1CHI::Driver::File(3)  User Contributed Perl Documentation CHI::Driver::File(3)
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NAME

6       CHI::Driver::File - File-based cache using one file per entry in a
7       multi-level directory structure
8

VERSION

10       version 0.61
11

SYNOPSIS

13           use CHI;
14
15           my $cache = CHI->new(
16               driver         => 'File',
17               root_dir       => '/path/to/cache/root',
18               depth          => 3,
19               max_key_length => 64
20           );
21

DESCRIPTION

23       This cache driver stores data on the filesystem, so that it can be
24       shared between processes on a single machine, or even on multiple
25       machines if using NFS.
26
27       Each item is stored in its own file. By default, during a set, a
28       temporary file is created and then atomically renamed to the proper
29       file. While not the most efficient, it eliminates the need for locking
30       (with multiple overlapping sets, the last one "wins") and makes this
31       cache usable in environments like NFS where locking might normally be
32       undesirable.
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34       By default, the base filename is the key itself, with unsafe characters
35       escaped similar to URL escaping. If the escaped key is larger than
36       "max_key_length" (default 248 characters), it will be digested. You may
37       want to lower "max_key_length" if you are storing a lot of items as
38       long filenames can be more expensive to work with.
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40       The files are evenly distributed within a multi-level directory
41       structure with a customizable "depth", to minimize the time needed to
42       search for a given entry.
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CONSTRUCTOR OPTIONS

45       When using this driver, the following options can be passed to
46       CHI->new() in addition to the CHI.
47
48       root_dir
49           The location in the filesystem that will hold the root of the
50           cache.  Defaults to a directory called 'chi-driver-file' under the
51           OS default temp directory (e.g. '/tmp' on UNIX). This directory
52           will be created as needed on the first cache set.
53
54       depth
55           The number of subdirectories deep to place cache files. Defaults to
56           2. This should be large enough that no leaf directory has more than
57           a few hundred files. Each non-leaf directory contains up to 16
58           subdirectories (0-9, A-F).
59
60       dir_create_mode
61           Permissions mode to use when creating directories. Defaults to
62           0775.
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64       file_create_mode
65           Permissions mode to use when creating files, modified by the
66           current umask.  Defaults to 0666.
67
68       file_extension
69           Extension to append to filename. Default is ".dat".
70

METHODS

72       path_to_key ( $key )
73           Returns the full path to the cache file representing $key, whether
74           or not that entry exists. Returns the empty list if a valid path
75           cannot be computed, for example if the key is too long.
76
77       path_to_namespace
78           Returns the full path to the directory representing this cache's
79           namespace, whether or not it has any entries.
80

TEMPORARY FILE RENAME

82       By default, during a set, a temporary file is created and then
83       atomically renamed to the proper file.  This eliminates the need for
84       locking. You can subclass and override method
85       generate_temporary_filename to either change the path of the temporary
86       filename, or skip the temporary file and rename altogether by having it
87       return undef.
88

SEE ALSO

90       CHI
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AUTHOR

93       Jonathan Swartz <swartz@pobox.com>
94

96       This software is copyright (c) 2021 by Jonathan Swartz.
97
98       This is free software; you can redistribute it and/or modify it under
99       the same terms as the Perl 5 programming language system itself.
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103perl v5.36.0                      2022-07-22              CHI::Driver::File(3)
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