What are some common mistakes that can lead to errors when working with form submissions and directory paths in PHP?

One common mistake when working with form submissions and directory paths in PHP is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection or directory traversal attacks. To prevent this, always use functions like `htmlspecialchars()` or `mysqli_real_escape_string()` to sanitize user input before using it in database queries or file paths. 

// Example of sanitizing user input before using it in a database query
$user_input = $_POST['user_input'];
$sanitized_input = mysqli_real_escape_string($connection, $user_input);

$query = "SELECT * FROM users WHERE username = '$sanitized_input'";
$result = mysqli_query($connection, $query);
```

```php
// Example of sanitizing user input before using it in a file path
$user_input = $_POST['user_input'];
$sanitized_input = htmlspecialchars($user_input);

$file_path = "/path/to/directory/" . $sanitized_input . ".txt";
$file_contents = file_get_contents($file_path);

Keywords

form submissions directory paths PHP errors validation file handling

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