Redis Expert
Installation
# Ubuntu
apt install redis-server -y
systemctl enable redis-server
# Docker
docker run -d --name redis -p 6379:6379 redis:alpine
Basic Commands
redis-cli
# Strings
SET key "value"
GET key
SETEX key 3600 "value" # With TTL (1 hour)
TTL key # Check TTL
# Hash (objects)
HSET user:1 name "John" email "john@example.com"
HGET user:1 name
HGETALL user:1
# Lists
LPUSH queue "task1"
RPOP queue
# Sets
SADD tags "node" "redis"
SMEMBERS tags
# Sorted Sets
ZADD leaderboard 100 "player1"
ZRANGE leaderboard 0 -1 WITHSCORES
Node.js Integration
import { createClient } from 'redis';
const redis = createClient({ url: 'redis://localhost:6379' });
await redis.connect();
// Cache pattern
async function getUser(id: string) {
const cached = await redis.get(`user:${id}`);
if (cached) return JSON.parse(cached);
const user = await db.user.findUnique({ where: { id } });
await redis.setEx(`user:${id}`, 3600, JSON.stringify(user));
return user;
}
// Invalidate
await redis.del(`user:${id}`);
Caching Strategies
| Strategy | Use Case | Implementation |
|---|
| Cache-Aside | Read-heavy | Check cache → Miss → Load DB → Store cache |
| Write-Through | Consistency | Write DB → Write cache |
| Write-Behind | Write-heavy | Write cache → Async write DB |
| TTL | General | Set expiration time |
Common Patterns
// Rate limiting
async function rateLimit(ip: string, limit = 100) {
const key = `rate:${ip}`;
const count = await redis.incr(key);
if (count === 1) await redis.expire(key, 60);
return count <= limit;
}
// Session storage
app.use(session({
store: new RedisStore({ client: redis }),
secret: 'secret',
resave: false,
saveUninitialized: false
}));
// Pub/Sub
await redis.subscribe('channel', (message) => {
console.log('Received:', message);
});
await redis.publish('channel', 'Hello!');
