echo slack-bot

main.go

package main

import (
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
)

const BotCommand = "!bot"

type BotResponse struct {
	Text string `json:"text"`
}

func NewBotResponse(s string) *BotResponse {
	return &BotResponse {
		Text: s,
	}
}

func main() {
	http.HandleFunc("/", root)
	http.HandleFunc("/bot", bot)
	http.ListenAndServe("0.0.0.0:8080", nil)
}

func root(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "hello, bot")
}

// echo bot server
func bot(w http.ResponseWriter, r *http.Request) {
	err := r.ParseForm()
	if err != nil {
		fmt.Fprintf(w, err.Error())
		return
	}

	original, err := url.QueryUnescape(r.PostForm.Get("text"))
	if err != nil {
		fmt.Fprintf(w, err.Error())
		return
	} else if !strings.HasPrefix(original, BotCommand) {
		fmt.Fprintf(w, `bot command starts from "!bot"`)
		return
	}

	splitted := strings.SplitN(original, " ", 2)
	resp := NewBotResponse(splitted[1])
	data, err := json.Marshal(resp)
	if err != nil {
		fmt.Fprintf(w, err.Error())
		return
	}
	fmt.Fprintf(w, string(data))
}