Why is my $_ENV array empty and why are environment variables appearing in $_SERVER?

Why an Empty $_ENV Variable and Mysterious $_SERVER Appearances?

In this perplexing PHP issue, users encounter an empty $_ENV array despite setting environment variables in their .htaccess file. Additionally, the variables inexplicably surface in the $_SERVER array in a seemingly duplicated manner.

Root of the Problem:

1. $_ENV is Hidden by Default:

   • php.ini's variables_order directive, typically set to "GPCS," excludes "E" (ENV) by default. Modifying this setting to "EGPCS" enables $_ENV.

2. SetEnv Variables Land in $_SERVER:

   • Setting environment variables using SetEnv in .htaccess places them in the $_SERVER array, not in $_ENV.

The Mysterious Duplication:

• The variables appear twice in $_SERVER ([REDIRECT_FOO] and [FOO]) because Apache Prefixes the original variable name with REDIRECT_ if it originates from the environment.

Alternative Solution:

• The getenv() function remains unaffected by the php.ini setting and always returns the correct value, regardless of case sensitivity.

Summary:

Understanding these settings and behavior differences helps unravel the mystery of why $_ENV can be empty and why environment variables end up in $_SERVER. Remember to modify variables_order if you need $_ENV populated and use getenv() for reliable retrieval of environment variables.

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