convert string to URL objective-C - objective-c

Question

I am creating a screen where user can input any text. Now that text has to be converted to a valid url. I have looked into lot of stack overflow question and they have come up with the fooling solution:
1. CFURLCreateStringByAddingPercentEscapes
NSString *encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(
NULL,
(CFStringRef)unencodedString,
NULL,
(CFStringRef)#"!*'();:#&=+$,/?%#[]",
kCFStringEncodingUTF8 );
2. Category on the string
- (NSString *)urlencode {
NSMutableString *output = [NSMutableString string];
const unsigned char *source = (const unsigned char *)[self UTF8String];
int sourceLen = strlen((const char *)source);
for (int i = 0; i < sourceLen; ++i) {
const unsigned char thisChar = source[i];
if (thisChar == ' '){
[output appendString:#"+"];
} else if (thisChar == '.' || thisChar == '-' || thisChar == '_' || thisChar == '~' ||
(thisChar >= 'a' && thisChar <= 'z') ||
(thisChar >= 'A' && thisChar <= 'Z') ||
(thisChar >= '0' && thisChar <= '9')) {
[output appendFormat:#"%c", thisChar];
} else {
[output appendFormat:#"%%%02X", thisChar];
}
}
return output;
}
Example: If the user manually puts the required %20 (for example) in the text instead of white space and then if we use any of the above solution the %20 would be converting to %25.
Could anybody let me know how can I fix the issue.

Answer 1

Because % will be urlencoded to %25, actually the %20 will be urlencoded to %2520, which is the desired output.
If you want to keep the %20 in the user input, you can replace all the %20 with a single white space, then urlencoded the replaced string.