Book Image

Blockchain Developer's Guide

By : Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty
Book Image

Blockchain Developer's Guide

By: Brenn Hill, Samanyu Chopra, Paul Valencourt, Narayan Prusty

Overview of this book

Blockchain applications provide a single-shared ledger to eliminate trust issues involving multiple stakeholders. It is the main technical innovation of Bitcoin, where it serves as the public ledger for Bitcoin transactions. Blockchain Developer's Guide takes you through the electrifying world of blockchain technology. It begins with the basic design of a blockchain and elaborates concepts, such as Initial Coin Offerings (ICOs), tokens, smart contracts, and other related terminologies. You will then explore the components of Ethereum, such as Ether tokens, transactions, and smart contracts that you need to build simple DApps. Blockchain Developer's Guide also explains why you must specifically use Solidity for Ethereum-based projects and lets you explore different blockchains with easy-to-follow examples. You will learn a wide range of concepts - beginning with cryptography in cryptocurrencies and including ether security, mining, and smart contracts. You will learn how to use web sockets and various API services for Ethereum. By the end of this Learning Path, you will be able to build efficient decentralized applications. This Learning Path includes content from the following Packt products: • Blockchain Quick Reference by Brenn Hill, Samanyu Chopra, Paul Valencourt • Building Blockchain Projects by Narayan Prusty
Table of Contents (37 chapters)
Title Page
About Packt

hooked-web3-provider and ethereumjs-tx libraries

Until now, all the examples of Web3.js library's sendTransaction() method we saw were using the from address that's present in the Ethereum node; therefore, the Ethereum node was able to sign the transactions before broadcasting. But if you have the private key of a wallet stored somewhere else, then geth cannot find it. Therefore, in this case, you will need to use the web3.eth.sendRawTransaction() method to broadcast transactions.

web3.eth.sendRawTransaction() is used to broadcast raw transactions, that is, you will have to write code to create and sign raw transactions. The Ethereum node will directly broadcast it without doing anything else to the transaction. But writing code to broadcast transactions using web3.eth.sendRawTransaction() is difficult because it requires generating the data part, creating raw transactions, and also signing the transactions.

The Hooked-Web3-Provider library provides us with a custom provider, which communicates...