slackEcho.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"

	"github.com/gorilla/websocket"
)

type authResponse struct {
	URL string `json:"url"`
}

type message struct {
	ID string `json:"id"`
	ReplyTo string `json:"reply_to"`
	Type    string `json:"type"`
	Channel string `json:"channel"`
	Text string `json:"text"`
}

func main() {
	token := "xoxb-put your token here"
	URL := getWebsocketURL(token)

	var dialer *websocket.Dialer

	conn, _, err := dialer.Dial(URL, nil)
	if err != nil {
		fmt.Println(err)
		return
	}

	for {
		m := message{}
		err := conn.ReadJSON(&m)
		if err != nil {
			fmt.Println(err)
		}

		fmt.Printf("received: %+v\n", m)

		if m.Type == "message" && m.ReplyTo != "1" {
			echo := message{
				ID:      "1",
				Type:    m.Type,
				Channel: m.Channel,
				Text:    m.Text,
			}

			conn.WriteJSON(echo)
		}
	}
}

func getWebsocketURL(token string) string {
	url := "https://slack.com/api/rtm.start?token=" + token
	resp, err := http.Get(url)
	if err != nil {
		fmt.Println(err)
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)

	res := authResponse{}
	json.Unmarshal([]byte(body), &res)
	return res.URL
}