Ios 错误的连接顺序

我有一个NSURLConnection（其中两个），它们以错误的顺序运行。
以下是我的方法：

- (void)loginToMistarWithPin:(NSString *)pin password:(NSString *)password {

    NSURL *url = [NSURL URLWithString:@"https://mistar.oakland.k12.mi.us/novi/StudentPortal/Home/Login"];

    //Create and send request
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];

    [request setHTTPMethod:@"POST"];

    NSString *postString = [NSString stringWithFormat:@"Pin=%@&Password=%@",
                            [self percentEscapeString:pin],
                            [self percentEscapeString:password]];
    NSData * postBody = [postString dataUsingEncoding:NSUTF8StringEncoding];
    [request setHTTPBody:postBody];

    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
     {
         // do whatever with the data...and errors
         if ([data length] > 0 && error == nil) {
             NSError *parseError;
             NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
             if (responseJSON) {
                 // the response was JSON and we successfully decoded it

                 NSLog(@"Response was = %@", responseJSON);
             } else {
                 // the response was not JSON, so let's see what it was so we can diagnose the issue

                 NSString *loggedInPage = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                 NSLog(@"Response was not JSON (from login), it was = %@", loggedInPage);
             }
         }
         else {
             NSLog(@"error: %@", error);
         }
     }];


    //Now redirect to assignments page

    NSURL *homeURL = [NSURL URLWithString:@"https://mistar.oakland.k12.mi.us/novi/StudentPortal/Home/PortalMainPage"];
    NSMutableURLRequest *requestHome = [[NSMutableURLRequest alloc] initWithURL:homeURL];
    [request setHTTPMethod:@"POST"];

    [NSURLConnection sendAsynchronousRequest:requestHome queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *homeResponse, NSData *homeData, NSError *homeError)
     {
         // do whatever with the data...and errors
         if ([homeData length] > 0 && homeError == nil) {
             NSError *parseError;
             NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:homeData options:0 error:&parseError];
             if (responseJSON) {
                 // the response was JSON and we successfully decoded it

                 NSLog(@"Response was = %@", responseJSON);
             } else {
                 // the response was not JSON, so let's see what it was so we can diagnose the issue

                 NSString *homePage = [[NSString alloc] initWithData:homeData encoding:NSUTF8StringEncoding];
                 NSLog(@"Response was not JSON (from home), it was = %@", homePage);
             }
         }
         else {
             NSLog(@"error: %@", homeError);
         }
     }];

}

- (NSString *)percentEscapeString:(NSString *)string
{
    NSString *result = CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                                                 (CFStringRef)string,
                                                                                 (CFStringRef)@" ",
                                                                                 (CFStringRef)@":/?@!$&'()*+,;=",
                                                                                 kCFStringEncodingUTF8));
    return [result stringByReplacingOccurrencesOfString:@" " withString:@"+"];
}

因此，添加到

[NSOperationQueue mainQueue]

的是两个

NSURLConnection

。我的输出显示，第二个

NSURLConnection

在第一个之前运行。因此，它尝试在我登录之前转到我下载数据的页面，因此它（显然）返回一个“您未登录”错误。

---

我如何一个接一个地安排它们呢？

您可以查看下面的链接吗。它是强制一个操作等待另一个操作

---

希望这能有所帮助。

我想您已经意识到，问题是您正在执行异步网络请求（这很好；您不想阻塞主队列），因此无法保证它们完成的顺序

最快、最简单的答案是将对第二个请求的调用放在第一个请求的完成块内，而不是放在它之后。除非第一次成功，否则你不想做第二次

为了避免代码变得笨拙，请将登录与主页请求分开。您可以使用异步方法中常见的完成块模式。您可以向

loginToMistarWithPin

添加一个参数，指定请求完成时应执行的操作。您可能有一个成功的完成块处理程序，一个失败的完成块处理程序：

- (void)loginToMistarWithPin:(NSString *)pin password:(NSString *)password success:(void (^)(void))successHandler failure:(void (^)(void))failureHandler {

