Two ways, simple in 2. with the help of an apache rule or in 1. with the help of custom code in a plugin.
1. Plugin
You can write a plugin using the init hook and the get-value $_GET[ 'file' ];. If the user has this get-value, jump in a function to check the rights for access on the files: For example, with a checkbox inside a Meta Box.
add_action( 'init', 'fb_init' );
function fb_init() {
// this in a function for init-hook
if ( '' != $_GET[ 'file' ] ) {
fb_get_file( $_GET[ 'file' ] );
}
}
the function fb_get_file()
function fb_get_file( $file ) {
$upload = wp_upload_dir();
$the_file = $file;
$file = $upload[ 'basedir' ] . '/' . $file;
if ( !is_file( $file ) ) {
status_header( 404 );
die( '404 — File not found.' );
}
else {
$image = get_posts( array( 'post_type' => 'attachment', 'meta_query' => array( array( 'key' => '_wp_attached_file', 'value' => $the_file ) ) ) );
if ( 0 < count( $image ) && 0 < $image[0] -> post_parent ) { // attachment found and parent available
if ( post_password_required( $image[0] -> post_parent ) ) { // password for the post is not available
wp_die( get_the_password_form() );// show the password form
}
$status = get_post_meta( $image[0] -> post_parent, '_inpsyde_protect_content', true );
if ( 1 == $status && !is_user_logged_in() ) {
wp_redirect( wp_login_url( $upload[ 'baseurl' ] . '/' . $the_file ) );
die();
}
}
else {
// not a normal attachment check for thumbnail
$filename = pathinfo( $the_file );
$images = get_posts( array( 'post_type' => 'attachment', 'meta_query' => array( array( 'key' => '_wp_attachment_metadata', 'compare' => 'LIKE', 'value' => $filename[ 'filename' ] . '.' . $filename[ 'extension' ] ) ) ) );
if ( 0 < count( $images ) ) {
foreach ( $images as $SINGLEimage ) {
$meta = wp_get_attachment_metadata( $SINGLEimage -> ID );
if ( 0 < count( $meta[ 'sizes' ] ) ) {
$filepath = pathinfo( $meta[ 'file' ] );
if ( $filepath[ 'dirname' ] == $filename[ 'dirname' ] ) {// current path of the thumbnail
foreach ( $meta[ 'sizes' ] as $SINGLEsize ) {
if ( $filename[ 'filename' ] . '.' . $filename[ 'extension' ] == $SINGLEsize[ 'file' ] ) {
if ( post_password_required( $SINGLEimage -> post_parent ) ) { // password for the post is not available
wp_die( get_the_password_form() );// show the password form
}
die('dD');
$status = get_post_meta( $SINGLEimage -> post_parent, '_inpsyde_protect_content', true );
if ( 1 == $status && !is_user_logged_in() ) {
wp_redirect( wp_login_url( $upload[ 'baseurl' ] . '/' . $the_file ) );
die();
}
}
}
}
}
}
}
}
}
$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 );
die();
}
You can also add a custom URL for files via the hook generate_rewrite_rules
add_filter( 'generate_rewrite_rules', 'fb_generate_rewrite_rules' );
function fb_generate_rewrite_rules( $wprewrite ) {
$upload = wp_upload_dir();
$path = str_replace( site_url( '/' ), '', $upload[ 'baseurl' ] );
$wprewrite -> non_wp_rules = array( $path . '/(.*)' => 'index.php?file=$1' );
return $wprewrite;
}
2. Apache check for the Cookie
Leave a new .htaccess file inside of the /wp-content/uploads/ directory. Or an other defined directory for the uploads.
How it works
Inside of the <IfModule> containers, there are three rules that do the following:
- Check if the request is for any file
- Check for the absence of a cookie that begins with
wordpress_logged_in_
- If these conditions are met, the file request will be denied via 403 "Forbidden" response
The trick here is step 2, then check for the absence of a cookie that begins with wordpress_logged_in_. When the user is logged in, WordPress adds a cookie to your browser that looks like:
wordpress_logged_in_1234567890abcdefghijklmnopqrstuvwxyz
Example rule with a check for file type
# require login for media files
<IfModule mod_rewrite.c>
RewriteCond %{REQUEST_FILENAME} (.*)
RewriteCond %{HTTP_COOKIE} !wordpress_logged_in_([a-zA-Z0-9_]*) [NC]
RewriteRule .* - [F,L]
</IfModule>
