Out of the box, Go is an excellent choice for writing web applications. The built-in net/http packages combined with packages such as html/template allow for fully featured modern web applications out of the box. It's so easy that it encourages spinning up web interfaces for the management of even basic long-running applications. Although the standard library is fully featured, there is still a large variety of third-party web packages for everything from routes to full-stack frameworks, including the following:

• https://github.com/urfave/negroni
• https://github.com/gin-gonic/gin
• https://github.com/labstack/echo
• http://www.gorillatoolkit.org/
• https://github.com/julienschmidt/httprouter

The recipes in this chapter will focus on basic tasks you might run into when working with handlers, when navigating response and request objects, and in dealing with concepts such as middleware.

In this chapter, the following recipes will be covered:

• Working with web handlers, requests, and ResponseWriter instances
• Using structures and closures for stateful handlers
• Validating input for Go structures and user inputs
• Rendering and content negotiation
• Implementing and using middleware
• Building a reverse proxy application
• Exporting GRPC as a JSON API