Redis (From Scratch)

A minimal Redis-compatible server written in Go.

Implements core Redis commands using the RESP (REdis Serialization Protocol).
You can use any standard Redis client (like redis-cli) to test and interact with it.

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✨ Features

• ✅ RESP protocol (serializer/deserializer) implemented from scratch
• ✅ TCP-based byte stream handling
• ✅ Command support:
  • PING
  • SET
  • GET
  • HSET
  • HGET
  • HGETALL
• ✅ Works with real Redis clients
• 🚫 No persistence yet (AOF not implemented)

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📁 Folder Structure

.
├── main.go         # Entry point for server
├── server/         # TCP server setup and connection handling
├── resp/           # RESP protocol (serialization/deserialization)
├── commands/       # Implementation of supported commands
├── writer/         # Response writer abstraction using bufio

## 🔌 RESP Protocol Overview

RESP is a **binary-safe**, **length-prefixed** protocol (not delimiter-based).

### Key Concepts:

- `*` denotes an **array**
- `$` denotes a **bulk string**
- `+` denotes a **simple string**

For example, the command:

GET name hamza

Is translated into RESP as:

*3\r\n
$3\r\n
GET\r\n
$4\r\n
name\r\n
$5\r\n
hamza\r\n


This means:

- `*3` → 3 elements in the array
- `$3 GET` → the command
- `$4 name`, `$5 hamza` → the arguments

Note: While the protocol is CRLF-based (`\r\n`), clients like `redis-cli` abstract that away—you can write inline commands normally.

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## 🧪 Testing the Server

### Prerequisite

Install a Redis client (`redis-cli`).  
Any client should work, but this was tested with the Debian package version.

### Run Instructions

Open two terminals:

**Terminal 1 – Start the server**

```bash
go run main.go
Terminal 2 – Test commands with redis-cli

redis-cli ping
redis-cli set mykey myvalue
redis-cli get mykey
redis-cli hset myhash field1 value1
redis-cli hget myhash field1
redis-cli hgetall myhash
🧠 How It Works

    resp/: Parses and constructs RESP messages (serializer and deserializer).

    commands/: Implements supported commands and stores them in a command map.

    writer/: Wraps bufio to abstract the TCP response sending mechanism.

    server/: Bootstraps the TCP listener and routes requests to handlers.

🚧 Data Persistence

Persistence is not implemented yet (AOF is not used like in real Redis).
Looking for a lightweight alternative—open to ideas and contributions!