WeatherAPI

Project URL: https://roadmap.sh/projects/weather-api-wrapper-service

A backend API that acts as a proxy and cache in front of the Visual Crossing weather API. A client asks for the weather in a city; the server checks a Redis cache first, and only calls Visual Crossing when there's no fresh answer already cached.

Features

• GET /weather/:cityCode — current weather for a city
• GET /health — basic liveness check
• Redis caching (cache-aside pattern) with a configurable TTL
• Rate limiting per IP
• Structured error responses (400/404/502) instead of generic failures

Prerequisites

• Node.js
• Redis running locally (or accessible via a connection URL)
• A free Visual Crossing API key

Setup

1. Clone the repo and install dependencies:

   git clone git@github.com:tuanhoang0117/WeatherAPI.git
   cd WeatherAPI
   npm install
   

2. Copy the example environment file and fill in your own values:

   cp .env.example .env
   

   Variable	Purpose
   WEATHER_API_KEY	Your Visual Crossing API key
   REDIS_URL	Redis connection string (defaults to redis://localhost:6379)
   PORT	Port the server listens on (defaults to 3000)
   CACHE_TTL_SECONDS	How long cached weather data stays valid

3. Make sure Redis is running:

   redis-cli ping
   

   Should return PONG.

4. Start the server:

   npm start
   

Usage

GET /health
GET /weather/:cityCode

GET /health returns { "status": "OK" } with no parameters — used to confirm the server itself is running, independent of Redis or Visual Crossing.

Example:

curl http://localhost:3000/weather/Sacramento

Success response — 200 OK

{
  "city": "Sacramento",
  "temperature": 85.7,
  "unit": "F",
  "conditions": "Clear"
}

Error responses

• 400 Bad Request — missing or empty city code
• 404 Not Found — city not recognized by Visual Crossing
• 429 Too Many Requests — rate limit exceeded
• 502 Bad Gateway — Visual Crossing is unreachable or erroring

All error responses share the same shape: { "error": "..." }.

Testing

Backend endpoints were manually tested using Postman, including:

• Successful requests against real cities
• Cache-hit vs. cache-miss response times
• Error cases (400, 404, 502)
• Rate limiting (429) via Postman's Collection Runner

Tech Stack

• Node.js + Express
• axios — HTTP client for calling Visual Crossing
• ioredis — Redis client
• express-rate-limit — rate limiting middleware
• dotenv — environment variable loading