Caching Strategies (Redis)

const redisClient = require('../config/redis');
const Product = require('../models/Product');

exports.getTrendingProducts = async (req, res) => {
    const cacheKey = 'products:trending';

    // 1. Check Redis Cache Memory first
    const cachedData = await redisClient.get(cacheKey);
    
    if (cachedData) {
        // Cache HIT: Bypass Database & return immediately
        return res.status(200).json(JSON.parse(cachedData));
    }

    // 2. Cache MISS: Query heavy data from MongoDB
    const products = await Product.find().sort({ views: -1 }).limit(10);

    // 3. Save to Redis with 1-hour expiration (3600 seconds)
    await redisClient.setEx(cacheKey, 3600, JSON.stringify(products));

    res.status(200).json(products);
};