proposal: bot.HandleFunc

[mattn]

Currently, response handler seems to be redundancy to handle events like below.

    http.HandleFunc("/callback", func(w http.ResponseWriter, req *http.Request) {
        events, err := bot.ParseRequest(req)
        if err != nil {
            if err == linebot.ErrInvalidSignature {
                w.WriteHeader(400)
            } else {
                w.WriteHeader(500)
            }
            return
        }
        // code here
    }

So I suggest to add new method client.HandleFunc like below.

diff --git a/linebot/receive.go b/linebot/receive.go
index 5354c8f..92068cb 100644
--- a/linebot/receive.go
+++ b/linebot/receive.go
@@ -279,6 +279,21 @@ func (client *Client) ParseRequest(r *http.Request) (events *ReceivedResults, e
    return
 }

+func (client *Client) HandleFunc(handler func(requests *ReceivedResults)) http.HandlerFunc {
+   return func(w http.ResponseWriter, req *http.Request) {
+       events, err := client.ParseRequest(req)
+       if err != nil {
+           if err == ErrInvalidSignature {
+               w.WriteHeader(400)
+           } else {
+               w.WriteHeader(500)
+           }
+           return
+       }
+       handler(events)
+   }
+}
+
 func (client *Client) validateSignature(signature string, body []byte) bool {
    decoded, err := base64.StdEncoding.DecodeString(signature)
    if err != nil {

Using this method, this part will be shorter.

func main() {
    bot, err := linebot.New(
        os.Getenv("CHANNEL_SECRET"),
        os.Getenv("CHANNEL_TOKEN"),
    )
    if err != nil {
        log.Fatal(err)
    }

    // Setup HTTP Server for receiving requests from LINE platform
    http.HandleFunc("/callback", bot.HandleFunc(events *linebot.ReceivedResults) {
        for _, event := range events {
            if event.Type == linebot.EventTypeMessage {
                switch message := event.Message.(type) {
                case *linebot.TextMessage:
                    source := event.Source
                    if source.Type == linebot.EventSourceTypeUser {
                        if _, err = bot.PushMessage(source.UserID, linebot.NewTextMessage(message.Text)).Do(); err != nil {
                            log.Print(err)
                        }
                    }
                }
            }
        }
    })
    if err := http.ListenAndServe(":"+os.Getenv("PORT"), nil); err != nil {
        log.Fatal(err)
    }
}

[mattn]

日本語ですみません。
最初になんでこれが欲しいと思ったかは、400と500の切り分けが今後さらに増えたりしないかなーと思ったのがきっかけで、であれば line 自身で模範解答があるのがいいのかなーと思った次第です。

[sugyan]

We added line-bot-sdk-go/linebot/httphandler that implements http.Handler. You can handle events easily by using this.
https://github.com/line/line-bot-sdk-go/blob/7de5817af0beb177af416ed4bb48cca4248b8849/examples/echo_bot_handler/server.go
Thanks!