encoding NSURL in ISO-8859-1

Question

I have a ViewController containing TextFields and I would need to send those values to a dedicated HTTP service. My main concern comes from the encoding type, as this app is in French and may contain some accents ('é', 'è', etc,...) but also I need to format correctly my fields as it may contain spaces as well....

I tried to use different ways but I still have a wrong encoding on the server side.

here is a sample of my code:

    let url_to_request = "http://11.22.33.44:8080/SRV/addRepertoire"

    var params = "owner=\(User.sharedInstance.email)&adresse=\(adresse.text!)&nom=\(nom.text!)&telephone=\(telephone.text!)&commentaires=\(commentaires.text!)"

    //trying to encode in ISO-8859-1
    let dt = NSString(CString: params, encoding: NSISOLatin1StringEncoding)
    //preparing string to be used in a NSURL
    let final_url = dt!.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())

    print("URL loadRepertoire: \(url_to_request+"?"+final_url!)")

for instance, field "nom" contains "bébé" which is encoded "b%C4%82%C5%A0b%C4%82%C5%A0" whereas my server is expecting "b%E9b%E9"

EDIT2:

I tried to use the following:

        let url_to_request = "http://11.22.33.44:8080/SRV/addRepertoire"

    let params = "owner=\(User.sharedInstance.email)&adresse=\(adresse.text!)&nom=\(nom.text!)&telephone=\(telephone.text!)&commentaires=\(commentaires.text!)"

    let tmp_url = url_to_request + "?" + params
    let final_url = tmp_url.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())!

    print("URL addRepertoire: \(final_url)")

but the result remains:

b%C3%83%C2%A9b%C3%83%C2%A9, diplayed bébé instead of bébé

Answer 1

Here is a solution in Swift 4:

extension String {

  // Url percent encoding according to RFC3986 specifications
  // https://tools.ietf.org/html/rfc3986#section-2.1
  func urlPercentEncoded(withAllowedCharacters allowedCharacters: 
    CharacterSet, encoding: String.Encoding) -> String {
    var returnStr = ""

    // Compute each char seperatly
    for char in self {
      let charStr = String(char)
      let charScalar = charStr.unicodeScalars[charStr.unicodeScalars.startIndex]
      if allowedCharacters.contains(charScalar) == false,
        let bytesOfChar = charStr.data(using: encoding) {
        // Get the hexStr of every notAllowed-char-byte and put a % infront of it, append the result to the returnString
        for byte in bytesOfChar {
          returnStr += "%" + String(format: "%02hhX", byte as CVarArg)
        }
      } else {
        returnStr += charStr
      }
    }

    return returnStr
  }

}

Usage:

"aouäöü!".urlPercentEncoded(withAllowedCharacters: .urlQueryAllowed,
                                         encoding: .isoLatin1) 
// Results in -> "aou%E4%F6%FC!"

Answer 2

stringByAddingPercentEncodingWithAllowedCharacters always uses UTF-8 representation, so I'm afraid you may need to do it yourself.

extension String {
    func stringByAddingPercentEncodingForISOLatin1() -> String? {
        let allowedCharacterSet = NSCharacterSet(charactersInString:
                    "0123456789"
                    + "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                    + "abcdefghijklmnopqrstuvwxyz"
                    + "_-.~"
                    + "=&" //You'd better remove this and encode each param.
        )
        if let data = self.dataUsingEncoding(NSISOLatin1StringEncoding) {
            var result = ""
            for i in 0..<data.length {
                let ch = UnsafePointer<UInt8>(data.bytes)[i]
                if ch >= 0x80 || !allowedCharacterSet.characterIsMember(unichar(ch)) {
                    result += String(format: "%%%02X", ch)
                } else {
                    result.append(UnicodeScalar(ch))
                }
            }
            return result
        } else {
            return nil
        }
    }
}
"bébé".stringByAddingPercentEncodingForISOLatin1()! //->"b%E9b%E9"

Answer 3

For Objective-C :

- (NSString *)stringByAddingPercentEncodingForISOLatin1 {

NSCharacterSet *allowedCharacterSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz_-.~=&"];

NSData *data = [self dataUsingEncoding:NSISOLatin1StringEncoding];
if (data) {
    NSMutableString *result = [@"" mutableCopy];
    const char *bytes = [data bytes];
    for (NSUInteger i = 0; i < [data length]; i++)
    {
        unsigned char ch = (unsigned char)bytes[i];
        if (ch >= 0x80 || ![allowedCharacterSet characterIsMember:ch]) {
            [result appendFormat:@"%%%02X", ch];
        } else {
            [result appendFormat:@"%c", ch];
        }
    }

    return [result copy];
}

return nil;}