Disallow default header to be overwritten (#577)

Co-authored-by: Hongyi Wang <[email protected]>

Author: whynick1

pyiceberg/catalog/rest.py

@@ -480,12 +480,12 @@ def _refresh_token(self, session: Optional[Session] = None, initial_token: Optio
             session.headers[AUTHORIZATION_HEADER] = f"{BEARER_PREFIX} {token}"
 
     def _config_headers(self, session: Session) -> None:
+        header_properties = self._extract_headers_from_properties()
+        session.headers.update(header_properties)
         session.headers["Content-type"] = "application/json"
         session.headers["X-Client-Version"] = ICEBERG_REST_SPEC_VERSION
         session.headers["User-Agent"] = f"PyIceberg/{__version__}"
         session.headers["X-Iceberg-Access-Delegation"] = "vended-credentials"
-        header_properties = self._extract_headers_from_properties()
-        session.headers.update(header_properties)
 
     def _extract_headers_from_properties(self) -> Dict[str, str]:
         return {key[len(HEADER_PREFIX) :]: value for key, value in self.properties.items() if key.startswith(HEADER_PREFIX)}

tests/catalog/test_rest.py

@@ -277,36 +277,55 @@ def test_properties_sets_headers(requests_mock: Mocker) -> None:
     )
 
     catalog = RestCatalog(
-        "rest", uri=TEST_URI, warehouse="s3://some-bucket", **{"header.Content-Type": "application/vnd.api+json"}
+        "rest",
+        uri=TEST_URI,
+        warehouse="s3://some-bucket",
+        **{"header.Content-Type": "application/vnd.api+json", "header.Customized-Header": "some/value"},
     )
 
     assert (
-        catalog._session.headers.get("Content-type") == "application/vnd.api+json"
-    ), "Expected 'Content-Type' header to be 'application/vnd.api+json'"
-
+        catalog._session.headers.get("Content-type") == "application/json"
+    ), "Expected 'Content-Type' default header not to be overwritten"
     assert (
-        requests_mock.last_request.headers["Content-type"] == "application/vnd.api+json"
+        requests_mock.last_request.headers["Content-type"] == "application/json"
     ), "Config request did not include expected 'Content-Type' header"
 
+    assert (
+        catalog._session.headers.get("Customized-Header") == "some/value"
+    ), "Expected 'Customized-Header' header to be 'some/value'"
+    assert (
+        requests_mock.last_request.headers["Customized-Header"] == "some/value"
+    ), "Config request did not include expected 'Customized-Header' header"
+
 
 def test_config_sets_headers(requests_mock: Mocker) -> None:
     namespace = "leden"
     requests_mock.get(
         f"{TEST_URI}v1/config",
-        json={"defaults": {"header.Content-Type": "application/vnd.api+json"}, "overrides": {}},
+        json={
+            "defaults": {"header.Content-Type": "application/vnd.api+json", "header.Customized-Header": "some/value"},
+            "overrides": {},
+        },
         status_code=200,
     )
     requests_mock.post(f"{TEST_URI}v1/namespaces", json={"namespace": [namespace], "properties": {}}, status_code=200)
     catalog = RestCatalog("rest", uri=TEST_URI, warehouse="s3://some-bucket")
     catalog.create_namespace(namespace)
 
     assert (
-        catalog._session.headers.get("Content-type") == "application/vnd.api+json"
-    ), "Expected 'Content-Type' header to be 'application/vnd.api+json'"
+        catalog._session.headers.get("Content-type") == "application/json"
+    ), "Expected 'Content-Type' default header not to be overwritten"
     assert (
-        requests_mock.last_request.headers["Content-type"] == "application/vnd.api+json"
+        requests_mock.last_request.headers["Content-type"] == "application/json"
     ), "Create namespace request did not include expected 'Content-Type' header"
 
+    assert (
+        catalog._session.headers.get("Customized-Header") == "some/value"
+    ), "Expected 'Customized-Header' header to be 'some/value'"
+    assert (
+        requests_mock.last_request.headers["Customized-Header"] == "some/value"
+    ), "Create namespace request did not include expected 'Customized-Header' header"
+
 
 def test_token_400(rest_mock: Mocker) -> None:
     rest_mock.post(