feat: app notifications (#149)

* wip

* feat: subscribe to topic on client and send to topic on server

* feat: fcm registration token table

* feat: send registration token to backend every time and store it in database

* deps: pnpm v9.15.1

* feat: send notifications when creating assignments in scheduler

* fix: dont initialize app in firebaseMessagingBackgroundHandler

* fix: initialize firebase admin app only if required

* fix: dont send firebase messages on CI

* fix: adjust messages

* fix: only do firebase stuff if supported platform

* fix: stuff from self-code-review

* fix: remove unused import

.github/workflows/ci.yml

@@ -50,7 +50,7 @@ jobs:
 
       - uses: pnpm/action-setup@v4
         with:
-          version: 9
+          version: 9.15.1
 
       - name: Install deps
         run: pnpm i

backend/.env.example

@@ -4,3 +4,6 @@ JWT_SECRET=****
 DATABASE_URL=postgres://postgres:changeme@localhost:5432/postgres
 NODE_ENV=development
 DB_PASSWORD=changeme
+
+# a oneline string containing valid json of the firebase service account (needed for firebase cloud messaging - app notifications)
+FIREBASE_SERVICE_ACCOUNT_JSON_CONTENT=

backend/package.json

@@ -6,7 +6,7 @@
   "private": true,
   "license": "UNLICENSED",
   "engines": {
-    "pnpm": "~9"
+    "pnpm": "9.15.1"
   },
   "scripts": {
     "build": "nest build",
@@ -34,6 +34,7 @@
     "@nestjs/serve-static": "4.0.2",
     "bcrypt": "5.1.1",
     "drizzle-orm": "0.37.0",
+    "firebase-admin": "^13.0.1",
     "pg": "8.11.5",
     "postgres": "3.4.4",
     "reflect-metadata": "0.2.0",
@@ -92,6 +93,5 @@
     ],
     "coverageDirectory": "../coverage",
     "testEnvironment": "node"
-  },
-  "packageManager": "[email protected]+sha512.60c18acd138bff695d339be6ad13f7e936eea6745660d4cc4a776d5247c540d0edee1a563695c183a66eb917ef88f2b4feb1fc25f32a7adcadc7aaf3438e99c1"
+  }
 }

backend/src/app.module.ts

@@ -11,14 +11,18 @@ import { AssignmentController } from './assignment/assignment.controller';
 import { TaskGroupController } from './tasks/task-group.controller';
 import { EventsGateway } from './shopping-list/events.gateway';
 import { ShoppingListController } from './shopping-list/shopping-list.controller';
+import { NotificationController } from './notifications/notification.controller';
+import { NotificationModule } from './notifications/notification.module';
 
 const rootPathStatic = join(__dirname, '../../src/client/public/');
 
 @Module({
   imports: [
     AuthModule,
+    // needed to active job scheduling from @nestjs/schedule
     ScheduleModule.forRoot(),
     AssignmentsModule,
+    NotificationModule,
     ServeStaticModule.forRoot({
       rootPath: rootPathStatic,
       exclude: ['/api/(.*)'],
@@ -31,6 +35,7 @@ const rootPathStatic = join(__dirname, '../../src/client/public/');
     TaskGroupController,
     UserGroupController,
     ShoppingListController,
+    NotificationController,
   ],
   providers: [EventsGateway],
 })

backend/src/assignment/assignment-scheduler.service.ts

@@ -3,10 +3,14 @@ import { Cron, CronExpression } from '@nestjs/schedule';
 import { dbInsertAssignments } from 'src/db/functions/assignment';
 import { hydrateTaskGroupsToAssignToAssignments } from './util';
 import { dbGetTaskGroupsToAssignForCurrentInterval } from 'src/db/functions/task-group';
+import { dbGetFCMRegistrationTokensByUserIds } from 'src/db/functions/notification';
+import { sendFirebaseMessages } from 'src/notifications/notification';
+import { Message } from 'firebase-admin/messaging';
 
 @Injectable()
 export class AssignmentSchedulerService {
-  @Cron(CronExpression.EVERY_10_SECONDS)
+  // TODO: optimally, this is not run this often, but just once in a day, and on task creation we immediately create assignments as needed.
+  @Cron(CronExpression.EVERY_30_SECONDS)
   async handleCreateAssignmentsCron() {
     const taskGroupsToAssign = await dbGetTaskGroupsToAssignForCurrentInterval({
       overrideNow: undefined,
@@ -29,6 +33,25 @@ export class AssignmentSchedulerService {
           2,
         )}`,
       );
+
+      if (process.env.CI === 'true') {
+        return;
+      }
+
+      const userIds = assignmentsToCreate.map(
+        (assignment) => assignment.userId,
+      );
+      const tokens = await dbGetFCMRegistrationTokensByUserIds(userIds);
+      const messages = tokens.map((token) => {
+        return {
+          token,
+          notification: {
+            title: '🚀 New Assignments Waiting!',
+            body: "You have new assignments waiting for you! Click to learn more. Let's get them done!",
+          },
+        } satisfies Message;
+      });
+      await sendFirebaseMessages({ messages });
     }
   }
 }

backend/src/auth/auth.controller.ts

@@ -15,7 +15,6 @@ import { userTable } from 'src/db/schema';
 import { AuthService } from './auth.service';
 import {
   dbAddUserToUserGroup,
-  dbGetUserGroupOfUser,
   dbGetUserGroupByInviteCode,
 } from 'src/db/functions/user-group';
 import { eq } from 'drizzle-orm';
@@ -115,13 +114,8 @@ export class AuthController {
         'The access token seemed valid, but the user id included in the jwt token could not be found in the database.',
       );
     }
-    const userGroup = await dbGetUserGroupOfUser(req.user.sub);
     return {
       userId: req.user.sub,
-      userGroup: {
-        id: userGroup?.userGroup.name,
-        name: userGroup?.userGroup.name,
-      },
       email: user.email,
       username: user.username,
     };

backend/src/db/functions/notification.ts

@@ -0,0 +1,13 @@
+import { inArray } from 'drizzle-orm';
+import { db } from '..';
+import { userFcmRegistrationTokenMappingTable } from '../schema';
+
+export async function dbGetFCMRegistrationTokensByUserIds(userIds: number[]) {
+  const result = await db
+    .select({
+      token: userFcmRegistrationTokenMappingTable.fcmRegistrationToken,
+    })
+    .from(userFcmRegistrationTokenMappingTable)
+    .where(inArray(userFcmRegistrationTokenMappingTable.userId, userIds));
+  return result.map((row) => row.token);
+}

backend/src/db/migrations/0013_loving_satana.sql

@@ -0,0 +1,13 @@
+CREATE TABLE IF NOT EXISTS "user_fcm_registration_token_mapping" (
+	"user_id" integer NOT NULL,
+	"fcm_registration_token" text NOT NULL,
+	"created_at" timestamp DEFAULT now() NOT NULL,
+	"updated_at" timestamp DEFAULT now() NOT NULL,
+	CONSTRAINT "user_fcm_registration_token_mapping_user_id_fcm_registration_token_pk" PRIMARY KEY("user_id","fcm_registration_token")
+);
+--> statement-breakpoint
+DO $$ BEGIN
+ ALTER TABLE "user_fcm_registration_token_mapping" ADD CONSTRAINT "user_fcm_registration_token_mapping_user_id_user_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."user"("id") ON DELETE no action ON UPDATE no action;
+EXCEPTION
+ WHEN duplicate_object THEN null;
+END $$;