Apache Module mod_speling

Summary

Requests to documents sometimes cannot be served by the core apache server because the request was misspelled or miscapitalized. This module addresses this problem by trying to find a matching document, even after all other modules gave up. It does its work by comparing each document name in the requested directory against the requested document namewithout regard to case, and allowingup to one misspelling (character insertion / omission / transposition or wrong character). A list is built with all document names which were matched using this strategy.Erroneous extension can also be fixed by this module.

If, after scanning the directory,

• no matching document was found, Apache will proceed as usual and return an error (404 - document not found).
• only one document is found that "almost" matches the request, then it is returned in the form of a redirection response (301 - Moved Permanently).
• more than one document with a close match was found, then the list of the matches is returned to the client, and the client can select the correct candidate (300 - Multiple Choices).

Directives

• CheckBasenameMatch
• CheckCaseOnly
• CheckSpelling

Bugfix checklist

• httpd changelog
• Known issues
• Report a bug

See also

• Comments

CheckBasenameMatchDirective

When set, this directive extends the action of the spelling correction to the file name extension. For example a filefoo.gif will match a request forfoo orfoo.jpg. This can be particularly useful in conjunction withMultiViews.

CheckCaseOnlyDirective

When set, this directive limits the action of the spelling correction to lower/upper case changes. Other potential corrections are not performed, except whenCheckBasenameMatch is also set.

CheckSpellingDirective

This directive enables or disables the spelling module. When enabled, keep in mind that

• the directory scan which is necessary for the spelling correction will have an impact on the server's performance when many spelling corrections have to be performed at the same time.
• the document trees should not contain sensitive files which could be matched inadvertently by a spelling "correction".
• the module is unable to correct misspelled user names (as inhttp://my.host/~apahce/), just file names or directory names.
• spelling corrections apply strictly to existing files, so a request for the<Location /status> may get incorrectly treated as the negotiated file "/stats.html".

mod_speling should not be enabled inDAV enabled directories, because it will try to "spell fix" newly created resource names against existing filenames, e.g., when trying to upload a new documentdoc43.html it might redirect to an existing documentdoc34.html, which is not what was intended.