PDFs not displaying correctly after htaccess redirect to php authentication script

Question

Mouthful of a title there.

Following this awesome post: https://wordpress.stackexchange.com/questions/37144/how-to-protect-uploads-if-user-is-not-logged-in I've created an htaccess rule to redirect a certain directory:

RewriteCond %{REQUEST_FILENAME} -s
RewriteRule ^wp-content/uploads/indres(.*)$ dl-file-indres.php?file=$1 [QSA,L]

to a php authentication script (altered a little from the original post to reflect a directory within WP's default upload path):

<?php 

require_once('wp-load.php');

current_user_can('edit_posts') || auth_redirect();

list($basedir) = array_values(array_intersect_key(wp_upload_dir(), array('basedir' => 1)))+array(NULL);

$file = rtrim($basedir,'/').'/indres/'.str_replace('..', '', isset($_GET[ 'file' ])?$_GET[ 'file' ]:'');
if (!$basedir || !is_file($file)) {
 status_header(404);
die('404 &#8212; File not found.');
}

$mime = wp_check_filetype($file);
if( false === $mime[ 'type' ] && function_exists( 'mime_content_type' ) )
$mime[ 'type' ] = mime_content_type( $file );

if( $mime[ 'type' ] )
$mimetype = $mime[ 'type' ];
else
$mimetype = 'image/' . substr( $file, strrpos( $file, '.' ) + 1 );

header( 'Content-Type: ' . $mimetype ); // always send this
if ( false === strpos( $_SERVER['SERVER_SOFTWARE'], 'Microsoft-IIS' ) )
header( 'Content-Length: ' . filesize( $file ) );

$last_modified = gmdate( 'D, d M Y H:i:s', filemtime( $file ) );
$etag = '"' . md5( $last_modified ) . '"';
header( "Last-Modified: $last_modified GMT" );
header( 'ETag: ' . $etag );
header( 'Expires: ' . gmdate( 'D, d M Y H:i:s', time() + 100000000 ) . ' GMT' );

// Support for Conditional GET
$client_etag = isset( $_SERVER['HTTP_IF_NONE_MATCH'] ) ? stripslashes( $_SERVER['HTTP_IF_NONE_MATCH'] ) : false;

if( ! isset( $_SERVER['HTTP_IF_MODIFIED_SINCE'] ) )
$_SERVER['HTTP_IF_MODIFIED_SINCE'] = false;

$client_last_modified = trim( $_SERVER['HTTP_IF_MODIFIED_SINCE'] );
// If string is empty, return 0. If not, attempt to parse into a timestamp
$client_modified_timestamp = $client_last_modified ? strtotime( $client_last_modified ) : 0;

// Make a timestamp for our most recent modification...
$modified_timestamp = strtotime($last_modified);

if ( ( $client_last_modified && $client_etag )
? ( ( $client_modified_timestamp >= $modified_timestamp) && ( $client_etag == $etag ) )
: ( ( $client_modified_timestamp >= $modified_timestamp) || ( $client_etag == $etag ) )
) {
status_header( 304 );
exit;
}

// If we made it this far, just serve the file
readfile( $file );

So this works exactly as intended, except for one big problem: all the pdfs are corrupted, no matter what browser I use, even if I force users to download the file using AddType application/octet-stream .pdf . It will download about 90% and display a message that it is not displaying correctly. If I comment out the .htaccess rules the pdf shows up just fine.

It seems to me that the problem lays within the php script itself, but I'm at a loss as to what in the script is causing it. Anyone have any ideas? Thanks much,

Answer 1

Turns out the conflict was with WP Minify plugin. Not sure why, but that's the culprit.