Chapter 5. Exposing Network Assets and Transactions

If you have reached this far, congratulations! You have built the core of your blockchain application and the smart contract that directly reads, and more importantly, manipulates, the ledger that is the System-of-Record for your network. But, you are not close to finishing yet. As you can imagine, the contract is a sensitive piece of code that must be protected from misuse or tampering.

To produce a robust and secure application that is safe to release to business users, you must wrap the smart contract with one or more layers of protection and engineer it as a service that clients can access remotely through appropriate safeguards. In addition, the various stakeholders that wish to share a ledger and a smart contract may have unique and specific business logic needs that only they, and not the others, need to implement over and above the contract. For this reason, one blockchain application running one smart contract may end up offering...

Building a complete application

In this section, you will learn how to build a complete application around the core smart contract that can be readily used by the business entities that have joined together to form a network. We will begin with a recap of the Hyperledger Fabric transaction pipeline to remind the reader what (and how) a blockchain application does from the perspective of the user (or client). Using code samples, we will show you how to build, design, and organize a network around the needs of business entities, create appropriate configurations, and effect the different stages of a blockchain transaction from start to finish. At the end of this process, the reader will understand how to engineer a Fabric application and expose its capabilities through a simple web interface. The only asset we need to possess in the beginning of this chapter is the contract, or chaincode, which was developed using either hands-on Go programming (see Chapter 4, Designing a data and transaction...

Integration with existing systems and processes

When discussing end-to-end solutions with customers, we often explain that blockchain-related components represent a very small percentage of the overall footprint. This is still a very important set of components, but nonetheless they represent a small footprint.

This section will focus on the touch point between our traditional systems and the Hyperledger Fabric and Composer API.

We will explore the various patterns of integration we have leveraged and see how some of the non-functional requirements can influence the integration deployment. Finally, we will explore some additional considerations that integrators will need to keep in mind when designing their integration layer.

In short, in this section, you will:

• Understand the design consideration of the integration layer
• Review the integration design patterns
• Explore the impact of non-functional requirements on the integration

Design considerations

By now, you have experience with Fabric SDK and...

Summary

Building a complete blockchain application is an ambitious and challenging project, not just because of the range of skills it requires—systems, networking, security, and web application development, to name a few—but because it requires concerted development, testing, and deployment by multiple organizations spanning multiple security domains.

In this chapter, we began with a simple smart contract and ended with a four-peer blockchain network that was ready to drive trade scenarios and store records in a tamper-resistant, shared, replicated ledger. In the process, we learned how to design an organization structure and configure a Fabric network. We learned how to build a channel, or an instance of a Fabric blockchain, get peers in a network to join the channel, and install and instantiate a smart contract on that channel, using the Fabric SDK. We learned how to expose the capabilities of our network and smart contract to end users through web applications, exposing service APIs....