Using RewriteBase without knowing it

So here's an interesting tidbit that I discovered this afternoon: you can use RewriteBase in a .htaccess file without knowing the actual base URL.  This is extremely useful for writing a portable .htaccess file.

In case you don't know, the RewriteBase directive to Apache's mod_rewrite is used to specify the base path used in relative rewrite rules.  Normally, if you don't specify a full path, mod_rewrite will just rewrite the URL relative to the current directory, i.e. the one where the .htaccess file is.  Unfortunately, this isn't always the right thing to do.  For example, if the .htaccess file is under an aliased directory, then mod_rewrite will try to make the URL relative to the filesystem path rather than the path alias, which won't work.

Turns out that you can account for this in four (relatively) simple lines:

RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond $1#%{REQUEST_URI} ([^#]*)#(.*)\1$
RewriteRule ^(.*)$ %2index.php [QSA,L]

All you need to do is substitute in your rewrite target for "index.php" and it "just works".  No changes to server configuration required and no need to edit the RewriteBase for the specific server.

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Comments #

    Avoid arvixe: cretinous support

    Wait until you discover variation host provider to another. And the fun rests atop unseen server side configuration

    • Comment posted on Wednesday 11 Feb 2015 at 9:00am
    • By Ray n'ing

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