执行HTTP请求，然后执行HTTP请求

Question

我是iOS中处理连接的初学者。我想执行一个POST请求和一个对url的GET请求。问题是，我需要首先完成POST，以便能够在JSON中得到解析的访问令牌，该令牌稍后将放置在get请求的头中，这样我就可以检索所需的登录数据。我使用的是自定义委托方法，但是当我运行这个方法时，GET请求比POST执行得早，所以在完成get之前无法获得密钥。有什么方法可以先发帖子然后再发邮件吗？这是我的代码：

- (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

您不需要将这两种方法全部调用在一起。

[self httpPostWithCustomDelegate];
[self sendHTTPGet];

你同时提出两个请求。但是哪一种反应将是第一位的，你无法确定。因为您需要来自"POST“请求的数据才能发出"GET”请求。做这样的事：

-(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];
  }

这将确保当您发出"GET“请求时，您有"access_token”。希望这一切都能顺利。:)