What are some common pitfalls to avoid when developing Multi-Page and Single-Page web applications in PHP?
One common pitfall to avoid when developing Multi-Page and Single-Page web applications in PHP is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection or cross-site scripting attacks. To solve this issue, always use prepared statements or parameterized queries when interacting with a database to prevent SQL injection attacks.
// Using prepared statements to prevent SQL injection
$stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username");
$stmt->bindParam(':username', $username);
$stmt->execute();
```
Another common pitfall is not properly validating and sanitizing user input before processing it, which can lead to unexpected behavior or vulnerabilities in the application. To solve this issue, always validate and sanitize user input using functions like `filter_input()` or `htmlspecialchars()`.
```php
// Validating and sanitizing user input
$username = filter_input(INPUT_POST, 'username', FILTER_SANITIZE_STRING);
$email = filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL);
$password = htmlspecialchars($_POST['password']);