Update server.py to accept IETF BCP 47 language tags (#1399), closes #…

…1352.

* Update server.py to accept local languages such as es-419
* Regression test for #1352.

Ref: https://en.wikipedia.org/wiki/IETF_language_tag

---------

Co-authored-by: Mathijs de Bruin <[email protected]>

backend/chainlit/server.py

@@ -645,7 +645,7 @@ async def oauth_azure_hf_callback(
 
 
 _language_pattern = (
-    "^[a-zA-Z]{2,3}(-[a-zA-Z]{2,3})?(-[a-zA-Z]{2,8})?(-x-[a-zA-Z0-9]{1,8})?$"
+    "^[a-zA-Z]{2,3}(-[a-zA-Z0-9]{2,3})?(-[a-zA-Z0-9]{2,8})?(-x-[a-zA-Z0-9]{1,8})?$"
 )
 
 

backend/tests/test_server.py

@@ -71,6 +71,18 @@ def test_project_translations_invalid_language(
     assert not mock_load_translation.called
 
 
+def test_project_translations_bcp47_language(
+    test_client: TestClient, mock_load_translation: Mock
+):
+    """Regression test for https://github.com/Chainlit/chainlit/issues/1352."""
+
+    response = test_client.get("/project/translations?language=es-419")
+    assert response.status_code == 200
+    assert "translation" in response.json()
+    mock_load_translation.assert_called_once_with("es-419")
+    mock_load_translation.reset_mock()
+
+
 @pytest.fixture
 def mock_get_current_user():
     """Override get_current_user() dependency."""