IoRedisClient.ts

IoRedisClient.ts SDD

Introduction and Overview

This document provides a detailed overview of the code found in IoRedisClient.ts. The file is responsible for implementing a Redis client using the ioredis library. The class IoredisClient is created to handle interactions with a Redis database using the provided RedisClient interface as a reference.

System Architecture

The system architecture depicted in this document utilizes the ioredis library, which acts as an abstraction layer between the client and the Redis database. The IoredisClient class is responsible for interacting with the Redis database using the Redis object provided during its construction. The RedisClient interface serves as a contract defining the required methods for this interaction.

Data Design

The data design in this system involves storing and retrieving data from a Redis database using key-value pairs. The keys serve as unique identifiers for the values stored within the database.

Key-Value Pair Structure

In this implementation, keys are strings, and values can be of any type. The specific data type of the value is not relevant to the IoredisClient class.

Redis Database Operations

The IoredisClient class implements methods for setting, getting, and evaluating scripts in the Redis database:

• set(key: string, value: string, options: { NX: boolean, PX: number }): Promise<string | null>

  • This method stores a key-value pair in the Redis database, with an optional expiration time (PX) and the 'NX' flag to prevent overwriting existing keys.

• eval(script: string, keys: string[], args: string[]): Promise<number>

  • This method executes a script on the Redis server, passing the provided arguments (keys and values) to the script. The script can perform any operation supported by the Redis protocol.

• getTTL(resource: string): Promise<number>

  • This method retrieves the time to live (TTL) of a key from the Redis database, indicating when the value associated with the key will expire.

• get(resource: string): Promise<string | null>

  • This method retrieves the value associated with a key from the Redis database.

Interface Design

The RedisClient interface is used to define the contract for the interactions between the client and the Redis database:

export interface RedisClient {
  set(key: string, value: string, options: { NX: boolean, PX: number }): Promise<string | null>;
  eval(script: string, keys: string[], args: string[]): Promise<number>;
  getTTL(resource: string): Promise<number>;
  get(resource: string): Promise<string | null>;
}

This interface ensures that any implementation of the IoredisClient class adheres to this contract, allowing for interchangeable Redis client implementations.

Component Design

The primary component in this system is the IoredisClient class, which serves as a proxy for interacting with a Redis database using the provided Redis object. The RedisClient interface further encapsulates the interactions and ensures that any implementation of the IoredisClient class follows the required method structure.

User Interface Design

The IoredisClient class itself does not have a direct user interface, as it is meant to be used as an abstract layer for interacting with a Redis database. The user interface would typically be provided by the application or service that utilizes this class.

Assumptions and Dependencies

The following assumptions and dependencies are present in this system:

• The ioredis library is required to communicate with the Redis database. This dependency must be managed separately from the codebase, as it is not included within the file.

• The Redis server is assumed to be running and accessible at the time of implementation.

Glossary of Terms

• Redis Database: A NoSQL key-value store database, known for its high performance and in-memory data structures.

• IoredisClient: A class responsible for interacting with a Redis database using the ioredis library.

• Redis Client: An interface defining the contract for interacting with a Redis database.

• Key: A unique identifier used to store and retrieve data from a Redis database.

• Value: The actual data stored within a Redis database, associated with its corresponding key.

• TTL (Time To Live): The amount of time a value remains in the Redis database before it expires.

Class Diagram (in Mermaid syntax)

Here is the class diagram in Mermaid syntax:

class IoredisClient {
  +constructor(client: Redis);
  +set(key: string, value: string, options: { NX: boolean, PX: number }): Promise<string | null>;
  +eval(script: string, keys: string[], args: string[]): Promise<number>;
  +getTTL(resource: string): Promise<number>;
  +get(resource: string): Promise<string | null>;
}

class RedisClient {
  +set(key: string, value: string, options: { NX: boolean, PX: number }): Promise<string | null>;
  +eval(script: string, keys: string[], args: string[]): Promise<number>;
  +getTTL(resource: string): Promise<number>;
  +get(resource: string): Promise<string | null>;
}

This diagram shows the relationship between the IoredisClient class and the RedisClient interface. The IoredisClient class is responsible for implementing the methods defined in the RedisClient interface to interact with a Redis database using the provided Redis object.