未定义变量：函数参数 (PHP)

Question

我是 PHP 的新手，如果未定义用户名和密码，我的 php 表单验证会出现 return 这个错误。

注意：未定义的变量：D:\hpsp\controller\loginvalidation.inc.php中的用户名第64行

我使用 2 个函数（usernameValidation 和 passwordValidation）来检查 $_POST 输入是否正确，但我不知道我必须把正确的脚本放在哪里，提前谢谢你。

<?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

用参数定义你的函数

function usernameValidation(){ ... }

并称之为

if ( usernameValidation() == true AND passwordValidation() == true )

Answer 2

<?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 3

将最后一个 if 条件更改为以下代码：

if ( usernameValidation($_POST['username']) == true AND passwordValidation($_POST['password']) == true )
{

}

在您的函数中仅使用变量 $username 和 $password 而不是（！）$_POST['username'] 和 $_POST['password']

Answer 4

我会做这样的事情（请注意，您永远不想回显电子邮件和密码的个别消息，以阻止黑客获取有关正确信息的信息：

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 5

你定义了$username和$password，就是$_POST['username']和$_POST['password']。你也可以在没有参数的情况下创建函数。通过进行这些更改，您的问题将得到解决。

未定义变量：函数参数 (PHP)

Undefined variable : function parameter (PHP)

php

post

function

undefined

function-parameter