grammY validator

---

What is this

This package solves two problems at once:

• Validating data received via Web Apps for a Telegram Bot
• Checking authorization data for Telegram Login Widget

How to use

Deno: import from this URL: https://deno.land/x/grammy_validator/mod.ts

Node.js: npm install @grammyjs/validator

Web Bots: Validation

Web Bots can get access to window.Telegram.WebApp.initData which must be sent to the server for validation. The string value of initData is a query string that you can simply append to a URL to fetch. Example:

const url = "https://grammy.dev?" + window.Telegram.WebApp.initData;
await fetch(url);

This library helps you validate the resulting search query in the backend.

import { validateWebAppData } from "./src/mod.ts";

const token = ""; // <-- put your bot token here
const url = ctx.request.url; // get `URL` object from your web framework

if (validateWebAppData(token, url.searchParams)) { // pass `URLSearchParams` object
    // data is from Telegram
}

Login Widget: Authorization

You can also check the signature if you are using a Telegram Login Widget.

import { checkSignature } from "./src/mod.ts";

const token = ""; // <-- put your bot token here

const payload = {
    id: "424242424242",
    first_name: "John",
    last_name: "Doe",
    username: "username",
    photo_url: "https://t.me/i/userpic/320/username.jpg",
    auth_date: "1519400000",
    hash: "87e5a7e644d0ee362334d92bc8ecc981ca11ffc11eca809505",
};

if (checkSignature(token, payload)) {
    // data is from Telegram
}