feat: Outlook Calendar Caching with Webhook Notifications for Calendar Changes

.env.example

@@ -459,3 +459,7 @@ DATABASE_CHUNK_SIZE=
 # Service Account Encryption Key for encrypting/decrypting service account keys
 # You can use: `openssl rand -base64 24` to generate one
 CALCOM_SERVICE_ACCOUNT_ENCRYPTION_KEY=
+
+# Token to verify incoming webhooks from Microsoft Office 365
+# Generate a random string for client state validation: openssl rand -base64 32
+OFFICE365_WEBHOOK_CLIENT_STATE=

apps/api/v1/test/lib/selected-calendars/_post.test.ts

@@ -88,6 +88,9 @@ describe("POST /api/selected-calendars", () => {
         googleChannelResourceId: null,
         googleChannelResourceUri: null,
         googleChannelExpiration: null,
+        office365SubscriptionId: null,
+        office365SubscriptionExpiration: null,
+        office365SubscriptionClientState: null,
         error: null,
         lastErrorAt: null,
         watchAttempts: 0,
@@ -130,6 +133,9 @@ describe("POST /api/selected-calendars", () => {
         googleChannelResourceId: null,
         googleChannelResourceUri: null,
         googleChannelExpiration: null,
+        office365SubscriptionId: null,
+        office365SubscriptionExpiration: null,
+        office365SubscriptionClientState: null,
         delegationCredentialId: null,
         domainWideDelegationCredentialId: null,
         eventTypeId: null,

packages/app-store/office365calendar/api/index.ts

@@ -1,2 +1,3 @@
 export { default as add } from "./add";
 export { default as callback } from "./callback";
+export { default as webhook } from "./webhook";

packages/app-store/office365calendar/api/webhook.ts

@@ -0,0 +1,96 @@
+import type { NextApiRequest, NextApiResponse } from "next";
+
+import { getCredentialForCalendarCache } from "@calcom/lib/delegationCredential/server";
+import { HttpError } from "@calcom/lib/http-error";
+import logger from "@calcom/lib/logger";
+import { safeStringify } from "@calcom/lib/safeStringify";
+import { defaultHandler } from "@calcom/lib/server/defaultHandler";
+import { defaultResponder } from "@calcom/lib/server/defaultResponder";
+import { SelectedCalendarRepository } from "@calcom/lib/server/repository/selectedCalendar";
+
+import { getCalendar } from "../../_utils/getCalendar";
+
+const log = logger.getSubLogger({ prefix: ["office365calendar", "webhook"] });
+
+async function getHandler(req: NextApiRequest, res: NextApiResponse) {
+  const validationToken = req.query.validationToken as string;
+  if (!validationToken) {
+    throw new HttpError({ statusCode: 400, message: "Missing validation token" });
+  }
+
+  res.setHeader("Content-Type", "text/plain");
+  res.status(200).send(validationToken);
+}
+
+async function postHandler(req: NextApiRequest, res: NextApiResponse) {
+  const validationToken = req.query.validationToken;
+  if (validationToken && typeof validationToken === "string") {
+    res.setHeader("Content-Type", "text/plain");
+    res.status(200).send(validationToken);
+    return;
+  }
+
+  const { value: notifications } = req.body;
+
+  if (!notifications || !Array.isArray(notifications)) {
+    throw new HttpError({ statusCode: 400, message: "Invalid notification payload" });
+  }
+
+  const expectedClientState = process.env.OFFICE365_WEBHOOK_CLIENT_STATE;
+  if (!expectedClientState) {
+    log.error("OFFICE365_WEBHOOK_CLIENT_STATE not configured");
+    throw new HttpError({ statusCode: 500, message: "Webhook not configured" });
+  }
+
+  for (const notification of notifications) {
+    if (notification.clientState !== expectedClientState) {
+      throw new HttpError({ statusCode: 403, message: "Invalid client state" });
+    }
+  }
+
+  for (const notification of notifications) {
+    try {
+      const { subscriptionId, resource } = notification;
+
+      if (!subscriptionId || !resource) {
+        log.warn("Notification missing required fields");
+        continue;
+      }
+
+      log.debug("Processing notification", { subscriptionId });
+
+      const selectedCalendar = await SelectedCalendarRepository.findFirstByOffice365SubscriptionId(
+        subscriptionId
+      );
+
+      if (!selectedCalendar) {
+        log.debug("No selected calendar found for subscription", { subscriptionId });
+        continue;
+      }
+
+      const { credential } = selectedCalendar;
+      if (!credential) {
+        log.debug("No credential found for selected calendar", { subscriptionId });
+        continue;
+      }
+
+      const { selectedCalendars } = credential;
+      const credentialForCalendarCache = await getCredentialForCalendarCache({ credentialId: credential.id });
+      const calendarServiceForCalendarCache = await getCalendar(credentialForCalendarCache);
+      await calendarServiceForCalendarCache?.fetchAvailabilityAndSetCache?.(selectedCalendars);
+      log.debug("Successfully updated calendar cache", { subscriptionId });
+    } catch (error) {
+      log.error(
+        "Error processing notification",
+        safeStringify({ error, subscriptionId: notification.subscriptionId })
+      );
+    }
+  }
+
+  return { message: "ok" };
+}
+
+export default defaultHandler({
+  GET: Promise.resolve({ default: defaultResponder(getHandler) }),
+  POST: Promise.resolve({ default: defaultResponder(postHandler) }),
+});