What are common pitfalls to avoid when writing PHP scripts for form data evaluation and Excel export?
One common pitfall to avoid when writing PHP scripts for form data evaluation is not properly sanitizing user input, which can lead to security vulnerabilities such as SQL injection attacks. To prevent this, always use functions like htmlspecialchars() or mysqli_real_escape_string() to sanitize user input before using it in database queries.
// Sanitize 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);
```
Another common pitfall to avoid when exporting data to Excel in PHP is not setting the correct headers for the Excel file, which can result in the file not being recognized as an Excel file when downloaded. To fix this, make sure to set the headers to indicate that the file being generated is an Excel file.
```php
// Set headers for Excel export
header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
header('Content-Disposition: attachment; filename="exported_data.xlsx"');
header('Cache-Control: max-age=0');
// Generate Excel file content
// Code to generate Excel file content goes here