rt-redirect/main.go

package main

import (
	"fmt"
	"github.com/gorilla/mux"
	"log"
	"net/http"
	"os"
	"time"
)

const (
	readTimeout = 30 * time.Second
)

func main() {
	port, hasPort := os.LookupEnv("PORT")
	if !hasPort {
		port = "8080"
	}

	routes := []struct {
		From string
		To   string
	}{
		{From: "/2022/04/a-case-for-mocking-in-unit-tests", To: "https://lmika.org/2022/04/12/a-case-for.html"},
		{From: "/2021/06/parametrising-your-bdd-tests-in-go", To: "https://www.workingset.net/development/go/parametrising-bdd-tests"},
		{From: "/2021/03/communication-among-stimulus-controllers-part-2", To: "https://lmika.org/2021/02/17/communication-among-stimulus.html"},
		{From: "/2021/02/communication-among-stimulus-controllers-part-1", To: "https://lmika.org/2021/02/17/communication-among-stimulus.html"},
		{From: "/2021/01/a-simple-source-ip-address-filter-in-go", To: "https://lmika.org/2021/01/20/a-simple-source.html"},
		{From: "/2021/01/building-sets-from-maps", To: "https://lmika.org/2021/01/09/building-sets-from.html"},
		{From: "/2020/12/test-helpers-and-test-packages-in-go", To: "https://www.workingset.net/development/go/test-helpers-and-packages"},
		{From: "/2020/12/a-tour-of-domain-records-for-email", To: "https://lmika.org/2020/12/18/a-tour-of.html"},
		{From: "/2020/12/dealing-with-errors-in-go", To: "https://lmika.org/2020/12/16/dealing-with-errors.html"},
		{From: "/2020/12/building-and-serving-go-wasm-projects", To: "https://www.workingset.net/development/go/go-and-wasm"},
		{From: "/2020/12/a-brief-look-at-stimulus", To: "https://lmika.org/2020/12/08/a-brief-look.html"},
		{From: "/2020/12/setting-go-variables-during-build", To: "https://www.workingset.net/development/go/set-variables-in-build"},
		{From: "/2020/12/posts-only-rss-feed-in-hugo", To: "https://www.workingset.net/development/web/posts-only-rss-feed-in-hugo"},
	}

	r := mux.NewRouter()
	for _, route := range routes {
		r.Handle(route.From+"/", redirectTo(route.To))
		r.Handle(route.From, redirectTo(route.To))
	}
	r.Handle("/", redirectTo("https://lmika.org/"))

	svr := http.Server{
		Addr:              fmt.Sprintf(":%v", port),
		Handler:           r,
		ReadTimeout:       readTimeout,
		ReadHeaderTimeout: readTimeout,
	}
	if err := svr.ListenAndServe(); err != nil {
		log.Fatal(err)
	}
}

func redirectTo(url string) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Redirect(w, r, url, http.StatusPermanentRedirect)
	})
}