How Can I Preserve Dot Characters in PHP Variable Names from User Input?

Preserving Dot Characters in PHP Variable Names from GET, POST, and COOKIE Input

In PHP, dot characters (.) in variable names passed through GET, POST, or COOKIE requests are automatically replaced with underscores (_). This can be problematic in certain scenarios.

Explanation of PHP's Behavior

According to PHP's documentation, dots are not valid characters in PHP variable names. PHP converts them to underscores to prevent syntax errors. The following characters are also converted to underscores:

• Space ( )
• Open square bracket ([)
• Various non-ASCII characters

Disabling Automatic Replacement

Unfortunately, there is no built-in PHP configuration option to disable this automatic replacement behavior. However, you can manually convert the underscores back to dots in your script.

Solution: Post-Processing Replacement

Method 1: Using str_replace

The following code replaces all underscores with dots using the str_replace function:

<?php
$var_with_underscores = $_SERVER['REQUEST_URI'];
$var_with_dots = str_replace('_', '.', $var_with_underscores);

Method 2: Using preg_replace

You can also use a regular expression to perform the replacement:

<?php
$var_with_underscores = $_SERVER['REQUEST_URI'];
$var_with_dots = preg_replace('/_/', '.', $var_with_underscores);

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