feat: Add configurable response data storage for notifications (#6684)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Frank Elsinga <frank@elsinga.de>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

test/backend-test/test-monitor-response.js

@@ -0,0 +1,36 @@
+const { describe, test } = require("node:test");
+const assert = require("node:assert");
+const Monitor = require("../../server/model/monitor");
+const Heartbeat = require("../../server/model/heartbeat");
+const { RESPONSE_BODY_LENGTH_DEFAULT } = require("../../src/util");
+
+describe("Monitor response saving", () => {
+    test("getSaveResponse and getSaveErrorResponse parse booleans", () => {
+        const monitor = Object.create(Monitor.prototype);
+        monitor.save_response = 1;
+        monitor.save_error_response = 0;
+
+        assert.strictEqual(monitor.getSaveResponse(), true);
+        assert.strictEqual(monitor.getSaveErrorResponse(), false);
+    });
+
+    test("saveResponseData stores and truncates response", async () => {
+        const monitor = Object.create(Monitor.prototype);
+        monitor.response_max_length = 5;
+
+        const bean = {};
+        await monitor.saveResponseData(bean, "abcdef");
+
+        assert.strictEqual(await Heartbeat.decodeResponseValue(bean.response), "abcde... (truncated)");
+    });
+
+    test("saveResponseData stringifies objects", async () => {
+        const monitor = Object.create(Monitor.prototype);
+        monitor.response_max_length = RESPONSE_BODY_LENGTH_DEFAULT;
+
+        const bean = {};
+        await monitor.saveResponseData(bean, { ok: true });
+
+        assert.strictEqual(await Heartbeat.decodeResponseValue(bean.response), JSON.stringify({ ok: true }));
+    });
+});