RewriteMap Question

Is the fallback url necessary after the '¦' pipe?

[5x54u]

RewriteCond %{REQUEST_URI} !-U
RewriteRule ^(.*) ${providers:$1¦}

The above code looks ahead to see if a directory will throw a 404 and then uses the providers text map. My question is, do I have to have a default fall back url after the pipe because if a directory is not found and the string is not in the providers map - i do want to throw a 404

[Caterham]

The above code looks ahead to see if a directory will throw a 404

Really? -U checks only access controls via a subrequest. I don't want to go into the details, but there is no 404 prior processing the content handler (and the subrequest doesn't run the content handler of course) unless you hacked a fixup hook to return HTTP_NOT_FOUND if r->finfo.filetype is 0.

. My question is, do I have to have a default fall back url after the pipe

Yes, due to to your rule-design. An empty substitution results in a HTTP 400 bad request. Use the map lookup in a condition and check for a non-empty value like

RewriteCond ${providers:$1} ^(.+)
RewriteRule ^(.*) %1 [L]

[5x54u]

That one does not work - how can I test to make sure it is seeing the map file.

This is what I have in the httpd.cof under the particular domain:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteOptions inherit
RewriteMap providers txt:/usr/local/apache2/conf/providers.map
</IfModule>

And I placed your suggestion in the .htaccess under the root of the site

[Caterham]

in the .htaccess

Why? That is not only inefficient since there's absolutely no need for .htaccess files if you have access to the server config but the directory context of mod_rewrite is due to the internal redirect not so efficient and more complex, too. Avoid that by putting the rules into the httpd.conf as well.

Examine problems with a RewriteLog.