[ios] Objective-C and Swift URL encoding

I have a NSString like this:

http://www.

but I want to transform it to:

http%3A%2F%2Fwww.

How can I do this?

NSString *str = (NSString *)CFURLCreateStringByAddingPercentEscapes(
                             NULL,
                             (CFStringRef)yourString, 
                             NULL, 
                             CFSTR("/:"), 
                             kCFStringEncodingUTF8);

You will need to release or autorelease str yourself.

This is how I am doing this in swift.

extension String {
    func encodeURIComponent() -> String {
        return self.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())!
    }

    func decodeURIComponent() -> String {
        return self.componentsSeparatedByString("+").joinWithSeparator(" ").stringByRemovingPercentEncoding!
    }
}

It's called URL encoding. More here.

-(NSString *)urlEncodeUsingEncoding:(NSStringEncoding)encoding {
    return (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,
           (CFStringRef)self,
           NULL,
           (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
           CFStringConvertNSStringEncodingToEncoding(encoding));
}

Google implements this in their Google Toolbox for Mac. So that's a good place to peak how they're doing it. Another option is to include the Toolbox and use their implementation.

Checkout the implementation here. (Which comes down to exactly what people have been posting here).

 NSString * encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(NUL,(CFStringRef)@"parameter",NULL,(CFStringRef)@"!*'();@&+$,/?%#[]~=_-.:",kCFStringEncodingUTF8 );

NSURL * url = [[NSURL alloc] initWithString:[@"address here" stringByAppendingFormat:@"?cid=%@",encodedString, nil]];

Swift iOS:

Just For Information : I have used this:

extension String {

    func urlEncode() -> CFString {
        return CFURLCreateStringByAddingPercentEscapes(
            nil,
            self,
            nil,
            "!*'();:@&=+$,/?%#[]",
            CFStringBuiltInEncodings.UTF8.rawValue
        )
    }

}// end extension String

Here's what I use. Note you have to use the @autoreleasepool feature or the program might crash or lockup the IDE. I had to restart my IDE three times until I realized the fix. It appears that this code is ARC compliant.

This question has been asked many times, and many answers given, but sadly all of the ones selected (and a few others suggested) are wrong.

Here's the test string that I used: This is my 123+ test & test2. Got it?!

These are my Objective C++ class methods:

static NSString * urlDecode(NSString *stringToDecode) {
    NSString *result = [stringToDecode stringByReplacingOccurrencesOfString:@"+" withString:@" "];
    result = [result stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    return result;
}

static NSString * urlEncode(NSString *stringToEncode) {
    @autoreleasepool {
        NSString *result = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(
                NULL,
                (CFStringRef)stringToEncode,
                NULL,
                (CFStringRef)@"!*'\"();:@&=+$,/?%#[]% ",
                kCFStringEncodingUTF8
            ));
        result = [result stringByReplacingOccurrencesOfString:@"%20" withString:@"+"];
        return result;
    }
}

This can work in Objective C ARC.Use CFBridgingRelease to cast a Core Foundation-style object as an Objective-C object and transfer ownership of the object to ARC .See Function CFBridgingRelease here.

+ (NSString *)encodeUrlString:(NSString *)string {
return CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes
                         (kCFAllocatorDefault,
                          (__bridge CFStringRef)string,
                          NULL,
                          CFSTR("!*'();:@&=+$,/?%#[]"),
                          kCFStringEncodingUTF8)
                         );}

int strLength = 0;
NSString *urlStr = @"http://www";
NSLog(@" urlStr : %@", urlStr );
NSMutableString *mutableUrlStr = [urlStr mutableCopy];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );
strLength = [mutableUrlStr length];
[mutableUrlStr replaceOccurrencesOfString:@":" withString:@"%3A" options:NSCaseInsensitiveSearch range:NSMakeRange(0, strLength)];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );
strLength = [mutableUrlStr length];
[mutableUrlStr replaceOccurrencesOfString:@"/" withString:@"%2F" options:NSCaseInsensitiveSearch range:NSMakeRange(0, strLength)];
NSLog(@" mutableUrlStr : %@", mutableUrlStr );

//use NSString instance method like this:

+ (NSString *)encodeURIComponent:(NSString *)string
{
NSString *s = [string stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return s;
}

+ (NSString *)decodeURIComponent:(NSString *)string
{
NSString *s = [string stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
return s;
}

remember,you should only do encode or decode for your parameter value, not all the url you request.

This is not my solution. Someone else wrote in stackoverflow but I have forgotten how.

Somehow this solution works "well". It handles diacritic, chinese characters, and pretty much anything else.

- (NSString *) URLEncodedString {
    NSMutableString * output = [NSMutableString string];
    const char * source = [self UTF8String];
    int sourceLen = strlen(source);
    for (int i = 0; i < sourceLen; ++i) {
        const unsigned char thisChar = (const unsigned char)source[i];
        if (false && 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;
}

If someone would tell me who wrote this code, I'll really appreciate it. Basically he has some explanation why this encoded string will decode exactly as it wish.

I modified his solution a little. I like space to be represented with %20 rather than +. That's all.