parseHttpDate function

TZDateTime parseHttpDate(String date)

Parses an HTTP-formatted date into a UTC DateTime.

This follows RFC 2616. It will throw a FormatException if date is invalid.

Implementation

tz.TZDateTime parseHttpDate(String date) {
  final scanner = StringScanner(date);

  if (scanner.scan(_longWeekdayRegExp)) {
    // RFC 850 starts with a long weekday.
    scanner.expect(', ');
    final day = _parseInt(scanner, 2);
    scanner.expect('-');
    final month = _parseMonth(scanner);
    scanner.expect('-');
    final year = 1900 + _parseInt(scanner, 2);
    scanner.expect(' ');
    final time = _parseTime(scanner);
    scanner.expect(' GMT');
    scanner.expectDone();

    return _makeDateTime(year, month, day, time);
  }

  // RFC 1123 and asctime both start with a short weekday.
  scanner.expect(_shortWeekdayRegExp);
  if (scanner.scan(', ')) {
    // RFC 1123 follows the weekday with a comma.
    final day = _parseInt(scanner, 2);
    scanner.expect(' ');
    final month = _parseMonth(scanner);
    scanner.expect(' ');
    final year = _parseInt(scanner, 4);
    scanner.expect(' ');
    final time = _parseTime(scanner);
    scanner.expect(' ');
    final offset = _parseLocation(scanner);
    scanner.expectDone();

    return _makeDateTime(year, month, day, time, offset);
  }

  // asctime follows the weekday with a space.
  scanner.expect(' ');
  final month = _parseMonth(scanner);
  scanner.expect(' ');
  final day = scanner.scan(' ') ? _parseInt(scanner, 1) : _parseInt(scanner, 2);
  scanner.expect(' ');
  final time = _parseTime(scanner);
  scanner.expect(' ');
  final year = _parseInt(scanner, 4);
  scanner.expectDone();

  return _makeDateTime(year, month, day, time);
}