaskWithRequest(request) { 
     data, response, error in 

     if data == nil { 
      print("request failed \(error)") 
      return 
     } 

     var parseError: NSError? 

     do { 
      if let json = NSJSONSerialization.JSONObjectWithData(data!, options: []) as? [String: String] { 

       let dropoffIndicator = json["dropoffIndicator"] 

       if (dropoffIndicator == "TRUE") { 
        dispatch_async(dispatch_get_main_queue()){ 
         let Storyboard = UIStoryboard(name: "Main", bundle: nil) 
         let MainVC : UIViewController = Storyboard.instantiateViewControllerWithIdentifier("dropoffSuccess") 

         self.presentViewController(MainVC, animated: true, completion: nil) 

        } 
       } 

      } else { 
       print("parsing error: \(parseError)") 
       let responseString = NSString(data: data!, encoding: NSUTF8StringEncoding) 
       print("raw response: \(responseString)") 
      } 
     } catch { 
      print("...") 
     } 
    } 
    task.resume() 
} 

Answer 2

let j = try? NSJSONSerialization.JSONObjectWithData(data!, options: []) 
if let json = j as? [String: String] { 
    // all your original code 
}