Defining a Caching Autopolicy
Caching policies control which Web content the system caches on a user's machine.
To create a Web caching autopolicy:
- Create a custom Web application resource profile.
- If available, click the Show ALL autopolicy types to display the autopolicy configuration options.
- Select the Autopolicy: Caching check box.
- In the Resource field, specify the resources to which this policy applies.
- In the Action field, select one of the following options:
- Smart - Select this option to send a cache-control:no-store header or a cache-control:no-cache header based on the user's Web browser and content type.
When you select this option, the system makes media files and zip files work properly by removing their origin server's cache-control headers. For example, the following logic searches for "msie" or "windows-media-player" in user-agent headers in order to remove cache or cache-control:no-store response headers and make the files cacheable:
(if content type has "audio/x-pn-realaudio" OR
if content type begins with "video/" OR
if content type begins with "audio/" OR
if content type is "application/octet-stream" and the file extension begins with "rm" or "ram"
)
If the system finds "msie" or "windows-media-player" in the user-agent header and any of the following apply:
- Request is for Flash, .xls, .pps, .ppt files
- Content-type is application/, text/rtf, text/xml, model/
- Origin server sends a content-disposition header
then the system sends the cache-control:no-store header and removes the origin server's cache-control header.
In all other cases, the system adds the pragma:no-cache or cache-control:no-store response headers.
Citrix .ica and QuickPlace files get some special treatment. Citrix .ica files get cache-control:private only when smart caching is enabled. QuickPlace files that do not match a specified rule files (which takes precedence) get CCNS and cache-control:private.
Also note that if you select this option, enable GZIP compression, and try to access a text file attachment using Domino Web Access 6.5 through Internet Explorer, you cannot open the attachment. To enable text attachments, you must either install the Internet Explorer 323308 patch or enable the No Store option.
- No-Store - Select this option to deliver attachments to Internet Explorer without saving them to the disk. (The browser temporarily writes files to the disk, but immediately removes them once it has opened the file in the browser.) When you select this option, the system removes the origin server's cache-control header and adds a cache-control:no-store response header if the user-agent string sent by the browser contains "msie" or "windows-media-player."
This option might slow browsing by causing repeated content fetches, which can cause performance issues on very slow connections.
- No-Cache - Select this option to prevent the user's browser from caching files to the disk. When you select this option, the system adds the standard HTTP pragma:no-cache header and cache-control:no-cache (CCNC) header (HTTP 1.1) to response files. Also, the system does not forward the origin server's caching headers, such as age, date, etag, last-modified, expires.
When no-cache headers are present on certain types of attachments (PDF, PPT, streaming files), Internet Explorer does not properly render the documents because the rendering process requires the browser to temporarily writes these files to cache.
- Unchanged - Select this option to forward the origin server's caching headers as is.
When using Citrix published applications through the Web interface, the Web interface server may send a Cache-Control:no-cache in the response header of the .ica file. Because the caching header is not removed when using the Unchanged setting, .ica files are not downloaded to the client PC. To resolve this, use the Smart caching option.
- Click Add.
- Click Save Changes.