Unfortunately, stringByAddingPercentEscapesUsingEncoding doesn't always work 100%. It encodes non-URL characters but leaves the reserved characters (like slash / and ampersand &) alone. Apparently this is a bug that Apple is aware of, but since they have not fixed it yet, I have been using this category to url-encode a string:
@implementation NSString (NSString_Extended)
- (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;
}
Used like this:
NSString *urlEncodedString = [@"SOME_URL_GOES_HERE" urlencode];
// Or, with an already existing string:
NSString *someUrlString = @"someURL";
NSString *encodedUrlStr = [someUrlString urlencode];
This also works:
NSString *encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(
NULL,
(CFStringRef)unencodedString,
NULL,
(CFStringRef)@"!*'();:@&=+$,/?%#[]",
kCFStringEncodingUTF8 );
Some good reading about the subject:
Objective-c iPhone percent encode a string?
Objective-C and Swift URL encoding
http://cybersam.com/programming/proper-url-percent-encoding-in-ios
https://devforums.apple.com/message/15674#15674
http://simonwoodside.com/weblog/2009/4/22/how_to_really_url_encode/