Module 1: Redis Fundamentals - Laying the Groundwork

• What is Redis? Explanation of Redis as an open-source, in-memory data structure store, used as a database, cache, message broker, stream engine, and more. Emphasis on its speed due to in-memory nature.
• Use Cases and Advantages:
  • Caching: Most common use case for improving application performance.
  • Session Management: Storing user session data.
  • Leaderboards and Real-time Analytics: Leveraging Sorted Sets.
  • Message Queues: Using Lists or dedicated libraries.
  • Pub/Sub: Real-time communication.
  • Rate Limiting: Controlling API access.
  • Geospatial Queries: Using Geo commands.
  • Advantages: Speed, versatility, rich data structures, persistence options, scalability features.
• Redis Architecture:
  • In-Memory: Data is primarily stored in RAM, leading to very low latency.
  • Persistence: Options for writing data to disk for durability (RDB and AOF).
  • Single-Threaded Model: Explanation of how Redis achieves high performance despite being single-threaded using non-blocking I/O and event loop. (Diagram: Simple representation of Redis single-threaded event loop processing client requests).
• Installing Redis Locally: Step-by-step instructions for installing Redis on various operating systems.
• Using redis-cli: Introduction to the Redis command-line interface for interacting with the Redis server. Basic commands like PING, SET, GET, DEL.
• Understanding Data Types:
  • Strings: Basic key-value pairs (SET, GET).
  • Lists: Ordered collections of strings (LPUSH, RPUSH, LPOP, RPOP, LRANGE).
  • Sets: Unordered collections of unique strings (SADD, SMEMBERS, SREM).
  • Hashes: Key-value pairs within a single key, useful for representing objects (HSET, HGET, HGETALL).
  • Sorted Sets: Sets where each member is associated with a score, allowing for ordered retrieval (ZADD, ZRANGE, ZREVRANGE).
  • Bitmaps: Space-efficient way to store and manipulate bit arrays (SETBIT, GETBIT, BITCOUNT).
  • HyperLogLogs: Probabilistic data structure for estimating the cardinality of a set (PFADD, PFCOUNT).
  • Streams (Introductory): Append-only, message-oriented data structure (XADD, XRANGE).
• CLI Commands: redis-server, redis-cli, PING, SET, GET, DEL, LPUSH, RPUSH, LPOP, RPOP, LRANGE, SADD, SMEMBERS, SREM, HSET, HGET, HGETALL, ZADD, ZRANGE, BITCOUNT, PFADD, PFCOUNT, XADD, XRANGE.
• Hands-on: Install Redis, start the server, and use redis-cli to experiment with basic commands and all the fundamental data types.

Module 2: Core Redis Operations - Mastering Data Manipulation

• CRUD Operations: Detailed exploration of commands for creating, reading, updating, and deleting data for each major data type.
  • Strings: SET, GET, MSET, MGET, INCR, DECR, APPEND.
  • Lists: LINDEX, LINSERT, LLEN, LREM, LTRIM, RPOPLPUSH.
  • Sets: SISMEMBER, SPOP, SRANDMEMBER, SINTER, SUNION, SDIFF.
  • Hashes: HEXISTS, HINCRBY, HKEYS, HVALS, HDEL.
  • Sorted Sets: ZREM, ZINCRBY, ZCOUNT, ZRANK, ZREVRANK, ZSCORE.
• Key Expiration:
  • EXPIRE: Set a timeout for a key in seconds.
  • TTL: Get the remaining time-to-live of a key.
  • PTTL: Get the remaining time-to-live in milliseconds.
  • PERSIST: Remove the expiration from a key.
• Pattern Matching and Key Scanning:
  • KEYS: Find all keys matching a given pattern (use with caution in production due to performance implications).
  • SCAN: Iteratively scan the keyspace, avoiding blocking the server.
• Pub/Sub Model:
  • SUBSCRIBE: Subscribe to one or more channels.
  • PUBLISH: Send a message to a specific channel.
  • UNSUBSCRIBE: Unsubscribe from one or more channels.
  • Use cases: Real-time notifications, chat applications. (Diagram: Simple representation of Redis Pub/Sub with publishers and subscribers).
• CLI Commands: MSET, MGET, INCR, DECR, APPEND, LINDEX, LINSERT, LLEN, LREM, LTRIM, RPOPLPUSH, SISMEMBER, SPOP, SRANDMEMBER, SINTER, SUNION, SDIFF, HEXISTS, HINCRBY, HKEYS, HVALS, HDEL, ZREM, ZINCRBY, ZCOUNT, ZRANK, ZREVRANK, ZSCORE, EXPIRE, TTL, PTTL, PERSIST, KEYS, SCAN, SUBSCRIBE, PUBLISH, UNSUBSCRIBE.
• Hands-on: Practice using all the core Redis operations with redis-cli. Experiment with key expiration and the Pub/Sub model.

Module 3: Integrating Redis with Node.js - Connecting Your Backend

• Setting up Redis Client: Instructions and code examples for connecting to Redis from a Node.js application using popular client libraries:

  • ioredis: Recommended for its performance and feature set.
  • redis: The original Node.js Redis client.

• Caching API Responses: Example of creating a middleware function in Express to cache API responses in Redis based on the request URL.JavaScript

  `// Installation: npm install ioredis express const Redis = require('ioredis'); const redis = new Redis(); const express = require('express'); const app = express();

  const cacheMiddleware = async (req, res, next) => { const key = api:${req.originalUrl}; const cachedResponse = await redis.get(key); if (cachedResponse) { return res.status(200).send(cachedResponse); } res.sendResponse = res.send; res.send = (body) => { redis.setex(key, 300, body); // Cache for 5 minutes res.sendResponse(body); }; next(); };

  app.get('/api/users', cacheMiddleware, async (req, res) => { // Simulate fetching data from database await new Promise(resolve => setTimeout(resolve, 1000)); res.json([{ id: 1, name: 'John Doe' }, { id: 2, name: 'Jane Smith' }]); });

  app.listen(3000, () => console.log('Server started on port 3000'));`

• Caching Computed Data: Examples of caching the results of expensive computations in Redis.