Blockchain CLI in Rust

This repository contains a simple blockchain demonstration implemented in Rust. The project illustrates core Rust principles through a minimal command-line application and integrates an MCP server to expose blockchain functionalities over a network.

Overview

The application implements a basic blockchain where each block includes:

• Index: The block's position in the chain.
• Timestamp: The creation time in ISO 8601 format.
• Data: User-supplied content.
• Previous Hash: The SHA-256 hash of the previous block.
• Current Hash: The SHA-256 hash computed from the block's contents.

A menu-driven CLI lets you:

• Add a new block.
• Print the current blockchain.
• Validate the blockchain's integrity.

Technologies

• Rust: A systems programming language focused on safety and performance.
• sha2: For computing SHA-256 hashes.
• chrono: For accurate timestamping using UTC time.
• serde & serde_json: For JSON serialization (used in MCP communication).

Getting Started

Prerequisites

• Rust (latest stable version)
• Cargo

Build and Run

To create and run the project using Cargo, execute in your terminal:

cargo new blockchain_app
cd blockchain_app && cargo run

Note: If you cloned this repository, simply navigate into the project folder and run cargo run.

Usage

When you run the application, the CLI displays the following options:

1. Add Block: Input data to create a new block.
2. Print Blockchain: Display all blocks in the blockchain.
3. Validate Blockchain: Verify that each block is properly linked.
4. Exit: Close the application.

MCP Server Integration

The project includes an MCP server that runs concurrently with the CLI. It listens on 127.0.0.1:7878 and allows external clients to interact with the blockchain using JSON commands.

Available MCP Commands

• latest_block: Retrieves the latest block in the blockchain.

  • Example:

    echo '{"command": "latest_block"}' | nc 127.0.0.1 7878
    

  • Sample Output:

    {"status":"ok","message":"Latest block retrieved","block":{"index":0,"timestamp":"2025-02-26T10:06:59.931506+00:00","data":"Genesis Block","previous_hash":"0","hash":"f465878acf7be88a124fd7ebc9a3640793612023828d9af8ad237eefd4a1a22e"}}
    

• add_block: Adds a new block with the provided data.

  • Example:

    echo '{"command": "add_block", "data": "sample transaction"}' | nc 127.0.0.1 7878
    

  • Sample Output:

    {"status":"ok","message":"Block added","block":null}
    

Testing the MCP Server

1. Run the Application:
   Open a terminal, navigate to the project directory (blockchain_app), and run:

   cargo run
   

   You will see the CLI menu and a message indicating that the MCP server is listening on 127.0.0.1:7878.

2. Query from a Separate Terminal:
   Open a new terminal window and test the MCP commands using netcat (nc). For example:

   • To retrieve the latest block:

     echo '{"command": "latest_block"}' | nc 127.0.0.1 7878
     

   • To add a new block:

     echo '{"command": "add_block", "data": "sample transaction"}' | nc 127.0.0.1 7878
     

Note: The MCP server runs in a separate thread alongside the CLI, so ensure you use a different terminal window for these tests.

Summary

This project demonstrates how to combine blockchain logic with an externally accessible MCP server in Rust. It serves as a practical example for networked tool integration.