Following redirects

/* example usage */
		JFFollowRedirect* follower = [[JFFollowRedirect alloc] init];
		[follower addObserver:self forKeyPath:@"redirectStr" options:NSKeyValueObservingOptionNew 
					  context:follower];
		// follow redirect
		[follower getRedirectURLStr:urlToFollow];

/ * header */
#import <Foundation/Foundation.h>

@interface JFFollowRedirect : NSObject {
	NSURL *url;
	
	// This class handles all errors by setting redirectStr to the originalURLStr
	NSString *redirectStr;
}

@property (nonatomic, retain) NSString *redirectStr;

// parse the header received from the HEAD request
- (void)handleReadFromStream:(CFReadStreamRef)aStream
				   eventType:(CFStreamEventType)eventType;

// starts the HEAD request
- (void)getRedirectURLStr:(NSString *)originalURLStr;
@end

/ * implementation */


#import "JFFollowRedirect.h"
#import <CFNetwork/CFNetwork.h>

void JFReadStreamCallBack
(
 CFReadStreamRef aStream,
 CFStreamEventType eventType,
 void* inClientInfo
 )
{
	JFFollowRedirect *follower = (JFFollowRedirect *)inClientInfo;
	[follower handleReadFromStream:aStream eventType:eventType];
}

@implementation JFFollowRedirect

@synthesize redirectStr;

- (id)init {
	if (self = [super init]) {
		url = nil;
	}
	return self;
}

- (void)dealloc {
	[super dealloc];

}

- (void)handleReadFromStream:(CFReadStreamRef)stream
				   eventType:(CFStreamEventType)eventType {
	if (eventType == kCFStreamEventEndEncountered) {
		CFHTTPMessageRef myResponse = (CFHTTPMessageRef)CFReadStreamCopyProperty(stream, kCFStreamPropertyHTTPResponseHeader);
		CFStringRef header = CFHTTPMessageCopyHeaderFieldValue(myResponse, CFSTR("Location"));
		if (header == nil) {
			NSLog(@" *** no Location: header found");
			self.redirectStr = [url absoluteString];
		} else {
			//NSLog(@"Location header found %@", header);
			self.redirectStr = [NSString stringWithFormat:@"%@", header];
			CFRelease(header);
		}
		CFRelease(myResponse);
		CFReadStreamUnscheduleFromRunLoop(stream, CFRunLoopGetCurrent(),
										 kCFRunLoopCommonModes);

	}
	CFReadStreamClose(stream);
	CFRelease(stream);
}

- (void)getRedirectURLStr:(NSString *)originalURLStr {
	url = [NSURL URLWithString:originalURLStr];
	if (url == nil) {
		self.redirectStr = originalURLStr;
		return;
	}
	//
	// Create the GET request
	//
	CFHTTPMessageRef message= CFHTTPMessageCreateRequest(NULL, (CFStringRef)@"HEAD", (CFURLRef)url, kCFHTTPVersion1_1);
	CFReadStreamRef stream = CFReadStreamCreateForHTTPRequest(NULL, message);
	CFRelease(message);

	//
	// Enable stream redirection
	//
	if (CFReadStreamSetProperty(
								stream,
								kCFStreamPropertyHTTPShouldAutoredirect,
								kCFBooleanFalse) == false)
	{
		self.redirectStr = originalURLStr;
		CFReadStreamClose(stream);
		CFRelease(stream);

		NSLog(@"error kCFStreamPropertyHTTPShouldAutoredirect");
		return ;
	}
	
	if (!CFReadStreamOpen(stream)) { // error 
		self.redirectStr = originalURLStr;
		CFReadStreamClose(stream);
		CFRelease(stream);

		NSLog(@"CFReadStreamOpen failed!");
		return;
	}
	
	//
	// Set our callback function to receive the data
	//
	CFStreamClientContext context = {0, self, NULL, NULL, NULL};
	CFReadStreamSetClient(
						  stream,
						  kCFStreamEventHasBytesAvailable | kCFStreamEventErrorOccurred | kCFStreamEventEndEncountered,
						  JFReadStreamCallBack,
						  &context);
	CFReadStreamScheduleWithRunLoop(stream, CFRunLoopGetCurrent(), kCFRunLoopCommonModes);
	
}


@end