Appcachify for WordPress Plugin Directory

The plugin adds an iframe to the footer of your website which points to example.com/manifest.

That URL is an empty page that references the generated manifest file at example.com/manifest.appcache.

The manifest itself is built in the following way:

adds URLs of all queued scripts and styles

searches theme files and folder for any images or other static assets

if a theme has a 307.php template it is used as an offline fallback

a timestamp of the most recently modified file is added to force appcache to refresh

The net result of all this is that your main static files are stored locally on your visitors devices. For mobile this greatly helps to improve download and rendering times.

Documentation Adding items to the manifest Appcache can do more than store static assets. You could cache entire pages, or add fallbacks for when a user is offline.

There are 3 main sections to a manifest:

CACHE The main CACHE section is for URLs that should be explicitly cached.

<?php add_filter( 'appcache_cache', function( $urls ) { $urls[] = '/page-available-offline/'; return $urls; } ); ?>

NETWORK This section is for specifying URLs that should never be cached.

<?php add_filter( 'appcache_network', function( $urls ) { $urls[] = '*'; $urls[] = '/online-only-page/'; return $urls; } ); ?>

FALLBACK The fallback section allows you to set fallback pages or images if the user is offline.

<?php add_filter( 'appcache_fallback', function( $patterns ) { $patterns[] = 'wp-content/uploads/ wp-content/uploads/offline.jpg'; return $patterns; } ); ?>

The update header Appcaches are refetched when the manifest file content changes so we add a few items as comments at the top of the file.

The current theme (and version if available)

The most recent modified time of any files we find the server path for

The size of all the files that we find a server path for

get_var( “SELECT post_modified FROM $wpdb->posts WHERE post_type = ‘post’ ORDER BY post_modified DESC LIMIT 1” );

return $headers;

} );

?>

More about appcache I strongly recommend learning more about what you can do with appcache by reading the following articles:

HTML5 Rock’s Introduction to Appcache

Application cache is a douchebag