Unique username

alembic/versions/2df7e2c6af43_users.py

@@ -1,8 +1,8 @@
 """Users
 
-Revision ID: 493f3f7529f3
+Revision ID: 2df7e2c6af43
 Revises: 
-Create Date: 2026-08-16 11:22:34.176552
+Create Date: 2026-08-17 12:42:05.103510
 
 """
 from typing import Sequence, Union
@@ -13,7 +13,7 @@ import sqlalchemy as sa
 import sqlmodel
 
 # revision identifiers, used by Alembic.
-revision: str = '493f3f7529f3'
+revision: str = '2df7e2c6af43'
 down_revision: Union[str, Sequence[str], None] = None
 branch_labels: Union[str, Sequence[str], None] = None
 depends_on: Union[str, Sequence[str], None] = None
@@ -29,6 +29,7 @@ def upgrade() -> None:
     sa.Column('password', sqlmodel.sql.sqltypes.AutoString(), nullable=False),
     sa.Column('admin', sa.Boolean(), nullable=False),
     sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('internal_username'),
     sa.UniqueConstraint('uuid')
     )
     # ### end Alembic commands ###

loon/mqtt/handlers/register_request.py

@@ -25,6 +25,14 @@ async def register_request_handler(client, userdata, msg, data):
                            json.dumps({"success": False, "error": "The user is already registered!"}))
             return
 
+        statement = select(User).where(User.internal_username == internal_username)
+        user = session.exec(statement).first()
+
+        if user is not None:
+            client.publish(f"loon/register/{uuid}/response",
+                           json.dumps({"success": False, "error": f"The {internal_username} is taken!"}))
+            return
+
         user = User(uuid=uuid, password=hash_password(password), internal_username=internal_username, admin=False)
         session.add(user)
         try:

loon/web/users/models.py

@@ -4,6 +4,6 @@ from sqlmodel import SQLModel, Field
 class User(SQLModel, table=True):
     id: int = Field(default=None, primary_key=True)
     uuid: str = Field(unique=True)
-    internal_username: str
+    internal_username: str = Field(unique=True)
     password: str
     admin: bool = Field(default=False)