How can information from an HTTP request be accessed before it is written to the database?

In PHP, access to information from an HTTP request can be obtained through superglobal arrays such as $_GET, $_POST, $_REQUEST, $_COOKIE, $_FILES, and $_SERVER. These arrays contain data sent by the client before it is written to the database.

For example, if a user submits a form via POST method, the data will be available in $_POST:

$name = $_POST['name'] ?? null;
$email = $_POST['email'] ?? null;

// Here, you can perform validation and processing of the data before saving to the database

Thus, you can retrieve and process request data before storing it in the database, ensuring validation, filtering, and security.