hoàn thành phần Authentication

backend/app/database.py

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+from sqlalchemy import create_engine
+from sqlalchemy.orm import DeclarativeBase, sessionmaker
+import os
+
+DATABASE_URL = os.getenv(
+    "DATABASE_URL",
+    "postgresql+psycopg2://lms_user:lms_password@db:5432/lms_db",
+)
+
+engine = create_engine(DATABASE_URL, pool_pre_ping=True)
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

backend/app/dependencies.py

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+from fastapi import Cookie, Depends, HTTPException, status
+from jose import JWTError
+from sqlalchemy.orm import Session
+
+from .database import get_db
+from .models import User
+from .security import decode_access_token
+
+
+def get_current_user(
+    access_token: str | None = Cookie(default=None),
+    db: Session = Depends(get_db),
+) -> User:
+    """
+    Reads the JWT from the HttpOnly `access_token` cookie,
+    validates it, and returns the authenticated User ORM object.
+    Raises 401 on any failure.
+    """
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Not authenticated.",
+    )
+
+    if access_token is None:
+        raise credentials_exception
+
+    try:
+        user_id = decode_access_token(access_token)
+    except JWTError:
+        raise credentials_exception
+
+    user = db.get(User, user_id)
+    if user is None:
+        raise credentials_exception
+
+    return user

backend/app/main.py

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+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+
+from .database import Base, engine
+from .routers import auth
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Create all tables on startup (use Alembic for migrations in production)
+    Base.metadata.create_all(bind=engine)
+    yield
+
+
+app = FastAPI(title="LMS API", lifespan=lifespan)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["http://localhost:3000"],  # Next.js dev server
+    allow_credentials=True,                   # required for cookies
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(auth.router, prefix="/api")

backend/app/models.py

@@ -0,0 +1,66 @@
+from datetime import datetime, timezone
+from sqlalchemy import (
+    Column,
+    Integer,
+    String,
+    Text,
+    ForeignKey,
+    DateTime,
+    UniqueConstraint,
+)
+from sqlalchemy.dialects.postgresql import JSONB
+from sqlalchemy.orm import relationship
+from .database import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id = Column(Integer, primary_key=True, index=True)
+    username = Column(String(64), unique=True, nullable=False, index=True)
+    email = Column(String(255), unique=True, nullable=False, index=True)
+    password_hash = Column(String(255), nullable=False)
+    created_at = Column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
+
+    # Relationships
+    pdfs = relationship("PDF", back_populates="owner", cascade="all, delete-orphan")
+    annotations = relationship("Annotation", back_populates="owner", cascade="all, delete-orphan")
+
+
+class PDF(Base):
+    __tablename__ = "pdfs"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    title = Column(String(255), nullable=False)
+    file_path = Column(Text, nullable=False)       # path inside Docker volume
+    total_pages = Column(Integer, nullable=True)   # populated after upload processing
+    created_at = Column(DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False)
+
+    # Relationships
+    owner = relationship("User", back_populates="pdfs")
+    annotations = relationship("Annotation", back_populates="pdf", cascade="all, delete-orphan")
+
+
+class Annotation(Base):
+    __tablename__ = "annotations"
+    __table_args__ = (
+        # One annotation record per (pdf, user, page) — upsert target
+        UniqueConstraint("pdf_id", "user_id", "page_number", name="uq_annotation_pdf_user_page"),
+    )
+
+    id = Column(Integer, primary_key=True, index=True)
+    pdf_id = Column(Integer, ForeignKey("pdfs.id", ondelete="CASCADE"), nullable=False, index=True)
+    user_id = Column(Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    page_number = Column(Integer, nullable=False)   # 1-based
+    canvas_data = Column(JSONB, nullable=False, default=dict)  # Fabric.js JSON state
+    updated_at = Column(
+        DateTime(timezone=True),
+        default=lambda: datetime.now(timezone.utc),
+        onupdate=lambda: datetime.now(timezone.utc),
+        nullable=False,
+    )
+
+    # Relationships
+    pdf = relationship("PDF", back_populates="annotations")
+    owner = relationship("User", back_populates="annotations")

