Add complete FastAPI backend for AI tutor application

- User authentication with JWT tokens (register/login)
- Tutor session management with CRUD operations
- Message tracking for tutor conversations
- SQLite database with Alembic migrations
- CORS configuration for frontend integration
- Health check and service info endpoints
- Proper project structure with models, schemas, and API routes

README.md

@@ -1,3 +1,77 @@
-# FastAPI Application
+# AI Tutor Backend Service
 
-This is a FastAPI application bootstrapped by BackendIM, the AI-powered backend generation platform.
+A FastAPI-based backend service for an AI-powered tutoring application.
+
+## Features
+
+- User authentication (register/login with JWT tokens)
+- Tutor session management
+- Message tracking for tutor conversations
+- SQLite database with Alembic migrations
+- CORS enabled for frontend integration
+- Health check endpoint
+
+## Environment Variables
+
+Copy `.env.example` to `.env` and set the following variables:
+
+- `SECRET_KEY`: JWT secret key for token generation (required for production)
+
+## Installation
+
+1. Install dependencies:
+```bash
+pip install -r requirements.txt
+```
+
+2. Run database migrations:
+```bash
+alembic upgrade head
+```
+
+3. Start the development server:
+```bash
+uvicorn main:app --reload
+```
+
+The API will be available at `http://localhost:8000`
+
+## API Documentation
+
+- Swagger UI: `http://localhost:8000/docs`
+- ReDoc: `http://localhost:8000/redoc`
+- OpenAPI JSON: `http://localhost:8000/openapi.json`
+
+## API Endpoints
+
+### Authentication
+- `POST /auth/register` - Register a new user
+- `POST /auth/login` - Login and get access token
+- `GET /auth/me` - Get current user profile
+
+### Tutor Sessions
+- `POST /tutor/sessions` - Create a new tutor session
+- `GET /tutor/sessions` - Get all user sessions
+- `GET /tutor/sessions/{session_id}` - Get specific session
+- `PUT /tutor/sessions/{session_id}` - Update session
+- `POST /tutor/sessions/{session_id}/messages` - Add message to session
+- `GET /tutor/sessions/{session_id}/messages` - Get session messages
+
+### Health
+- `GET /health` - Health check endpoint
+- `GET /` - Service information
+
+## Database
+
+The application uses SQLite database stored at `/app/storage/db/db.sqlite`. The database includes:
+
+- `users` - User accounts
+- `tutor_sessions` - Tutoring sessions 
+- `tutor_messages` - Messages within sessions
+
+## Development
+
+To run in development mode:
+```bash
+uvicorn main:app --reload --host 0.0.0.0 --port 8000
+```

alembic.ini

@@ -0,0 +1,41 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+version_path_separator = os
+sqlalchemy.url = sqlite:////app/storage/db/db.sqlite
+
+[post_write_hooks]
+
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

alembic/env.py

@@ -0,0 +1,55 @@
+from logging.config import fileConfig
+from sqlalchemy import engine_from_config
+from sqlalchemy import pool
+from alembic import context
+import sys
+import os
+
+sys.path.append(os.path.dirname(os.path.dirname(__file__)))
+
+from app.db.base import Base
+from app.models.user import User
+from app.models.tutor_session import TutorSession
+from app.models.tutor_message import TutorMessage
+
+config = context.config
+
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

alembic/script.py.mako

@@ -0,0 +1,24 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision = ${repr(up_revision)}
+down_revision = ${repr(down_revision)}
+branch_labels = ${repr(branch_labels)}
+depends_on = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

