Configuring how browser requests are cached
If content is cached on the browser the first time that it is loaded, the browser does not have to request that content again. This helps to improve performance as well as the network load.
When a browser sends a request to the mid tier server, the response might contain a Cache-Control header. The browser uses this Cache-Control header to identify whether the content should be cached and when this cached content expires. The browser uses the cached content until it expires, after which it sends a new request to the mid tier server. If the response does not contain the Cache-Control header, the browser sends a new request each time.
After browser cache is enabled, if the content on the mid tier server changes, the browser does not detect the change because it uses the content from its cache.
How browser cache works
When the browser sends a request to the server, the server controls the response that goes back to the browser. Depending on the type of request, the mid tier server determines whether to send a Cache-Control header in the response. The types of requests are:
Dynamic—These requests fetch dynamic data, such as records, from the database, and thus are not cached on the browser.
Resources—These requests handle static data, such as static Javascript files (.js) or style sheets (.css), and thus can be cached.
When a new patch or hotfix is applied, the content of these files might change.
You can adjust the Cache-Control expiry time for these requests in the config.properties file. See Modifying the cache expiry settings below.
Form HTML / Javascript—These requests fetch the HTML and active link .js files for a requested form or schema.
The content of these requests can change when changes are made to form definitions or workflows.
You can adjust the Cache-Control expiry time for these requests in the config.properties file.
Modifying the cache expiry settings
As an administrator, you can adjust the cache expiry settings from the config.properties file located at /midTierInstallDir/WEB-INF/classes/. The browser uses these settings to determine how long the content is cached.
- Resources—The default setting for this request type is 86400 seconds (1 day). To change the cache expiry settings for this request type, modify the following entry:
arsystem.resource_expiry_interval=86400 - Form HTML / Javascript—The default setting for this request type is 3600 seconds (1 hour). To change the cache expiry settings for this request type, modify the following entry:
arsystem.formhtmljs_expiry_interval=3600
Updating browser cache
When a service pack, patch, or hotfix is applied to the binaries, or when changes are made to the definition files, you must manually flush the browser cache.
When flushing the cache, remember these tips:
- You need not manually flush the browser cache whenever there is a change in forms and other metadata in the . The changed forms are automatically fetched from the mid tier and are reloaded in your browser.
- If you have a server group setup with a load balancer, the browser cache approximately takes 10 minutes to update and reflect the changes. You must sync the cache after the shared database is updated with the changes.
Whenever there are changes in the , to keep the cache up-to-date, you must still do a sync cache or flush cache.
In a cluster environment, to maintain consistency across all users, make sure that the sync cache or flush cache operation is successfully completed across all s.
If the browser cache is not up-to-date, you might get some JavaScript errors. For information about these errors and the importance of updating the browser cache, see Knowledge Base article ID 000096746.
To flush the cache, you need to delete the temporary internet files. (You do not need to delete the cookies, form data, saved passwords, or browsing history.) Use one of the following methods to delete the temporary internet files:
- Microsoft Internet Explorer 8 or 9—Browse to Tools > Internet Options > Browsing History > Delete > Delete Browsing History, clear all options except Temporary Internet Files, and click Delete.
- Mozilla Firefox—Browse to Tools > Options > Advanced > Network, and click Clear Now.
- Apple Safari—Browse to Edit > Empty Cache, and click Empty.
Each browser vendor uses different options to delete the temporary internet files. As a user, be aware of these options so that you do not delete the cookies that store other important information, such as saved passwords.