執行HTTP POST請求，然後執行HTTP GET請求

Question

我是初學者，處理iOS中的連接。我想對一個url執行一個POST請求和一個GET請求。問題是我需要首先執行POST，這樣我才能獲得以JSON解析的訪問標記，稍後將放置在GET請求的標題中，以便檢索我需要的登錄數據。我正在使用自定義委託方法，但是當我運行此操作時，GET請求比POST執行得早，所以在GET完成之前我無法獲得密鑰。有沒有辦法先執行POST，然後執行GET？這裏是我的代碼：

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 
// Do any additional setup after loading the view. 

//params 
self.user = @"carlos"; 
self.pass = @"1234"; 
self.grantType = @"password"; 
self.clientId = @"7da713e69afc96cf894e"; 
self.clientSecret = @"2c14ec54cfdfd6faec4ef56ca7f0870ab83f820b"; 

// Set the side bar button action. When it's tapped, it'll show up the sidebar. 
self.sideBarButton.target = self.revealViewController; 

self.sideBarButton.action = @selector(revealToggle:); 

// Set the gesture 
[self.view addGestureRecognizer:self.revealViewController.panGestureRecognizer]; 

[self httpPostWithCustomDelegate]; 

[self sendHTTPGet]; 

} 


-(void) httpPostWithCustomDelegate 
{ 
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration]; 
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: nil delegateQueue: [NSOperationQueue mainQueue]]; 

NSURL * url = [NSURL URLWithString:@"http://192.237.241.175:8090/oauth2/access_token/"]; 
NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:url]; 
NSString * params =[NSString stringWithFormat:@"&username=%@&password=%@&grant_type=%@&client_id=%@&client_secret=%@&scope=write",self.user,self.pass,self.grantType,self.clientId,self.clientSecret]; 
[urlRequest setHTTPMethod:@"POST"]; 
[urlRequest setHTTPBody:[params dataUsingEncoding:NSUTF8StringEncoding]]; 

NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest 
                completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { 
                 NSLog(@"Retrieving Data"); 
                 // NSLog(@"Response:%@ %@\n", response, error); 
                 if(error == nil) 
                 { 
                  //Test Display 
                  //                NSString * text = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding]; 
                  //                NSLog(@"Data = %@",text); 

                  self.responseDataPost = [[NSMutableData alloc] init]; 
                  [self.responseDataPost appendData:data]; 

                  NSError *error; 

                  NSMutableDictionary *receivedData = [NSJSONSerialization JSONObjectWithData:self.responseDataPost options:NSJSONReadingMutableContainers error:&error]; 

                  //obtener del dictionary el access token y meter como header Authorization Bearer + id 

                  //NSArray *accessToken = [receivedData valueForKeyPath:@"access_token"]; 

                  self.connTxtPost.text = [receivedData valueForKeyPath:@"access_token"]; 
                  self.recData = [receivedData valueForKeyPath:@"access_token"]; 

                 } 

                }]; 
[dataTask resume]; 

} 

-(void) sendHTTPGet 
{ 
NSURLSessionConfiguration *defaultConfigObject = [NSURLSessionConfiguration defaultSessionConfiguration]; 
NSURLSession *defaultSession = [NSURLSession sessionWithConfiguration: defaultConfigObject delegate: self delegateQueue: [NSOperationQueue mainQueue]]; 

NSURL * url = [NSURL URLWithString:@"http://192.237.241.175:8090/snippets/"]; 

NSMutableURLRequest * urlRequest = [NSMutableURLRequest requestWithURL:url]; 

[urlRequest setHTTPMethod:@"GET"]; 
self.connTxtGet.text = self.recData ; 

[urlRequest setValue:self.recData forHTTPHeaderField:@"Authorization"]; 


NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest 
                completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { 
                 //NSLog(@"Response:%@ %@\n", response, error); 
                 if(error == nil) 
                 { 
                  NSString * text = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding]; 
                  NSLog(@"Data = %@",text); 

                 } 

                }]; 

[dataTask resume]; 

} 

Answer 1

你不需要一起調用這兩種方法。

[self httpPostWithCustomDelegate]; 
[self sendHTTPGet]; 

您正在同時提出兩個請求。但是，首先得出哪種答案，你無法確定。因爲您需要「POST」請求中的數據來發出「GET」請求。做這樣的事情：

-(void) httpPostWithCustomDelegate{ 
    ............. 
    NSURLSessionDataTask * dataTask =[defaultSession dataTaskWithRequest:urlRequest 
               completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { 
                 ................... 
                 ................... 
                 self.connTxtPost.text = [receivedData valueForKeyPath:@"access_token"]; 
                 self.recData = [receivedData valueForKeyPath:@"access_token"]; 
                 [self sendHTTPGet]; 
                } 

               }]; 
    [dataTask resume]; 
    } 

這將確保當你讓「GET」請求你有「access_token」。希望這會工作得很好。 :)