A cache buster allows the application to notify the browser to refresh the resources only when the application resources have been changed. Otherwise the resources can always be fetched from the browser's cache.
SAPUI5 supports the cache buster concept for Java and ABAP servers and for SAP HANA Cloud Platform. SAP HANA XS does not support the cache buster concept.
When you want to cache your resources permanently, you simply need to change the URL in the SAPUI5 bootstrap tag from resources/sap-ui-core.js to resources/sap-ui-cachebuster/sap-ui-core.js.
The cache buster mechanism allows to always put the SAPUI5 resources into the browsers cache until a UI library or a web application has been changed. The default behavior of the SAPUI5 resource handler is either to cache the resources for a specific amount of time or alternatively in development mode it is using the 304/NOT MODIFIED mechanism to check the SAPUI5 resources for being up-to-date. Both mechanisms are not optimal in a final, productive scenario - that is the reason for the implementation of the cache buster mechanism. Applications, which want to use the cache buster mechanism have to explicitly decide to use it.
Date: Mon, 16 Jul 2012 05:17:54 GMT Expires: Thu, 14 Jul 2022 05:17:54 GMT Cache-Control: max-age=315360000, public
By default all cache buster resources will be cached for one year.
When using the cache buster mechanism, the first request must never be cached because it is being used to determine the timestamp / and to finally redirect to the correct script. The following list explains the flow:
resources/sap-ui-cachebuster/sap-ui-core.js => NO_CACHE
If you are interested in the timestamp of the cache buster, you can grab it with the following request:
The response is text/plain with such value: ~20120716-0201~