Book Image

Learn Blockchain Programming with JavaScript

By : Eric Traub
Book Image

Learn Blockchain Programming with JavaScript

By: Eric Traub

Overview of this book

Learn Blockchain Programming with JavaScript begins by giving you a clear understanding of what blockchain technology is. You’ll then set up an environment to build your very own blockchain and you’ll add various functionalities to it. By adding functionalities to your blockchain such as the ability to mine new blocks, create transactions, and secure your blockchain through a proof-of-work you’ll gain an in-depth understanding of how blockchain technology functions. As you make your way through the chapters, you’ll learn how to build an API server to interact with your blockchain and how to host your blockchain on a decentralized network. You’ll also build a consensus algorithm and use it to verify data and keep the entire blockchain network synchronized. In the concluding chapters, you’ll finish building your blockchain prototype and gain a thorough understanding of why blockchain technology is so secure and valuable. By the end of this book, you'll understand how decentralized blockchain networks function and why decentralization is such an important feature for securing a blockchain.
Table of Contents (10 chapters)

Building the /block/:blockHash endpoint

Let's use the getBlock method inside of /block/:blockHash endpoint to retrieve a specific block by its blockHash. Let's follow these next steps to build the endpoint:

  1. The first thing that we want to do in this endpoint is to use the blockHash value that is sent with the /block/:blockHash request. We can access this blockHash on the req.params object. Go to the dev/networkNode.js file and in the /block/:blockHash endpoint that we defined previously, add the following highlighted code:
app.get('/block/:blockHash', function(req, res) { 
const blockHash = req.params.blockHash;

Essentially, when we hit the /block/:blockHash endpoint, we're accessing the hash value of a block present on a particular node in the network. We're also accessing the hash value using the req.params object, which will give...