Understanding the REDIRECT_ Prefix in htaccess Environment Variables
When working with environment variables in an .htaccess file, you may encounter instances where the REDIRECT_ prefix is added to variable names. This typically occurs within a directory context when the rewrite engine "starts over" or "loops." During subsequent passes by the rewrite engine, environment variables from the previous phase inherit the REDIRECT_ prefix.
To understand the exact reason for this behavior, it's essential to examine your entire .htaccess file, including the <Directory> containers in the server configuration. Without this information, it's challenging to determine why the prefix is being added and how to potentially avoid it.
However, to prevent additional passes by the rewrite engine and subsequently avoid the REDIRECT_ prefix, you can try including the L flag or END (Apache 2.4) in your rewrite rule. This will effectively terminate the rewrite process after the first pass.
RewriteRule ^(en|de|fr|ar)/(.*) /$2 [E=language:$1,END]
Additionally, depending on your server configuration, you may be able to access the "top-level" variable in PHP using the following code:
<?php
$value = apache_getenv('language',true);
?>
Please note that the behavior of environment variables within an .htaccess file can vary depending on the specific directives and rules you have defined. If you're experiencing unexpected behavior, carefully reviewing your configuration and testing different approaches is recommended.