While writing the new Image Downloader (Blocking) QC patch for CoreMelt, I ran into what appears to be a bug in Mac OS X’s NSURLConnection framework — if you construct an NSURLRequest and specify a timeout of less than 30 seconds, it’s ignored when you perform a [NSURLConnection sendSynchronousRequest:returningResponse:error:]. The request takes at least 30 seconds to time out, contrary to what the documentation suggests..

Steps to Reproduce:

1. Construct an NSURL with an http-based url pointing to a server that is currently offline.
2. Execute the following code block:

   NSLog(@"begin");
   NSURLRequest *request=[NSURLRequest
       requestWithURL:url
       cachePolicy:NSURLRequestReloadIgnoringCacheData
       timeoutInterval:5.0];
   NSData *data=[NSURLConnection
       sendSynchronousRequest:request
       returningResponse:&response
       error:&error];
   NSLog(@"end");

3. Compare the timestamps of “begin” and “end”. though they should presumably differ by 5 seconds, they actually differ by exactly 30 seconds.

Any ideas?