alembic/versions/001_initial_migration.py

@@ -0,0 +1,64 @@
+"""Initial migration
+
+Revision ID: 001
+Revises: 
+Create Date: 2024-01-01 00:00:00.000000
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = '001'
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table('users',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('email', sa.String(), nullable=False),
+    sa.Column('hashed_password', sa.String(), nullable=False),
+    sa.Column('full_name', sa.String(), nullable=True),
+    sa.Column('is_active', sa.Boolean(), nullable=True),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True),
+    sa.Column('updated_at', sa.DateTime(timezone=True), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
+    op.create_index(op.f('ix_users_id'), 'users', ['id'], unique=False)
+    
+    op.create_table('tutor_sessions',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('user_id', sa.Integer(), nullable=False),
+    sa.Column('subject', sa.String(), nullable=False),
+    sa.Column('topic', sa.String(), nullable=True),
+    sa.Column('difficulty_level', sa.String(), nullable=True),
+    sa.Column('session_status', sa.String(), nullable=True),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True),
+    sa.Column('updated_at', sa.DateTime(timezone=True), nullable=True),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_tutor_sessions_id'), 'tutor_sessions', ['id'], unique=False)
+    
+    op.create_table('tutor_messages',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('session_id', sa.Integer(), nullable=False),
+    sa.Column('message_type', sa.String(), nullable=False),
+    sa.Column('content', sa.Text(), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('(CURRENT_TIMESTAMP)'), nullable=True),
+    sa.ForeignKeyConstraint(['session_id'], ['tutor_sessions.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_tutor_messages_id'), 'tutor_messages', ['id'], unique=False)
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_tutor_messages_id'), table_name='tutor_messages')
+    op.drop_table('tutor_messages')
+    op.drop_index(op.f('ix_tutor_sessions_id'), table_name='tutor_sessions')
+    op.drop_table('tutor_sessions')
+    op.drop_index(op.f('ix_users_id'), table_name='users')
+    op.drop_index(op.f('ix_users_email'), table_name='users')
+    op.drop_table('users')

app/api/auth.py

@@ -0,0 +1,95 @@
+from fastapi import APIRouter, Depends, HTTPException, status
+from fastapi.security import HTTPBearer, HTTPAuthorizationCredentials
+from sqlalchemy.orm import Session
+from jose import JWTError, jwt
+from app.db.session import get_db
+from app.models.user import User
+from app.schemas.user import UserCreate, UserLogin, User as UserSchema
+from app.core.security import (
+    verify_password, 
+    get_password_hash, 
+    create_access_token,
+    SECRET_KEY,
+    ALGORITHM
+)
+
+router = APIRouter()
+security = HTTPBearer()
+
+
+def get_user_by_email(db: Session, email: str):
+    return db.query(User).filter(User.email == email).first()
+
+
+def create_user(db: Session, user: UserCreate):
+    hashed_password = get_password_hash(user.password)
+    db_user = User(
+        email=user.email,
+        hashed_password=hashed_password,
+        full_name=user.full_name,
+    )
+    db.add(db_user)
+    db.commit()
+    db.refresh(db_user)
+    return db_user
+
+
+def authenticate_user(db: Session, email: str, password: str):
+    user = get_user_by_email(db, email)
+    if not user:
+        return False
+    if not verify_password(password, user.hashed_password):
+        return False
+    return user
+
+
+def get_current_user(
+    credentials: HTTPAuthorizationCredentials = Depends(security),
+    db: Session = Depends(get_db)
+):
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(credentials.credentials, SECRET_KEY, algorithms=[ALGORITHM])
+        user_id: int = payload.get("sub")
+        if user_id is None:
+            raise credentials_exception
+    except JWTError:
+        raise credentials_exception
+    
+    user = db.query(User).filter(User.id == user_id).first()
+    if user is None:
+        raise credentials_exception
+    return user
+
+
+@router.post("/register", response_model=UserSchema)
+def register(user: UserCreate, db: Session = Depends(get_db)):
+    db_user = get_user_by_email(db, email=user.email)
+    if db_user:
+        raise HTTPException(
+            status_code=400,
+            detail="Email already registered"
+        )
+    return create_user(db=db, user=user)
+
+
+@router.post("/login")
+def login(user_credentials: UserLogin, db: Session = Depends(get_db)):
+    user = authenticate_user(db, user_credentials.email, user_credentials.password)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect email or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+    access_token = create_access_token(subject=user.id)
+    return {"access_token": access_token, "token_type": "bearer"}
+
+
+@router.get("/me", response_model=UserSchema)
+def read_users_me(current_user: User = Depends(get_current_user)):
+    return current_user

