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S42 Core

S42Core RedisDB Class

REDISDB

RedisClient Class Documentation

The RedisClient class in S42-Core provides a robust and flexible way to interact with Redis. It implements a Singleton pattern and handles multiple Redis connections for general operations, publishing, and subscribing. This class ensures stability by retrying connections and offering a simple API for common Redis tasks.

Features

  • Singleton Pattern: Ensures a single instance of the Redis client throughout the application.
  • Multiple Connections: Dedicated connections for general commands, publishing, and subscribing.
  • Retry Mechanism: Automatically retries connections to Redis in case of failures.
  • Typed Interface: Ensures predictable and type-safe operations.
  • Built-in Error Handling: Provides informative error messages for troubleshooting.

Installation

Install the S42-core package:

Terminal window
bun add s42-core

Example Usage

Basic Setup

import { RedisClient } from 's42-core';


const connectionURI = 'redis://localhost:6379';
const redisClient = RedisClient.getInstance(connectionURI);


// Perform operations
(async () => {
  await redisClient.hset('user:1', { name: 'John Doe', age: '30' });
  const userName = await redisClient.hget('user:1', 'name');
  console.log('User Name:', userName);
})();

Publish and Subscribe

const redisClient = RedisClient.getInstance();


// Subscribe to a channel
redisClient.subscribe('notifications', (message) => {
  console.log('Received message:', message);
});


// Publish a message to the channel
redisClient.publish('notifications', { type: 'alert', content: 'This is a test message' });

Graceful Shutdown

process.on('SIGINT', () => {
  redisClient.close();
  process.exit(0);
});

API Documentation

Methods

getInstance(connectionURI: string = 'localhost'): RedisClient

Returns the singleton instance of RedisClient.

  • Parameters:
    • connectionURI (string): Redis connection URI. Defaults to localhost.
  • Returns:
    • (RedisClient): The singleton instance.

hset(key: string, value: Record<string, any>): Promise<void>

Sets a hash field in Redis.

  • Parameters:
    • key (string): The key of the hash.
    • value (Record<string, any>): The data to set.

hget(key: string, subkey: string): Promise<string | null>

Gets a value from a hash field.

  • Parameters:
    • key (string): The key of the hash.
    • subkey (string): The field to retrieve.
  • Returns:
    • (string | null): The value of the field or null if not found.

hgetall(key: string): Promise<Record<string, string>>

Gets all fields and values from a hash.

  • Parameters:
    • key (string): The key of the hash.
  • Returns:
    • (Record<string, string>): All fields and values.

subscribe<T>(channelName: string, callback: (payload: T) => void): void

Subscribes to a Redis channel.

  • Parameters:
    • channelName (string): The channel name to subscribe to.
    • callback (function): Callback invoked with the message payload.

publish(channelName: string, payload: Record<string, any>): Promise<void>

Publishes a message to a Redis channel.

  • Parameters:
    • channelName (string): The channel name to publish to.
    • payload (Record<string, any>): The message payload.

unsubscribe(channelName: string): void

Unsubscribes from a Redis channel.

  • Parameters:
    • channelName (string): The channel name to unsubscribe from.

close(): void

Closes all Redis connections.

Error Handling

The RedisClient class provides robust error handling mechanisms. If a connection or operation fails, informative error messages are logged to aid debugging.

Retry Mechanism

Each connection attempts to reconnect up to 3 times before throwing an error. This ensures better resilience in unstable network conditions.

License

This project is licensed under the MIT License. See the LICENSE file for details.