输出text文件给用户

$date=date("Ymd");
$filename = $date."-".$this->user_id.".txt";
$fp = fopen('./plugins/bijidown/'.$filename, 'w') or die("Unable to open file!");
fwrite($fp, $str);
$fp = fopen('./plugins/bijidown/'.$filename, 'r') or die("Unable to open file!");
Header ( "Content-type: application/octet-stream" );
Header ( "Accept-Ranges: bytes" );
Header ( "Accept-Length: " . filesize ( './plugins/bijidown/' . $filename ) );
Header ( "Content-Disposition: attachment; filename=" . $filename );
//输出文件内容
//读取文件内容并直接输出到浏览器
echo fread ( $fp, filesize ( './plugins/bijidown/' . $filename ) );
fclose ( $fp );
exit ();