Dropshipping API - SDE Intern Assignment

A REST API for managing Suppliers and their Inventory Products in a minimal dropshipping setup, built with TypeScript, Express.js, TypeORM, and MySQL.

Features

• Supplier Management: Create, list, and retrieve suppliers with analytics
• Product Management: Create, list, retrieve, and update product stock
• Custom Validation: Custom validation classes for data integrity
• Category Filtering: Filter products by category (ELECTRONICS, FASHION, HOME, OTHER)
• Analytics: Supplier-level analytics (total products, total stock)
• Error Handling: Comprehensive error handling with proper HTTP status codes

Tech Stack

• Language: TypeScript
• Framework: Express.js
• Database: MySQL
• ORM: TypeORM
• Validation: Custom validation classes
• Environment: Node.js

Database Schema

Suppliers Table

• id (Primary Key, Auto Increment)
• name (String, required, min 2 chars)
• email (Unique, must be valid)
• phone (10 digits, starts with 7-9)
• country (String, not empty)
• created_at (timestamp)

Products Table

• id (Primary Key, Auto Increment)
• supplier_id (FK → Supplier)
• title (String, required, max 100 chars)
• price (Decimal, > 0)
• stock_quantity (Integer, >= 0)
• category (Enum: ELECTRONICS, FASHION, HOME, OTHER)
• created_at (timestamp)

Setup Instructions

Prerequisites

• Node.js (v18 or higher)
• MySQL server running
• npm or yarn package manager

1. Clone and Install Dependencies

```bash git clone cd WellFound-Task npm install ```

2. Environment Configuration

Create a `.env` file in the project root: ```env PORT=8000 DB_HOST=localhost DB_PORT=3306 DB_USER=root DB_PASS=your_mysql_password DB_NAME=synegrow CORS_ORIGIN=* NODE_ENV=development ```

3. Database Setup

1. Create the MySQL database: ```sql CREATE DATABASE synegrow; ```

2. The application will automatically create tables when you start it (synchronize: true in development).

4. Build and Start

```bash

Build the project

npm run build

Start development server

npm run dev

Or start production server

npm start ```

The server will start on `http://localhost:8000\`

API Endpoints

Suppliers

POST /api/suppliers

Create a new supplier.

Request Body: ```json { "name": "Tech Supplier", "email": "[email protected]", "phone": "9876543210", "country": "India" } ```

cURL Example: ```bash curl -X POST http://localhost:8000/api/suppliers \ -H "Content-Type: application/json" \ -d '{ "name": "Tech Supplier", "email": "[email protected]", "phone": "9876543210", "country": "India" }' ```

GET /api/suppliers

List all suppliers with analytics.

cURL Example: ```bash curl http://localhost:8000/api/suppliers ```

GET /api/suppliers/:id

Get supplier details with products and analytics.

cURL Example: ```bash curl http://localhost:8000/api/suppliers/1 ```

Products

POST /api/products

Create a new product.

Request Body: ```json { "supplier_id": 1, "title": "Gaming Laptop", "price": 1299.99, "stock_quantity": 5, "category": "ELECTRONICS" } ```

cURL Example: ```bash curl -X POST http://localhost:8000/api/products \ -H "Content-Type: application/json" \ -d '{ "supplier_id": 1, "title": "Gaming Laptop", "price": 1299.99, "stock_quantity": 5, "category": "ELECTRONICS" }' ```

GET /api/products

List all products with optional category filter.

cURL Examples: ```bash

Get all products

curl http://localhost:8000/api/products

Filter by category

curl "http://localhost:8000/api/products?category=FASHION" ```

GET /api/products/:id

Get product details.

cURL Example: ```bash curl http://localhost:8000/api/products/1 ```

PATCH /api/products/:id

Update product stock quantity.

Request Body: ```json { "stock_quantity": 15 } ```

cURL Example: ```bash curl -X PATCH http://localhost:8000/api/products/1 \ -H "Content-Type: application/json" \ -d '{ "stock_quantity": 15 }' ```

Postman Collection

Environment Variables

Create a Postman environment with:

• `baseUrl`: `http://localhost:8000\`

Sample Requests

1. Create Supplier

   • Method: POST
   • URL: `{{baseUrl}}/api/suppliers`
   • Body: Raw JSON ```json { "name": "Electronics Hub", "email": "[email protected]", "phone": "9123456789", "country": "India" } ```

2. Create Product

   • Method: POST
   • URL: `{{baseUrl}}/api/products`
   • Body: Raw JSON ```json { "supplier_id": 1, "title": "Wireless Headphones", "price": 99.99, "stock_quantity": 20, "category": "ELECTRONICS" } ```

3. Filter Products by Category

   • Method: GET
   • URL: `{{baseUrl}}/api/products?category=FASHION`

Validation Rules

Supplier Validation

• name: Required, string, minimum 2 characters
• email: Required, valid email format, unique
• phone: Required, exactly 10 digits, starts with 7, 8, or 9
• country: Required, non-empty string

Product Validation

• supplier_id: Required, positive integer, must reference existing supplier
• title: Required, non-empty string, maximum 100 characters
• price: Required, positive number
• stock_quantity: Required, non-negative integer
• category: Required, must be one of: ELECTRONICS, FASHION, HOME, OTHER

Error Handling

All validation errors return HTTP 400 with details: ```json { "statusCode": 400, "message": "Validation failed", "success": false, "errors": [ "Name must be at least 2 characters long", "Email must be valid" ] } ```

Not found errors return HTTP 404: ```json { "statusCode": 404, "message": "Supplier not found", "success": false, "errors": [] } ```

Project Structure

``` src/ ├── entities/ # TypeORM entities │ ├── Supplier.ts │ └── Product.ts ├── validators/ # Custom validation classes │ ├── SupplierValidator.ts │ └── ProductValidator.ts ├── controllers/ # Route controllers │ ├── supplier.controllers.ts │ └── product.controllers.ts ├── routes/ # Express routes │ ├── supplier.routes.ts │ └── product.routes.ts ├── utils/ # Utility classes │ ├── ApiError.ts │ ├── ApiResponse.ts │ └── asyncHandler.ts ├── migrations/ # TypeORM migrations ├── data-source.ts # TypeORM configuration ├── app.ts # Express app setup └── index.ts # Application entry point ```

Architecture Highlights

Custom Validation Classes

• Reusable: Validation logic separated into dedicated classes
• Comprehensive: Validates data types, formats, and business rules
• Error Aggregation: Collects all validation errors and returns them together

Clean Service Structure

• Separation of Concerns: Controllers, validators, and entities are separate
• Error Handling: Centralized error handling with custom ApiError class
• Response Format: Consistent API response format with ApiResponse class

Extensibility

• Easy to Add Fields: Add new fields to entities and update validators
• New Entities: Follow the same pattern for new entities
• Middleware Support: Ready for authentication, logging, etc.

Development

Adding New Endpoints

1. Create/update entity in `src/entities/`
2. Create/update validator in `src/validators/`
3. Create controller in `src/controllers/`
4. Create routes in `src/routes/`
5. Register routes in `src/app.ts`

Database Migrations

```bash

Generate migration

npm run migration:generate

Run migrations

npm run migration:run

Revert migration

npm run migration:revert ```

License

This project is licensed under the ISC License.

Author

Parikshit Jaiswal

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Submission Date: September 11, 2025
Deadline: September 14, 2025 by 7:00 PM