Mail Sidebar

Overview

The mail sidebar integrates OpenRegister with the Nextcloud Mail app by injecting a sidebar panel that displays objects linked to the currently viewed email.

Architecture

Backend

• EmailLink (lib/Db/EmailLink.php) — Entity mapping emails to objects via openregister_email_links table.
• EmailLinkMapper (lib/Db/EmailLinkMapper.php) — Database queries for email links with findByAccountAndMessage, findBySender, findExistingLink.
• EmailService (lib/Service/EmailService.php) — Business logic for reverse-lookup (findByMessageId, findObjectsBySender), quickLink creation, and deleteLink.
• EmailsController (lib/Controller/EmailsController.php) — REST endpoints: GET /api/emails/by-message/{accountId}/{messageId}, GET /api/emails/by-sender?sender=, POST /api/emails/quick-link, DELETE /api/emails/{linkId}.
• MailAppScriptListener (lib/Listener/MailAppScriptListener.php) — Injects sidebar script into Mail app when conditions are met (Mail enabled, user has register access).

Frontend

• mail-sidebar.js — Webpack entry point that mounts Vue sidebar into Mail app DOM.
• MailSidebar.vue — Root component with collapsible panel, error/loading states, link/unlink actions.
• LinkedObjectsList.vue — Displays explicitly linked objects for current email.
• SuggestedObjectsList.vue — Displays sender-based discovery results.
• ObjectCard.vue — Card component with title, schema, register, deep link, unlink button.
• LinkObjectDialog.vue — Modal dialog for searching and linking objects.
• useMailObserver.js — Composable observing Mail app URL changes (hash-based routing).
• useEmailLinks.js — Composable for API state management with caching and abort control.
• emailLinks.js — Axios API wrapper for all email link endpoints.

Styling

• css/mail-sidebar.css — NL Design System compatible styles using Nextcloud CSS variables.

API Routes

Method	URL	Purpose
GET	/api/emails/by-message/{accountId}/{messageId}	Objects linked to specific email
GET	/api/emails/by-sender?sender=	Objects from same sender
POST	/api/emails/quick-link	Link email to object
DELETE	/api/emails/{linkId}	Remove email-object link

Database

Table openregister_email_links with columns: id, mail_account_id, mail_message_id, mail_message_uid, subject, sender, mail_date, object_uuid, register_id, schema_id, linked_by, linked_at.

Indexes: composite on (mail_account_id, mail_message_id), sender, object_uuid. Unique constraint on (mail_account_id, mail_message_id, object_uuid).

Dependencies

Requires the Nextcloud Mail app to be installed for sidebar functionality. OpenRegister works normally without Mail app.