Memo Service

Relevant source files

• internal/email/email.go
• proto/api/v1/memo_service.proto
• proto/gen/api/v1/apiv1connect/memo_service.connect.go
• proto/gen/api/v1/memo_service.pb.go
• proto/gen/api/v1/memo_service.pb.gw.go
• proto/gen/api/v1/memo_service_grpc.pb.go
• server/router/api/v1/idp_service.go
• server/router/api/v1/memo_attachment_service.go
• server/router/api/v1/memo_relation_service.go
• server/router/api/v1/memo_service.go
• server/router/api/v1/memo_service_converter.go
• server/router/api/v1/memo_share_service.go
• server/router/api/v1/memo_update_helpers.go
• server/router/api/v1/reaction_service.go
• server/router/api/v1/shortcut_service.go
• server/router/api/v1/sse_event_helpers.go
• server/router/api/v1/sse_service_test.go
• server/router/api/v1/test/idp_service_test.go
• server/router/api/v1/test/memo_attachment_service_test.go
• server/router/api/v1/test/memo_relation_service_test.go
• server/router/api/v1/test/memo_share_service_test.go
• server/router/api/v1/test/reaction_service_test.go
• store/attachment.go
• store/db/mysql/attachment.go
• store/db/mysql/memo_relation.go
• store/db/postgres/attachment.go
• store/db/postgres/memo_relation.go
• store/db/sqlite/attachment.go
• store/db/sqlite/memo_relation.go
• store/memo_relation.go
• web/src/hooks/useMemoShareQueries.ts
• web/src/types/proto/api/v1/memo_service_pb.ts

The Memo Service is the core backend service responsible for all memo-related operations in the Memos application. It provides a comprehensive gRPC API for creating, reading, updating, and deleting memos, along with advanced features like tags, attachments, relations, comments, and reactions. The service handles visibility controls, permission checks, content processing, and real-time event broadcasting.

Service Architecture

The Memo Service is implemented as part of the APIV1Service struct and provides the server-side implementation of the MemoService gRPC interface. It sits between the API gateway and the data storage layer, orchestrating business logic and coordinating with other services.

Sources: server/router/api/v1/memo_service.go70-498 proto/api/v1/memo_service.proto17-147 proto/gen/api/v1/memo_service.pb.gw.go40-152 server/router/api/v1/memo_relation_service.go16-51 server/router/api/v1/reaction_service.go60-109

Core CRUD Operations

Create Memo

The CreateMemo operation creates a new memo with validation, content processing, and optional attachments and relations.

Processing Flow:

1. Authentication: Fetches current user via s.fetchCurrentUser(ctx) server/router/api/v1/memo_service.go71
2. UID Generation: Validates or generates a UID via ValidateAndGenerateUID server/router/api/v1/memo_service.go79
3. Timestamping: Sets custom timestamps if provided in the request (CreateTime, UpdateTime) server/router/api/v1/memo_service.go92-99
4. Content Processing: Validates content length and calls memopayload.RebuildMemoPayload to extract metadata and tags server/router/api/v1/memo_service.go101-110
5. Persistence: Saves to DB via s.Store.CreateMemo server/router/api/v1/memo_service.go115
6. Side Effects:
   • Sets attachments server/router/api/v1/memo_service.go130
   • Sets relations server/router/api/v1/memo_service.go143
   • Dispatches webhooks via DispatchMemoCreatedWebhook server/router/api/v1/memo_service.go157
   • Broadcasts live refresh event via s.SSEHub.Broadcast (skipped if SSE is suppressed) server/router/api/v1/memo_service.go162-169

Sources: server/router/api/v1/memo_service.go70-176

List Memos

The ListMemos operation provides flexible memo listing with advanced filtering and pagination.

• Visibility Filtering: Unauthenticated users only see PUBLIC memos. Authenticated users see their own memos plus PUBLIC and PROTECTED memos server/router/api/v1/memo_service.go218-228
• State Filtering: Can filter by NORMAL or ARCHIVED status. Archived memos are only visible to their creator server/router/api/v1/memo_service.go188-199
• Ordering: Supports custom ordering via parseMemoOrderBy, defaulting to creation time descending server/router/api/v1/memo_service.go202-209

Sources: server/router/api/v1/memo_service.go178-232

Comment and Reaction Systems

Comments System

Comments are implemented as memos linked to a parent memo via a COMMENT relation.

• Creation: CreateMemoComment internally calls CreateMemo but wraps the context with withSuppressSSE to prevent duplicate broadcast events for the new memo server/router/api/v1/memo_service.go30-32 server/router/api/v1/memo_service.go498-533
• Relations: A relation of type MemoRelation_COMMENT is automatically created between the parent and the comment proto/gen/api/v1/memo_service.pb.go91

Reactions System

Reactions allow users to add emojis (e.g., "👍", "❤️") to memos.

• Upserting: UpsertMemoReaction checks memo visibility before allowing a reaction. If the memo is PRIVATE, only the creator or a superuser can react server/router/api/v1/reaction_service.go83-85
• Real-time: Upserting or deleting a reaction triggers an SSEHub broadcast with types SSEEventReactionUpserted or SSEEventReactionDeleted server/router/api/v1/reaction_service.go106-161

Sources: server/router/api/v1/reaction_service.go15-181 server/router/api/v1/memo_service.go22-37

Relations and Attachments

Memo Relations

Relations define links between memos, such as references or comments.

Type	Code Symbol	Description
Reference	MemoRelation_REFERENCE	A standard link/reference to another memo.
Comment	MemoRelation_COMMENT	A hierarchical link representing a comment.

Internal Logic:

• SetMemoRelations replaces all existing REFERENCE type relations for a memo server/router/api/v1/memo_relation_service.go54-61
• It ignores reflexive relations (linking a memo to itself) server/router/api/v1/memo_relation_service.go65

Sources: server/router/api/v1/memo_relation_service.go16-91 store/memo_relation.go9-14

Attachments Management

The service manages file attachments associated with memos. SetMemoAttachments allows replacing the full set of attachments for a memo.

• Normalization: normalizeMemoAttachmentRequest ensures that only valid attachments owned by the user (or accessible by superusers) are added server/router/api/v1/memo_attachment_service.go102-125
• Motion Media: Special handling exists for "motion media" groups to ensure all group members are requested together server/router/api/v1/memo_attachment_service.go169-172

Sources: server/router/api/v1/memo_attachment_service.go16-185

Data Flow: Memo Conversion

When retrieving memos, the service converts internal store.Memo objects into v1pb.Memo messages.

• Snippet Generation: During conversion, a plain-text snippet is generated for the memo content via getMemoContentSnippet server/router/api/v1/memo_service_converter.go76-80
• Creators Mapping: The service batch-fetches creators to avoid N+1 queries during conversion server/router/api/v1/memo_service_converter.go24-33

Sources: server/router/api/v1/memo_service_converter.go23-83

Database Implementation (Memo Relations)

The system supports multiple database drivers (SQLite, MySQL, PostgreSQL) for managing relations.

• PostgreSQL: Uses ON CONFLICT (memo_id, related_memo_id, type) DO UPDATE and RETURNING store/db/postgres/memo_relation.go20-21
• Filtering: Supports complex filtering of relations using the CEL filter engine store/db/postgres/memo_relation.go82-110

Sources: store/db/postgres/memo_relation.go12-173 store/memo_relation.go43-53