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Object Interactions

Overview​

OpenRegister objects support rich human collaboration through a unified interaction API that wraps Nextcloud's native subsystems: ICommentsManager for notes, CalDAV for tasks, IRootFolder for file attachments, and Nextcloud Tags. Any consuming app (Procest, Pipelinq, OpenCatalogi, ZaakAfhandelApp) can use these unified sub-resource endpoints without knowledge of the underlying Nextcloud internals.

Notes​

Notes are persistent comments attached to an object, stored via Nextcloud's ICommentsManager:

GET    /api/objects/{register}/{schema}/{id}/notes         List notes on an object
POST   /api/objects/{register}/{schema}/{id}/notes         Add a note
GET    /api/objects/{register}/{schema}/{id}/notes/{nid}   Get a specific note
PUT    /api/objects/{register}/{schema}/{id}/notes/{nid}   Edit a note (author only)
DELETE /api/objects/{register}/{schema}/{id}/notes/{nid}   Delete a note (author or admin)

Notes are stored with objectType: "openregister" and objectId: {uuid}. NoteService resolves actor display names via IUserManager and indicates whether the current user authored each note.

Tasks​

Tasks (TODOs) are linked to objects via Nextcloud's CalDAV infrastructure:

GET    /api/objects/{register}/{schema}/{id}/tasks         List tasks
POST   /api/objects/{register}/{schema}/{id}/tasks         Create a task
GET    /api/objects/{register}/{schema}/{id}/tasks/{tid}   Get a task
PUT    /api/objects/{register}/{schema}/{id}/tasks/{tid}   Update a task
DELETE /api/objects/{register}/{schema}/{id}/tasks/{tid}   Delete a task

Tasks conform to RFC 5545 (iCalendar VTODO) and RFC 9253 (iCalendar LINK property). The LINK property connects the VTODO to the OpenRegister object URI:

LINK;VALUE=URI:openregister://objects/{uuid}

Task fields include: summary, description, due, dtstart, status (NEEDS-ACTION, IN-PROCESS, COMPLETED, CANCELLED), priority, assigned-to.

File Attachments​

Files are attached to objects via Nextcloud's file system (IRootFolder):

GET    /api/objects/{register}/{schema}/{id}/files         List attached files
POST   /api/objects/{register}/{schema}/{id}/files         Attach a file (upload)
GET    /api/objects/{register}/{schema}/{id}/files/{fid}   Get file metadata
DELETE /api/objects/{register}/{schema}/{id}/files/{fid}   Remove attachment
GET    /api/objects/{register}/{schema}/{id}/files/{fid}/download  Download file

File metadata tracked per attachment:

FieldDescription
nameOriginal filename
sizeFile size in bytes
mimeTypeMIME type
pronomPRONOM identifier (for archival)
checksumSHA-256 hash
uploadedByNextcloud user ID
uploadedAtUTC timestamp

File attachments are included in MDTO SIP packages when objects are transferred to e-Depot.

Tags​

Objects can be tagged using Nextcloud's tag system:

GET    /api/objects/{register}/{schema}/{id}/tags         List tags
POST   /api/objects/{register}/{schema}/{id}/tags         Add a tag
DELETE /api/objects/{register}/{schema}/{id}/tags/{tag}   Remove a tag

Tags are shared across all OpenRegister objects and are visible in Nextcloud's standard tag browser.

Object Locking​

Object locking prevents concurrent conflicting edits:

POST   /api/objects/{register}/{schema}/{id}/lock         Acquire lock
DELETE /api/objects/{register}/{schema}/{id}/lock         Release lock
GET    /api/objects/{register}/{schema}/{id}/lock         Check lock status

Lock metadata includes:

FieldDescription
lockedByNextcloud user ID
lockedAtUTC timestamp
expiresAtAuto-release timestamp (configurable timeout)
sessionIdNextcloud session or browser tab identifier

If a user tries to save an object that is locked by someone else, a 423 Locked response is returned with details of who holds the lock.

Activity Feed​

All interactions (notes, tasks, attachments, locks, status changes) appear in the object's activity feed:

GET /api/objects/{register}/{schema}/{id}/activity        List all activity

The activity feed combines:

  • Audit trail entries (create, update, delete)
  • Notes (created, edited, deleted)
  • Task status changes
  • File attachments (added, removed)
  • Lock events (acquired, released, expired)

Standards​

StandardRole
RFC 5545 (iCalendar)Task/VTODO format
RFC 9253 (iCalendar LINK)Object-to-task linking
Nextcloud ICommentsManagerNotes storage
Nextcloud IRootFolderFile attachment storage