[New Feature] Rest API implementation to showcase the OpenDBM features

rest_api/app/services/auth/auth.py

@@ -0,0 +1,94 @@
+from datetime import datetime, timedelta
+from schemas.user import User, UserInDB
+from schemas.token import Token, TokenData
+from services.main import OpenDBMSessionContext
+from config.db import get_db
+from fastapi.security import OAuth2PasswordBearer, OAuth2PasswordRequestForm
+from fastapi import Depends, HTTPException, status
+from passlib.context import CryptContext
+from jose import JWTError, jwt
+from typing import Union
+import os
+from dotenv import load_dotenv
+
+load_dotenv()
+
+
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="odbm/v1/login")
+SECRET_KEY = os.getenv('JWT_SECRET', 'DUMMY_SECRET')
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = int(os.getenv('TOKEN_EXPIRE', 30))
+
+pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")
+db = get_db()
+
+def get_user(username: str):
+    if username in db:
+        user_dict = db[username]
+        return UserInDB(**user_dict)
+
+def verify_password(plain_password, hashed_password):
+    return pwd_context.verify(plain_password, hashed_password)
+
+
+def get_password_hash(password):
+    return pwd_context.hash(password)
+
+def authenticate_user(username: str, password: str):
+    user = get_user(username)
+    if not user:
+        return False
+    if not verify_password(password, user.hashed_password):
+        return False
+    return user
+
+def create_access_token(data: dict, expires_delta: Union[timedelta, None] = None):
+    to_encode = data.copy()
+    if expires_delta:
+        expire = datetime.utcnow() + expires_delta
+    else:
+        expire = datetime.utcnow() + timedelta(minutes=15)
+    to_encode.update({"exp": expire})
+    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+    return encoded_jwt
+
+async def get_current_user(token: str = Depends(oauth2_scheme)):
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username: str = payload.get("sub")
+        if username is None:
+            raise credentials_exception
+        token_data = TokenData(username=username)
+    except JWTError:
+        raise credentials_exception
+    user = get_user(username=token_data.username)
+    if user is None:
+        raise credentials_exception
+    return user
+
+async def get_current_active_user(current_user: User = Depends(get_current_user)):
+    if current_user.disabled:
+        raise HTTPException(status_code=400, detail="Inactive user")
+    return current_user
+
+def login(form_data: OAuth2PasswordRequestForm):
+    hashed_pwd = get_password_hash(form_data.password)
+    user = authenticate_user(form_data.username, form_data.password)
+    if not user:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+    access_token_expires = timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    access_token = create_access_token(
+        data={"sub": user.username}, expires_delta=access_token_expires
+    )
+    token = Token(access_token=access_token, token_type="bearer")
+    return token
+