Netscape ENTERPRISE SERVER 6.1, Руководство пользователя

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Appendix F
Dynamic Results Caching Functions
The functions described in this appendix allow you to write a results caching
plugin for Netscape Enterprise Server. A results caching plugin, which is a
Service
SAF, caches data, a page, or part of a page in the web server address
space, which the web server can refresh periodically on demand. An
Init
SAF
initializes the callback function that performs the refresh.
A results caching plugin can generate a page for a request in three parts:
• A header, such as a page banner, which changes for every request
• A body, which changes less frequently
• A footer, which also changes for every request
Without this feature, a plugin would have to generate the whole page for every
request (unless an IFRAME is used, where the header or footer is sent in the first
response along with an IFRAME pointing to the body; in this case the browser
must send another request for the IFRAME).
If the body of a page has not changed, the plugin needs to generate only the header
and footer and to call the
dr_net_write
function (instead of
net_write
) with the
following arguments:
• header
• footer
• handle to cache
• key to identify the cached object
The web server constructs the whole page by fetching the body from the cache. If
the cache has expired, it calls the refresh function and sends the refreshed page
back to the client.