Mini Redis in Python

A simplified Redis-like in-memory key-value store built with Python, demonstrating DSA, OOP, Networking, and Persistence concepts.

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Project Overview

Mini Redis is a lightweight, simplified version of Redis with the following features:

• Key-Value Store: Store data as key-value pairs in memory.
• LRU Cache: Frequently accessed keys are cached for faster retrieval.
• TTL (Time-To-Live): Keys can expire automatically after a given time.
• Persistence: Data is saved to a JSON file to survive server restarts.
• Multi-Client Support: Handles multiple clients concurrently using threading.
• Redis-like Commands: SET, GET, DEL, EXPIRE, PERSIST, PING, QUIT.

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Data Structures Used

• Dictionary → Main key-value store (O(1) access).
• OrderedDict → LRU Cache for eviction of least recently used keys.
• Heap → TTL expiration management (efficient lookup of next key to expire).
• Lock (Threading) → Thread-safe access to store and cache.

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Commands

Command	Description
SET key value [EX seconds]	Store a key-value pair with optional TTL.
GET key	Retrieve value of a key (checks cache first).
DEL key	Delete a key from store and cache.
EXPIRE key seconds	Set TTL for an existing key.
PERSIST key	Remove TTL from a key.
PING	Health check → returns PONG.
QUIT	Disconnect client.

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How to Run

1. Start the server

python main.py server --host 127.0.0.1 --port 6379
### 2. Start the Client
python main.py client --host 127.0.0.1 --port 6379
### 3. Example Session
>> SET name Vivek
OK
>> GET name
Vivek
>> EXPIRE name 5
OK
>> PING
PONG
>> DEL name
OK
>> QUIT
BYE