saslprep static method

String saslprep(String input, { SaslprepOptions? options, })

This computes the saslprep algorithm. to allow allow unassigned use the options and set options.allowUnassigned to true

Implementation

static String saslprep(String input, {SaslprepOptions? options}) {
  if (input.isEmpty) {
    return '';
  }

  // 1. Map
  var mapped_input = toCodePoints(input)
      // 1.1 mapping to space
      .map((character) =>
          (non_ASCII_space_characters.contains(character) ? 0x20 : character))
      // 1.2 mapping to nothing
      .where((character) => !commonly_mapped_to_nothing.contains(character));

  // 2. Normalize
  var normalized_input = unorm.nfkc(String.fromCharCodes(mapped_input));

  var normalized_map = toCodePoints(normalized_input);

  // 3. Prohibit
  var hasProhibited = normalized_map
      .any((character) => prohibited_characters.contains(character));

  if (hasProhibited) {
    throw Exception(
        'Prohibited character, see https://tools.ietf.org/html/rfc4013#section-2.3');
  }

  // Unassigned Code Points
  if (options == null || options.allowUnassigned != true) {
    var hasUnassigned = normalized_map
        .any((character) => unassigned_code_points.contains(character));
    if (hasUnassigned) {
      throw Exception(
          'Unassigned code point, see https://tools.ietf.org/html/rfc4013#section-2.5');
    }
  }

  // 4. check bidi
  var hasBidiRAL = normalized_map
      .any((character) => bidirectional_r_al.contains(character));
  var hasBidiL =
      normalized_map.any((character) => bidirectional_l.contains(character));

  // 4.1 If a string contains any RandALCat character, the string MUST NOT
  // contain any LCat character.
  if (hasBidiRAL && hasBidiL) {
    throw Exception(
        'String must not contain RandALCat and LCat at the same time, see https://tools.ietf.org/html/rfc3454#section-6');
  }

  //4.2 If a string contains any RandALCat character, a RandALCat
  //character MUST be the first character of the string, and a
  //RandALCat character MUST be the last character of the string.
  var isFirstBidiRAL =
      bidirectional_r_al.contains(normalized_input.codeUnitAt(0));
  var isLastBidiRAL = bidirectional_r_al
      .contains(normalized_input.codeUnitAt(normalized_input.length - 1));

  if (hasBidiRAL && !(isFirstBidiRAL && isLastBidiRAL)) {
    throw Exception(
        'Bidirectional RandALCat character must be the first and the last character of the string, see https://tools.ietf.org/html/rfc3454#section-6');
  }

  return normalized_input;
}