LWP::ConnCache(3pm)            User Contributed Perl Documentation            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.

SEE ALSO
       LWP::UserAgent

COPYRIGHT
       Copyright 2001 Gisle Aas.

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



perl v5.18.2                                2014-04-23                        LWP::ConnCache(3pm)