This article continues in WooCommerce and cache – Part 2: new Cache Handler plugin
One of the most common questions we receive from our customers is how to make a highly dynamic, multi-currency, multi-pricing, geolocation-enabled sites work properly with caching enabled. This is not always an easy task, because caching systems are designed with the assumption that the content served by a site doesn’t change depending on the visitor. Such assumption holds true in many cases, as a large number of sites does indeed serve the same content to whoever views a page. In such case, the standard behaviour of caching systems, which is storing one copy of each page in the cache, is acceptable.
As soon as multi-currency features are added, the same behaviour proves itself too limited, because the assumption behind it becomes incorrect. A multi-currency shop serves different content to different visitors, depending on the currency and other criteria (applicable taxes, regional pricing, etc). Quite simply, having one cached copy of each page just doesn’t cut it anymore.
Until recently, the only way to prevent caching from interfering with the multi-currency features was to disable it on catalogue pages. Doing so ensures that the shop can produce content dynamically, showing the correct information to each visitor. In some cases, when the caching system in use is too rigid, this is still the only solution.
How WooCommerce handles the issue
WooCommerce itself has to deal with caching since its team introduced geolocation features in it. The WC team added a workaround to “trick” caching systems into letting WooCommerce serve the correct data. Such workaround works by reloading the shop pages in a way that cache is ignored. This ensures that the page shows the correct content but, in our opinion, it’s not an ideal approach. We certainly appreciate the effort put into it, and the fact that there isn’t much more that a plugin can do to correct the behaviour of the caching system. However, we decided to find an alternative, more robust solution.
Our opinion is that caching systems should adapt to your site, not the other way round. Issues caused by caching should be solved by fixing the caching. With this in mind, instead of implementing a workaround, we tackled the issue at its root, and wrote an algorithm for dynamic caching that takes into account the needs of a multi-currency website.
The algorithm is straightforward, and solves the issue by addressing its cause: instead of one copy of each page, it allows caching systems and plugins to store multiple copies of each page (such as one for each currency). With that in place, visitors from all over the world will see the content that applies to them, with the correct currency and taxes applied. If visitors choose another currency, or country, then our plugins track their choice, and the dynamic caching logic uses it to serve them the correct content.
Our solution grants top performance, with maximum flexibility.
Dynamic caching is a great solution for highly dynamic, multi-currency sites. However, it can only work if the caching system in use supports it. As of October 2015, the following plugins and systems support, or are planning to support, dynamic caching.
For caching plugins and systems that do not support dynamic caching, disabling cache on catalogue pages is still necessary to allow the multi-currency features to work correctly.
How to add dynamic caching to your site
Adding it to your site can be as simple as copying one file, or changing one configuration file. In order to allow you to get started quickly, we wrote an implementation of dynamic caching for the following systems:
- ZenCache/Comet Cache
You can find detailed instructions to install and configure each of our solutions, as well as indications for other systems, in our knowledge base: How to add dynamic caching to your site.
We also discussed the implementation extensively with the WP Rocket Team, and provided them with code examples for integration. They confirmed that they are going to add support for dynamic caching and multi-currency sites directly in their plugin.
With dynamic caching and our Currency Switcher, your WooCommerce site will be faster and more flexible than ever!
What about systems that don’t support dynamic caching?
Plugins and caching systems that don’t support dynamic caching still have to be disabled on the catalogue, at least until they are updated. We believe that caching systems should be flexible, and support for dynamic caching is not particularly difficult to implement.
If you are using a plugin, or a caching system that doesn’t support dynamic caching, we recommend thar you get in touch with its authors and express your interest in such feature. You can also suggest them to contact us directly, if they have any questions. We will be happy to provide them with all the information they need to improve their solution.
We hope that you enjoyed this great news. A faster e-commerce means more customers, and that is always good! If you have any questions about our solutions, or if you would like to send us your feedback, please feel free to contact us. We will get back to you in no time.
Thank for your time and continued support.
The Aelia Team