I\'m using this code snippet to encode characters to be friendly with a POST request:
NSString *unescaped = [textField text];
NSString *escapedString =
First, you don't want to use __bridge_retained in your cast to a CFStringRef. Just use __bridge.
Second, you don't have to escape the quotes manually by string replacement. Just add the quote character to the set of characters to be quoted when calling CFURLCreateStringByAddingPercentEscapes(). Like so:
NSString *unescaped = [textField text];
NSString *escapedString = CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(NULL,
(__bridge CFStringRef)unescaped,
NULL,
CFSTR("!*'();:@&=+$,/?%#[]\""),
kCFStringEncodingUTF8));
(In addition to adding the quote to the set, I changed to use CFBridgingRelease() rather than a __bridge_transfer cast because I find it clearer. It satisfies the feeling that all CF "Create" functions need a corresponding "Release". Also, I changed the use of a @"" literal cast to CFStringRef to just a CFSTR("") literal.)