Go is great for writing high-performance, concurrent server applications and tools, and the Web is the perfect medium over which to deliver them. It would be difficult these days to find a gadget that is not web-enabled and allows us to build a single application that targets almost all platforms and devices.
Our first project will be a web-based chat application that allows multiple users to have a real-time conversation right in their web browser. Idiomatic Go applications are often composed of many packages, which are organized by having code in different folders, and this is also true of the Go standard library. We will start by building a simple web server using the net/http package, which will serve the HTML files. We will then go on to add support for web sockets through which our messages will flow.
In languages such as C#, Java, or Node.js, complex threading code and clever use of locks need to be employed in order to keep all clients in sync. As we will see, Go helps us enormously with its built-in channels and concurrency paradigms.
In this chapter, you will learn how to:
Use the
net/httppackage to serve HTTP requestsDeliver template-driven content to users' browsers
Satisfy a Go interface to build our own
http.HandlertypesUse Go's goroutines to allow an application to perform multiple tasks concurrently
Use channels to share information between running Go routines
Upgrade HTTP requests to use modern features such as web sockets
Add tracing to the application to better understand its inner workings
Write a complete Go package using test-driven development practices
Return unexported types through exported interfaces
Note
Complete source code for this project can be found at https://github.com/matryer/goblueprints/tree/master/chapter1/chat. The source code was periodically committed so the history in GitHub actually follows the flow of this chapter too.