slack websocket api example

slack_rtm.go

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"golang.org/x/net/websocket"
)

type RtmResponse struct {
	Ok    bool            `json:"ok"`
	Error string          `json:"error"`
	Url   string          `json:"url"`
	Self  RtmResponseSelf `json:"self"`
}

type Message struct {
	Id      uint64 `json:"id"`
    Type    string `json:"type"`
    Channel string `json:"channel"`
    Text    string `json:"text"`
}

type RtmResponseSelf struct {
	Id string `json:"id"`
}

var token = flag.String("t", "", "slack token")

func main() {

	flag.Parse()

	url := fmt.Sprintf("https://slack.com/api/rtm.start?token=%s", *token)
	resp, err := http.Get(url)
	if err != nil {
		log.Println("ERROR:", err)
		return
	}

	body, err := ioutil.ReadAll(resp.Body)

	if err != nil {
		log.Println("ERROR:", err)
		return
	}

	var rtmResp RtmResponse
	err = json.Unmarshal(body, &rtmResp)

	if err != nil {
		log.Println("ERROR:", err)
		return
	}

	log.Println("RESPONSE:", rtmResp.Url)

	ws, err := websocket.Dial(rtmResp.Url, "", "https://api.slack.com/")

	if err != nil {
		log.Println("ERROR:", err)
		return
	}


	for {
		var m Message
		err = websocket.JSON.Receive(ws, &m) 

		if err != nil {
			log.Println("ERROR:", err) 
		}

		log.Println("MESSAGE:", m.Type, m.Text) 
	
		if m.Type == "message" {
			m.Text = "Reply"
			websocket.JSON.Send(ws, m) 
		}
		
	}
}