CHI::Driver::File - File-based cache using one file per entry in a multi-level
my $cache = CHI->new(
driver => 'File',
root_dir => '/path/to/cache/root',
depth => 3,
max_key_length => 64
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
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
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
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.
When using this driver, the following options can be passed to
CHI->new() in addition to the CHI.
- 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.
- 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
- Permissions mode to use when creating directories. Defaults to 0775.
- Permissions mode to use when creating files, modified by the current
umask. Defaults to 0666.
- Extension to append to filename. Default is
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.
Jonathan Swartz <email@example.com>
This software is copyright (c) 2012 by Jonathan Swartz.
- 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.
- Returns the full path to the directory representing this cache's
namespace, whether or not it has any entries.
This is free software; you can redistribute it and/or modify it
under the same terms as the Perl 5 programming language system itself.