PHP and MySQL Web Development 4th Ed-tqw-_darksiderg

582 Chapter 27 Building User Authentication and Personalization
As you can see, you call the register() function with the username, email address, and
password that were entered. If this call succeeds, you register the username as a session
variable and provide the user with a link to the main members page. (If it fails, this function
will throw an exception that will be caught in the catch block.) The output is
shown in Figure 27.5.
Figure 27.5
Registration was successful; the user can now go
to the members page.
The register() function is in the included library called user_auth_fns.php.This
function is shown in Listing 27.9.
Listing 27.9 register()Function from user_auth_fns.php—This Function
Attempts to Put the New User’s Information in the Database
function register($username, $email, $password) {
// register new person with db
// return true or error message
// connect to db
$conn = db_connect();
// check if username is unique
$result = $conn->query("select * from user where username='".$username."'");
if (!$result) {
throw new Exception('Could not execute query');