What are the common pitfalls to avoid when passing variables between PHP scripts and forms in a web application?

One common pitfall when passing variables between PHP scripts and forms in a web application is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection or cross-site scripting attacks. To avoid this, always use functions like htmlspecialchars() or mysqli_real_escape_string() to sanitize user input before using it in your scripts. 

// Example of sanitizing user input using htmlspecialchars()
$name = htmlspecialchars($_POST['name']);
$email = htmlspecialchars($_POST['email']);
```

Another pitfall is not validating user input before processing it, which can result in unexpected behavior or errors in your application. Always validate user input to ensure it meets the expected format or criteria before using it in your scripts.

```php
// Example of validating user input with a regular expression
if (preg_match("/^[a-zA-Z ]*$/", $_POST['name'])) {
    $name = $_POST['name'];
} else {
    echo "Invalid name input";
}
```

Lastly, be cautious when using global variables like $_GET or $_POST directly in your scripts, as it can make your code harder to maintain and debug. Instead, consider using a more structured approach like passing variables through functions or using sessions to store and retrieve data across multiple scripts.

```php
// Example of passing variables through a function
function processForm($name, $email) {
    // Process the form data here
}

$name = $_POST['name'];
$email = $_POST['email'];
processForm($name, $email);

Keywords

variable passing PHP scripts forms web application security vulnerabilities

Related Questions