Htaccess Rewrite for Redirecting Uppercase to Lowercase

Want to redirect all links with any uppercase characters to lowercase using pure mod_rewrite within an .htaccess file? Sure why not! OR how to use RewriteMap and mod_speling for those with access to httpd.conf

Htaccess to Redirect Uppercase to Lowercase

This should go at the very top of your .htaccess file. At least it should go above ANY other RewriteRules. That is because this uses a loop, until there are no more uppercase characters to convert, it will keep starting at the first HASCAPS:TRUE RewriteRule. Oh, and this is actually really quick and isn't gonna slow down anything.

RewriteEngine On
RewriteBase /

# If there are caps, set HASCAPS to true and skip next rule
RewriteRule [A-Z] - [E=HASCAPS:TRUE,S=1]

# Skip this entire section if no uppercase letters in requested URL
RewriteRule ![A-Z] - [S=28]

# Replace single occurance of CAP with cap, then process next Rule.
RewriteRule ^([^A]*)A(.*)$ $1a$2
RewriteRule ^([^B]*)B(.*)$ $1b$2
RewriteRule ^([^C]*)C(.*)$ $1c$2
RewriteRule ^([^D]*)D(.*)$ $1d$2
RewriteRule ^([^E]*)E(.*)$ $1e$2
RewriteRule ^([^F]*)F(.*)$ $1f$2
RewriteRule ^([^G]*)G(.*)$ $1g$2
RewriteRule ^([^H]*)H(.*)$ $1h$2
RewriteRule ^([^I]*)I(.*)$ $1i$2
RewriteRule ^([^J]*)J(.*)$ $1j$2
RewriteRule ^([^K]*)K(.*)$ $1k$2
RewriteRule ^([^L]*)L(.*)$ $1l$2
RewriteRule ^([^M]*)M(.*)$ $1m$2
RewriteRule ^([^N]*)N(.*)$ $1n$2
RewriteRule ^([^O]*)O(.*)$ $1o$2
RewriteRule ^([^P]*)P(.*)$ $1p$2
RewriteRule ^([^Q]*)Q(.*)$ $1q$2
RewriteRule ^([^R]*)R(.*)$ $1r$2
RewriteRule ^([^S]*)S(.*)$ $1s$2
RewriteRule ^([^T]*)T(.*)$ $1t$2
RewriteRule ^([^U]*)U(.*)$ $1u$2
RewriteRule ^([^V]*)V(.*)$ $1v$2
RewriteRule ^([^W]*)W(.*)$ $1w$2
RewriteRule ^([^X]*)X(.*)$ $1x$2
RewriteRule ^([^Y]*)Y(.*)$ $1y$2
RewriteRule ^([^Z]*)Z(.*)$ $1z$2

# If there are any uppercase letters, restart at very first RewriteRule in file.
RewriteRule [A-Z] - [N]

RewriteCond %{ENV:HASCAPS} TRUE
RewriteRule ^/?(.*) /$1 [R=301,L]

Using RewriteMap in httpd.conf

This is technically a faster way to do this, but it has to be in the httpd.conf file, not .htaccess

RewriteEngine on
RewriteBase /
RewriteMap lowercase int:tolower
RewriteCond $1 [A-Z]
RewriteRule ^/?(.*)$ /${lowercase:$1} [R=301,L]

Using mod_speling in httpd.conf

You can check out enabling the mod_speling apache module also. I personally don't use it, but many people love it.

CheckCaseOnly On
CheckSpelling On