app/api/tutor.py

@@ -0,0 +1,128 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy.orm import Session
+from typing import List
+from app.db.session import get_db
+from app.models.user import User
+from app.models.tutor_session import TutorSession
+from app.models.tutor_message import TutorMessage
+from app.schemas.tutor_session import (
+    TutorSessionCreate, 
+    TutorSessionUpdate, 
+    TutorSession as TutorSessionSchema
+)
+from app.schemas.tutor_message import (
+    TutorMessageCreate, 
+    TutorMessage as TutorMessageSchema
+)
+from app.api.auth import get_current_user
+
+router = APIRouter()
+
+
+@router.post("/sessions", response_model=TutorSessionSchema)
+def create_tutor_session(
+    session: TutorSessionCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    db_session = TutorSession(
+        user_id=current_user.id,
+        subject=session.subject,
+        topic=session.topic,
+        difficulty_level=session.difficulty_level
+    )
+    db.add(db_session)
+    db.commit()
+    db.refresh(db_session)
+    return db_session
+
+
+@router.get("/sessions", response_model=List[TutorSessionSchema])
+def get_user_sessions(
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    return db.query(TutorSession).filter(
+        TutorSession.user_id == current_user.id
+    ).all()
+
+
+@router.get("/sessions/{session_id}", response_model=TutorSessionSchema)
+def get_session(
+    session_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    session = db.query(TutorSession).filter(
+        TutorSession.id == session_id,
+        TutorSession.user_id == current_user.id
+    ).first()
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    return session
+
+
+@router.put("/sessions/{session_id}", response_model=TutorSessionSchema)
+def update_session(
+    session_id: int,
+    session_update: TutorSessionUpdate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    session = db.query(TutorSession).filter(
+        TutorSession.id == session_id,
+        TutorSession.user_id == current_user.id
+    ).first()
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    
+    update_data = session_update.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(session, field, value)
+    
+    db.commit()
+    db.refresh(session)
+    return session
+
+
+@router.post("/sessions/{session_id}/messages", response_model=TutorMessageSchema)
+def add_message_to_session(
+    session_id: int,
+    message: TutorMessageCreate,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    session = db.query(TutorSession).filter(
+        TutorSession.id == session_id,
+        TutorSession.user_id == current_user.id
+    ).first()
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    
+    db_message = TutorMessage(
+        session_id=session_id,
+        message_type=message.message_type,
+        content=message.content
+    )
+    db.add(db_message)
+    db.commit()
+    db.refresh(db_message)
+    return db_message
+
+
+@router.get("/sessions/{session_id}/messages", response_model=List[TutorMessageSchema])
+def get_session_messages(
+    session_id: int,
+    db: Session = Depends(get_db),
+    current_user: User = Depends(get_current_user)
+):
+    session = db.query(TutorSession).filter(
+        TutorSession.id == session_id,
+        TutorSession.user_id == current_user.id
+    ).first()
+    if not session:
+        raise HTTPException(status_code=404, detail="Session not found")
+    
+    return db.query(TutorMessage).filter(
+        TutorMessage.session_id == session_id
+    ).order_by(TutorMessage.created_at).all()

app/core/security.py

@@ -0,0 +1,33 @@
+import os
+from datetime import datetime, timedelta
+from typing import Any, Union
+from jose import jwt
+from passlib.context import CryptContext
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+SECRET_KEY = os.getenv("SECRET_KEY", "your-secret-key-here")
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = 30
+
+
+def create_access_token(
+    subject: Union[str, Any], expires_delta: timedelta = None
+) -> str:
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(
+            minutes=ACCESS_TOKEN_EXPIRE_MINUTES
+        )
+    to_encode = {"exp": expire, "sub": str(subject)}
+    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+    return encoded_jwt
+
+
+def verify_password(plain_password: str, hashed_password: str) -> bool:
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password: str) -> str:
+    return pwd_context.hash(password)

app/db/base.py

@@ -0,0 +1,3 @@
+from sqlalchemy.ext.declarative import declarative_base
+
+Base = declarative_base()

app/db/session.py

@@ -0,0 +1,23 @@
+from pathlib import Path
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker
+
+DB_DIR = Path("/app") / "storage" / "db"
+DB_DIR.mkdir(parents=True, exist_ok=True)
+
+SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_DIR}/db.sqlite"
+
+engine = create_engine(
+    SQLALCHEMY_DATABASE_URL,
+    connect_args={"check_same_thread": False}
+)
+
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

app/models/tutor_message.py

@@ -0,0 +1,16 @@
+from sqlalchemy import Column, Integer, Text, DateTime, String, ForeignKey
+from sqlalchemy.sql import func
+from sqlalchemy.orm import relationship
+from app.db.base import Base
+
+
+class TutorMessage(Base):
+    __tablename__ = "tutor_messages"
+
+    id = Column(Integer, primary_key=True, index=True)
+    session_id = Column(Integer, ForeignKey("tutor_sessions.id"), nullable=False)
+    message_type = Column(String, nullable=False)  # "user" or "tutor"
+    content = Column(Text, nullable=False)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+
+    session = relationship("TutorSession", back_populates="messages")

