Brushed up the backend, added writing task 1 academic prompt gen and grading ENCOA-274

ielts_be/middlewares/authentication.py

@@ -0,0 +1,48 @@
+import os
+from typing import Tuple
+
+import jwt
+from jwt import InvalidTokenError
+from pydantic import BaseModel, Field
+from starlette.authentication import AuthenticationBackend
+from starlette.middleware.authentication import (
+    AuthenticationMiddleware as BaseAuthenticationMiddleware,
+)
+from starlette.requests import HTTPConnection
+
+
+class Session(BaseModel):
+    authenticated: bool = Field(False, description="Is user authenticated?")
+
+
+class AuthBackend(AuthenticationBackend):
+    async def authenticate(
+        self, conn: HTTPConnection
+    ) -> Tuple[bool, Session]:
+        session = Session()
+        authorization: str = conn.headers.get("Authorization")
+        if not authorization:
+            return False, session
+
+        try:
+            scheme, token = authorization.split(" ")
+            if scheme.lower() != "bearer":
+                return False, session
+        except ValueError:
+            return False, session
+
+        jwt_secret_key = os.getenv("JWT_SECRET_KEY")
+        if not jwt_secret_key:
+            return False, session
+
+        try:
+            jwt.decode(token, jwt_secret_key, algorithms=["HS256"])
+        except InvalidTokenError:
+            return False, session
+
+        session.authenticated = True
+        return True, session
+
+
+class AuthenticationMiddleware(BaseAuthenticationMiddleware):
+    pass