Task Management API (Assignment 3)

Secure REST API with event-driven reminders, category/tag management, and simulated external webhook integration.

Tech Stack

• Node.js + Express.js
• PostgreSQL (pg) for users
• MongoDB (mongodb) for tasks, categories, tags
• JWT auth (jsonwebtoken), password hashing (bcryptjs)
• Validation with joi

Features

Core Auth + Task Management

• Register/login with hashed password and JWT.
• Authenticated profile endpoint.
• Task CRUD scoped by userId (no cross-user access).

Real-time Task Reminders (Simulated)

• On task create/update with dueDate (due_date alias supported), system schedules in-memory reminder.
• Reminder fires REMINDER_LEAD_MINUTES before due date (default 60).
• If due date updated, old reminder canceled and new one scheduled.
• If task marked completed or deleted, reminder canceled.
• Reminder event logs to console + logs/notifications.log.
• Optional reminder webhook call if REMINDER_WEBHOOK_URL exists.

Categories + Tags

• Dynamic user-owned categories (/api/categories CRUD).
• Dynamic user-owned tags (/api/tags CRUD), tag text is free-form.
• Task supports category (string) and tags (array of strings).
• Filter endpoint supports category/tags/status: GET /api/tasks/filter.

External Analytics Webhook (Simulated)

• When task status transitions to completed, API emits event.
• Event handler sends POST webhook to ANALYTICS_WEBHOOK_URL.
• Retry logic: up to 3 retries, exponential backoff (1s, 2s, 4s).
• Delivery logs written to console + logs/notifications.log.

Setup

1) Install

npm install

2) Configure env

Create .env (or copy from .env.example):

PORT=3001
POSTGRES_URI=postgres://taskuser:taskpassword@localhost:5433/taskdb
MONGODB_URI=mongodb://localhost:27017/taskapp
JWT_SECRET=replace_with_strong_secret

# Reminder config
REMINDER_LEAD_MINUTES=60
REMINDER_WEBHOOK_URL=

# Analytics webhook on task completion
ANALYTICS_WEBHOOK_URL=

3) Run option A (Dockerized app + databases)

docker-compose up --build

App runs on http://localhost:3001.

4) Run option B (Local Node app + Docker databases)

Run databases first:

docker-compose up -d postgres mongodb

Run API locally:

npm run dev

or

npm start

Folder Structure

• src/config/ DB connection config.
• src/controllers/ route handlers.
• src/events/ event bus + event handler registration.
• src/middlewares/ auth + global error handler.
• src/models/ DB collection/table wrappers.
• src/routes/ API route definitions.
• src/services/ reminder scheduler, notifications, webhook retry logic.
• src/validators/ Joi schemas.

Design Choices

Categories

• Chosen dynamic user-defined categories.
• Reason: flexible for personal/team workflows, no hardcoded enum migration.
• Category rename/delete cascades into user tasks for consistency.

Tags

• Tags stored as free-form strings in task docs.
• Separate tag CRUD endpoints maintain reusable tag list per user.
• Tag rename/delete propagates to existing user tasks.

Reminder Scheduling

• In-memory setTimeout scheduler for simplicity.
• taskId -> timeout map enables cancellation/reschedule.
• Scheduler rehydrates on server boot by scanning pending tasks with due date.
• Tradeoff: in-memory jobs lost if process restarts; acceptable for simulation scope.

Webhook Retry

• Event-driven completion webhook (decoupled from request/response path).
• fetch + retry loop with exponential backoff.
• Logs every retry/success/failure to file + console.

API Documentation

All endpoints below require Authorization: Bearer <token> except register/login.

Auth

POST /api/auth/register

{
  "email": "user@example.com",
  "password": "password123"
}

POST /api/auth/login

{
  "email": "user@example.com",
  "password": "password123"
}

GET /api/auth/profile

Tasks

POST /api/tasks

{
  "title": "Finish report",
  "description": "Quarterly report",
  "dueDate": "2026-04-12T20:00:00.000Z",
  "status": "pending",
  "category": "Work",
  "tags": ["High Priority", "Client A"]
}

Notes:

• due_date also accepted (converted to dueDate).
• status default = pending.

GET /api/tasks

Get all user tasks.

GET /api/tasks/filter?category=Work&tags=High%20Priority,Client%20A&status=pending

Filter by any combination of category, comma-separated tags (all tags must match), and status.

GET /api/tasks/:id

PUT /api/tasks/:id

Partial updates allowed.

DELETE /api/tasks/:id

Categories

POST /api/categories

{ "name": "Work" }

GET /api/categories

GET /api/categories/:id

PUT /api/categories/:id

{ "name": "Personal" }

DELETE /api/categories/:id

Tags

POST /api/tags

{ "name": "High Priority" }

GET /api/tags

GET /api/tags/:id

PUT /api/tags/:id

{ "name": "Bug Fix" }

DELETE /api/tags/:id

Error Handling

• 400 validation or malformed IDs.
• 401 missing/invalid JWT.
• 404 not found.
• 500 internal errors.

Demo Checklist (for 7-min video)

• Setup (docker + npm run dev).
• Register/login.
• Create task with due date and show reminder log line.
• Create categories/tags and create tasks using them.
• Filter tasks with /api/tasks/filter.
• Mark task completed and show webhook payload delivery on webhook.site.
• Show reminder cancel/reschedule by updating due date and completing task.