Database (MongoDB)

All data is stored in MongoDB.

Core Collections

• configs: Published experiment configurations.
  • Schema: { configId, owner, config, checksum, metadata, requireAuth, allowRetake, createdAt, updatedAt }
• sessions: Participant experimentation sessions (application state).
  • Schema: { id, configId, config, currentPageId, session_state, prolific?, userId?, endedAt?, createdAt, updatedAt }
• events: Audit events and telemetry.
  • Schema: { sessionId, configId, pageId, componentType, componentId, type, timestamp, data, createdAt }
• chat_messages: Chat message history.
  • Schema: { messageId, groupId, sessionId, senderId, senderType, content, createdAt }

Authentication (Better Auth)

Managed by Better Auth.

• user: Registered users.
• session: Authentication sessions (login state) - distinct from experiment sessions.
• account: Linked OAuth accounts.

Media (Storage Abstraction)

Media storage is handled by a StorageAbstraction layer that supports multiple backends based on the STORAGE_BACKEND environment variable.

Interface

The abstraction provides a unified interface: - upload(path, data, options) - list(bucket, prefix) - delete(path) - getUrl(path)

Backends

1. Local Filesystem (local):

   • Used for development.
   • Stores files in ./storage (mounted volume in Docker).
   • Serves files statically via Elysia.

2. Google Cloud Storage (gcs):

   • Used for production.
   • Stores files in a GCS bucket (configured via STORAGE_PATH).
   • Requires GOOGLE_APPLICATION_CREDENTIALS or Workload Identity.

Management

Manager endpoints interact with this abstraction layer. - POST /media/upload -> storage.upload() - GET /media -> storage.list() - DELETE /media/:object -> storage.delete()