Unlike many PC-based browsers, the HTML 5 engine on the BrightSign player does not cache any HTML content by default. As a result, whenever a page is loaded, the player will retrieve all page content as if it were new. If the page is being loaded from local storage, this process is seamless and nearly instantaneous. However, if the page is being hosted on a remote server, frequently refreshing the page can consume considerable bandwidth; furthermore, page elements will be loaded as they arrive over the connection, which can result in poor aesthetics.
Follow the steps below to enable the HTML app cache on the BrightSign player and use it to cache remote resources.
1. Enable the HTML application cache for your BrightAuthor:connected presentation: Navigate to the Admin > Application Preferences > Storage tab and set the HTML data cache to the desired amount.
Note: If you are using a custom autorun or script to display HTML content, you can enable the application cache using the SetAppCacheSize() and SetAppCacheDir() methods available on the roHtmlWidget object.
2. Create a cache manifest file specifying the assets that should be cached locally. See below for an example of a simple cache manifest; the formatting and behavior of cache manifest files is outlined in detail on this Mozilla Developer Network page.
3. Ensure the cache manifest contains a "NETWORK" section that specifies all ("*") files that will be used by the presentation. If you wish to be more specific, you can also specify the URL that contains all required files (e.g. "http://www.example.com/").
4. Reference the cache manifest file in the HTML of the page (e.g. <html manifest="cache.manifest">).
5. Upload the cache manifest and index.html file to your web server. The cache manifest should be in the same directory as the index.html file.
When you need the player to download new copies of the cached content, upload a new cache manifest file to the web server with a new version number and date:
Note: Changing the comment containing the number/date is a recommended practice when updating a cache manifest, but, technically, the player will download a new cache manifest file whenever any of the bytes that make up the file are changed.