1 files changed, 97 insertions, 0 deletions
diff --git a/api/util/authentication.py b/api/util/authentication.py
new file mode 100644
index 0000000..43b147a
--- /dev/null
+++ b/api/util/authentication.py
@@ -0,0 +1,97 @@
+import random
+import bcrypt
+from fastapi import Depends, HTTPException, status, Request, Cookie
+from fastapi.security import OAuth2PasswordBearer
+from fastapi.responses import Response
+from jwt.exceptions import InvalidTokenError, ExpiredSignatureError
+from datetime import datetime, timedelta
+import jwt
+
+from api.util.db_dependency import get_db
+from sqlalchemy.orm import Session
+from api.schemas.auth_schemas import *
+from models import User as UserModel
+
+secret_key = random.randbytes(32)
+algorithm = "HS256"
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="api/auth/token")
+
+"""
+Helper functions for authentication
+"""
+
+
+def verify_password(plain_password, hashed_password):
+    return bcrypt.checkpw(
+        plain_password.encode("utf-8"), hashed_password.encode("utf-8")
+    )
+
+
+def get_user(db, username: str):
+    """
+    Get the user object from the database
+    """
+    user = db.query(UserModel).filter(UserModel.username == username).first()
+    if user:
+        return UserInDB(**user.__dict__)
+
+
+def authenticate_user(db, username: str, password: str):
+    """
+    Determine if the correct username and password were provided
+    If so, return the user object
+    """
+    user = get_user(db, username)
+    if not user:
+        return False
+    if not verify_password(password, user.hashed_password):
+        print("WHY")
+        return False
+    return user
+
+
+def create_access_token(data: dict, expires_delta: timedelta):
+    """
+    Return an encoded JWT token with the given data
+    """
+    to_encode = data.copy()
+    expire = datetime.utcnow() + expires_delta
+    to_encode.update({"exp": expire})
+    encoded_jwt = jwt.encode(to_encode, secret_key, algorithm=algorithm)
+    return encoded_jwt
+
+
+def raise_unauthorized():
+    raise HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+
+
+async def get_current_user(
+    request: Request,
+    db=Depends(get_db),
+):
+    """
+    Return the current user object if the access token is valid
+
+    All failed attempts will return a 401
+    """
+    token = request.cookies.get("access_token")
+
+    try:
+        payload = jwt.decode(token, secret_key, algorithms=[algorithm])
+        id: int = payload.get("sub")
+        username: str = payload.get("username")
+        if not id or not username:
+            return raise_unauthorized()
+
+    except InvalidTokenError:
+        return raise_unauthorized()
+
+    user = get_user(db, username)
+    if user is None:
+        return raise_unauthorized()
+
+    return user