我有一个NSURLConnection（其中两个），他们以错误的顺序运行。
这是我的方法：
- (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，NSURLConnection添加了两个[NSOperationQueue mainQueue]。NSURLConnection。我的输出显示的是 second {{1}}在第一个之前运行 。因此，它会尝试转到我登录之前下载数据的页面，因此它（显然）会返回＆＃34;您还没有登录＆＃34;错误。
我如何一个接一个地安排它们？
答案 0 :(得分：1)
我怀疑你已经意识到这个问题是你正在做异步网络请求（这很好;你不想阻止主队列），所以没有确保他们完成的订单。
最快和最简单的答案是简单地将第二个请求的调用放在第一个请求的完成块之内，而不是之后。除非第一个成功，否则你不想成为第二个。
为了防止代码变得笨拙，请将登录名与主页请求分开。您可以使用异步方法常用的完成块模式。您向loginToMistarWithPin添加一个参数，指定请求完成后应该执行的操作。您可能有一个完成块处理程序用于成功，一个用于失败：
- (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，更改那些successHandler和failureHandler块参数以包含您需要传回的任何数据，但希望它能说明这个想法。保持您的方法简短，并使用完成块参数来指定异步方法在完成后应该执行的操作。
答案 1 :(得分：0)