Add parameter to stop refresh of loans feed. (#1899)

src/palace/manager/api/controller/loan.py

@@ -6,6 +6,7 @@
 from flask import Response, redirect
 from flask_babel import lazy_gettext as _
 from lxml import etree
+from pydantic import parse_obj_as
 from werkzeug import Response as wkResponse
 
 from palace.manager.api.circulation_exceptions import (
@@ -49,6 +50,14 @@ def sync(self) -> Response:
         """
         patron: Patron = flask.request.patron  # type: ignore[attr-defined]
 
+        try:
+            # Parse the refresh query parameter as a boolean.
+            refresh = parse_obj_as(bool, flask.request.args.get("refresh", "true"))
+        except ValueError:
+            # If we can't parse the refresh query parameter, default to True.
+            self.log.exception(f"Could not parse refresh query parameter.")
+            refresh = True
+
         # Save some time if we don't believe the patron's loans or holds have
         # changed since the last time the client requested this feed.
         response = self.handle_conditional_request(patron.last_loan_activity_sync)
@@ -64,7 +73,7 @@ def sync(self) -> Response:
 
         # First synchronize our local list of loans and holds with all
         # third-party loan providers.
-        if patron.authorization_identifier:
+        if patron.authorization_identifier and refresh:
             header = self.authorization_header()
             credential = self.manager.auth.get_credential_from_header(header)
             try:

tests/manager/api/controller/test_loan.py

@@ -1505,6 +1505,36 @@ def handle_conditional_request(last_modified=None):
             # patron.last_loan_activity_sync was updated.
             assert patron.last_loan_activity_sync > new_sync_time
 
+    @pytest.mark.parametrize(
+        "refresh,expected_sync_call_count",
+        [
+            ["true", 1],
+            ["abc", 1],
+            ["t", 1],
+            ["1", 1],
+            [None, 1],
+            ["false", 0],
+            ["f", 0],
+            ["0", 0],
+        ],
+    )
+    def test_loans_refresh(
+        self,
+        loan_fixture: LoanFixture,
+        refresh: str | None,
+        expected_sync_call_count: int,
+    ):
+        url = f"loans/?refresh={refresh}" if refresh is not None else "/"
+        with (
+            loan_fixture.request_context_with_library(
+                url, headers=dict(Authorization=loan_fixture.valid_auth)
+            ),
+            patch.object(loan_fixture.manager.d_circulation, "sync_bookshelf") as sync,
+        ):
+            loan_fixture.manager.loans.authenticated_patron_from_request()
+            loan_fixture.manager.loans.sync()
+            assert sync.call_count == expected_sync_call_count
+
     @pytest.mark.parametrize(
         "target_loan_duration, "
         "db_loan_duration, "