Book Image

Blockchain Development with Hyperledger

By : Salman A. Baset, Luc Desrosiers, Nitin Gaur, Petr Novotny, Anthony O'Dowd, Venkatraman Ramakrishna, Weimin Sun, Xun (Brian) Wu
Book Image

Blockchain Development with Hyperledger

By: Salman A. Baset, Luc Desrosiers, Nitin Gaur, Petr Novotny, Anthony O'Dowd, Venkatraman Ramakrishna, Weimin Sun, Xun (Brian) Wu

Overview of this book

Blockchain and Hyperledger are open source technologies that power the development of decentralized applications. This Learning Path is your helpful reference for exploring and building blockchain networks using Ethereum, Hyperledger Fabric, and Hyperledger Composer. Blockchain Development with Hyperledger will start off by giving you an overview of blockchain and demonstrating how you can set up an Ethereum development environment for developing, packaging, building, and testing campaign-decentralized applications. You'll then explore the de facto language Solidity, which you can use to develop decentralized applications in Ethereum. Following this, you'll be able to configure Hyperledger Fabric and use it to build private blockchain networks and applications that connect to them. Toward the later chapters, you'll learn how to design and launch a network, and even implement smart contracts in chain code. By the end of this Learning Path, you'll be able to build and deploy your own decentralized applications by addressing the key pain points encountered in the blockchain life cycle. This Learning Path includes content from the following Packt products: • Blockchain Quick Start Guide by Xun (Brian) Wu and Weimin Sun • Hands-On Blockchain with Hyperledger by Nitin Gaur et al.
Table of Contents (25 chapters)
Title Page
Copyright
About Packt
Contributors
Preface
Index

Creating a chaincode


We are now ready to start to implementing our chaincode, which we will program in the Go language. There are several IDEs available that provide support for Go. Some of the better IDEs include Atom, Visual Studio Code, and many more. Whatever environment you opt for will work with our example.

The chaincode interface

Every chaincode must implement the Chaincode interface, whose methods are called in response to the received transaction proposals. The Chaincode interface defined in the SHIM package is shown in the following listing:

type Chaincode interface { 
    Init(stub ChaincodeStubInterface) pb.Response 
    Invoke(stub ChaincodeStubInterface) pb.Response 
} 

As you can see, the Chaincode type defines two functions: Init and Invoke.

Both functions have a single argument, stub, of the type ChaincodeStubInterface.

The stub argument is the main object that we will use when implementing the chaincode functionality, as it provides functions for accessing and modifying the...