HTTP

Lot of the tutorials on the Web show different ways of writing Go HTTP middlewares, but most of them use functional approach meaning using functions that get dependencies as parameters and return HTTP handler function or handler. There is nothing wrong about this, but it can be quite messy to write a complex middlewares like database based authentication and authorization or simply middlewares which have lot of dependencies. In this article I am going to explain how to use more object oriented way of writing such middlewares. Let’s start with the basic object oriented middleware example:

Few days ago Go 1.18beta1 was released and with it the first official generics support. I was embarrassed with standard Go’s HTTP handler functions for quite a while. If you are not familiar with Go, you probably wonder why, but if you are familiar, I believe you know. For example, implementing a RESTful API using idiomatic Go requires lot of code repetition in order to JSON decode request bodies and JSON encode response bodies. This problem was possible to solve in some way but never in such elegant way like using generics.