Noncents

Problem Domain

This project is our initial attempt to understand and replicate the blockchain technology and potential applications.

Due to the blockchain's immutability, it allows both the sender and receiver to trust that the information sent follows a dictated structure and has a determined result.

We included the ability for distributed nodes to add to the blockchain with a simple terminal command.

Prerequisites

Install the stable version of Node JS, which is available at the following link https://nodejs.org/en/

This environment should allow you to run all code present in this repository.

Installing

Create a new directory where you would like to store our project.

ex:

mkdir noncents

Clone the repository to this directory

git clone https://github.com/HashMoney/Noncents.git

Install NPM dependencies

npm install 

If you would like to begin mining immediately, use the following command

node index.js

↑ Before Mining

After Mining ↓

For advanced users, a server side code base is available under the branch herokuStaging at the project's git repository.

https://github.com/HashMoney/Noncents.git

Running the tests

To run the tests, you type into the command line npm run test This will run all tests and output a coverage level (provided by Jest) describing percentage of lines covered across documents.

Main Server Test Results:

Node Server Test Results:

Server Endpoints

• POST /block

  • Node sends request to Heroku server to post new block to stable chain.
  • Heroku server checks to see if it is the next valid block in the chain.
  • If block is valid, Heroku server returns a 204 success status code to the node.
  • If block is valid, Heroku appends new block to the stable chain.
  • Returns a 400 failure status code to the node if either the index, previous hash, current hash are invalid or if this information is missing.

• GET /chain

  • Node sends a request to the Heroku server for the current stable chain.
  • Heroku server retrieves stable chain from database and sends stable chain back to node.
  • Heroku server returns a 200 success status code to the node.
  • Returns a 404 failure status code if an incorrect route is specified.

• /

  • Catch all route for any unspecified routes.
  • Returns a 404 Not Found

Built With

• Node - JS Runtime Build
• Mongo DB - Chain Persistence
• Heroku - Hosted Deployment
• Travis CI - Integration Testing

Code Examples

Block from Chain

{
        "index": 1,
        "previousHash": "000lUu0u82sRhgvltSGzbBJZefYnbv+E6py9dC1/0NU=",
        "timeStamp": "Fri Jan 05 2018 08:54:21 GMT-0800 (PST)",
        "ledger": "necessitatibus aut enim voluptates ut est sed dolor voluptas nulla",
        "currentHash": "0006dXneGWKoICEfxybrwhwwu257M/cmFytTXdye4l0=",
        "nonce": 616877
      },

Hashing Code Example

chainSchema.methods.makeBlockHash = function(index, timeStamp, previousHash, ledger, nonce){
  let SHA256 = new Hashes.SHA256;
  let nextHash = SHA256.b64(index + timeStamp + previousHash + ledger);
  let nonceHash = SHA256.b64(nextHash + nonce);
  return nonceHash;
};

NPM Packages Used

• Express - CRUD routes to server
• Jest, Superagent - Unit Testing
• Mongoose - Data manipulation within Mongo
• JS Hashes - SHA256 Hashing
• Eslint - Linting
• HttpErrors, Winston - Activity/Error Logging

Authors

• Kerry Nordstrom
• Seth Donohue
• Nicholas Carignan
• Jacob Evans
• Sam Hamm

License

This project is licensed under the MIT License - see the LICENSE.md file for details

WIKI: https://github.com/HashMoney/Noncents/wiki

Travis CI: https://travis-ci.org/HashMoney/Noncents

Heroku App Deployment: https://noncents.herokuapp.com/

Heroku Chain Get Route: http://noncents.herokuapp.com/chain

Acknowledgments

• We referenced a compact 200-line blockchain called Naivechain, written in JS, in order to define best practices for our code https://github.com/lhartikk/naivechain/blob/master/main.js