The Caching Proxy has several interfaces written into its processing sequence where custom processing can be added or substituted for standard processing. Customizations that can be executed include altering or augmenting tasks like the following:
Custom application programs, which are also known as Caching Proxy plug-ins, are called at predetermined points in the proxy server's processing sequence.
The Caching Proxy API has been used to implement certain system features. For example, the proxy server's LDAP support is implemented as a plug-in.
The Caching Proxy API describes the interface in detail and includes steps for configuring the proxy server to use plug-in programs.