Predefined variables PHP

$_SERVER: http://www.php.net/manual/zh/reserved.variables.server.php

$_ENV: http://www.php.net/manual/zh/reserved.variables.environment. The data in php

$_POST and $_GET can be obtained through $_REQUEST, but $_REQUEST will be slower than $_GET and $_POST.

$_FILE: File upload, http://www.php.net/manual/zh/features.file-upload.post-method.php only has data when uploading files via POST. Refer to Example #3 on the help page

$_COOKIE and $_SESSION are used for session control.

In addition, if you want to customize the value in $_SERVER, you only need to add some commonly used variables (mostly used in clusters) in fastcgi_params. Add the following codes:

fastcgi_param DB4_USER root;
fastcgi_param DB4_PASS "";
fastcgi_param DB4_HOST localhost;
fastcgi_param DB4_PORT 3306;
fastcgi_param DB4_NAME test;

Then get the current environment variable value in $_SERVER["DB4_USER"] root.