DateTime::Format::Mail(3)

NAME
DateTime::Format::Mail - Convert between DateTime and RFC2822/822 formats

SYNOPSIS
    use DateTime::Format::Mail;

    # From RFC2822 via class method:

    my $datetime = DateTime::Format::Mail->parse_datetime(
        "Sat, 29 Mar 2003 22:11:18 -0800"
    );
    print $datetime->ymd('.'); # "2003.03.29"

    #  or via an object

    my $pf = DateTime::Format::Mail->new();
    print $pf->parse_datetime(
        "Fri, 23 Nov 2001 21:57:24 -0600"
    )->ymd; # "2001-11-23"

    # Back to RFC2822 date

    use DateTime;
    my $dt = DateTime->new(
        year => 1979, month => 7, day => 16,
        hour => 16, minute => 45, second => 20,
        time_zone => "Australia/Sydney"
    );
    my $str = DateTime::Format::Mail->format_datetime( $dt );
    print $str; # "Mon, 16 Jul 1979 16:45:20 +1000"

    # or via an object
    $str = $pf->format_datetime( $dt );
    print $str; # "Mon, 16 Jul 1979 16:45:20 +1000"

DESCRIPTION
RFCs 2822 and 822 specify date formats to be used by email. This module parses and emits such dates.

RFC2822 (April 2001) introduces a slightly different format of date than that used by RFC822 (August 1982). The main correction is that the preferred format is more limited, and thus easier to parse programmatically.

Despite the ease of generating and parsing perfectly valid RFC822 and RFC2822 people still get it wrong. So this module provides four things for those handling mail dates:

1.  A strict parser that will only accept RFC2822 dates, so you can see where you're right.

2.  A strict formatter, so you can generate the right stuff to begin with.

3.  A loose parser, so you can take the misbegotten output from other programs and turn it into something useful. This includes various minor errors as well as some somewhat more bizarre mistakes. The file t/sample_dates in this module's distribution should give you an idea of what's valid, while t/invalid.t should do the same for what's not. Those regarded as invalid are just a bit too strange to allow.

4.  Interoperation with the rest of the DateTime suite. These are a collection of modules to handle dates in a modern and accurate fashion. In particular, they make it trivial to parse, manipulate and then format dates. Shifting timezones is a doddle, and converting between formats is a cinch.

As a future direction, I'm contemplating an even stricter parser that will only accept dates with no obsolete elements.

CONSTRUCTORS

  new
Creates a new "DateTime::Format::Mail" instance. This is generally not required for simple operations. If you wish to use a different parsing style from the default, strict, parser then you'll need to create an object.

   my $parser = DateTime::Format::Mail->new()
   my $copy = $parser->new();

If called on an existing object then it clones the object.

It has two optional named parameters.

•   "loose" should be a true value if you want a loose parser, else either don't specify it or give it a false value.

•   "year_cutoff" should be an integer greater than or equal to zero specifying the cutoff year. See "set_year_cutoff" for details.

    my $loose = DateTime::Format::Mail->new( loose => 1 );

    my $post_2049 = DateTime::Format::Mail->new(
        year_cutoff => 60
    );

  clone
For those who prefer to explicitly clone via a method called clone(). If called as a class method it will die.

   my $clone = $original->clone();

PARSING METHODS
These methods work on either our objects or as class methods.

  loose, strict
These methods set the parsing strictness.

    my $parser = DateTime::Format::Mail->new;
    $parser->loose;
    $parser->strict; # (the default)

    my $p = DateTime::Format::Mail->new->loose;

  parse_datetime
Given an RFC2822 or 822 datetime string, return a "DateTime" object representing that date and time. Unparseable strings will cause the method to die.

See the synopsis for examples.

  set_year_cutoff
Two digit years are treated as valid in the loose translation and are translated up to a 19xx or 20xx figure. By default, following the specification of RFC2822, if the year is greater than '49', it's treated as being in the 20th century (19xx). If lower, or equal, then the 21st (20xx). That is, 50 becomes 1950 while 49 is 2049.

set_year_cutoff() allows you to modify this behaviour by specifying a different cutoff.

The return value is the object itself.

    $parser->set_year_cutoff( 60 );

  year_cutoff
Returns the current cutoff. Can be used as either a class or object method.

    my $cutoff = $parser->set_year_cutoff;

  default_cutoff
Returns the default cutoff. A useful method to override for subclasses.

    my $default = $parser->default_cutoff;

  fix_year
Takes a year and returns it normalized.

   my $fixed = $parser->fix_year( 3 );

FORMATTING METHODS

  format_datetime
Given a "DateTime" object, return it as an RFC2822 compliant string.

    use DateTime;
    use DateTime::Format::Mail;
    my $dt = DateTime->new(
        year => 1979, month => 7, day => 16, time_zone => 'UTC'
    );
    my $mail = DateTime::Format::Mail->format_datetime( $dt );
    print $mail, "\n";

    # or via an object
    my $formatter = DateTime::Format::Mail->new();
    my $rfcdate = $formatter->format_datetime( $dt );
    print $rfcdate, "\n";

THANKS FROM SPOON
Dave Rolsky (DROLSKY) for kickstarting the DateTime project.

Roderick A. Anderson for noting where the documentation was incomplete in places.

Joshua Hoblitt (JHOBLITT) for inspiring me to check what the standard said about interpreting two digit years.

SUPPORT
Support for this module is provided via the datetime@perl.org email list. See <http://datetime.perl.org/mailing_list.html> for more details.

Alternatively, log them via the CPAN RT system via the web or email:

    http://rt.cpan.org/NoAuth/ReportBug.html?Queue=DateTime-Format-Mail
    bug-datetime-format-mail@rt.cpan.org

This makes it much easier for me to track things and thus means your problem is less likely to be neglected.

LICENCE AND COPYRIGHT
Copyright © Iain Truskett, 2003. All rights reserved.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the licences can be found in the LICENSE file included with this module, or in perlartistic and perlgpl in Perl 5.8.1 or later.

AUTHORS
Originally written by Iain Truskett <spoon@cpan.org>, who died on December 29, 2003.

Maintained by Dave Rolsky <autarch@urth.org> from 2003 to 2013.

Maintained by Philippe Bruhat (BooK) <book@cpan.org> since 2014.

SEE ALSO
"datetime@perl.org" mailing list.

<http://datetime.perl.org/>

perl, DateTime

RFCs 2822 and 822.