Fix the MQTT node, suggest message names, and drop Items

- MQTT nodes failed to build: the topic map was renamed to talk in ports, but
  __slots__ still declared the old name, so every MQTT node raised
  AttributeError. Building one of each node type is now a test, since __slots__
  makes this failure invisible until someone places the node.
- Port names offer the messages already in play: everything published is worth
  reading, and an input nobody provides yet is worth publishing. A message only
  connects when both ends spell it the same way, so choosing beats typing.
- Adding a port focuses its name field.
- Dragging onto an input that already reads something offers the extra port as
  well as the replacement — an MQTT or InfluxDB node usually wants both.
- The template's Item model, its routes, screens and table are gone.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016WzrvW7rjQbynnhF6pxh6i

backend/app/alembic/versions/b7c41d2f8a30_drop_item_table.py

@@ -0,0 +1,40 @@
+"""Drop the item table
+
+The template's example model. Flows are persisted as files in their own git
+repository, so nothing in the app uses it any more.
+
+Revision ID: b7c41d2f8a30
+Revises: fe56fa70289e
+Create Date: 2026-08-15
+
+"""
+
+import sqlalchemy as sa
+import sqlmodel.sql.sqltypes
+from alembic import op
+
+revision = "b7c41d2f8a30"
+down_revision = "fe56fa70289e"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.drop_table("item")
+
+
+def downgrade():
+    op.create_table(
+        "item",
+        sa.Column("id", sa.Uuid(), nullable=False),
+        sa.Column(
+            "title", sqlmodel.sql.sqltypes.AutoString(length=255), nullable=False
+        ),
+        sa.Column(
+            "description", sqlmodel.sql.sqltypes.AutoString(length=255), nullable=True
+        ),
+        sa.Column("created_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("owner_id", sa.Uuid(), nullable=False),
+        sa.ForeignKeyConstraint(["owner_id"], ["user.id"], ondelete="CASCADE"),
+        sa.PrimaryKeyConstraint("id"),
+    )

backend/app/api/main.py

@@ -1,13 +1,12 @@
 from fastapi import APIRouter
 
-from app.api.routes import flows, items, login, private, secrets, users, utils
+from app.api.routes import flows, login, private, secrets, users, utils
 from app.core.config import settings
 
 api_router = APIRouter()
 api_router.include_router(login.router)
 api_router.include_router(users.router)
 api_router.include_router(utils.router)
-api_router.include_router(items.router)
 api_router.include_router(flows.router)
 api_router.include_router(flows.ws_router)
 api_router.include_router(secrets.router)

backend/app/api/routes/items.py

@@ -1,112 +0,0 @@
-import uuid
-from typing import Any
-
-from fastapi import APIRouter, HTTPException
-from sqlmodel import col, func, select
-
-from app.api.deps import CurrentUser, SessionDep
-from app.models import Item, ItemCreate, ItemPublic, ItemsPublic, ItemUpdate, Message
-
-router = APIRouter(prefix="/items", tags=["items"])
-
-
-@router.get("/", response_model=ItemsPublic)
-def read_items(
-    session: SessionDep, current_user: CurrentUser, skip: int = 0, limit: int = 100
-) -> Any:
-    """
-    Retrieve items.
-    """
-
-    if current_user.is_superuser:
-        count_statement = select(func.count()).select_from(Item)
-        count = session.exec(count_statement).one()
-        statement = (
-            select(Item).order_by(col(Item.created_at).desc()).offset(skip).limit(limit)
-        )
-        items = session.exec(statement).all()
-    else:
-        count_statement = (
-            select(func.count())
-            .select_from(Item)
-            .where(Item.owner_id == current_user.id)
-        )
-        count = session.exec(count_statement).one()
-        statement = (
-            select(Item)
-            .where(Item.owner_id == current_user.id)
-            .order_by(col(Item.created_at).desc())
-            .offset(skip)
-            .limit(limit)
-        )
-        items = session.exec(statement).all()
-
-    return ItemsPublic(data=items, count=count)
-
-
-@router.get("/{id}", response_model=ItemPublic)
-def read_item(session: SessionDep, current_user: CurrentUser, id: uuid.UUID) -> Any:
-    """
-    Get item by ID.
-    """
-    item = session.get(Item, id)
-    if not item:
-        raise HTTPException(status_code=404, detail="Item not found")
-    if not current_user.is_superuser and (item.owner_id != current_user.id):
-        raise HTTPException(status_code=403, detail="Not enough permissions")
-    return item
-
-
-@router.post("/", response_model=ItemPublic)
-def create_item(
-    *, session: SessionDep, current_user: CurrentUser, item_in: ItemCreate
-) -> Any:
-    """
-    Create new item.
-    """
-    item = Item.model_validate(item_in, update={"owner_id": current_user.id})
-    session.add(item)
-    session.commit()
-    session.refresh(item)
-    return item
-
-
-@router.put("/{id}", response_model=ItemPublic)
-def update_item(
-    *,
-    session: SessionDep,
-    current_user: CurrentUser,
-    id: uuid.UUID,
-    item_in: ItemUpdate,
-) -> Any:
-    """
-    Update an item.
-    """
-    item = session.get(Item, id)
-    if not item:
-        raise HTTPException(status_code=404, detail="Item not found")
-    if not current_user.is_superuser and (item.owner_id != current_user.id):
-        raise HTTPException(status_code=403, detail="Not enough permissions")
-    update_dict = item_in.model_dump(exclude_unset=True)
-    item.sqlmodel_update(update_dict)
-    session.add(item)
-    session.commit()
-    session.refresh(item)
-    return item
-
-
-@router.delete("/{id}")
-def delete_item(
-    session: SessionDep, current_user: CurrentUser, id: uuid.UUID
-) -> Message:
-    """
-    Delete an item.
-    """
-    item = session.get(Item, id)
-    if not item:
-        raise HTTPException(status_code=404, detail="Item not found")
-    if not current_user.is_superuser and (item.owner_id != current_user.id):
-        raise HTTPException(status_code=403, detail="Not enough permissions")
-    session.delete(item)
-    session.commit()
-    return Message(message="Item deleted successfully")

