https://shogi-img.appspot.com/

app.go

package app

import (
	"bytes"
	"image/gif"
	"image/jpeg"
	"image/png"
	"net/http"
	"path"
	"strings"

	"github.com/sugyan/shogi/format/csa"
	"github.com/sugyan/shogi/util/image"
	"google.golang.org/appengine"
	"google.golang.org/appengine/log"
)

func init() {
	http.Handle("/", http.StripPrefix("/", http.HandlerFunc(handler)))
}

func handler(w http.ResponseWriter, r *http.Request) {
	if r.URL.Path == "favicon.ico" {
		http.NotFound(w, r)
		return
	}

	ctx := appengine.NewContext(r)
	b := bytes.NewBuffer([]byte{})
	for _, l := range strings.Split(r.URL.Path, "/") {
		if strings.HasPrefix(l, "P") {
			b.WriteString(l + "\n")
		}
	}
	state, err := csa.Parse(b)
	if err != nil {
		log.Errorf(ctx, "failed to parse: %s", err.Error())
		http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
		return
	}
	var options *image.StyleOptions
	if strings.HasPrefix(path.Base(r.URL.Path), "simple") {
		options = &image.StyleOptions{
			Board: image.BoardStripe,
			Piece: image.PieceDirty,
		}
	}
	if strings.HasPrefix(path.Base(r.URL.Path), "random") {
		options = &image.StyleOptions{
			Board: image.BoardRandom,
			Grid:  image.GridRandom,
			Piece: image.PieceRandom,
		}
	}
	img, err := image.Generate(state, options)
	if err != nil {
		log.Errorf(ctx, "failed to generate: %s", err.Error())
		http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		return
	}
	switch path.Ext(r.URL.Path) {
	case ".jpg":
		fallthrough
	case ".jpeg":
		w.Header().Set("Content-Type", "image/jpeg")
		if err := jpeg.Encode(w, img, nil); err != nil {
			log.Errorf(ctx, "failed to encode: %s", err.Error())
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		}
	case ".gif":
		w.Header().Set("Content-Type", "image/gif")
		if err := gif.Encode(w, img, nil); err != nil {
			log.Errorf(ctx, "failed to encode: %s", err.Error())
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		}
	default:
		w.Header().Set("Content-Type", "image/png")
		if err := png.Encode(w, img); err != nil {
			log.Errorf(ctx, "failed to encode: %s", err.Error())
			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
		}
	}
}

app.yaml

runtime: go
api_version: go1

handlers:
- url: /.*
  script: _go_app

automatic_scaling:
  max_idle_instances: 1