Case Study: Advanced Delivery Service System
Tags: systemdesign, webdev, redis, reactnative
Published: 2024-03-28 21:11:30

**1. Understanding the Problem:**

In response to the growing demand for efficient delivery services, our client required a sophisticated system capable of managing deliveries for both business owners and regular users. With a focus on optimizing order assignment and real-time tracking, our goal was to create a robust solution that enhances user experience and supports business growth.

**High-Level Requirements:**
- User Authentication: Secure authentication for business owners and regular users.
- Order Creation: Flexible order creation process allowing receipt uploads or item specifications.
- Order Assignment: Intelligent assignment of delivery boys to optimize delivery efficiency.
- Subscription Management: Subscription plans enabling users to manage order limits.
- Real-Time Tracking: Seamless tracking of order status and delivery boy locations.
- Payment Integration: Secure payment options for transaction completion.

**Non-Functional Requirements:**
- Scalability: Ability to handle increasing user base and order volumes.
- Performance: Optimal response times for order management and tracking.
- Security: Robust data encryption and storage to protect user information.
- Reliability: Minimal downtime and error handling to ensure uninterrupted service.
- Usability: Intuitive user interfaces for easy navigation and interaction.

**High-Level Design:**
- **Backend Development:** Utilizing TypeScript and Express.js, the backend was designed to handle core functionalities such as user authentication, order management, and delivery boy assignment. Integration with Redis facilitated efficient order assignment and real-time tracking.
- **Admin Dashboard:** Developed using Next.js, the admin dashboard provided business owners with insights into order history, subscription management, and payment transactions.
- **Mobile Apps:** Separate apps built with React Native catered to users and delivery boys, offering intuitive interfaces for order creation, tracking, and communication.

**Additional Features and Modules:**
1. **Optimized Order Assignment Algorithm:** Implemented a sophisticated algorithm leveraging Redis sets to efficiently assign orders to delivery boys based on factors like proximity and workload, ensuring timely and efficient deliveries.
2. **Enhanced Real-Time Tracking:** Leveraged Redis geospatial capabilities to track delivery boy locations in real-time, enabling users to monitor their orders' progress accurately.
3. **Feedback and Rating System:** Integrated a feedback and rating system allowing users to provide input on their delivery experience, facilitating continuous service improvement.


**Proposed Improvements:**
1. **Predictive Analytics:** Utilized Redis for storing and analyzing historical order data to predict demand patterns, enabling proactive resource allocation and capacity planning.
2. **Offline Support:** Implemented Redis caching to support offline functionality in mobile apps, allowing users to create orders and track deliveries even without an internet connection, ensuring uninterrupted service.

**Data Entities:**
1. Users (Business Owners, Regular Users)
2. Orders (Including Order Details and Status)
3. Delivery Boys (Including Location and Active Orders Count)
4. Subscription Plans (Including Order Limits and Payment Details)
5. Receipt Images (For Orders Created by Business Owners)
6. Admin (For monitoring the system)
7. Payment Transactions (For Order Payments)
8. Active Locations (Where the Service Currently Operates)
9. Plans (Subscription Plans Created by Admin)

**Redis Integration:**

Redis integration plays a pivotal role in enhancing the functionality and performance of the delivery service system. By leveraging Redis's powerful features, such as data structures and pub/sub messaging, we can optimize various aspects of the system, including order assignment, real-time tracking, and event handling.

1. **Order Assignment:**
   Redis sets are utilized to efficiently manage active orders for each delivery boy. When a new order is created, the system evaluates the workload of available delivery boys by querying the active orders set stored in Redis. This allows for quick and effective assignment of orders to delivery boys with the least workload, ensuring timely deliveries and optimal resource utilization.

2. **Real-Time Tracking:**
   Redis geospatial capabilities enable real-time tracking of delivery boy locations. When a delivery boy updates their location, the system stores the longitude and latitude coordinates in Redis using the `GEOADD` command. Clients can then query nearby delivery boys within a specified radius using the `GEORADIUS` command, providing users with accurate and up-to-date information on their orders' progress.

3. **Event Pub/Sub:**
   Redis pub/sub (publish/subscribe) messaging mechanism facilitates seamless communication and event handling within the system. When a new order is created, the system publishes a new order event to a specific channel using the `PUBLISH` command. Subscribed clients, such as the order assignment module, receive notifications of new orders via the `SUBSCRIBE` command, allowing for immediate processing and assignment of orders to delivery boys.

**Pub/Sub Explanation:**

Pub/sub is a messaging paradigm where senders (publishers) distribute messages to multiple receivers (subscribers) without requiring them to know each other. In the context of the delivery service system:

- **Publisher:** When a new order is created, the system acts as the publisher and publishes a new order event to a designated channel in Redis. This is achieved using the `PUBLISH` command, which broadcasts the order data to all subscribers of the channel.

- **Subscriber:** Various components of the system, such as the order assignment module, act as subscribers and subscribe to specific channels of interest using the `SUBSCRIBE` command. When a new order event is published to the subscribed channel, the subscriber receives the event message and can take appropriate action, such as assigning the order to a delivery boy.

By utilizing Redis pub/sub, the delivery service system achieves real-time event-driven communication, enabling efficient handling of new orders and seamless coordination between different system modules. This enhances system responsiveness and scalability, ensuring smooth and reliable order processing even during peak demand periods.

**Conclusion:**
By incorporating advanced features and leveraging Redis integration, the delivery service system offers a comprehensive solution that meets the evolving needs of users and businesses. With optimized order assignment, enhanced tracking capabilities, and proactive analytics, the system provides a seamless and efficient delivery experience, driving customer satisfaction and business success.