Redis From Scratch 🚀

Welcome to Redis From Scratch — a minimal Redis clone built to understand the internals of Redis. This project walks through the fundamental components of a Redis server, implementing features like in-memory storage, key-value operations, persistence through RDB files, and client-server communication using the RESP protocol.

Features ✨

• Key-Value Store: Support for basic SET, GET, and DEL commands.
• Persistence: Implements Redis RDB file parsing to load data at startup.
• RESP Protocol: Handles Redis Serialization Protocol (RESP) to communicate with clients.
• Multiple Data Types: Support for strings, lists, and expiration settings.
• Command Handling: Processes common Redis commands like PING, ECHO, and KEYS.
• Error Handling: Gracefully handles unknown commands and file-related issues.

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Project Structure 📂

├── src  
│   ├── main/java  
│   │   ├── Main.java              # Entry point for the server  
│   │   ├── ClientHandler.java     # Handles client requests  
│   │   ├── RDBParser.java         # Parses RDB files  
│   │   ├── Cache.java             # Manages Cache  
│   │   └── Config.java            # Configuration management  
└── README.md                      # Project documentation  

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How to Run 🛠️

Prerequisites

• Java 11+
• Maven

Steps

1. Clone the Repository

   git clone https://github.com/Lavdeep-Singh/redis-from-scratch.git  
   cd redis-from-scratch  

2. Build the Project

   javac -d out src/main/java/*.java 

3. Run the Server

   java -cp out src/main/java/Main.java

4. Test with Redis CLI

   redis-cli -p 6379  
   > PING  
   > SET key value  
   > GET key  

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Configuration ⚙️

You can modify the server's configuration using the Config class:

• Port: Default is 6379.
• Data Directory: Specify the path for RDB files.
• DB Filename: Set the default RDB filename to load at startup.

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Example Commands 🗂️

• PING:

  > PING  
  +PONG  
  

• SET/GET:

  > SET name "Codecrafters"  
  > GET name  
  "Codecrafters"  
  

• KEYS:

  > KEYS *  
  1) "name"  
  

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Development Notes 📝

RDB Parsing

The project includes a custom RDB parser that reads and decodes binary Redis dump files. If the file does not exist, the server treats the database as empty.

Handling Special Encodings

The parser supports multiple length encoding schemes, including special markers for 32-bit and 64-bit lengths.

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Contributing 🤝

Contributions are welcome! Feel free to fork the repo, submit issues, or create pull requests.

1. Fork the repo
2. Create a new branch
3. Commit your changes
4. Open a pull request

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License 📝

This project is licensed under the MIT License.

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Acknowledgments 🙌

• Inspired by Redis.
• Thanks to Codecrafters.io for the challenge idea.

Happy hacking! 🎉