pdf file displays as text/html instead of application/pdf - php

Question

I'm trying to display a .pdf file in a php application. It works perfectly well on my local development setup but on production, the same code displays the pdf as garbled text.
These are the request headers i'm using:
<?php
$file = $_GET["f"];
$filename = 'contrato.pdf';
header('Content-type: application/pdf');
header('Content-Disposition: inline; filename="' .$filename. '"');
header('Content-Transfer-Encoding: binary');
header('Accept-Ranges: bytes');
readfile($file);
?>
These are the production response headers according to chrome:
Connection:Keep-Alive
Content-Encoding:gzip
Content-Type:text/html
Date:Mon, 03 Apr 2017 21:31:19 GMT
Keep-Alive:timeout=15, max=189
Server:Apache
Transfer-Encoding:chunked
Vary:Accept-Encoding
On the development setup, the response headers are these:
Accept-Ranges:bytes
Connection:Keep-Alive
Content-Disposition:inline; filename="contrato.pdf"
Content-Transfer-Encoding:binary
Content-Type:application/pdf
Date:Mon, 03 Apr 2017 21:33:44 GMT
Keep-Alive:timeout=5, max=100
Server:Apache/2.4.7 (Win32) PHP/5.5.8
Transfer-Encoding:chunked
X-Powered-By:PHP/5.5.8
Could it be due to the apache settings?

Answer 1

I think it's the error in this line:
header('Content-type: application/pdf');
Note the small letter t
this line should be like this:
header('Content-Type: application/pdf');
also note that you are reading a file using the $_GET["f"]
this is wrong, instead read the file from $filename variable.
Change the last line to :
readfile($filename);
Anyway here's the correction of your code:
<?php
$file = $_GET["f"];
$filename = 'abc.pdf';
header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename="' .$file. '"');
header('Content-Transfer-Encoding: binary');
header('Accept-Ranges: bytes');
readfile($filename);
?>