redirect.go

package api

import (
	"net/http"
	"strings"
)

// HTTPSRedirect returns middleware that redirects HTTP requests to HTTPS.
func HTTPSRedirect() Middleware {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.TLS == nil && r.Header.Get("X-Forwarded-Proto") != "https" {
				target := "https://" + r.Host + r.URL.RequestURI()
				http.Redirect(w, r, target, http.StatusMovedPermanently)
				return
			}
			next.ServeHTTP(w, r)
		})
	}
}

// TrailingSlash returns middleware that strips trailing slashes and redirects.
func TrailingSlash() Middleware {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if r.URL.Path != "/" && strings.HasSuffix(r.URL.Path, "/") {
				target := strings.TrimRight(r.URL.Path, "/")
				if r.URL.RawQuery != "" {
					target += "?" + r.URL.RawQuery
				}
				http.Redirect(w, r, target, http.StatusMovedPermanently)
				return
			}
			next.ServeHTTP(w, r)
		})
	}
}

// NonWWWRedirect returns middleware that redirects www subdomain to non-www.
func NonWWWRedirect() Middleware {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			if strings.HasPrefix(r.Host, "www.") {
				target := r.URL.Scheme + "://" + strings.TrimPrefix(r.Host, "www.") + r.URL.RequestURI()
				http.Redirect(w, r, target, http.StatusMovedPermanently)
				return
			}
			next.ServeHTTP(w, r)
		})
	}
}