lwp::conncache(3pm)

NAME

LWP::ConnCache - Connection cache manager

NOTE

This module is experimental. Details of its interface is likely to
change in the future.

SYNOPSIS

use LWP::ConnCache;
my $cache = LWP::ConnCache->new;
$cache->deposit($type, $key, $sock);
$sock = $cache->withdraw($type, $key);

DESCRIPTION

The "LWP::ConnCache" class is the standard connection cache manager for LWP::UserAgent.

The following basic methods are provided:

$cache = LWP::ConnCache->new( %options ): This method constructs a new "LWP::ConnCache" object. The only
option currently accepted is 'total_capacity'. If specified it
initialize the total_capacity option. It defaults to the value 1.
$cache->total_capacity( [$num_connections] ): Get/sets the number of connection that will be cached. Connections will start to be dropped when this limit is reached. If set to 0, then all connections are immediately dropped. If set to "undef",
then there is no limit.
$cache->capacity($type, [$num_connections] ): Get/set a limit for the number of connections of the specified type that can be cached. The $type will typically be a short string
like "http" or "ftp".
$cache->drop( [$checker, [$reason]] ): Drop connections by some criteria. The $checker argument is a
subroutine that is called for each connection. If the routine
returns a TRUE value then the connection is dropped. The routine
is called with ($conn, $type, $key, $deposit_time) as arguments.; Shortcuts: If the $checker argument is absent (or "undef") all
cached connections are dropped. If the $checker is a number then
all connections untouched that the given number of seconds or more are dropped. If $checker is a string then all connections of the
given type are dropped.; The $reason argument is passed on to the dropped() method.
$cache->prune: Calling this method will drop all connections that are dead. This is tested by calling the ping() method on the connections. If the ping() method exists and returns a FALSE value, then the connection is dropped.
$cache->get_types: This returns all the 'type' fields used for the currently cached
connections.
$cache->get_connections( [$type] ): This returns all connection objects of the specified type. If no
type is specified then all connections are returned. In scalar
context the number of cached connections of the specified type is
returned.
The following methods are called by low-level protocol modules to try to save away connections and to get them back.
$cache->deposit($type, $key, $conn): This method adds a new connection to the cache. As a result other already cached connections might be dropped. Multiple connections with the same $type/$key might added.
$conn = $cache->withdraw($type, $key): This method tries to fetch back a connection that was previously
deposited. If no cached connection with the specified $type/$key
is found, then "undef" is returned. There is not guarantee that a deposited connection can be withdrawn, as the cache manger is free to drop connections at any time.
The following methods are called internally. Subclasses might want to override them.
$conn->enforce_limits([$type]): This method is called with after a new connection is added
(deposited) in the cache or capacity limits are adjusted. The
default implementation drops connections until the specified
capacity limits are not exceeded.
$conn->dropping($conn_record, $reason): This method is called when a connection is dropped. The record
belonging to the dropped connection is passed as the first argument and a string describing the reason for the drop is passed as the
second argument. The default implementation makes some noise if
the $LWP::ConnCache::DEBUG variable is set and nothing more.

SUBCLASSING

For specialized cache policy it makes sense to subclass
"LWP::ConnCache" and perhaps override the deposit(), enforce_limits() and dropping() methods.

The object itself is a hash. Keys prefixed with "cc_" are reserved for the base class.

COPYRIGHT

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

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