When building a website, there is one inevitable thing: 301 permanent redirection. The cases that have to involve 301 includes:

• Redirection from www subdomain to naked domain or vise versa.
• Redirection from slashed pretty URL to unslashed URL or vise versa.

301 is easy to implement with Go:

func redirect301(w http.ResponseWriter, url string) {
    w.Header().Set("Location", url)
    w.WriteHeader(http.StatusMovedPermanently)
}

There is one more thing that needs attention: The root path of a domain always contains a slash (GET / in HTTP request), regardless the user enters the slash or not, so the root path needs no redirection.