backend/app/api/routes/users.py

@@ -2,7 +2,7 @@ import uuid
 from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException
-from sqlmodel import col, delete, func, select
+from sqlmodel import col, func, select
 
 from app import crud
 from app.api.deps import (
@@ -13,7 +13,6 @@ from app.api.deps import (
 from app.core.config import settings
 from app.core.security import get_password_hash, verify_password
 from app.models import (
-    Item,
     Message,
     UpdatePassword,
     User,
@@ -224,8 +223,6 @@ def delete_user(
         raise HTTPException(
             status_code=403, detail="Super users are not allowed to delete themselves"
         )
-    statement = delete(Item).where(col(Item.owner_id) == user_id)
-    session.exec(statement)
     session.delete(user)
     session.commit()
     return Message(message="User deleted successfully")

backend/app/crud.py

@@ -1,10 +1,9 @@
-import uuid
 from typing import Any
 
 from sqlmodel import Session, select
 
 from app.core.security import get_password_hash, verify_password
-from app.models import Item, ItemCreate, User, UserCreate, UserUpdate
+from app.models import User, UserCreate, UserUpdate
 
 
 def create_user(*, session: Session, user_create: UserCreate) -> User:
@@ -58,11 +57,3 @@ def authenticate(*, session: Session, email: str, password: str) -> User | None:
         session.commit()
         session.refresh(db_user)
     return db_user
-
-
-def create_item(*, session: Session, item_in: ItemCreate, owner_id: uuid.UUID) -> Item:
-    db_item = Item.model_validate(item_in, update={"owner_id": owner_id})
-    session.add(db_item)
-    session.commit()
-    session.refresh(db_item)
-    return db_item

backend/app/flow/nodes.py

@@ -776,7 +776,7 @@ class MqttNode(Node):
         "qos",
         "retain",
         "keepalive",
-        "_topic_to_messages",
+        "_topic_to_ports",
         "_subscription_task",
         "_mqtt_client",
         "_stop_event",
@@ -1001,7 +1001,7 @@ class MqttNode(Node):
         logger.info(
             "Started MQTT subscription for node '%s' to topics %s",
             self.name,
-            list(self._topic_to_messages.keys()),
+            list(self._topic_to_ports.keys()),
         )
 
     async def stop_subscription(self) -> None:
@@ -1034,7 +1034,7 @@ class MqttNode(Node):
         Background loop that listens for MQTT messages and triggers the pipeline.
 
         Subscribes to all unique topics from the ``topics`` mapping and
-        uses the reverse lookup ``_topic_to_messages`` to route incoming
+        uses the reverse lookup ``_topic_to_ports`` to route incoming
         payloads to the correct pipeline message names.
         """
         import json
@@ -1052,7 +1052,7 @@ class MqttNode(Node):
                     keepalive=self.keepalive,
                 ) as client:
                     # Subscribe to every unique topic
-                    for topic in self._topic_to_messages:
+                    for topic in self._topic_to_ports:
                         await client.subscribe(topic, qos=self.qos)
                         logger.info("[%s] Subscribed to %s", self.name, topic)
 

backend/app/models.py

@@ -3,7 +3,7 @@ from datetime import datetime, timezone
 
 from pydantic import EmailStr
 from sqlalchemy import DateTime
-from sqlmodel import Field, Relationship, SQLModel
+from sqlmodel import Field, SQLModel
 
 
 def get_datetime_utc() -> datetime:
@@ -53,7 +53,6 @@ class User(UserBase, table=True):
         default_factory=get_datetime_utc,
         sa_type=DateTime(timezone=True),  # type: ignore
     )
-    items: list["Item"] = Relationship(back_populates="owner", cascade_delete=True)
 
 
 # Properties to return via API, id is always required
@@ -67,47 +66,6 @@ class UsersPublic(SQLModel):
     count: int
 
 
-# Shared properties
-class ItemBase(SQLModel):
-    title: str = Field(min_length=1, max_length=255)
-    description: str | None = Field(default=None, max_length=255)
-
-
-# Properties to receive on item creation
-class ItemCreate(ItemBase):
-    pass
-
-
-# Properties to receive on item update
-class ItemUpdate(ItemBase):
-    title: str | None = Field(default=None, min_length=1, max_length=255)  # type: ignore
-
-
-# Database model, database table inferred from class name
-class Item(ItemBase, table=True):
-    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
-    created_at: datetime | None = Field(
-        default_factory=get_datetime_utc,
-        sa_type=DateTime(timezone=True),  # type: ignore
-    )
-    owner_id: uuid.UUID = Field(
-        foreign_key="user.id", nullable=False, ondelete="CASCADE"
-    )
-    owner: User | None = Relationship(back_populates="items")
-
-
-# Properties to return via API, id is always required
-class ItemPublic(ItemBase):
-    id: uuid.UUID
-    owner_id: uuid.UUID
-    created_at: datetime | None = None
-
-
-class ItemsPublic(SQLModel):
-    data: list[ItemPublic]
-    count: int
-
-
 # Generic message
 class Message(SQLModel):
     message: str