How can the PHP configuration settings, such as file_uploads and upload_tmp_dir, affect the functionality of a local file upload script?

The PHP configuration settings file_uploads and upload_tmp_dir dictate whether file uploads are allowed and where uploaded files are stored temporarily. If these settings are not correctly configured, a local file upload script may not function properly. To ensure the script works as intended, make sure file_uploads is set to "On" and upload_tmp_dir points to a valid directory where PHP has write permissions.

// Check if file uploads are allowed
if (ini_get('file_uploads') != 1) {
    // Enable file uploads
    ini_set('file_uploads', '1');
}

// Set the upload_tmp_dir to a valid directory
if (ini_get('upload_tmp_dir') != '/path/to/upload/tmp/dir') {
    // Set the upload_tmp_dir to a valid directory
    ini_set('upload_tmp_dir', '/path/to/upload/tmp/dir');
}