fix: add spec version header to polling connector requests

UnleashClient/connectors/polling_connector.py

@@ -7,7 +7,7 @@
 
 from UnleashClient.api import get_feature_toggles
 from UnleashClient.cache import BaseCache
-from UnleashClient.constants import ETAG, FEATURES_URL
+from UnleashClient.constants import APPLICATION_HEADERS, ETAG, FEATURES_URL
 from UnleashClient.events import UnleashEventType, UnleashFetchedEvent
 from UnleashClient.utils import LOGGER
 
@@ -58,6 +58,7 @@ def _fetch_and_load(self):
             app_name=self.app_name,
             instance_id=self.instance_id,
             headers={
+                **APPLICATION_HEADERS,
                 **self.headers,
                 "unleash-interval": str(self.refresh_interval * 1000),
             },

tests/unit_tests/connectors/test_polling_connector.py

@@ -19,7 +19,11 @@
     URL,
 )
 from UnleashClient.connectors import PollingConnector
-from UnleashClient.constants import ETAG, FEATURES_URL
+from UnleashClient.constants import (
+    CLIENT_SPEC_VERSION,
+    ETAG,
+    FEATURES_URL,
+)
 
 FULL_FEATURE_URL = URL + FEATURES_URL
 
@@ -56,6 +60,40 @@ def test_polling_connector_fetch_and_load(cache_empty):
     assert temp_cache.get(ETAG) == ETAG_VALUE
 
 
+@responses.activate
+def test_polling_connector_sends_spec_version_header(cache_empty):
+    """Test that the polling connector sends the spec version header automatically"""
+    engine = UnleashEngine()
+    scheduler = BackgroundScheduler()
+    responses.add(
+        responses.GET,
+        FULL_FEATURE_URL,
+        json=MOCK_FEATURE_RESPONSE,
+        status=200,
+        headers={"etag": ETAG_VALUE},
+    )
+    temp_cache = cache_empty
+
+    connector = PollingConnector(
+        engine=engine,
+        cache=temp_cache,
+        scheduler=scheduler,
+        url=URL,
+        app_name=APP_NAME,
+        instance_id=INSTANCE_ID,
+        custom_options=CUSTOM_OPTIONS,
+        request_timeout=REQUEST_TIMEOUT,
+        request_retries=REQUEST_RETRIES,
+    )
+
+    connector._fetch_and_load()
+
+    assert len(responses.calls) == 1
+    request = responses.calls[0].request
+    assert "Unleash-Client-Spec" in request.headers
+    assert request.headers["Unleash-Client-Spec"] == CLIENT_SPEC_VERSION
+
+
 @responses.activate
 def test_polling_connector_fetch_and_load_project(cache_empty):
     engine = UnleashEngine()

tests/unit_tests/test_client.py

@@ -43,7 +43,12 @@
 )
 from UnleashClient import INSTANCES, UnleashClient
 from UnleashClient.cache import FileCache
-from UnleashClient.constants import FEATURES_URL, METRICS_URL, REGISTER_URL
+from UnleashClient.constants import (
+    CLIENT_SPEC_VERSION,
+    FEATURES_URL,
+    METRICS_URL,
+    REGISTER_URL,
+)
 from UnleashClient.events import BaseEvent, UnleashEvent, UnleashEventType
 from UnleashClient.utils import InstanceAllowType
 
@@ -1470,6 +1475,35 @@ def test_identification_values_are_passed_in():
         assert False, "Invalid UUID format in UNLEASH-CONNECTION-ID"
 
 
+@responses.activate
+def test_uc_polling_connector_sends_spec_version_header(readyable_unleash_client):
+    """Test that the client sends spec version header when using polling connector"""
+    unleash_client, ready_signal, _ = readyable_unleash_client
+
+    responses.add(responses.POST, URL + REGISTER_URL, json={}, status=202)
+    responses.add(
+        responses.GET, URL + FEATURES_URL, json=MOCK_FEATURE_RESPONSE, status=200
+    )
+    responses.add(responses.POST, URL + METRICS_URL, json={}, status=202)
+
+    unleash_client.initialize_client()
+    ready_signal.wait(timeout=1)
+
+    features_requests = [
+        call
+        for call in responses.calls
+        if call.request.method == "GET" and FEATURES_URL in call.request.url
+    ]
+
+    assert len(features_requests) >= 1, "No features request found"
+    features_request = features_requests[0].request
+
+    assert (
+        "Unleash-Client-Spec" in features_request.headers
+    ), "Spec version header missing"
+    assert features_request.headers["Unleash-Client-Spec"] == CLIENT_SPEC_VERSION
+
+
 def test_uc_bootstrap_initializes_offline_connector():
     """Test that UnleashClient initializes OfflineConnector when bootstrapped."""
     cache = FileCache("MOCK_CACHE")