app.go

package linebot

import (
	"encoding/base64"
	"encoding/json"
	"net/http"
	"net/url"
	"os"

	"golang.org/x/net/context"

	"google.golang.org/appengine"
	"google.golang.org/appengine/log"
	"google.golang.org/appengine/taskqueue"
	"google.golang.org/appengine/urlfetch"

	"github.com/joho/godotenv"
	"github.com/line/line-bot-sdk-go/linebot"
	"github.com/line/line-bot-sdk-go/linebot/httphandler"
)

var botHandler *httphandler.WebhookHandler

func init() {
	err := godotenv.Load("line.env")
	if err != nil {
		panic(err)
	}

	botHandler, err = httphandler.New(
		os.Getenv("LINE_BOT_CHANNEL_SECRET"),
		os.Getenv("LINE_BOT_CHANNEL_TOKEN"),
	)
	botHandler.HandleEvents(handleCallback)

	http.Handle("/callback", botHandler)
	http.HandleFunc("/task", handleTask)
}

// Webhook を受け取って TaskQueueに詰める関数
func handleCallback(evs []*linebot.Event, r *http.Request) {
	c := appengine.NewContext(r)
	ts := make([]*taskqueue.Task, len(evs))
	for i, e := range evs {
		j, err := json.Marshal(e)
		if err != nil {
			log.Errorf(c, "json.Marshal: %v", err)
			return
		}
		data := base64.StdEncoding.EncodeToString(j)
		t := taskqueue.NewPOSTTask("/task", url.Values{"data": {data}})
		ts[i] = t
	}
	taskqueue.AddMulti(c, ts, "")
}

// 受け取ったメッセージを処理する関数
func handleTask(w http.ResponseWriter, r *http.Request) {
	c := appengine.NewContext(r)
	data := r.FormValue("data")
	if data == "" {
		log.Errorf(c, "No data")
		return
	}

	j, err := base64.StdEncoding.DecodeString(data)
	if err != nil {
		log.Errorf(c, "base64 DecodeString: %v", err)
		return
	}

	e := new(linebot.Event)
	err = json.Unmarshal(j, e)
	if err != nil {
		log.Errorf(c, "json.Unmarshal: %v", err)
		return
	}

	bot, err := newLINEBot(c)
	if err != nil {
		log.Errorf(c, "newLINEBot: %v", err)
		return
	}

	log.Infof(c, "EventType: %s\nMessage: %#v", e.Type, e.Message)

	var msg linebot.Message = linebot.NewTextMessage("ok")
	switch m := e.Message.(type) {
	case *linebot.TextMessage:
		msg = linebot.NewTextMessage(m.Text)
		if m.Text == "スタンプ" {
			msg = &linebot.StickerMessage{
				PackageID: "1",
				StickerID: "1",
			}
		}
	}

	if _, err = bot.ReplyMessage(e.ReplyToken, msg).WithContext(c).Do(); err != nil {
		log.Errorf(c, "ReplayMessage: %v", err)
		return
	}

	w.WriteHeader(200)
}

func newLINEBot(c context.Context) (*linebot.Client, error) {
	return botHandler.NewClient(
		linebot.WithHTTPClient(urlfetch.Client(c)),
	)
}