Blockchain Data

Blockchain has the potential to change the way that the world approaches data. Develop Blockchain skills by understanding the data model behind Blockchain by developing your own simplified private blockchain.

Getting Started

These instructions will get you a copy of the project up and running on your local machine for development and testing purposes.

Prerequisites

Installing Node and NPM is pretty straightforward using the installer package available from the (Node.js® web site)[https://nodejs.org/en/].

Must use node@^v8.0.0 or greater.

Configuring your project

Use yarn or npm to install the dependencies

yarn

npm install

Using

I took the liberty to update how the LevelDB was implemented. Instead of only having a single database, I encapsulated all the functionality to a Database class. You need to pass it a path location (string) when instantiating a new one.

The Blockchain makes a new chain based on the Database class. Therefore, you need to pass the new Blockchain class a string to setup the database.

Also, the blockchain object has an init() method to create the genesis block.

At minimum, you will need to run:

(async () => {
// instantiate new blockchain (note that it is asynchronous)
const blockchain = await new Blockchain('./path/to/create/database');

// now we can add new blocks as needed.
await blockchain.addBlock(new Block('the second block in the chain'));

// and check to see that the chain is good.
await blockchain.validateChain();

})();

Testing

Test cases were created to meet rubric critera for the project.

The test will create a new database for each described feature, and then after it is complete. It will automatically clean up the /test-chaindata folder for you.

Warning: if the test fails, it will not get a chance to clean up the test-database directories; you will have to do that manually before re-running the tests.

To run tests, use either yarn or npm like so:

yarn test

npm test

Should get something like so:

PASS  tests/levelSandbox.test.js
PASS  tests/simpleChain.test.js

Or if you only test the blockchain:

PASS  tests/simpleChain.test.js
  addBlock()
    √ should include a method to store newBlock with LevelDB (49ms)
    √ should persist the Genesis block as the first block in the blockchain using LevelDB (41ms)
  validateBlock()
    √ should validate a block stored within levelDB (37ms)
    √ should validate blockchain stored within levelDB (40ms)
  getBlock()
    √ should retrieve a block by block height within the LevelDB chain (40ms)
  getBlockHeight()
    √ should retrieve the current block height within the LevelDB chain (50ms)

Test Suites: 1 passed, 1 total
Tests:       6 passed, 6 total
Snapshots:   0 total
Time:        2.24s
Ran all test suites.

leocreatini / udacity-blockchain-project-2