Features and interfaces

Description

A user folder such as PAS provides a number of different services: it takes care of user authentication, it asks users to login if needed, and it allows you to search for users and groups.

In order to make both configuration and implementation simpler and more powerful, all these different tasks have been divided into different interfaces. Each interface describes how a specific feature, such as authenticating a user, has to be implemented.

Within PAS, plugins are used to provide these features. Plugins are small pieces of logic which implement one or more functions as defined by these interfaces.

This separation is useful for different reasons:

• it makes it possible to configure different aspects of the system separately. For example how users authenticate (cookies, login forms, etc.) can be configured separately from where user information is stored (ZODB, LDAP, RADIUS, SQL, etc.). This flexibility makes it very easy to tune the system to specific needs.
• it makes it possible for developers to write small pieces of code that only perform a single task. This leads to code that is easier to understand, more testable and better maintainable.