backend/app/routers/auth.py

@@ -0,0 +1,84 @@
+from fastapi import APIRouter, Depends, HTTPException, Response, status
+from sqlalchemy.orm import Session
+
+from ..database import get_db
+from ..dependencies import get_current_user
+from ..models import User
+from ..schemas import UserLogin, UserOut, UserRegister
+from ..security import (
+    ACCESS_TOKEN_EXPIRE_MINUTES,
+    create_access_token,
+    hash_password,
+    verify_password,
+)
+
+router = APIRouter(prefix="/auth", tags=["auth"])
+
+_COOKIE_NAME = "access_token"
+_COOKIE_MAX_AGE = ACCESS_TOKEN_EXPIRE_MINUTES * 60   # seconds
+
+
+def _set_auth_cookie(response: Response, user_id: int) -> None:
+    token = create_access_token(user_id)
+    response.set_cookie(
+        key=_COOKIE_NAME,
+        value=token,
+        httponly=True,
+        secure=True,        # send only over HTTPS (Nginx handles TLS in prod)
+        samesite="lax",
+        max_age=_COOKIE_MAX_AGE,
+        path="/",
+    )
+
+
+# ── POST /auth/register ───────────────────────────────────────────────────────
+
+@router.post("/register", response_model=UserOut, status_code=status.HTTP_201_CREATED)
+def register(body: UserRegister, response: Response, db: Session = Depends(get_db)):
+    if db.query(User).filter(User.username == body.username).first():
+        raise HTTPException(status_code=400, detail="Username already taken.")
+    if db.query(User).filter(User.email == body.email).first():
+        raise HTTPException(status_code=400, detail="Email already registered.")
+
+    user = User(
+        username=body.username,
+        email=body.email,
+        password_hash=hash_password(body.password),
+    )
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+
+    _set_auth_cookie(response, user.id)
+    return user
+
+
+# ── POST /auth/login ──────────────────────────────────────────────────────────
+
+@router.post("/login", response_model=UserOut)
+def login(body: UserLogin, response: Response, db: Session = Depends(get_db)):
+    user: User | None = db.query(User).filter(User.username == body.username).first()
+
+    # Constant-time: always verify even when user is None to prevent timing attacks
+    dummy_hash = "$2b$12$KIXyb/r7MBJ3z32Dc3y8YuNfj7DhpNcaYgU2q8uGiHjJ6YFe6RVxm"
+    password_ok = verify_password(body.password, user.password_hash if user else dummy_hash)
+
+    if not user or not password_ok:
+        raise HTTPException(status_code=401, detail="Invalid username or password.")
+
+    _set_auth_cookie(response, user.id)
+    return user
+
+
+# ── POST /auth/logout ─────────────────────────────────────────────────────────
+
+@router.post("/logout", status_code=status.HTTP_204_NO_CONTENT)
+def logout(response: Response):
+    response.delete_cookie(key=_COOKIE_NAME, path="/")
+
+
+# ── GET /auth/me ──────────────────────────────────────────────────────────────
+
+@router.get("/me", response_model=UserOut)
+def me(current_user: User = Depends(get_current_user)):
+    return current_user

backend/app/schemas.py

@@ -0,0 +1,47 @@
+from datetime import datetime
+from pydantic import BaseModel, EmailStr, field_validator
+import re
+
+
+# ── Auth ─────────────────────────────────────────────────────────────────────
+
+class UserRegister(BaseModel):
+    username: str
+    email: EmailStr
+    password: str
+
+    @field_validator("username")
+    @classmethod
+    def username_valid(cls, v: str) -> str:
+        v = v.strip()
+        if not re.match(r"^[A-Za-z0-9_]{3,64}$", v):
+            raise ValueError(
+                "Username must be 3–64 characters, letters/numbers/underscore only."
+            )
+        return v
+
+    @field_validator("password")
+    @classmethod
+    def password_strength(cls, v: str) -> str:
+        if len(v) < 8:
+            raise ValueError("Password must be at least 8 characters.")
+        return v
+
+
+class UserLogin(BaseModel):
+    username: str
+    password: str
+
+
+class UserOut(BaseModel):
+    id: int
+    username: str
+    email: str
+    created_at: datetime
+
+    model_config = {"from_attributes": True}
+
+
+class TokenPayload(BaseModel):
+    sub: int   # user id
+    exp: int

backend/app/security.py

@@ -0,0 +1,43 @@
+from datetime import datetime, timedelta, timezone
+import os
+
+from jose import JWTError, jwt
+from passlib.context import CryptContext
+
+# ── Config (override via environment variables) ───────────────────────────────
+SECRET_KEY: str = os.environ["JWT_SECRET_KEY"]          # must be set — no default
+ALGORITHM: str = os.getenv("JWT_ALGORITHM", "HS256")
+ACCESS_TOKEN_EXPIRE_MINUTES: int = int(
+    os.getenv("ACCESS_TOKEN_EXPIRE_MINUTES", "60")
+)
+
+# ── Password hashing ──────────────────────────────────────────────────────────
+_pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+
+def hash_password(plain: str) -> str:
+    return _pwd_context.hash(plain)
+
+
+def verify_password(plain: str, hashed: str) -> bool:
+    return _pwd_context.verify(plain, hashed)
+
+
+# ── JWT ───────────────────────────────────────────────────────────────────────
+
+def create_access_token(user_id: int) -> str:
+    expire = datetime.now(timezone.utc) + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    payload = {"sub": str(user_id), "exp": expire}
+    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)
+
+
+def decode_access_token(token: str) -> int:
+    """
+    Decode the JWT and return the user_id (int).
+    Raises JWTError on any validation failure.
+    """
+    payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+    sub = payload.get("sub")
+    if sub is None:
+        raise JWTError("Missing subject claim.")
+    return int(sub)

backend/main.py

@@ -0,0 +1 @@
+from app.main import app

backend/requirements.txt

@@ -0,0 +1,8 @@
+fastapi==0.115.6
+uvicorn[standard]==0.30.6
+sqlalchemy==2.0.36
+psycopg2-binary==2.9.10
+passlib[bcrypt]==1.7.4
+python-jose[cryptography]==3.3.0
+pydantic[email]==2.9.2
+python-multipart==0.0.12