Nav Interview PokeAPI Reverse Proxy

main.go

package main

import (
	"fmt"
	"log"
	"net"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
	"strings"

	"github.com/go-chi/chi"
	"github.com/go-chi/chi/middleware"
)

func handleProxyRequest(w http.ResponseWriter, r *http.Request) {
	// Include /api/v2/ in the path so I don't have to
	u, err := url.Parse("https://pokeapi.co/api/v2/")
	if err != nil {
		http.Error(w, fmt.Sprintf("unable to create pokeapi url: %v", err), http.StatusBadGateway)
		return
	}

	proxy := httputil.ReverseProxy{
		Director: func(r *http.Request) {
			r.URL.Scheme = u.Scheme
			r.URL.Host = u.Host
			r.Host = u.Host

			// pokeapi redirects non-trailing slashes, so this is required if we
			// want to stay on proxy host.
			r.URL.Path = u.Path + strings.TrimRight(r.URL.Path, "/") + "/"

			r.Header.Set("X-Forwarded-Host", r.Header.Get("Host"))
		},
	}

	proxy.ServeHTTP(w, r)
}

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

	r := chi.NewMux()

	r.Use(middleware.Logger)
	r.Use(middleware.Recoverer)

	r.Mount("/*", http.HandlerFunc(handleProxyRequest))

	httpServer := &http.Server{
		Addr:    net.JoinHostPort("", port),
		Handler: r,
	}

	log.Printf("http server listening at %s", httpServer.Addr)
	if err := httpServer.ListenAndServe(); err != nil {
		log.Panic(err)
	}
}