    NSURL *url = [NSURL URLWithString:@"https://mistar.oakland.k12.mi.us/novi/StudentPortal/Home/Login"];

    //Create and send request
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];

    [request setHTTPMethod:@"POST"];

    NSString *postString = [NSString stringWithFormat:@"Pin=%@&Password=%@",
                            [self percentEscapeString:pin],
                            [self percentEscapeString:password]];
    NSData * postBody = [postString dataUsingEncoding:NSUTF8StringEncoding];
    [request setHTTPBody:postBody];

    [NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
     {
         // do whatever with the data...and errors
         if ([data length] > 0 && error == nil) {
             NSError *parseError;
             NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:data options:0 error:&parseError];
             if (responseJSON) {
                 // the response was JSON and we successfully decoded it

                 NSLog(@"Response was = %@", responseJSON);

                 // assuming you validated that everything was successful, call the success block

                 if (successHandler)
                     successHandler();
             } else {
                 // the response was not JSON, so let's see what it was so we can diagnose the issue

                 NSString *loggedInPage = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
                 NSLog(@"Response was not JSON (from login), it was = %@", loggedInPage);

                 if (failureHandler)
                     failureHandler();
             }
         }
         else {
             NSLog(@"error: %@", error);

             if (failureHandler)
                 failureHandler();
         }
     }];
}

- (void)requestMainPage {

    //Now redirect to assignments page

    NSURL *homeURL = [NSURL URLWithString:@"https://mistar.oakland.k12.mi.us/novi/StudentPortal/Home/PortalMainPage"];
    NSMutableURLRequest *requestHome = [[NSMutableURLRequest alloc] initWithURL:homeURL];
    [requestHome setHTTPMethod:@"GET"]; // this looks like GET request, not POST

    [NSURLConnection sendAsynchronousRequest:requestHome queue:[NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *homeResponse, NSData *homeData, NSError *homeError)
     {
         // do whatever with the data...and errors
         if ([homeData length] > 0 && homeError == nil) {
             NSError *parseError;
             NSDictionary *responseJSON = [NSJSONSerialization JSONObjectWithData:homeData options:0 error:&parseError];
             if (responseJSON) {
                 // the response was JSON and we successfully decoded it

                 NSLog(@"Response was = %@", responseJSON);
             } else {
                 // the response was not JSON, so let's see what it was so we can diagnose the issue

                 NSString *homePage = [[NSString alloc] initWithData:homeData encoding:NSUTF8StringEncoding];
                 NSLog(@"Response was not JSON (from home), it was = %@", homePage);
             }
         }
         else {
             NSLog(@"error: %@", homeError);
         }
     }];

}

然后，当您想要登录时，您可以执行以下操作：

[self loginToMistarWithPin:@"1234" password:@"pass" success:^{
    [self requestMainPage];
} failure:^{
    NSLog(@"login failed");
}];

---

现在，将那些

successHandler

和

failureHandler

块参数更改为包含需要传回的任何数据，但希望它能说明这一点。保持方法简短紧凑，并使用完成块参数指定异步方法完成时应执行的操作。

它可能正在工作，但不确定。如何下载

HTML的内容https://mistar.oakland.k12.mi.us/novi/StudentPortal/Home/PortalMainPage

从区块内部？我试着从

发送异步请求

打印

家庭数据

，但没有给我任何帮助。很抱歉，我没有实现你的更改（因为我的白痴），它工作得很好，非常感谢。现在我要在成功块中添加另一个成功块，这是明智的还是我应该用其他方式？因为现在我想

将一些数据发布到
PortalMainPage
@AndrewSB，只要您希望调用方法的代码能够指定异步请求成功（或不成功）完成时应调用的代码块，就可以使用该完成块模式。所以，底线是，在任何合适的地方都可以随意使用它。