Build a url query string in obj-c from a dictionary of params like jquery does

buildquerystring.m

+(NSString*)urlEscape:(NSString *)unencodedString {
	NSString *s = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
		(CFStringRef)unencodedString,
		NULL,
		(CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
		kCFStringEncodingUTF8);
	return [s autorelease]; // Due to the 'create rule' we own the above and must autorelease it
}

// Put a query string onto the end of a url
+(NSString*)addQueryStringToUrl:(NSString *)url params:(NSDictionary *)params {
	NSMutableString *urlWithQuerystring = [[[NSMutableString alloc] initWithString:url] autorelease];
	// Convert the params into a query string
	if (params) {
		for(id key in params) {
			NSString *sKey = [key description];
			NSString *sVal = [[params objectForKey:key] description];
			// Do we need to add ?k=v or &k=v ?
			if ([urlWithQuerystring rangeOfString:@"?"].location==NSNotFound) {
				[urlWithQuerystring appendFormat:@"?%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
			} else {
				[urlWithQuerystring appendFormat:@"&%@=%@", [Http urlEscape:sKey], [Http urlEscape:sVal]];
			}
		}
	}
	return urlWithQuerystring;
}