Modules

Hook functions (possibly intended for different hooks) are grouped into modules. A module in Apache is a set of hook functions, together with some administrative data structures that allow registration of the hook functions with their respective hooks. Usually, a module provides hook functions for a small subset of available hooks, as it is not interested in changing the request processing entirely (see Figure 3.3). For example, one can implement a module supporting a new access control policy, or a module translating the server output depending on the location of the client.

Figure 3.3: Hook functions usually come from different modules