Create authAPI.py

authAPI.py

@@ -0,0 +1,86 @@
+from fastapi import APIRouter, HTTPException, Depends, status
+from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
+from passlib.context import CryptContext
+from jose import JWTError, jwt
+from sqlalchemy.orm import Session
+from datetime import datetime, timedelta
+from models import User  # Your SQLAlchemy User model
+from database import get_db  # DB Session dependency
+
+SECRET_KEY = "your-secret-key"  # Use env var in production!
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = 60
+
+auth_router = APIRouter(tags=["Authentication"])
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="auth/login")
+
+
+def hash_password(password: str):
+    return pwd_context.hash(password)
+
+
+def verify_password(plain_password: str, hashed_password: str):
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def create_access_token(data: dict, expires_delta: timedelta = None):
+    to_encode = data.copy()
+    expire = datetime.utcnow() + (expires_delta or timedelta(minutes=15))
+    to_encode.update({"exp": expire})
+    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+
+
+def get_user_by_username(db: Session, username: str):
+    return db.query(User).filter(User.username == username).first()
+
+
+def authenticate_user(db: Session, username: str, password: str):
+    user = get_user_by_username(db, username)
+    if not user or not verify_password(password, user.password):
+        return None
+    return user
+
+
+async def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Invalid authentication credentials.",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username = payload.get("sub")
+        if username is None:
+            raise credentials_exception
+    except JWTError:
+        raise credentials_exception
+
+    user = get_user_by_username(db, username)
+    if user is None:
+        raise credentials_exception
+    return user
+
+
+@auth_router.post("/auth/signup")
+def signup(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
+    if get_user_by_username(db, form_data.username):
+        raise HTTPException(status_code=400, detail="Username already taken")
+    user = User(
+        username=form_data.username,
+        password=hash_password(form_data.password),
+    )
+    db.add(user)
+    db.commit()
+    db.refresh(user)
+    return {"msg": "User created successfully"}
+
+
+@auth_router.post("/auth/login")
+def login(form_data: OAuth2PasswordRequestForm = Depends(), db: Session = Depends(get_db)):
+    user = authenticate_user(db, form_data.username, form_data.password)
+    if not user:
+        raise HTTPException(status_code=400, detail="Incorrect username or password")
+
+    token = create_access_token(data={"sub": user.username}, expires_delta=timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES))
+    return {"access_token": token, "token_type": "bearer"}