The uploaded file
Tie-Scalar-Timeout-1.2.tar.gz
has entered CPAN as
file: $CPAN/authors/id/M/MA/MARCEL/Tie-Scalar-Timeout-1.2.tar.gz
size: 3919 bytes
md5: 494eb852e6fb4ef482d61c1b3a9fa55f
NAME
Tie::Scalar::Timeout - Scalar variables that time out
SYNOPSIS
use Tie::Scalar::Timeout;
tie my $k, 'Tie::Scalar::Timeout', EXPIRES => '+2s';
$k = 123;
sleep(3);
# $k is now undef
tie my $m, 'Tie::Scalar::Timeout', NUM_USES => 3, VALUE => 456;
tie my $n, 'Tie::Scalar::Timeout', VALUE => 987, NUM_USES => 1,
POLICY => 777;
tie my $p, 'Tie::Scalar::Timeout', VALUE => 654, NUM_USES => 1,
POLICY => \&expired;
sub expired { $is_expired++ }
DESCRIPTION
This module allows you to tie a scalar variable whose value will be
reset (subject to an expiry policy) after a certain time and/or a
certain number of uses. One possible application for this module might
be to time out session variables in mod_perl programs.
When tying, you can specify named arguments in the form of a hash. The
following named parameters are supported:
`EXPIRES'
Use `EXPIRES' to specify an interval or absolute time after which
the value will be reset. (Technically, the value will still be
there, but the module's FETCH sub will return the value as dictated
by the expiry policy.)
Values for the `EXPIRES' field are modelled after Netscape's cookie
expiration times. Except, of course, that negative values don't
really make sense in a universe with linear, one-way time. The
following forms are all valid for the `EXPIRES' field:
+30s 30 seconds from now
+10m ten minutes from now
+1h one hour from now
+3M in three months
+10y in ten years time
25-Apr-2001 00:40:33 at the indicated time & date
Assigning a value to the variable causes `EXPIRES' to be reset to
the original value.
`VALUE'
Using the `VALUE' hash key, you can specify an initial value for the
variable.
`NUM_USES'
Alternatively or in addition to `EXPIRES', you can also specify a
maximum number of times the variable may be read from before it
expires. If both `EXPIRES' and `NUM_USES' are set, the variable will
expire when either condition becomes true. If `NUM_USES' isn't set
or set to a negative value, it won't influence the expiry process.
Assigning a value to the variable causes `NUM_USES' to be reset to
the original value.
`POLICY'
The expiration policy determines what happens to the variable's
value when it expires. If you don't specify a policy, the variable
will be `undef' after it has expired. You can specify either a
scalar value or a code reference as the value of the `POLICY'
parameter. If you specify a scalar value, that value will be
returned after the variable has expired. Thus, the default
expiration policy is equivalent to
POLICY => undef
If you specify a code reference as the value of the `POLICY'
parameter, that code will be called when the variable value is
`FETCH()'ed after it has expired. This might be used to set some
other variable, or reset the variable to a different value, for
example.
BUGS
None known so far. If you find any bugs or oddities, please do tell me
about them.
AUTHOR
Marcel Gr�nauer <[EMAIL PROTECTED]>
COPYRIGHT
Copyright 2000 Marcel Gr�nauer. All rights reserved.
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
SEE ALSO
perl(1), Tie::Scalar(3pm).
Marcel
--
We are Perl. Your table will be assimilated. Your waiter will adapt to
service us. Surrender your beer. Resistance is futile.
-- London.pm strategy aka "embrace and extend" aka "mark and sweep"
