Design

Architecture

Delegate Account is a Moodle local plugin with three layers:

• Entry points: web-service functions (classes/external/), pages (pages/), and two hooks (after_config, extend_user_menu).
• Services: static classes in classes/. manager holds the rules of delegations, session_capabilities stores and applies overrides, notification_manager sends messages, permission maps actions to capabilities.
• Persistence: two tables, local_delegateaccount and local_delegateaccount_caps.

Two decisions shape the design. First, access is re-evaluated on every request by a hook, so a revoked delegation ends its sessions without a background job. Second, session permissions are applied to the access data of the session, not stored in roles, so they can be changed while sessions are open and never leave a role behind.

Design classes

Components

The plugin sits on five parts of Moodle: login-as, the capability system, the event log, messaging and the database. It adds no table to them and no change to core.

Data model

Use-case realizations

ID	Use case	Sequence
UC-001	Create delegations	sequence
UC-002	Open a delegated account	sequence
UC-003	Edit session permissions	sequence