Failed to open pdf file [duplicate] - php

Question

This question already has answers here:
Chrome has "Failed to load PDF document" error message on inline PDFs
(7 answers)
Closed 5 years ago.
My code is working fine. My files are downloading also but when I open one file then it is not opening giving an error "Error
Failed to load PDF document."
<?php
$pno = $_GET['pno'];
$sql = "SELECT file FROM tenders WHERE Tno = $id";
$file = "data/" . $mysql_row['file '];
header("Content-type:application/pdf");
header("Content-Disposition:attachment;filename='downloaded.pdf'");
readfile($file);
?>

Answer 1

$file = "path_to_file";
$fp = fopen($file, "r") ;
header("Cache-Control: maxage=1");
header("Pragma: public");
header("Content-type: application/pdf");
header("Content-Disposition: inline; filename=".$myFileName."");
header("Content-Description: PHP Generated Data");
header("Content-Transfer-Encoding: binary");
header('Content-Length:' . filesize($file));
ob_clean();
flush();
while (!feof($fp)) {
$buff = fread($fp, 1024);
print $buff;
}
exit;

Answer 2

I would recommend to always check if the file exists. If it doesn't readfile() would eventually put an error inside your pdf-file which may cause the problem. Try it like this:
$pno = $_GET['pno'];
$sql = "SELECT file FROM tenders WHERE Tno = $id";
$file = "data/" . $mysql_row['file '];
if(file_exists($file)){
header("Content-type:application/pdf");
header("Content-Disposition:attachment;filename='downloaded.pdf'");
readfile($file);
} else {
echo "File does not exist!";
}
Also there is no declaration of the $id variable. Could it be that $pno should be changed to $id?