What are some potential pitfalls to avoid when working with PHP file upload functionality?

One potential pitfall to avoid when working with PHP file upload functionality is not properly validating the file type before allowing it to be uploaded. This can leave your server vulnerable to malicious files being uploaded and executed. To prevent this, always check the file type using the `$_FILES['file']['type']` variable and make sure it matches an allowed file type before moving the file to its final destination. 

// Check file type before allowing upload
$allowedTypes = ['image/jpeg', 'image/png', 'image/gif'];
if (!in_array($_FILES['file']['type'], $allowedTypes)) {
    die('Invalid file type. Allowed types are: jpeg, png, gif');
}

// Move uploaded file to final destination
move_uploaded_file($_FILES['file']['tmp_name'], 'uploads/' . $_FILES['file']['name']);
echo 'File uploaded successfully!';

Keywords

file upload security vulnerabilities file size limit file type validation error handling

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