Question about header Upload

Please refer to the following code for header Download. a blank file is downloaded every time you click it. How to modify if (! Empty ($ _ GET [fn]) {header ('content-Encoding: none'); header ('content-Type: Ask: header download question
Download with the implementation header. the code is as follows. each click is to download a blank file. How to modify
If (! Empty ($ _ GET [fn]) {

Header ('content-Encoding: none ');
Header ('content-Type: text/plain ');
Header ('content-Length: '. filesize ($ file_name ));
Header ('content-Disposition: attachment; filename = ". $ fn ."');

}
There is also a get button, so I won't send it out, and there is no score for new people.

------ Solution --------------------
If (! Empty ($ _ GET [fn]) {
$ Fn = $ _ GET ['FN '];
Header ('content-Encoding: none ');
Header ('content-Type: text/plain ');
Header ('content-Length: '. filesize ($ fn ));
Header ('content-Disposition: attachment; filename = "'. $ fn .'"');
Readfile ($ fn );
}
------ Solution --------------------
You only sent the header, but did not send the body
------ Solution --------------------
The readfile ('path/filename ') is missing.