Question

Is there a simple way to escape a NSString so I can use it in a HTTP POST request?

I’ve tried stringByAddingPercentEscapesUsingEncoding, but the following:

[@"~!@#$%^&*()-+\"'" stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]

gives me:

~!@%23$%25%5E&*()-+%22'

which is not usable in a HTTP POST query because the & is left unescaped; therefore the other end interprets whatever follows it as another argument.

Answer 1

The following function, part of NSString+URLEncoding.m, does exactly what I need:

- (NSString *)encodedURLParameterString {
NSString *result = (NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
                                                                       (CFStringRef)self,
                                                                       NULL,
                                                                       CFSTR(":/=,!$&'()*+;[]@#?"),
                                                                       kCFStringEncodingUTF8);
    return [result autorelease];
}