Creating a PHP database connection file from a form

The ever common PHP MySQL database connection file, mostly named something like dbconnection.php or dbcon.php which gets used in a require_once situation whereby you need a connection to the database.

The code inside this file is either a MySQLi or PDO connection which needs hostname, database name, user and password parameters.

Of course manually filling this out is very easy however you can also use a HTML form and some PHP to create the file.

As you can see below nothing special is used, simple POST from a form with PHP fopen() and fwrite(). You can even choose the name of the output PHP file and the form plus create.php get deleted once you have made the connection file.

Example code

The form (index.html):

<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.3.1/css/bootstrap.min.css">
<div class="container">
    <form action="create.php" method="post">
        <div class="form-group row">
            <label for="host" class="col-4 col-form-label">Host</label>
            <div class="col-8">
                <input id="host" name="host" placeholder="localhost" type="text" class="form-control"
                       required="required">
            </div>
        </div>
        <div class="form-group row">
            <label for="db" class="col-4 col-form-label">Database</label>
            <div class="col-8">
                <input id="db" name="db" placeholder="database name" type="text" class="form-control"
                       required="required">
            </div>
        </div>
        <div class="form-group row">
            <label for="user" class="col-4 col-form-label">Username</label>
            <div class="col-8">
                <input id="user" name="user" placeholder="User" type="text" class="form-control" required="required">
            </div>
        </div>
        <div class="form-group row">
            <label for="password" class="col-4 col-form-label">Password</label>
            <div class="col-8">
                <input id="password" name="password" type="text" class="form-control" required="required">
            </div>
        </div>
        <div class="form-group row">
            <label for="filename" class="col-4 col-form-label">File name</label>
            <div class="col-8">
                <input id="filename" name="filename" placeholder="dbconnect" type="text" class="form-control"
                       required="required">
            </div>
        </div>
        <div class="form-group row">
            <div class="offset-4 col-8">
                <button name="submit" type="submit" class="btn btn-primary">Create</button>
            </div>
        </div>
    </form>
</div>

create.php:

<?php
function create_db_connection($hostname, $database, $user, $password, $filename)
{
    $content = '<?php
$db = new PDO("mysql:host=' . $hostname . ';dbname=' . $database . ';charset=utf8mb4", "' . $user . '", "' . $password . '");
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);';
    $the_file = fopen("$filename.php", "w") or die("Unable to open file!");
    fwrite($the_file, $content);
    fclose($the_file);
}

create_db_connection($_POST['host'], $_POST['db'], $_POST['user'], $_POST['password'], $_POST['filename']);

unlink('index.html');//Deletes
unlink('create.php');