demo hour code. written quickly.

dogs.go

package main

import (
	"io"
	"log"
	"math/rand"
	"net/http"
	"os"
)

var puppyFiles = []string{
	"serene.jpg",
	"rabid_dog.gif",
	"cool.gif",
	"glasses.jpeg",
}

func main() {
	http.Handle("/puppies", http.HandlerFunc(randomPuppy))
	http.Handle("/puppies/", http.HandlerFunc(randomPuppy))

	log.Fatal(http.ListenAndServe(":24004", nil))
}

func randomPuppy(w http.ResponseWriter, r *http.Request) {
	n := rand.Intn(len(puppyFiles))
	f, err := os.Open("./dog_images/" + puppyFiles[n])
	if err != nil {
		w.WriteHeader(500)
		w.Write([]byte("sorry, we broke"))
		return
	}
	w.WriteHeader(200)
	io.Copy(w, f)
	return
}