app/models/tutor_session.py

@@ -0,0 +1,20 @@
+from sqlalchemy import Column, Integer, String, DateTime, Text, ForeignKey
+from sqlalchemy.sql import func
+from sqlalchemy.orm import relationship
+from app.db.base import Base
+
+
+class TutorSession(Base):
+    __tablename__ = "tutor_sessions"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    subject = Column(String, nullable=False)
+    topic = Column(String, nullable=True)
+    difficulty_level = Column(String, nullable=True)
+    session_status = Column(String, default="active")
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    user = relationship("User", back_populates="tutor_sessions")
+    messages = relationship("TutorMessage", back_populates="session")

app/models/user.py

@@ -0,0 +1,18 @@
+from sqlalchemy import Column, Integer, String, DateTime, Boolean
+from sqlalchemy.sql import func
+from sqlalchemy.orm import relationship
+from app.db.base import Base
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id = Column(Integer, primary_key=True, index=True)
+    email = Column(String, unique=True, index=True, nullable=False)
+    hashed_password = Column(String, nullable=False)
+    full_name = Column(String, nullable=True)
+    is_active = Column(Boolean, default=True)
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    updated_at = Column(DateTime(timezone=True), onupdate=func.now())
+
+    tutor_sessions = relationship("TutorSession", back_populates="user")

app/schemas/tutor_message.py

@@ -0,0 +1,20 @@
+from pydantic import BaseModel
+from datetime import datetime
+
+
+class TutorMessageBase(BaseModel):
+    message_type: str
+    content: str
+
+
+class TutorMessageCreate(TutorMessageBase):
+    session_id: int
+
+
+class TutorMessage(TutorMessageBase):
+    id: int
+    session_id: int
+    created_at: datetime
+
+    class Config:
+        from_attributes = True

app/schemas/tutor_session.py

@@ -0,0 +1,42 @@
+from pydantic import BaseModel
+from datetime import datetime
+from typing import Optional, List
+
+
+class TutorSessionBase(BaseModel):
+    subject: str
+    topic: Optional[str] = None
+    difficulty_level: Optional[str] = None
+
+
+class TutorSessionCreate(TutorSessionBase):
+    pass
+
+
+class TutorSessionUpdate(BaseModel):
+    subject: Optional[str] = None
+    topic: Optional[str] = None
+    difficulty_level: Optional[str] = None
+    session_status: Optional[str] = None
+
+
+class TutorMessage(BaseModel):
+    id: int
+    message_type: str
+    content: str
+    created_at: datetime
+
+    class Config:
+        from_attributes = True
+
+
+class TutorSession(TutorSessionBase):
+    id: int
+    user_id: int
+    session_status: str
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+    messages: List[TutorMessage] = []
+
+    class Config:
+        from_attributes = True

app/schemas/user.py

@@ -0,0 +1,27 @@
+from pydantic import BaseModel, EmailStr
+from datetime import datetime
+from typing import Optional
+
+
+class UserBase(BaseModel):
+    email: EmailStr
+    full_name: Optional[str] = None
+
+
+class UserCreate(UserBase):
+    password: str
+
+
+class UserLogin(BaseModel):
+    email: EmailStr
+    password: str
+
+
+class User(UserBase):
+    id: int
+    is_active: bool
+    created_at: datetime
+    updated_at: Optional[datetime] = None
+
+    class Config:
+        from_attributes = True

main.py

@@ -0,0 +1,39 @@
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from app.api import auth, tutor
+from app.db.session import engine
+from app.db.base import Base
+
+Base.metadata.create_all(bind=engine)
+
+app = FastAPI(
+    title="AI Tutor Backend Service",
+    description="Backend API for AI-powered tutoring application",
+    version="1.0.0",
+    openapi_url="/openapi.json"
+)
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(auth.router, prefix="/auth", tags=["authentication"])
+app.include_router(tutor.router, prefix="/tutor", tags=["tutor"])
+
+
+@app.get("/")
+def read_root():
+    return {
+        "title": "AI Tutor Backend Service",
+        "documentation": "/docs",
+        "health": "/health"
+    }
+
+
+@app.get("/health")
+def health_check():
+    return {"status": "healthy", "service": "AI Tutor Backend"}

requirements.txt

@@ -0,0 +1,9 @@
+fastapi==0.104.1
+uvicorn[standard]==0.24.0
+sqlalchemy==2.0.23
+alembic==1.12.1
+python-multipart==0.0.6
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+python-dotenv==1.0.0
+ruff==0.1.6