WIP: Telegram Passport support

[tjhorner]

Description

This pull request is a work in progress. Still needed:

• Unit tests
• getPassportFile method for retrieving + decrypting Passport files all at once

This pull request adds support for Telegram Passport and decryption of Telegram Passport data with the telegram-passport package.

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

A simple way to test this change would be:

const Telegraf = require('./telegraf.js')

const bot = new Telegraf("BOT_TOKEN", {
  privateKey: "BOT_PRIVATE_KEY_IN_PEM_FORMAT"
})

bot.on("passport_data", ctx => {
  console.log(ctx.decryptPassportData()) // will print the decrypted Passport data
})

bot.startPolling()

Test Configuration:

• Node.js Version: v8.4.0
• Operating System: Windows 10 Home / Ubuntu 16.04

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[dotcypress]

Looks good to me!

[tjhorner]

Do we want something that automatically fetches and then decrypts Passport-related files, maybe an extension to getFile. getPassportFile?

[dotcypress]

Yes, I think getPassportFile will be useful in some cases! 👍

[Piterden]

Btw guys, it's not fully related, but could be interesting for you sergeysova/telegram-typings#23

[lifehome]

Will there be chances this issue get resolved in 2019? :wonder:

[tjhorner]

@lifehome the only thing blocking this PR from being merged is tests. Unfortunately, I don't have the time to write them myself, but if someone else wants to contribute I would be glad to accept a PR into my own branch!

[dotcypress]

@tjhorner thank you a lot for telegram-passport library and this PR 👍🔥.
I decided to use delegation pattern with passport feature instead of adding new dependency:

const Telegraf = require('telegraf')
const TelegramPassport = require('telegram-passport')

const bot = new Telegraf(process.env.BOT_TOKEN)
const passport = new TelegramPassport("PRIVATE_KEY_IN_PEM_FORMAT")

bot.on('passport_data', (ctx) => {
  const decryptedPasswordData = passport.decrypt(ctx.passportData)
  console.log(decryptedPasswordData)
  return ctx.setPassportDataErrors([
    { source: 'selfie', type: 'driver_license', file_hash: 'file-hash', message: 'Selfie photo is too low quality'}
  ])
})

New version will be published shortly.