Margelet

Telegram Bot Framework for Go is based on telegram-bot-api

It uses Redis to store it's states, configs and so on.

Any low-level interactions with Telegram Bot API(downloading files, keyboards and so on) should be performed through telegram-bot-api.

Margelet is just a thin layer, that allows you to solve basic bot tasks quickly and easy.

Installation

go get github.com/zhulik/margelet

Simple usage

package main

import (
	"github.com/zhulik/margelet"
)

func main() {
	bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)

	if err != nil {
		panic(err)
	}

	err = bot.Run()
	if err != nil {
		panic(err)
	}
}

Out of the box, margelet supports only /help command, it responds something like this

/help - Show bot help

Concept

Margelet is based on some concepts:

• Message handlers
• Command handlers
• Session handlers
• Chat configs
• Inline handlers

Message handlers

Message handler is a struct that implements Handler interface. It receives all chat messages dependant on bot's Privacy mode. It doesn't receive commands.

Simple example:

package margelet_test

import (
	"../margelet"
)

// EchoHandler is simple handler example
type EchoHandler struct {
}

// Response send message back to author
func (handler EchoHandler) HandleMessage(m margelet.Message) error {
	_, err := m.QuickSend(m.Message().Text)
	return err
}

This handler will repeat any user's message back to chat.

Message helpers can be added to margelet with AddMessageHandler function:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
bot.AddMessageHandler(EchoHandler{})
bot.Run()

Command handlers

Command handler is struct that implements CommandHandler interface. CommandHandler can be subscribed on any command you need and will receive all message messages with this command, only if there is no active session with this user in this chat

Simple example:

package margelet

import (
	"fmt"
	"strings"
)

// HelpHandler Default handler for /help command. Margelet will add this automatically
type HelpHandler struct {
	Margelet *Margelet
}

// HandleCommand sends default help message
func (handler HelpHandler) HandleCommand(message Message) error {
	lines := []string{}
	for command, h := range handler.Margelet.CommandHandlers {
		lines = append(lines, fmt.Sprintf("/%s - %s", command, h.handler.HelpMessage()))
	}

	for command, h := range handler.Margelet.SessionHandlers {
		lines = append(lines, fmt.Sprintf("/%s - %s", command, h.handler.HelpMessage()))
	}

	_, err := message.QuickSend(strings.Join(lines, "\n"))
	return err
}

// HelpMessage return help string for HelpHandler
func (handler HelpHandler) HelpMessage() string {
	return "Show bot help"
}

Command handlers can be added to margelet with AddCommandHandler function:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
bot.AddCommandHandler("help", HelpHandler{bot})
bot.Run()

Session handlers

Session here is an interactive dialog with user, like @BotFather does. User runs session with a command and then response to bot's questions until bot collects all needed information. It can be used for bot configuration, for example.

Session handlers API is still developing

Session handler is struct that implements SessionHandler interface. Simple example:

package margelet_test

import (
	"fmt"
	"strconv"

	"../margelet"
	"gopkg.in/telegram-bot-api.v4"
)

// SumSession - simple example session, that can sum numbers
type SumSession struct {
}

// HandleResponse - Handlers user response
func (s SumSession) HandleSession(session margelet.Session) error {
	switch len(session.Responses()) {
	case 0:
		session.QuickReply("Hello, please, write one number per message, after some iterations write 'end'.")
	default:
		if session.Message().Text == "end" {
			var sum int
			for _, m := range session.Responses() {
				n, _ := strconv.Atoi(m.Text)
				sum += n
			}
			session.QuickReply(fmt.Sprintf("Your sum: %d", sum))
			session.Finish()
			return nil
		}

		_, err := strconv.Atoi(session.Message().Text)
		if err != nil {
			session.QuickReply("Sorry, not a number")
			return err
		}
	}

	return nil
}

// CancelResponse - Chance to clean up everything
func (s SumSession) CancelSession(session margelet.Session) {
	//Clean up all variables only used in the session

}

func (session SumSession) response(bot margelet.MargeletAPI, message *tgbotapi.Message, msg tgbotapi.MessageConfig) {
	msg.ChatID = message.Chat.ID
	msg.ReplyToMessageID = message.MessageID
	msg.ReplyMarkup = tgbotapi.ForceReply{ForceReply: true, Selective: true}
	bot.Send(msg)
}

// HelpMessage return help string for SumSession
func (session SumSession) HelpMessage() string {
	return "Sum your numbers and print result"
}

Session handlers can be added to margelet with AddSessionHandler function:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
bot.AddSessionHandler("help", SumSession{})
bot.Run()

On each user response it receives all previous user responses, so you can restore session state. HandleResponse return values it important:

• first(bool), means that margelet should finish session, so return true if you receive all needed info from user, false otherwise
• second(err), means that bot cannot handle user's message. This message will not be added to session dialog history. Return any error if you can handle user's message and return nil if message is accepted.

Inline handlers

Inline handler is struct that implements InlineHandler interface. InlineHandler can be subscribed on any inline queries.

Simple example:

package margelet_test

import (
	"github.com/zhulik/margelet"
	"gopkg.in/telegram-bot-api.v4"
)

type InlineImage struct {
}

func (handler InlineImage) HandleInline(bot margelet.MargeletAPI, query *tgbotapi.InlineQuery) error {
	testPhotoQuery := tgbotapi.NewInlineQueryResultPhoto(query.ID, "https://telegram.org/img/t_logo.png")
	testPhotoQuery.ThumbURL = "https://telegram.org/img/t_logo.png"

	config := tgbotapi.InlineConfig{
		InlineQueryID: query.ID,
		CacheTime:     2,
		IsPersonal:    false,
		Results:       []interface{}{testPhotoQuery},
		NextOffset:    "",
	}

	bot.AnswerInlineQuery(config)
	return nil
}

Inline handler can be added to margelet by InlineHandler assignment:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
m.InlineHandler = &InlineImage{}
bot.Run()

Callback handlers

Callback handler is struct that implements CallbackHandler interface. CallbackHandler can be subscribed on any callback queries.

Simple example:

package margelet_test

import (
	"../margelet"
	"gopkg.in/telegram-bot-api.v4"
)

type CallbackMessage struct {
}

func (handler CallbackMessage) HandleCallback(query margelet.CallbackQuery) error {
	config := tgbotapi.CallbackConfig{
		CallbackQueryID: query.Query().ID,
		Text:            "Done!",
		ShowAlert:       false,
	}

	query.Bot().AnswerCallbackQuery(config)
	return nil
}

Callback handler can be added to margelet by CallbackHandler assignment:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
m.CallbackHandler = &CallbackMessage{}
bot.Run()

Chat configs

Bots can store any config string(you can use serialized JSON) for any chat. It can be used for storing user's configurations and other user-related information. Simple example:

bot, err := margelet.NewMargelet("<your awesome bot name>", "<redis addr>", "<redis password>", 0, "your bot token", false)
...
bot.GetConfigRepository().Set(<chatID>, "<info>")
...
info := bot.GetConfigRepository().Get(<chatID>)

OR

type userInfo struct{
  FavColor string // First character has to be Capital otherwise it wont be saved
}
...
user := userInfo{FavColor: "Green"}
bot.GetConfigRepository().SetWithStruct(<chatID>, user)
...
var user userInfo
bot.GetConfigRepository().GetWithStruct(<chatID>, &user)

Chat config repository can be accessed from session handlers.

Example project

Simple and clean example project can be found here. It provides command handling and session configuration.