PHP Working with files

gistfile1.php

<?php

// Downloading a file
header("Content-type: application/csv");
header("Content-Disposition: attachment; filename=".date('Ymd-His ').$this->query.".csv");
header("Pragma: no-cache");
header("Expires: 0");


// Check if file exists
if (file_exists(strtolower($filename).'.'.$this->extension)) {}


// Save file
$filehandle = fopen($filename, 'w') or die("Error");
$fwrite = fwrite($filehandle, $text);
fclose($filehandle);


// Delete file
unlink($this->filename);