CHI::Driver::File(3) User Contributed Perl Documentation CHI::Driver::File(3)NAMECHI::Driver::File - File-based cache using one file per entry in a
multi-level directory structure
VERSION
version 0.55
SYNOPSIS
use CHI;
my $cache = CHI->new(
driver => 'File',
root_dir => '/path/to/cache/root',
depth => 3,
max_key_length => 64
);
DESCRIPTION
This cache driver stores data on the filesystem, so that it can be
shared between processes on a single machine, or even on multiple
machines if using NFS.
Each item is stored in its own file. By default, during a set, a
temporary file is created and then atomically renamed to the proper
file. While not the most efficient, it eliminates the need for locking
(with multiple overlapping sets, the last one "wins") and makes this
cache usable in environments like NFS where locking might normally be
undesirable.
By default, the base filename is the key itself, with unsafe characters
escaped similar to URL escaping. If the escaped key is larger than
"max_key_length" (default 248 characters), it will be digested. You may
want to lower "max_key_length" if you are storing a lot of items as
long filenames can be more expensive to work with.
The files are evenly distributed within a multi-level directory
structure with a customizable "depth", to minimize the time needed to
search for a given entry.
CONSTRUCTOR OPTIONS
When using this driver, the following options can be passed to
CHI->new() in addition to the CHI.
root_dir
The location in the filesystem that will hold the root of the
cache. Defaults to a directory called 'chi-driver-file' under the
OS default temp directory (e.g. '/tmp' on UNIX). This directory
will be created as needed on the first cache set.
depth
The number of subdirectories deep to place cache files. Defaults to
2. This should be large enough that no leaf directory has more than
a few hundred files. Each non-leaf directory contains up to 16
subdirectories (0-9, A-F).
dir_create_mode
Permissions mode to use when creating directories. Defaults to
0775.
file_create_mode
Permissions mode to use when creating files, modified by the
current umask. Defaults to 0666.
file_extension
Extension to append to filename. Default is ".dat".
METHODS
path_to_key ( $key )
Returns the full path to the cache file representing $key, whether
or not that entry exists. Returns the empty list if a valid path
cannot be computed, for example if the key is too long.
path_to_namespace
Returns the full path to the directory representing this cache's
namespace, whether or not it has any entries.
TEMPORARY FILE RENAME
By default, during a set, a temporary file is created and then
atomically renamed to the proper file. This eliminates the need for
locking. You can subclass and override method
generate_temporary_filename to either change the path of the temporary
filename, or skip the temporary file and rename altogether by having it
return undef.
SEE ALSO
CHI
AUTHOR
Jonathan Swartz <swartz@pobox.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Jonathan Swartz.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.14.2 2012-07-04 CHI::Driver::File(3)
