Imagine you are creating an activity stream for your site. You'd like to use Views because it gives you all the power you need to query items and style them on the page - all in time for your 11am nap. However, the resulting page is static and users have to keep refreshing it manually to see updates. In 2011, that's just uncool.
That's why I created Views Auto-Refresh, a Views Hacks sub-module that implements an auto-refreshing mechanism that integrates right into Views 2 or 3. Here's how it works:
$interval = 15000; // 15000 msec = 15 sec print theme('views_autorefresh', $interval);
Now, automagically, your view will be refreshed every 15 seconds.
That's pretty cool, but your server ends up re-querying the same items every 15 seconds, for each user on that page, which is a bit scary. To alleviate the problem a bit, Views Auto-Refresh includes a more advanced mode for "incremental" refresh. The main idea is to create a secondary view, hopefully less heavy than the first one, that only returns new items since the last refresh. The module is responsible for merging those new items into the existing items on the page. Here's how that works in its simplest form:
$interval = 15000; // 15000 msec = 15 sec print theme('views_autorefresh', $interval, array( 'view_base_path' => 'my_view/autorefresh', 'view_display_id' => 'page_2', 'view_name' => 'my_view', 'sourceSelector' => '.view-content', 'targetSelector' => '.view-content', 'firstClass' => 'views-row-first', 'lastClass' => 'views-row-last', 'oddClass' => 'views-row-odd', 'evenClass' => 'views-row-even', ));
The additional settings are used to inform Views Auto-Refresh on which secondary view to hit (given its name, display and path), as well as how to merge the items from the source (the secondary view) into the target (the primary, on-screen view). The code will fetch all items inside the
sourceSelector container and prepend them to the
targetSelector. Then, it will fix up the odd/even, first/last and row number classes based on the settings.
So far, this module has been successfully tested with exposed filters. Clicking on an exposed filter disables the auto-refresh to allow the user to complete the interaction without disruption.