Add request validation function as dependency

Author: marvinbuss

code/function/fastapp/health/__init__.py

@@ -0,0 +1,18 @@
+from typing import Annotated
+from fastapi import Header, HTTPException
+from hashlib import sha256
+import base64
+from fastapp.core.config import settings
+
+async def verify_health_auth_header(x_ms_auth_internal_token: Annotated[str, Header()]) -> bool:
+    """Returns true if SHA256 of header_value matches WEBSITE_AUTH_ENCRYPTION_KEY.
+    
+    x_ms_auth_internal_token: Value of the x-ms-auth-internal-token header.
+    RETURNS (bool): Specifies whether the header matches.
+    """
+    website_auth_encryption_key = settings.WEBSITE_AUTH_ENCRYPTION_KEY
+    hash = base64.b64encode(sha256(website_auth_encryption_key.encode('utf-8')).digest()).decode('utf-8')
+    if hash != x_ms_auth_internal_token:
+        raise HTTPException(status_code=400, detail="x-ms-auth-internal-token is invalid")
+    else:
+        return True