Add parameter validation to Request::deliver

Author: wravery

src/GraphQLService.cpp

@@ -2333,8 +2333,24 @@ void Request::deliver(std::launch launch, const SubscriptionName& name,
 	const SubscriptionFilterCallback& applyDirectives,
 	const std::shared_ptr<Object>& subscriptionObject) const
 {
+	const auto itrOperation = _operations.find(strSubscription);
+
+	if (itrOperation == _operations.end())
+	{
+		// There may be an empty entry in the operations map, but if it's completely missing then
+		// that means the schema doesn't support subscriptions at all.
+		throw std::logic_error("Subscriptions not supported");
+	}
+
 	const auto& optionalOrDefaultSubscription =
-		subscriptionObject ? subscriptionObject : _operations.find(strSubscription)->second;
+		subscriptionObject ? subscriptionObject : itrOperation->second;
+
+	if (!optionalOrDefaultSubscription)
+	{
+		// If there is no default in the operations map, you must pass a non-empty
+		// subscriptionObject parameter to deliver.
+		throw std::invalid_argument("Missing subscriptionObject");
+	}
 
 	auto itrListeners = _listeners.find(name);
 

test/TodayTests.cpp

@@ -705,6 +705,32 @@ TEST_F(TodayServiceCase, SubscribeNextAppointmentChangeOverride)
 	}
 }
 
+TEST_F(TodayServiceCase, DeliverNextAppointmentChangeNoSubscriptionObject)
+{
+	auto service = std::make_shared<today::Operations>(nullptr, nullptr, nullptr);
+	auto query = R"(subscription TestSubscription {
+			nextAppointment: nextAppointmentChange {
+				nextAppointmentId: id
+				when
+				subject
+				isNow
+			}
+		})"_graphql;
+	bool exception = false;
+
+	try
+	{
+		service->deliver("nextAppointmentChange", nullptr);
+	}
+	catch (std::invalid_argument& ex)
+	{
+		EXPECT_TRUE(ex.what() == "Missing subscriptionObject"sv) << "exception should match";
+		exception = true;
+	}
+
+	ASSERT_TRUE(exception) << "expected an exception";
+}
+
 TEST_F(TodayServiceCase, Introspection)
 {
 	auto query = R"({