什么是错在下面的URLConnection？

问题描述：

Objective-C异步Web请求与饼干

我花了一天写这篇code和任何人都可以告诉我什么是错在这里？

I spent a day writing this code and can anyone tell me what is wrong here?

WSHelper从NSObject的继承，我甚至尝试NSDocument和NSObjectController和一切..

WSHelper is inherited from NSObject, I even tried NSDocument and NSObjectController and everything..

-(void) loadUrl: (NSString*) urlStr{
    url = [[NSURL alloc] initWithString:urlStr];
    request = [NSURLRequest requestWithURL:url cachePolicy: NSURLRequestReloadIgnoringCacheData timeoutInterval: 60.0];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
    if(connection)
    {
    	receivedData = [[NSMutableData data] retain];
            //[connection start];
    }
    else
    {       display error etc...   }
    NSApplication * app = [NSApplication sharedApplication];
    [app runModalForWindow: waitWindow];// <-- this is the problem...
}

-(void)connection: (NSURLConnection*)connection didReceiveData:(NSData*)data{
    progressText = @"Receiving Data...";
    [receivedData appendData:data];
}

-(void)connection: (NSURLConnection *)connection didFailWithError:(NSError *)error{
    progressText = @"Error...";
    NSAlert * alert = [[NSAlert alloc] init];
    [alert setMessageText:[error localizedDescription]];
    [alert runModal];
}


- (void)connectionDidFinishLoading:(NSURLConnection *)connection{
    progressText = @"Done...";
    pData = [[NSData alloc] initWithData:receivedData];
    [self hideWindow];
}

在code只是不会做任何事情，它不进步可言。我甚至尝试了/不startImmediately：是的，但没有运气!!!，这是在主窗口所以即使是线程中执行和它的运行循环运行成功

The code just wont do anything, it doesnt progress at all. I even tried it with/without startImmediately:YES but no luck !!!, this is executed in main window so even the thread and its run loop is running successfully.

我打过电话同步请求，并且其正常工作！但我需要异步的解决方案。

I tried calling synchronous request, and it is working correctly !! But I need async solution.

我在项目中加入CoreServices.Framework，有什么更多的，我应该加入到这个项目？任何编译器设置？或者我必须初始化任何东西之前，我可以使用NSURLConnection的？

I have added CoreServices.Framework in project, is there anything more I should be adding to the project? any compiler settings? Or do i have to initialize anything before I can use NSURLConnection?

任何解决方案来对自己的NSRunLoop不同的线程，Objective-C的运行NSURLConnection的MAC和发展有没有样品code在文档中的任何地方，让一切都这么难code。

Any solution to run NSURLConnection on different thread on its own NSRunLoop, Objective-C and MAC Development has no sample code anywhere in documentation that makes everything so difficult to code.

答

首先，你正在做启动连接太复杂。更改为：

Firstly you're making starting the connection too complicated. Change to:

connection = [[NSURLConnection alloc] initWithRequest:request delegate:self]

删除 [连接开始] 。现在：

是您的应用程序运行的绝对运行循环是否正常？ NSURLConnection的需要这个工作。

您能够执行URL请求的同步负荷？

在调试器中，你能看到网址是你希望它是什么？这是什么？

是否有可能接收到的任何代表消息之前，你重新分配WSHelper？ NSURLConnection的是asynchoronous毕竟。

Is your app definitely running the run loop normally? NSURLConnection requires this to work.
Are you able to perform a synchronous load of the URL request?
In the debugger, can you see that url is what you expect it to be? What is it?
Is it possible that you're deallocating WSHelper before any delegate messages are received? NSURLConnection is asynchoronous after all.

一个人并不需要做什么特别的使用NSURLConnection的，它的基础框架的一个简单的一部分。不需要特殊的编译器设置。在使用前没有初始化。没有。请不要盲目地开始尝试像引进CoreServices.Framework的东西。

One does not need to do anything special to use NSURLConnection, it's a straightforward part of the Foundation framework. No special compiler settings required. No initialization before use. Nothing. Please don't start blindly trying stuff like bringing in CoreServices.Framework.

由于同步发送请求的作品，一定有什么问题与您的异步方面的处理。它可以是：

As sending the request synchronously works, there must be something wrong with your handling of the asynchronous aspect. It could be:

的runloop没有在 NSDefaultRunLoopMode 运行，这样的连接是无法安排自己。

您$ C $ C的其他部分正在调用 -cancel 在连接上它有一个机会来加载之前。

您正在设法释放连接的时候有机会先加载。

The runloop is not running in NSDefaultRunLoopMode so the connection is unable to schedule itself.
Some other part of your code is calling -cancel on the connection before it has a chance to load.
You are managing to deallocate the connection before it has a chance to load.

嗯，其实我刚刚意识到发生了什么事情。您呼叫：

Ah, in fact I've just realised what's going on. You are calling:

-[NSApp runModalForWindow:]

阅读一下这种方法确实的说明。这不是在运行运行的循环如 NSURLConnection的的期望。我想说的是真的，你不想被presenting一个窗口，很喜欢这个运行时为它的URL连接。

Read the description of what this method does. It's not running the run loop like NSURLConnection expects. I'd say that really, you don't want to be presenting a window quite like this while running a URL connection for it.

我也建议你实施 -connection：didReceiveResponse：委托方法了。要检查这里的服务器返回预期的状态code。

I'd also suggest that you implement the -connection:didReceiveResponse: delegate method too. You want to check here that the server is returning the expected status code.

什么是错在下面的URLConnection？

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