Undefined variable : function parameter (PHP) - php

Question

I'am newbie with PHP and i have a issue with my php form validation that return this error, if the username and the password are not defined.
Notice: Undefined variable: username in D:\hpsp\controller\loginvalidation.inc.php on line 64
I use 2 functions (usernameValidation & passwordValidation) to check if $_POST input are correct or not but i don't know what's and where i have to put the correct script, Thank you in advance.
<?php
session_start();
require_once('../model/pdo.inc.php');
// function for checking the username validation (not empty & Regex)
function usernameValidation($username) // Username as parameter
{
if ( !empty($_POST['username']) )
{
$username = strtolower(htmlspecialchars($_POST['username'])); // username will be tranform to lowercase before regex matching
if ( preg_match('#^[a-z0-9\.]{5,20}$#', $username) ) // 5 <= username lenght <= 20 in lowercase character to be valid
{
return true; // return true when the username is valid
}
else
{
echo "Invalid username, please re-try" ;
}
}
else
{
echo "Enter your username";
}
}
// function for checking the password validation (not empty & Regex)
function passwordValidation($password) // Password as parameter
{
if ( !empty($_POST['password']) )
{
$password = htmlspecialchars($_POST['password']) ; // Protect the password
if ( preg_match('#^[a-zA-Z0-9\.-_#$()]{6,10}$#', $password) ) // 6 <= password length <= 10 character to be valid
{
return true; // return true when password is valid
}
else
{
echo "Invalid password, please re-try";
}
}
else
{
echo "Enter your password";
}
}
if ( usernameValidation($username) == true AND passwordValidation($password) == true )
{
// PDO Query (SELECT ...)
}

Answer 1

I would do something like this (note you never want to echo out individual messages for email and password to stop hackers gaining information about which is correct:
session_start();
require_once('../model/pdo.inc.php');
//username and password will contain the posted resulte or FALSE
$username = usernameValidation();
$password = passwordValidation();
if (!$username OR !$password) {
echo 'Invalid username or password!';
die;
}
// PDO Query (SELECT ...)
// function for checking the username validation (not empty & Regex)
function usernameValidation() { // Username as parameter
if (!empty($_POST['username'])) {
$username = strtolower(htmlspecialchars($_POST['username'])); // username will be tranform to lowercase before regex matching
if (preg_match('#^[a-z0-9\.]{5,20}$#', $username)) { // 5 <= username lenght <= 20 in lowercase character to be valid
return $username; // return true when the username is valid
}
}
return FALSE;
}
// function for checking the password validation (not empty & Regex)
function passwordValidation() { // Password as parameter
if (!empty($_POST['password'])) {
$password = htmlspecialchars($_POST['password']); // Protect the password
if (preg_match('#^[a-zA-Z0-9\.-_#$()]{6,10}$#', $password)) { // 6 <= password length <= 10 character to be valid
return $password; // return true when password is valid
}
}
return FALSE;
}

Answer 2

Define your functions withow arguments
function usernameValidation(){ ... }
and call it
if ( usernameValidation() == true AND passwordValidation() == true )

Answer 3

<?php
session_start();
require_once('../model/pdo.inc.php');
// function for checking the username validation (not empty & Regex)
function usernameValidation($username) // Username as parameter
{
if ( !empty($_POST['username']) )
{
$username = strtolower(htmlspecialchars($_POST['username'])); // username will be tranform to lowercase before regex matching
if ( preg_match('#^[a-z0-9\.]{5,20}$#', $username) ) // 5 <= username lenght <= 20 in lowercase character to be valid
{
return true; // return true when the username is valid
}
else
{
echo "Invalid username, please re-try" ;
}
}
else
{
echo "Enter your username";
}
}
// function for checking the password validation (not empty & Regex)
function passwordValidation($password) // Password as parameter
{
if ( !empty($_POST['password']) )
{
$password = htmlspecialchars($_POST['password']) ; // Protect the password
if ( preg_match('#^[a-zA-Z0-9\.-_#$()]{6,10}$#', $password) ) // 6 <= password length <= 10 character to be valid
{
return true; // return true when password is valid
}
else
{
echo "Invalid password, please re-try";
}
}
else
{
echo "Enter your password";
}
}
$username = $_POST['username'];
$password = $_POST['password'];
if ( usernameValidation($username) == true AND passwordValidation($password) == true )
{
// PDO Query (SELECT ...)
}

Answer 4

Change your last if condition to the code below:
if ( usernameValidation($_POST['username']) == true AND passwordValidation($_POST['password']) == true )
{
}
In your functions only use the variables $username and $password and not(!) $_POST['username'] and $_POST['password']

Answer 5

you are defined $username and $password, it is $_POST['username'] and $_POST['password']. And you can also make function without parameter. by making these change your problem will solved.