I hope the book is good, but I guess I'll never know.
You already know the book is pretty good, you just wanted to complain about DRM, I suspect. I hope that's not the case.
A single data point is not authoritative, but my comment shows a pretty solid trend toward "pretty good." I expect you'll run out to go find some rotten carrots to eat now?
I'd also recommend learning to write web APIs with the standard library so you know the primitives. Writing Web Applications on golang.org covers the basics.
One thing to note is that Gin's Context is not the standard context.Context, which some find problematic. Most (vocal?) Gophers prefer sticking with the standard library and Gorilla.
context: working in large org building backend services that speak to other backend services via various crappy http / rest / soap APIs.
From the writer of this blog: https://www.thepolyglotdeveloper.com/
For an example