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🚀 NGINX CACHING SERVER — END-TO-END TUTORIAL

NGINX can act as a cache layer between the client and your backend server.
This gives:

✔ Faster response times
✔ Less load on backend
✔ Handles more traffic
✔ Reduces DB/API usage

📌 1. What is NGINX Caching? (Simple Explanation)

Flow:

Client → NGINX (Cache Layer) → Backend Server

When a request comes:

  1. NGINX checks: Is response already cached?

  2. If YES → returns cached response instantly

  3. If NO → fetches from backend → stores cache → returns response

📁 2. Prerequisites

🧱 3. Create Cache Directory

sudo mkdir -p /var/cache/nginx_cache
sudo chmod 777 /var/cache/nginx_cache

⚙️ 4. Configure NGINX Cache

Edit your site config:

sudo nano /etc/nginx/sites-available/cache_server

Paste this:

proxy_cache_path /var/cache/nginx_cache levels=1:2 keys_zone=my_cache:10m max_size=1g inactive=60m use_temp_path=off;

server {
    listen 80;
    server_name example.com;

    location / {
        proxy_cache my_cache;
        proxy_pass http://127.0.0.1:3000;

        proxy_cache_valid 200 302 10m;
        proxy_cache_valid 404 1m;

        proxy_cache_use_stale error timeout updating http_500 http_502 http_503 http_504;

        add_header X-Cache-Status $upstream_cache_status;
    }
}

What each line means:

  • proxy_cache_path → Where cache files are stored

  • keys_zone=my_cache:10m → Cache index memory

  • max_size=1g → Maximum cache size

  • inactive=60m → Remove unused cache entries

  • proxy_cache_valid → Cache success for 10 minutes

  • use_stale → Serve old cache if backend fails

  • X-Cache-Status → Shows HIT / MISS in response header

🔗 5. Enable the Site

sudo ln -s /etc/nginx/sites-available/cache_server /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx

🧪 6. Test Cache Behavior

Make request:

curl -I http://your-domain

You will see:

  • MISS → (first request, cache empty)

  • HIT → (subsequent requests, served from cache)

Example:

X-Cache-Status: MISS

then:

X-Cache-Status: HIT

🎉 This confirms caching is working.

⚡ 7. Cache Control Per Path (Optional)

Cache /api/products/ for 5 minutes:

location /api/products/ {
    proxy_cache my_cache;
    proxy_pass http://127.0.0.1:3000;
    proxy_cache_valid 200 5m;
}

Disable cache for login routes:

location /login {
    proxy_no_cache 1;
    proxy_cache_bypass 1;
    proxy_pass http://127.0.0.1:3000;
}

🔐 8. Ignore Cookies / Headers (Optional)

Don't let cookies break caching:

proxy_ignore_headers Cache-Control Expires Set-Cookie;

⭐ 9. Microcaching (High-Performance API Cache)

Microcaching caches responses for 1–2 seconds — reduces backend load massively.

proxy_cache_valid 200 1s;

This is used by:

✔ High-traffic APIs
✔ E-commerce sites
✔ Crypto dashboards
✔ News feeds
✔ Leaderboards

🔥 10. Purge Cache (Manually)

Clear entire cache:

sudo rm -rf /var/cache/nginx_cache/*
sudo systemctl reload nginx

📊 11. Monitoring Cache

View cache folder:

ls /var/cache/nginx_cache

Monitor logs:

tail -f /var/log/nginx/access.log
tail -f /var/log/nginx/error.log

🛡 12. Combine with Reverse Proxy + Load Balancer

NGINX can do all 3 together:

Client → NGINX (Cache + SSL) → Load Balancer → Backend API cluster

Let me know if you want this architecture too.

🎉 Caching Server Setup Completed!

You now have:

✔ NGINX caching layer
✔ File system cache
✔ Per-path caching rules
✔ Microcaching
✔ Cache purge
✔ Cache monitoring
✔ Failover with stale cache

❓ What do you want next?

I can provide:

🔹 CDN-style caching (advanced)
🔹 Cache + Load Balancer + Reverse Proxy combo
🔹 High-availability caching architecture
🔹 Cache invalidation rules for APIs
🔹 Caching with Docker

Tell me what you want!