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LLeMbas/src/lembas/db/models/user.py
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Jaroslav Beneš 1d3f6c450b Users, groups, permissions, model settings and reasoning display
Four features, plus the schema machinery they needed.

**Schema sync.** The first live instance had data in it, and create_all
only creates missing *tables* -- a new column silently never appeared.
db/migrations.py now diffs the declared models against the database and
ALTER TABLE ... ADD COLUMN for what is missing, deriving a backfill
default from the column type (SQLite refuses a NOT NULL column without
one, and a Python-side `default=dict` cannot be expressed in DDL).
Verified against a copy of the live database: eight changes applied, all
rows preserved, second run a no-op. Renames, drops and retypes are still
manual and say so.

**Permissions.** A flat set of named booleans: an instance baseline
widened by each group the user belongs to. A group grants and never
denies -- with denies, "why can this user not do X" cannot be answered
without simulating every group. Admins bypass entirely, because an admin
can grant it back to themselves in two clicks and pretending otherwise
is theatre. Model *access* is separate: public, or granted to groups.
The picker is not the boundary -- switching a chat to a model you cannot
reach is a 403.

**Model settings.** Ordering, pinned-first, an instance default and a
per-user default, display names, descriptions, capability flags, and
uploaded images. Images are stored and served locally rather than by
URL: a remote URL makes every page render a request to a third party.
Uploads are validated by magic number, not the declared content type,
and stored under a random name. Models with no image get a generated
initial whose hue is derived from the model id, so it is stable.

**Reasoning display.** Streams into its own collapsible block above the
answer, labelled "Thought for 14 seconds", collapsed once finished, and
never replayed as context on the next turn. Two sources: the
reasoning_content delta field, and <think> tags inline in content -- the
latter needs a streaming splitter because the tags arrive split across
chunks. Models emitting no reasoning show nothing, via a :has() rule
rather than JavaScript. Verified against qwen35-9b on llama-swap: 694
reasoning events, 52 answer tokens, cleanly separated.

Two bugs found and fixed while testing:

- A bare `Mapped[list]` relationship is treated by SQLAlchemy as a scalar
  and returns None instead of []. It needs the element type.
- FastAPI substitutes the default for an empty form value, so with
  `x: str | None = Form(None)` a submitted `x=` is indistinguishable from
  an absent field. That silently broke clearing a system prompt or a
  temperature. update_chat now reads the raw form and checks key presence.

143 tests, ruff clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-21 11:49:32 +02:00

101 lines
3.9 KiB
Python

"""Users, groups and login sessions."""
from __future__ import annotations
from datetime import datetime
from typing import TYPE_CHECKING, Any
from sqlalchemy import Boolean, Column, DateTime, ForeignKey, Index, String, Table, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship
from lembas.db.base import Base, Timestamps, UUIDPrimaryKey
from lembas.db.types import JSONDict
if TYPE_CHECKING:
# Annotation only; SQLAlchemy resolves the real class from its registry.
from lembas.db.models.connection import Model
# Roles are a simple ordered ladder rather than a permission matrix. Groups
# (below) carry finer-grained permissions once the users/groups UI lands.
ROLE_ADMIN = "admin"
ROLE_USER = "user"
ROLE_PENDING = "pending" # registered but awaiting admin approval
user_groups = Table(
"user_groups",
Base.metadata,
Column("user_id", String(32), ForeignKey("users.id", ondelete="CASCADE"), primary_key=True),
Column("group_id", String(32), ForeignKey("groups.id", ondelete="CASCADE"), primary_key=True),
)
class User(UUIDPrimaryKey, Timestamps, Base):
__tablename__ = "users"
email: Mapped[str] = mapped_column(String(320), unique=True, nullable=False, index=True)
name: Mapped[str] = mapped_column(String(120), nullable=False)
password_hash: Mapped[str] = mapped_column(Text, nullable=False)
role: Mapped[str] = mapped_column(String(16), default=ROLE_USER, nullable=False)
active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)
last_login_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
# Per-user preferences: theme, default model, composer behaviour, etc.
settings_json: Mapped[dict[str, Any]] = mapped_column(JSONDict, default=dict)
groups: Mapped[list[Group]] = relationship(secondary=user_groups, back_populates="users")
sessions: Mapped[list[Session]] = relationship(
back_populates="user", cascade="all, delete-orphan"
)
@property
def is_admin(self) -> bool:
return self.role == ROLE_ADMIN
def __repr__(self) -> str:
return f"<User {self.email} role={self.role}>"
class Group(UUIDPrimaryKey, Timestamps, Base):
"""A named set of users. Permissions are enforced once the RBAC pass lands."""
__tablename__ = "groups"
name: Mapped[str] = mapped_column(String(120), unique=True, nullable=False)
description: Mapped[str] = mapped_column(Text, default="")
# Only the granted keys need be present. Absent means "no opinion", not
# "deny" -- permissions union across a user's groups. See
# lembas.security.permissions.
permissions_json: Mapped[dict[str, Any]] = mapped_column(JSONDict, default=dict)
users: Mapped[list[User]] = relationship(secondary=user_groups, back_populates="groups")
models: Mapped[list[Model]] = relationship(
"Model", secondary="model_groups", back_populates="groups"
)
class Session(UUIDPrimaryKey, Timestamps, Base):
"""Server-side login session.
Sessions live in the database rather than in a signed JWT so that logging
out, banning a user, or rotating a device actually revokes access
immediately instead of waiting for a token to expire.
"""
__tablename__ = "sessions"
user_id: Mapped[str] = mapped_column(
String(32), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
)
# SHA-256 of the cookie value. The raw token is shown to the browser once
# and never stored, so a database leak does not hand over live sessions.
token_hash: Mapped[str] = mapped_column(String(64), unique=True, nullable=False)
expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
user_agent: Mapped[str] = mapped_column(Text, default="")
ip_address: Mapped[str] = mapped_column(String(45), default="")
user: Mapped[User] = relationship(back_populates="sessions")
Index("ix_sessions_user_id", Session.user_id)