Further topics
Caching
We haven't dealt with caching in this article. In a company-intranet
situation, the connection from the proxy to the application servers is
the local LAN, which is probably fast and has ample capacity. In such
cases, caching at the proxy will have little effect, and can probably
be omitted.
If we want to cache pages, we can of course do so with mod_cache But
that is beyond the scope of this article.
Content Transformation
Another powerful use for a proxy is to transform the content
on-the-fly according to the user's preferences. This author's flagship
mod_accessibility product (from which mod_proxy_html is a spinoff)
serves to transform HTML and XHTML on-demand to enhance usability and
accessibility.
Filtering and Security
A reverse proxy is not the natural place for a "family filter", but is
ideal for defining access controls and imposing security restrictions.
We could, for example, configure the proxy to recognise a custom
header from an origin server and block content based on it. This
delegates control to the application servers.
