Check for DVWA database connection issues

dvwa_db_connection_test.php

<?php
/*
Put this file in the root of the DVWA installation then access it through a browser.
*/

require_once "config/config.inc.php";

function var_dump_pre ($data) {
    print "<pre>";
    var_dump ($data);
    print "</pre>";
}

print "These are the configuration options that will be use:<br />";
                                                                                                                                           
var_dump_pre ($_DVWA[ 'db_server' ]);
var_dump_pre ($_DVWA[ 'db_database' ]);
var_dump_pre ($_DVWA[ 'db_user' ]);
var_dump_pre ($_DVWA[ 'db_password' ]);

print "Connecting to the database<br />";

$conn = mysqli_connect( $_DVWA[ 'db_server' ],  $_DVWA[ 'db_user' ],  $_DVWA[ 'db_password' ] );

print "This is the result of the connection (NULL is bad)<br />";
var_dump_pre ($conn);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

print "Connection made OK, switching to the right database<br />";

$res = mysqli_select_db($conn, $_DVWA['db_database']);

if (!$res) {
    die("Could not switch to database");
}

print "Closing connection<br />";
$conn->close();
print "Connection closed, all looks good";