Added/deleted-type websocket messages

Events are now sent for not only when an object changes but also when one is created or deleted.

For now it's not really possible to subscribe to these events however.

This breaks backwards-compatibility with the websocket messages.

spoolman/api/v1/models.py

@@ -1,6 +1,7 @@
 """Pydantic data models for typing the FastAPI request/responses."""
 
 from datetime import datetime, timezone
+from enum import Enum
 from typing import Optional
 
 from pydantic import BaseModel as PydanticBaseModel
@@ -228,3 +229,37 @@ class BackupResponse(BaseModel):
         description="Path to the created backup file.",
         example="/home/app/.local/share/spoolman/backups/spoolman.db",
     )
+
+
+class EventType(str, Enum):
+    """Event types."""
+
+    ADDED = "added"
+    UPDATED = "updated"
+    DELETED = "deleted"
+
+
+class Event(BaseModel):
+    """Event."""
+
+    type: EventType = Field(description="Event type.")
+    date: datetime = Field(description="When the event occured. UTC Timezone.")
+    payload: BaseModel
+
+
+class SpoolEvent(Event):
+    """Event."""
+
+    payload: Spool = Field(description="Updated spool.")
+
+
+class FilamentEvent(Event):
+    """Event."""
+
+    payload: Filament = Field(description="Updated filament.")
+
+
+class VendorEvent(Event):
+    """Event."""
+
+    payload: Vendor = Field(description="Updated vendor.")