Webtask bot sample

Readme.md

This is a sample Telegram Bot to showcase Webtask.

Hints included

• Main function promisification through Bluebird.try and asCallback.
• Query params and body access.
• Secrets (TG_TOKEN)
• Get the Webtask runner URL
• Basic Telegram Bot API usage

Setup

• Go to https://webtask.io/make and create a new Webtask Function
• Paste the code
• Use Botfather to get your Telegram Bot Token
• Add your token as TG_TOKEN secret on Webtask took icon
• PROFIT!

Warning

• Webtask uses Nodejs v4.8.5, so stay aware of some ES6 features

index.js

const Bluebird = require('bluebird@3.5.0')
const axios = require('axios@0.15.2')

const TG = (TG_TOKEN) => (path, options) => axios(Object.assign({}, {
  method: 'POST',
  url: `https://api.telegram.org/bot${TG_TOKEN}/${path}`,
  json: true
}, options))
.then(resp => {
   const data = resp.data
   console.log('Response from TG %j', data)
   return data
})

const setWebHook = (tg, url) => {
  return tg('setWebHook', {data: {url: url}})
}

const sendMessage = (tg, chat_id, text) => {
  return tg('sendMessage', {data: {chat_id: chat_id, text: text}})
}

const sendDocument = (tg, chat_id, document) => {
  return tg('sendDocument', {data: {chat_id: chat_id, document: document}})
}

const getOwnURL = (ctx) => {
  const wtParams = JSON.parse(Buffer.from(ctx.headers['x-wt-params'], 'base64').toString());
  const subdomain = wtParams.container
  const name = wtParams.jtn
  return `https://webtask.it.auth0.com/api/run/${subdomain}/${name}`
}

const randomPhrase = [
  'Sample text',
  'https://thecatapi.com/api/images/get'
]
const getRandomPhrase = () => {
  return randomPhrase[Math.floor(Math.random() * frasesRandom.length)];
}

// Promisified main function
const main = (ctx) => Bluebird.try(() => {
  const query = ctx.query
  const body = ctx.body
  console.log('Query %j', query)
  console.log('Body: %j', body)
  
  const tg = TG(ctx.secrets.TG_TOKEN)
  
  // If "activate" is provided in query strings, set the webhook
  if (query && query.activate) {
    const url = getOwnURL(ctx)
    console.log('Setting webHook %s', url)
    return setWebHook(tg, url)
  } else if (body.message) {
    // Message comming from Telegram
    const text = body.message.text
    const chatId = body.message.chat.id
    if (text === '/start') {
      const frase = getRandomPhrase()
      // If its a URL send it as file
      if (/^https?:/.test(frase)) {
        sendDocument(tg, chatId, frase)
      } else {
        sendMessage(tg, chatId, frase)
      }
    }
    // Answer the request without waiting TG
    return 'OK'
  } else {
    return 'WTF'
  }
})

module.exports = (ctx, cb) => main(ctx)
  .catch(err => {
    console.error('Error on webtask', err)
    const e = new Error('Error on request')
    e.stack = '' // Clean stack race
    throw e
  })
  .asCallback(cb)