NAME

DateTime::Format::ICal - Parse and format iCal datetime and duration strings

SYNOPSIS

  use DateTime::Format::ICal;
  my $dt = DateTime::Format::ICal->parse_datetime( '20030117T032900Z' );
  my $dur = DateTime::Format::ICal->parse_duration( '+P3WT4H55S' );
  # 20030117T032900Z
  DateTime::Format::ICal->format_datetime($dt);
  # +P3WT4H55S
  DateTime::Format::ICal->format_duration($dur);

DESCRIPTION

This module understands the ICal date/time and duration formats, as defined in RFC 2445. It can be used to parse these formats in order to create the appropriate objects.

METHODS

This class offers the following methods.

parse_datetime($string)
Given an iCal datetime string, this method will return a new "DateTime" object.

If given an improperly formatted string, this method may die.
parse_duration($string)
Given an iCal duration string, this method will return a new "DateTime::Duration" object.

If given an improperly formatted string, this method may die.
parse_period($string)
Given an iCal period string, this method will return a new "DateTime::Span" object.

If given an improperly formatted string, this method may die.
parse_recurrence( recurrence => $string, ... )
Given an iCal recurrence description, this method uses "DateTime::Event::ICal" to create a "DateTime::Set" object representing that recurrence. Any parameters given to this method beside "recurrence" will be passed directly to the "DateTime::Event::ICal->recur" method.

If given an improperly formatted string, this method may die.

This method accepts optional parameters "dtstart" and "dtend". These parameters must be "DateTime" objects.

The iCal spec requires that "dtstart" always be included in the recurrence set, unless this is an "exrule" statement. Since we don't know what kind of statement is being parsed, we do not include "dtstart" in the recurrence set.
format_datetime($datetime)
Given a "DateTime" object, this methods returns an iCal datetime string.

The iCal spec requires that datetimes be formatted either as floating times (no time zone), UTC (with a 'Z' suffix) or with a time zone id at the beginning ('TZID=America/Chicago;...'). If this method is asked to format a "DateTime" object that has an offset-only time zone, then the object will be converted to the UTC time zone internally before formatting.

For example, this code:
```
    my $dt = DateTime->new( year => 1900, hour => 15, time_zone => '-0100' );
    print $ical->format_datetime($dt);
    
```
will print the string "19000101T160000Z".
format_duration($duration)
Given a "DateTime::Duration" object, this methods returns an iCal duration string.

The iCal standard does not allow for months or years in a duration, so if a duration for which "delta_months()" is not zero is given, then this method will die.
format_period($span)
Given a "DateTime::Span" object, this methods returns an iCal period string, using the format "DateTime/DateTime".
format_period_with_duration($span)
Given a "DateTime::Span" object, this methods returns an iCal period string, using the format "DateTime/Duration".
format_recurrence($arg [,$arg...] )
This method returns a list of strings containing ICal statements. In scalar context it returns a single string which may contain embedded newlines.

The argument can be a "DateTime" list, a "DateTime::Span" list, a "DateTime::Set", or a "DateTime::SpanSet".

ICal "DATE" values are not supported. Whenever a date value is found, a "DATE-TIME" is generated.

If a recurrence has an associated "DTSTART" or "DTEND", those values must be formatted using "format_datetime()". The "format_recurrence()" method will not do this for you.

If a "union" or "complement" of recurrences is being formatted, they are assumed to have the same "DTSTART" value.

Only "union" and "complement" operations are supported for recurrences. This is a limitation of the ICal specification.

If given a set it cannot format, this method may die.

Only "DateTime::Set::ICal" objects are formattable. A set may change class after some set operations:
```
    $recurrence = $recurrence->union( $dt_set );
    # Ok - $recurrence still is a DT::Set::ICal
    $recurrence = $dt_set->union( $recurrence );
    # Not Ok! - $recurrence is a DT::Set now
    
```
The only unbounded recurrences currently supported are the ones generated by the "DateTime::Event::ICal" module.

You can add ICal formatting support to a custom recurrence by using the "DateTime::Set::ICal" module:
```
    $custom_recurrence =
        DateTime::Set::ICal->from_recurrence
            ( recurrence =>
              sub { $_[0]->truncate( to => 'month' )->add( months => 1 ) }
            );
    $custom_recurrence->set_ical( include => [ 'FREQ=MONTHLY' ] );
    
```

SUPPORT

Support for this module is provided via the datetime@perl.org email list. See http://lists.perl.org/ for more details.

AUTHORS

Dave Rolsky <autarch@urth.org> and Flavio Soibelmann Glock <fglock@pucrs.br>

Some of the code in this module comes from Rich Bowen's "Date::ICal" module.

COPYRIGHT

The full text of the license can be found in the LICENSE file included with this module.