In this chapter, we are going to look at middleware functionality. What is middleware, and how can we build it from scratch? Next, we will move to a better middleware solution written for us, called Gorilla Handlers. We will then try to understand a few use cases where middleware can be helpful. After that, we will start building our RPC services with Go's internal RPC and JSON RPC. Then we will move to an advanced RPC framework, such Gorilla HTTP RPC.

The topics we cover in this chapter are:

• What is middleware?
• What is an RPC (Remote Procedure Call)?
• How can we implement RPC and JSON RPC in Go?