examples

Redis Client Examples

This directory contains comprehensive examples demonstrating various features of the Redis client library.

Running Examples

Make sure you have Redis running locally on 127.0.0.1:6379 (default configuration) before running the examples.

# Run a specific example
deno run -A examples/basic.ts

# Or use the task
deno task example

Examples Overview

1. Basic Operations (basic.ts)

Demonstrates fundamental Redis operations:

• Connecting to Redis server
• String operations (GET, SET, INCR, DECR)
• Hash operations (HSET, HGET, HMGET)
• List operations (LPUSH, RPUSH, LRANGE)
• Key management (EXISTS, EXPIRE, TTL)
• Error handling
• Connection cleanup

Topics covered:

• Connection establishment
• Basic data types
• Error handling patterns
• Resource cleanup

2. Pub/Sub Messaging (pubsub.ts)

Comprehensive Redis publish/subscribe messaging demonstration:

• Basic channel subscriptions and message publishing
• Pattern-based subscriptions with wildcards (user:*, log:*)
• Multiple subscribers and message broadcasting
• Real-time messaging simulation (chat room example)
• Dynamic subscription management (add/remove channels)
• Advanced monitoring patterns with message statistics
• Error handling and graceful connection cleanup
• Performance tracking and analytics

Topics covered:

• Publisher/Subscriber pattern fundamentals
• Pattern matching and flexible routing
• Concurrent message handling across multiple subscribers
• Real-time communication patterns
• Dynamic subscription management
• Message statistics and monitoring
• Best practices for pub/sub architectures

3. Pipelining (pipeline.ts)

Demonstrates command pipelining for performance:

• Basic pipeline usage
• Performance comparisons
• Batch data processing
• Error handling in pipelines
• Transaction-like operations

Topics covered:

• Command batching
• Performance optimization
• Error handling in batches
• Atomic-like operations

4. Redis Streams (streams.ts)

Comprehensive Redis Streams functionality demonstration:

• Basic stream operations with automatic and custom IDs
• Stream range queries (forward, reverse, by ID, with limits)
• Consumer groups for distributed message processing
• Real-time event processing with blocking reads
• Stream information and monitoring commands
• Memory management with stream trimming (MAXLEN, MINID)
• Multiple consumers with task distribution
• Event sourcing patterns and best practices
• IoT sensor data simulation
• Application event processing workflow

Topics covered:

• Event streaming and message ordering
• Consumer groups and distributed processing
• Message acknowledgment and delivery guarantees
• Stream queries and data retrieval patterns
• Real-time processing with blocking operations
• Memory management and stream maintenance
• Event sourcing architectures
• IoT and time-series data handling

5. Advanced Features (advanced.ts)

Explores advanced Redis features:

• Redis transactions (MULTI/EXEC)
• Optimistic locking with WATCH
• Connection pooling simulation
• Advanced data structures
• Error handling and recovery
• Health checks

Topics covered:

• ACID transactions
• Concurrent access patterns
• Connection management
• Advanced data types

Prerequisites

Redis Server

Make sure Redis is installed and running:

# macOS with Homebrew
brew install redis
brew services start redis

# Ubuntu/Debian
sudo apt install redis-server
sudo systemctl start redis-server

# Docker
docker run -d -p 6379:6379 redis:latest

Permissions

Examples require network permissions:

# Allow network access
deno run --allow-net examples/basic.ts

# Or allow all permissions
deno run -A examples/basic.ts

Configuration

Examples use default Redis configuration:

• Host: 127.0.0.1
• Port: 6379
• Database: 0
• No authentication

To use different settings, modify the connection configuration in each example:

const redis = await connect({
  hostname: "your-redis-host",
  port: 6380,
  password: "your-password",
  db: 1,
});

Environment Variables

You can also use environment variables:

export REDIS_HOST=localhost
export REDIS_PORT=6379
export REDIS_PASSWORD=mypassword

deno run --allow-net --allow-env examples/basic.ts

Example Patterns

Error Handling

All examples demonstrate proper error handling:

try {
  const redis = await connect(config);
  // ... operations
} catch (error) {
  if (error instanceof ConnectionClosedError) {
    console.error("Connection closed");
  } else if (error instanceof AuthenticationError) {
    console.error("Authentication failed");
  } else {
    console.error("Unexpected error:", error);
  }
} finally {
  redis.close();
}

Resource Cleanup

Always close connections when done:

const redis = await connect(config);
try {
  // ... operations
} finally {
  redis.close(); // Always cleanup
}

Performance Monitoring

Examples include timing measurements:

const start = performance.now();
await operation();
const time = performance.now() - start;
console.log(`Operation took ${time.toFixed(2)}ms`);

Troubleshooting

Connection Issues

Error: Connection refused

• Make sure Redis is running
• Check host/port configuration
• Verify firewall settings

Authentication Errors

Error: Authentication failed

• Check Redis AUTH configuration
• Verify username/password
• Ensure Redis is configured for authentication

Permission Errors

Error: Network access is not allowed

• Run with --allow-net flag
• Or use --allow-all / -A for all permissions

Memory Issues

Error: Out of memory

• Check Redis memory configuration
• Monitor Redis memory usage
• Use appropriate data expiration

Best Practices

1. Always close connections: Use try/finally blocks
2. Handle errors gracefully: Use appropriate error types
3. Use pipelining: For multiple operations
4. Monitor performance: Measure operation timing
5. Clean up test data: Remove keys after examples
6. Use connection pooling: For high-throughput applications

Contributing

When adding new examples:

1. Follow the existing file structure
2. Include comprehensive comments
3. Add error handling
4. Clean up test data
5. Update this README
6. Test with a clean Redis instance

---

For more information, see the main README.md and API documentation.