MediaType.parse constructor

MediaType.parse(String mediaType)

Parses a media type.

This will throw a FormatError if the media type is invalid.

Implementation

factory MediaType.parse(String mediaType) =>
    // This parsing is based on sections 3.6 and 3.7 of the HTTP spec:
    // http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html.
    wrapFormatException('media type', mediaType, () {
      final scanner = StringScanner(mediaType);
      scanner.scan(whitespace);
      scanner.expect(token);
      final type = scanner.lastMatch![0]!;
      scanner.expect('/');
      scanner.expect(token);
      final subtype = scanner.lastMatch![0]!;
      scanner.scan(whitespace);

      final parameters = <String, String>{};
      while (scanner.scan(';')) {
        scanner.scan(whitespace);
        scanner.expect(token);
        final attribute = scanner.lastMatch![0]!;
        scanner.expect('=');

        String value;
        if (scanner.scan(token)) {
          value = scanner.lastMatch![0]!;
        } else {
          value = expectQuotedString(scanner);
        }

        scanner.scan(whitespace);
        parameters[attribute] = value;
      }

      scanner.expectDone();
      return MediaType(type, subtype, parameters);
    });