interview_api_server

A simple Express API server with WebSocket support for demonstrating real-time order status updates.

Overview

This project provides a REST API endpoint for fetching orders and a WebSocket connection that pushes random order status updates to connected clients in real-time.

Features

• REST API: GET endpoint to retrieve all orders
• WebSocket Server: Real-time updates of order statuses every second
• In-memory Data Store: 8 sample orders with randomized statuses

Installation

npm install

Usage

Start the server:

npm start

The server will run on port 3000 by default (or the port specified in the PORT environment variable).

API Endpoints

GET /

Returns an HTML landing page with an overview of the API, its endpoints, and usage instructions.

GET /orders

Returns a JSON array of all orders.

Response:

[
  { "id": 1, "status": "NEW" },
  { "id": 2, "status": "PROCESSING" },
  ...
]

GET /meta

Returns API metadata in JSON format, including information about available endpoints and important notes.

Response:

{
  "name": "Orders Demo API",
  "version": "1.0.0",
  "endpoints": {
    "/": "HTML landing page with API overview",
    "/orders": "GET order list",
    "/meta": "API metadata (JSON)",
    "WebSocket": "Connect to same base URL for random status updates"
  },
  "notes": [
    "Orders stored in memory only",
    "Statuses update randomly every second",
    "REST and WebSocket order states may diverge"
  ]
}

WebSocket

Connect to the WebSocket server at ws://localhost:3000 to receive real-time order status updates.

Message Format:

{ "id": 1, "status": "SHIPPED" }

A random order status update is sent every second to all connected clients.

Order Statuses

• NEW
• PROCESSING
• SHIPPED
• CANCELLED

Testing

The tests/ folder contains quick test scripts to verify the API functionality:

test-rest.js

Tests the REST API endpoints (/meta and /orders). Run with:

node tests/test-rest.js

This script fetches data from both endpoints and displays the responses.

test-ws.js

Tests the WebSocket connection and listens for real-time order status updates. Run with:

node tests/test-ws.js

This script connects to the WebSocket server and logs incoming status updates.

Note: The test files are configured to connect to the Railway production deployment at interviewapiserver-production.up.railway.app. Update the URLs in the test files to test against your local server.

Important Notes

• Orders are stored in memory only and reset on server restart
• Order statuses are randomized on startup
• Status updates via WebSocket occur every second with random values
• REST and WebSocket order states may diverge as updates are independent

Technologies

• Express (^4.19.0) - Web framework
• ws (^8.17.0) - WebSocket implementation
• ES Modules - Modern JavaScript module system