fix request handler

Author: thrau

aws-replicator/aws_replicator/client/auth_proxy.py

@@ -29,6 +29,7 @@
 from localstack_ext.bootstrap.licensingv2 import ENV_LOCALSTACK_API_KEY, ENV_LOCALSTACK_AUTH_TOKEN
 from werkzeug import Request, Response
 from werkzeug import serving as werkzeug_serving
+from werkzeug.datastructures import Headers
 
 from aws_replicator import config as repl_config
 from aws_replicator.client.utils import truncate_content
@@ -77,6 +78,8 @@ def do_shutdown(self):
     @Request.application
     def _wsgi_app(self, request: Request) -> Response:
         """A wsgi-compatible interface for serving the proxy server."""
+        # make headers mutable (needed for serving through werkzeug)
+        request.headers = Headers(request.headers)
         return self.proxy_request(request)
 
     def proxy_request(self, request: Request) -> Response: