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How to make a bitcoin telegram bot in Golang

Tomas Sirio

Hey There!

So I’ve been having these 3 things in my head for a couple of months right now:

  • Golang: Because I wanted to learn a new Backend language
  • Telegram: Because f@!$ Whatsapp
  • Bitcoin: Because f@!$ The police printed money

So, I got an idea, and you will not be able to guess what it was.

That’s right, merging all 3 into a single project.

Table of Contents
  1. Bitcoin Telegram Bot
  2. Hands On
  3. Hosting It
  4. Usage
  5. Final Words

Bitcoin telegram bot

Since I’ve created a couple of bots for the last Hacktoberfest, I decided to create a simple telegram bot that could retrieve Bitcoin’s Price for the friends I could convince that Telegram was far superior to Whatsapp.

Hands on

Bot father

Telegram has a Bot of Botsa Bot-bot. In order to create a new Bot, we will need a TOKEN. So, let’s head to Telegram, start a conversation with @BotFather, and ask for a new Token:

image

You can also play a little bit more with @BotFather. For example, you can use the /setcommands to define the uses your bot has on the / icon:

/price - gets BTC actual price
/historic - gets a percentage between Today's and Yesterday's price
/summary - gets both the price and historic values

image

Bitcoin API

After getting the TOKEN, I needed Bitcoin’s price and, as far as I knew, I wasn’t going to hardcode it into a Bot or hot-swap its value manually. So, I looked for an API that could do that for me.

image

(We all look up things like this, don’t let the impostor syndrome tell you otherwise.)

I found this public API that didn’t need a user, token, or anything to consult BTC’s price.

With a simple CURL, we can get a JSON with the prices. So I decided to use this:

image

A little bit of code

If you read my previous posts, I’ve been researching and testing how GO modules work. I don’t like convoluted files that make things hard to find, so my folder structure looks like this:

image

Model

I began by writing a model for Bitex’s response:

package model

type Price struct {
	Last            float32 `json:"last"`
	PriceBeforeLast float32 `json:"price_before_last"`
	Open            float32 `json:"open"`
	High            float32 `json:"high"`
	Low             float32 `json:"low"`
	Vwap            float32 `json:"vwap"`
	Volume          float32 `json:"volume"`
	Bid             float32 `json:"bid"`
	Ask             float32 `json:"ask"`
}

I then utilized it on another module that was only intended for the API Call.

API Call

package utils

import (
	"encoding/json"
	"net/http"

	"github.com/tomassirio/bitcoinTelegram/model"
)

func GetApiCall() (*model.Price, error) {
	resp, err := http.Get("https://bitex.la/api-v1/rest/btc_usd/market/ticker")
	p := &model.Price{}

	if err != nil {
		return p, err
	}

	err = json.NewDecoder(resp.Body).Decode(p)
	return p, err
}

Lovely, GO handles the REST requests like a boss.

Handler

The handler is a bit sloppy written. I’ve been using JavaScript, which I’m definitely not too keen on, to create Discord Bots. So, I tried to emulate my previous handlers in GO – we have this now:

package handler

import (
	"github.com/tomassirio/bitcoinTelegram/commands"
	tb "gopkg.in/tucnak/telebot.v2"
)

func LoadHandler(b *tb.Bot) map[string]func(m *tb.Message) {
	commandMap := make(map[string]func(m *tb.Message))

	commandMap["/price"] = func(m *tb.Message) {
		res, _ := commands.GetPrice()
		b.Send(m.Chat, "BTC's Current price is: U$S "+res)
	}

	commandMap["/historic"] = func(m *tb.Message) {
		res, g, _ := commands.GetHistoric()
		b.Send(m.Chat, "BTC's Price compared to yesterday is: "+res)
		b.Send(m.Chat, g)
	}

	commandMap["/summary"] = func(m *tb.Message) {
		p, h, _ := commands.GetSummary()
		b.Send(m.Chat, "BTC's Current price is: U$S "+p+"\nBTC's Price compared to yesterday is: "+h)
	}

	return commandMap
}

What’s most remarkable about this handler is that it’s basically a Map from String to a function. This will make sense once we get to the main function.

Commands

I only created three commands for this bot as it wasn’t a deep project (it was mostly just for fun). So, please bear with the simplicity of them for now:

func GetPrice() (string, error) {
	p, err := utils.GetApiCall()
	return fmt.Sprintf("%.2f", p.Last), err
}

func GetHistoric() (string, *tb.Animation, error) {
	p, err := utils.GetApiCall()
	l := p.Last
	o := p.Open
	his := ((l - o) / o) * 100
	if !math.Signbit(float64(his)) {
		g := &tb.Animation{File: tb.FromURL("https://i.pinimg.com/originals/e4/38/99/e4389936b099672128c54d25c4560695.gif")}
		return "%" + fmt.Sprintf("%.2f", ((l-o)/o)*100), g, err
	} else {
		g := &tb.Animation{File: tb.FromURL("http://www.brainlesstales.com/bitcoin-assets/images/fan-versions/2015-01-osEroUI.gif")}
		return "-%" + fmt.Sprintf("%.2f", -1*((l-o)/o)*100), g, err
	}
}

func GetSummary() (string, string, error) {
	p, err := utils.GetApiCall()
	l := p.Last
	o := p.Open
	his := ((l - o) / o) * 100
	if !math.Signbit(float64(his)) {
		return fmt.Sprintf("%.2f", p.Last), "%" + fmt.Sprintf("%.2f", ((l-o)/o)*100), err
	} else {
		return fmt.Sprintf("%.2f", p.Last), "-%" + fmt.Sprintf("%.2f", -1*((l-o)/o)*100), err
	}
}

Telegram Config

'Member that Token we got from @BotFather? Oooh, I 'member. Of course, there’s another module for that. How do you think we could find these things if there were no structure?

type Config struct {
	Token string
}

func LoadConfig() *Config {
	// load .env file from given path
	// we keep it empty it will load .env from current directory
	err := godotenv.Load(".env")

	if err != nil {
		log.Fatalf("Error loading .env file")
	}

	return &Config{Token: os.Getenv("TOKEN")}
}

I’m not going to copy the contents of the .env file, but I will show you the .env.example:

TOKEN=REPLACE_WITH_TOKEN

I really hope you weren’t expecting anything else.

The main file

Our Bot is almost built, now we have to tell Go, “Dude, we need this up and running:”

func main() {

	b, err := tb.NewBot(tb.Settings{
		// You can also set custom API URL.
		// If field is empty it equals to "https://api.telegram.org".
		Token:  config.LoadConfig().Token,
		Poller: &tb.LongPoller{Timeout: 10 * time.Second},
	})

	if err != nil {
		log.Fatal(err)
		return
	}

	for k, v := range handler.LoadHandler(b) {
		b.Handle(k, v)
		log.Println(k + "✅ Loaded!")
	}

	b.Start()

}

So, basically, the program basically the TOKEN from the Config module, checks that there are no errors, and (here comes my favorite part) we cycle through the command map on the Handler module in order to load every single command onto the Bot.

Let’s look at it again since it was so satisfying:

image

Hosting it

I used my Raspberry 4 to host this bot (as well as the others), but you can use Heroku, AWS, Gcloud, or just an old computer that you’re not using right now.

To host it you will need:

  • A computer, service, or server where you can host the bot
  • Git
  • Golang v1.13
  • A device with Telegram (to use it)

First, open a Terminal and copy these commands (Linux & Mac devices):

cd ~
git clone https://github.com/tomassirio/BitcoinTelegramBot.git
cd ./BitcoinTelegramBot
mv .env.example .env
go get github.com/tomassirio/bitcoinTelegram
go run main.go

Warning: This won’t work unless you replace REPLACE_WITH_TOKEN on the .env file with the Token granted by @BotFather

Usage

Now, head over to Telegram and look for the Bot you created on @BotFather. Then, use any of the 3 commands that were configured:

    * /price : Get's bitcoin's Last price
    * /historic : Gets a percentage between Today's and Yesterday's price
    * /summary : Gets both the price and historic values

image

You can also can this bot to your favorite group (or any group whatsoever) by tapping on the chat’s options, and the Add to Group Button:

https://i.imgur.com/4Qs7ejo.png

Final words

I really hope you enjoyed reading this post as much as I did writing it. I don’t consider myself a good developer, but that’s exactly why I’m writing these posts. You don’t need to be an expert in order to share your experiences with other people.

If you want to check out the repository, you can do so by going to the following link.

You can:

  • Fork it and do your own version of it.
  • Tweak it and create a pull request to merge it to the original version.
  • Do whatever you want with it because it’s open-source.
  • If you want to leave a Star on it, I’ll be really grateful since it will help me in my professional career.
  • If you want to buy me a beer, the link is in the footer of the repository.

As always, happy coding!

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