Getenv() VS. $_Env in PHP

getenv() vs. $_ENV in PHP

According to the php documentation about getenv, they are exactly the same, except that getenv will look for the variable in a case-insensitive manner when running on case-insensitive file systems (like Windows). On Linux hosts it still works as case-sensitive. Most of the time it probably doesn't matter, but one of the comments on the documentation explains:

For example on Windows $_SERVER['Path'] is like you see, with the first letter capitalized, not 'PATH' as you might expect.

Because of that, I would probably opt to use getenv to improve cross-platform behavior, unless you are certain about the casing of the environment variable you are trying to retrieve.

Steve Clay's comment in this answer highlights another difference:

Added getenv() advantage: you don't need to check isset/empty before access. getenv() won't emit notices.

Why is my $_ENV empty?

Turns out there was two issues here:

1. $_ENV is only populated if php.ini allows it, which it doesn't seem to do by default, at least not in the default WAMP server installation.

; This directive determines which super global arrays are registered when PHP
; starts up. If the register_globals directive is enabled, it also determines
; what order variables are populated into the global space. G,P,C,E & S are
; abbreviations for the following respective super globals: GET, POST, COOKIE,
; ENV and SERVER. There is a performance penalty paid for the registration of
; these arrays and because ENV is not as commonly used as the others, ENV is
; is not recommended on productions servers. You can still get access to
; the environment variables through getenv() should you need to.
; Default Value: "EGPCS"
; Development Value: "GPCS"
; Production Value: "GPCS";
; http://php.net/variables-order
variables_order = "GPCS"

When I set the variables_order back to EGPCS, $_ENV is no longer empty.

2. When you use SetEnv in your .htaccess, it ends up in $_SERVER, not in $_ENV, which I gotta say is a tad confusing when it's named SetEnv...

# .htaccess
SetEnv ENV dev
SetEnv BASE /ssl/

# php
var_dump($_SERVER['ENV'], $_SERVER['BASE']);

// string 'dev' (length=3)
// string '/ssl/' (length=5)

3. The getenv function will always work and is not affected by the PHP setting for $_ENV Additionally it seems to do so insensitive to case, which might be useful.

var_dump(getenv('os'), getenv('env'));

// string 'Windows_NT' (length=10)
// string 'dev' (length=3)

How to Loads environment variables from .env to getenv() PHP MVC

According to the documentation, you should use Dotenv::createUnsafeImmutable()

So instead of:

$dotenv = Dotenv\Dotenv::createMutable(BASE_PATH);

Use:

$dotenv = Dotenv\Dotenv::createUnsafeImmutable(BASE_PATH);

PHP: difference between getenv() and apache_getenv()

getenv calls apache_getenv if you're running the Apache SAPI, otherwise it asks the system. So, no, there is no real functional difference. Stick with getenv.

how can I access environment vars in php

You can access env variables through this function:

getenv ( string $varname )

So, if for example you want the database name:

$db = getenv('DATABASE');

Documentation:

http://php.net/manual/en/function.getenv.php

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