feat: Add trigger beforeUnsubscribe for LiveQuery

spec/ParseLiveQuery.spec.js

@@ -800,6 +800,45 @@ describe('ParseLiveQuery', function () {
     await object.save();
   });
 
+  it('can handle select beforeUnsubscribe trigger', async done => {
+    await reconfigureServer({
+      liveQuery: {
+        classNames: ['TestObject'],
+      },
+      startLiveQueryServer: true,
+      verbose: false,
+      silent: true,
+    });
+    const user = new Parse.User();
+    user.setUsername('username');
+    user.setPassword('password');
+    await user.signUp();
+
+    Parse.Cloud.beforeSubscribe(TestObject, req => {
+      expect(req.requestId).toBe(1);
+      expect(req.user).toBeDefined();
+    });
+
+    Parse.Cloud.beforeUnsubscribe(TestObject, req => {
+      expect(req.requestId).toBe(1);
+      expect(req.user).toBeDefined();
+      expect(req.user.get('username')).toBe('username');
+      done();
+    });
+
+    const object = new TestObject();
+    await object.save();
+
+    const query = new Parse.Query(TestObject);
+    query.equalTo('objectId', object.id);
+    const subscription = await query.subscribe();
+
+    object.set({ foo: 'bar', yolo: 'abc' });
+    await object.save();
+
+    await subscription.unsubscribe();
+  });
+
   it('LiveQuery with ACL', async () => {
     await reconfigureServer({
       liveQuery: {

src/LiveQuery/ParseLiveQueryServer.js

@@ -968,7 +968,7 @@ class ParseLiveQueryServer {
     this._handleSubscribe(parseWebsocket, request);
   }
 
-  _handleUnsubscribe(parseWebsocket: any, request: any, notifyClient: boolean = true): any {
+  async _handleUnsubscribe(parseWebsocket: any, request: any, notifyClient: boolean = true): any {
     // If we can not find this client, return error to client
     if (!Object.prototype.hasOwnProperty.call(parseWebsocket, 'clientId')) {
       Client.pushError(
@@ -1015,11 +1015,33 @@ class ParseLiveQueryServer {
       return;
     }
 
+    const subscription = subscriptionInfo.subscription;
+    const className = subscription.className;
+    const trigger = getTrigger(className, 'beforeUnsubscribe', Parse.applicationId);
+    if (trigger) {
+      const auth = await this.getAuthFromClient(client, request.requestId, request.sessionToken);
+      if (auth && auth.user) {
+        request.user = auth.user;
+      }
+
+      request.sessionToken = subscriptionInfo.sessionToken;
+      request.useMasterKey = client.hasMasterKey;
+      request.installationId = client.installationId;
+
+      try {
+        await runTrigger(trigger, `beforeUnsubscribe.${className}`, request, auth);
+      } catch (error) {
+        Client.pushError(parseWebsocket, error.code || Parse.Error.SCRIPT_FAILED, error.message || error, false);
+        logger.error(
+          `Failed running beforeUnsubscribe for session ${request.sessionToken} with:\n Error: ` +
+            JSON.stringify(error)
+        );
+      }
+    }
+
     // Remove subscription from client
     client.deleteSubscriptionInfo(requestId);
     // Remove client from subscription
-    const subscription = subscriptionInfo.subscription;
-    const className = subscription.className;
     subscription.deleteClientSubscription(parseWebsocket.clientId, requestId);
     // If there is no client which is subscribing this subscription, remove it from subscriptions
     const classSubscriptions = this.subscriptions.get(className);

src/cloud-code/Parse.Cloud.js

@@ -729,6 +729,42 @@ ParseCloud.onLiveQueryEvent = function (handler) {
   triggers.addLiveQueryEventHandler(handler, Parse.applicationId);
 };
 
+/**
+ * Registers a before live query subscription function.
+ *
+ * **Available in Cloud Code only.**
+ *
+ * If you want to use beforeUnsubscribe for a predefined class in the Parse JavaScript SDK (e.g. {@link Parse.User}), you should pass the class itself and not the String for arg1.
+ * ```
+ * Parse.Cloud.beforeUnsubscribe('MyCustomClass', (request) => {
+ *   // code here
+ * }, (request) => {
+ *   // validation code here
+ * });
+ *
+ * Parse.Cloud.beforeUnsubscribe(Parse.User, (request) => {
+ *   // code here
+ * }, { ...validationObject });
+ *```
+ *
+ * @method beforeUnsubscribe
+ * @name Parse.Cloud.beforeUnsubscribe
+ * @param {(String|Parse.Object)} arg1 The Parse.Object subclass to register the before subscription function for. This can instead be a String that is the className of the subclass.
+ * @param {Function} func The function to run before a subscription. This function can be async and should take one parameter, a {@link Parse.Cloud.TriggerRequest}.
+ * @param {(Object|Function)} validator An optional function to help validating cloud code. This function can be an async function and should take one parameter a {@link Parse.Cloud.TriggerRequest}, or a {@link Parse.Cloud.ValidatorObject}.
+ */
+ParseCloud.beforeUnsubscribe = function (parseClass, handler, validationHandler) {
+  validateValidator(validationHandler);
+  const className = triggers.getClassName(parseClass);
+  triggers.addTrigger(
+    triggers.Types.beforeUnsubscribe,
+    className,
+    handler,
+    Parse.applicationId,
+    validationHandler
+  );
+};
+
 /**
  * Registers an after live query server event function.
  *

src/triggers.js

@@ -14,6 +14,7 @@ export const Types = {
   afterFind: 'afterFind',
   beforeConnect: 'beforeConnect',
   beforeSubscribe: 'beforeSubscribe',
+  beforeUnsubscribe: 'beforeUnsubscribe',
   afterEvent: 'afterEvent',
 };