PlainFileStoreContrib

Store Foswiki data using plain text files

This is a full implementation of a Foswiki store that uses nothing more sophisticated than plain files and directories In the Foswiki spirit these files are organised in a simple and clear structure using intention-revealing file names.

Advantages:

• Uses simple files - no shell commands used
• Incorporates script for moving between store implementations

The traditional store implementations (RcsLite and RcsWrap) use a version control methodology called. RCS uses something called "deltas" to represent the differences between successive versions of topics. This has the advantage that the store is kept reasonably small, but there are some issues with these implementations:

• RcsWrap invokes external programs. These are reasonably fast, but can cause major performance problems when used with a web server accelerator, such as fcgi or mod_perl. Most sites using accelerators therefore use:
• RcsLite, which is a pure-perl implementation of RCS. This doesn't use any external programs but is very inefficient with topics that have large numbers of versions.

The PlainFileStoreContrib implements topic and attachment histories by keeping a complete file for each version of the topic/attachment. This means it is less efficient in terms of disk space than RCS - at least, it is less efficient for text files; binary files, such as images, are equal. For many sites this is an acceptable tradeoff, as disk space is relatively cheap, and Foswiki doesn't use much even with this store.

• Webs map to directories, like in the RCS stores
• Topics are stored in data/web/topic.txt, like in the RCS stores
• Topic histories are in data/web/topic,pfv/
• Attachments are in pub/web/topic/attachment, like in the RCS stores
• Attachment histories are in pub/web/topic/attachment,pfv/
• Meta-data is stored in a separate file data/web/topic.m or pub/web/topic/attachment.m
• Histories consist of files numbered for the revision they store (each with a corresponding metafile)

The latest rev also has a history file (note: this means that everything is stored at least twice; same as in the RCS stores)

• Automatic attachment of files placed in pub directories is not supported for performance reasons.
• Mapping the 'TWiki' web to the Foswiki 'System' web (as required for the TWikiCompatibilityPlugin) is not supported. If you require TWiki compatibility, use one of the RCSStoreContrib stores.

Developers note: this contrib is tested using the standard store unit tests.

Moving between store implementations

Foswiki < 2.0

The tools/bulk_copy.pl script (part of the Foswiki 2.0 release package, or available from github or ) allows you to move between different store implementations. Do not share data areas between different store implementations.

Developer Notes

Testing is performed using the standard system tests. Because some of these tests are written assuming a broken store (the RCS based stores have problems with "inconsistent topics") they are known to fail with the PlainFileStore. The tests that are relevant to this store are:

• HierarchicalWebsTests
• StoreImplementationTests
• StoreTests

A subset of the VC* store tests may also be run as a sanity check, but expect failures as this store maintains a correct version history, unlike the RCS stores.

Installation

You do not need to install anything in the browser to use this extension. The following instructions are for the administrator who installs the extension on the server.

Open configure, and open the "Extensions" section. "Extensions Operation and Maintenance" Tab -> "Install, Update or Remove extensions" Tab. Click the "Search for Extensions" button. Enter part of the extension name or description and press search. Select the desired extension(s) and click install. If an extension is already installed, it will not show up in the search results.

You can also install from the shell by running the extension installer as the web server user: (Be sure to run as the webserver user, not as root!)

cd /path/to/foswiki
perl tools/extension_installer <NameOfExtension> install

If you have any problems, or if the extension isn't available in configure, then you can still install manually from the command-line. See https://foswiki.org/Support/ManuallyInstallingExtensions for more help.

Info

Many thanks to the following sponsors for supporting this work

• C-Dot Consulting
• TRIN, The Taxonomy Research & Information Network

Dependencies

Change History