Print to screen and save to file the most important global PHP variables: _POST, _GET, _SERVER, _FILES, _REQUEST.

request.php

<?php
/**
 * Print to screen and save to file the most important global PHP
 * variables: _POST, _GET, _SERVER, _FILES, _REQUEST.
 *
 * As an alternative, consider also the free service http://requestb.in/.
 *
 * Created by Guido W. Pettinari on 06/06/2016.
 * Latest version: https://gist.github.com/2eae82be7d5b4c35dbfd73fcf5c7eefb
 */
?>

<?php

/* We don't want to print the output straight away */
ob_start( );

/* Echo all the useful global variables */
echo "<<<<< _POST >>>>>>" . PHP_EOL;
print_r($_POST);
echo PHP_EOL . PHP_EOL . PHP_EOL;

echo "<<<<< _GET >>>>>>" . PHP_EOL;
print_r($_GET);
echo PHP_EOL . PHP_EOL . PHP_EOL;

echo "<<<<< _SERVER >>>>>>" . PHP_EOL;
print_r($_SERVER);
echo PHP_EOL . PHP_EOL . PHP_EOL;

echo "<<<<< _FILES >>>>>>" . PHP_EOL;
print_r($_FILES);
echo PHP_EOL . PHP_EOL . PHP_EOL;

echo "<<<<< _REQUEST >>>>>>" . PHP_EOL;
print_r($_REQUEST);
echo PHP_EOL . PHP_EOL . PHP_EOL;

/* Store the variables in a string */
$output = ob_get_clean( );

/* Output the string to screen */
echo $output;

/* Write the string to file */
file_put_contents('request.txt', $output);

?>