WhatsApp event scraper

gistfile1.txt

// ==UserScript==
// @name         WhatsApp event scraper
// @namespace    http://tampermonkey.net/
// @version      2024-05-31
// @description  try to take over the world!
// @author       You
// @match        https://web.whatsapp.com/
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

// 23-27 July 2024
// 11 July to 25 August 2024(
// 20 May to 19 June
// 9-13 September
// 19 July to 14 August 2024
// 6-12 October 2024
// 17-21 September
//
// "Mohamed Eladly
// +20 114 558 3074
// 209 kB
// Open call for volunteers from European and non European countries to join one month summer volunteering project in Bulgaria  from 8 July - 8 August 2024 (fully funded)
//
//
// All details and how to apply are available on our website from the following link
// https://www.opportunit4u.com/2024/04/next-chapter-esc-teams-volunteering-in-bulgaria.html
//
// Best wishes
// 2:11 pm"

function scrape()
{
    let events = {};    // We use a dictionary because it means that events encountred multiple times will not be duplicated.

    // Divs that are probably chat bubbles
    let bubbles = Array.from(document.getElementsByTagName('div'))
        .filter(e => e.hasAttribute('data-pre-plain-text'));

    // Go through them
    for (let i = 0; i < bubbles.length; i++)
    {
        let div = bubbles[i];

        let url   = undefined;
        let start = new Date();
        let end   = new Date();

        // Find dates
        const names = ["jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec"];
        let matches = div.innerText.matchAll(/(\d\d?)(st|nd|rd|th)?\s?(Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|June?|July?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?)?\s?(-|to)?\s?(\d\d?)?(st|nd|rd|th)? (Jan(?:uary)?|Feb(?:ruary)?|Mar(?:ch)?|Apr(?:il)?|May|June?|July?|Aug(?:ust)?|Sep(?:tember)?|Oct(?:ober)?|Nov(?:ember)?|Dec(?:ember)?)/g);
        let match   = matches.next().value;

        if (!match) continue;

        // Parse dates
        start.setDate(parseInt(match[1]));
        end  .setDate(parseInt(match[5] ?? start.getDate() + 1));

        end  .setMonth(names.indexOf(match[7].toLowerCase().slice(0,3)))
        start.setMonth(match[3] ? names.indexOf(match[3].toLowerCase().slice(0,3)) : end.getMonth())

        // Parse link
        let link = (div.innerText.match(/https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)/g) ?? [])[0];

        events[link] = {start: start, end: end};
    }

    return events;
}

function toICSDate(d)
{
    let t = "";
    t += d.getUTCFullYear().toString();
    t += ("0" + d.getUTCMonth().toString()).slice(-2);
    t += ("0" + d.getUTCDate().toString()).slice(-2);
    t += "T000000Z";
    return t;
}

function makeICS(events)
{
    let text = (
        "BEGIN:VCALENDAR\n" +
        "VERSION:2.0\n" +
        "PRODID:-//hacksw/handcal//NONSGML v1.0//EN\n"
    );

    for (let [url, date] of Object.entries(events))
    {
        text += "BEGIN:VEVENT\n";
        text += `SUMMARY:${url.split('/').at(-1)}\n`;
        text += `URL:${url}\n`; // https://en.wikipedia.org/wiki/ICalendar
        text += `DTSTART:${toICSDate(date.start)}\n`;
        text += `DTEND:${toICSDate(date.end)}\n`;
        text += "END:VEVENT\n";
    }

    text += "END:VCALENDAR\n";
    return text;
}

// Create button
let b = document.createElement('button');
b.style.position="absolute";
b.style.right="20px";
b.style.top="50%";
b.style.zIndex=10000;

b.style.background="lightgreen";
b.style.padding="40px"

document.body.appendChild(b);

// Call scraper
document._scraped = scrape();

setInterval(() => {
    document._scraped = Object.assign({}, document._scraped, scrape());     // Merge newly scraped events with existing ones
    b.innerText = `Scrape ${Object.entries(document._scraped).length} events`;
}, 200);

b.onclick = () => {
    // https://stackoverflow.com/a/48968694/6130358

    let blob = new Blob([makeICS(document._scraped)]);

    const a = document.createElement('a');
    document.body.appendChild(a);
    const url = window.URL.createObjectURL(blob);
    a.href = url;
    a.download = 'events.ics';
    a.click();
    setTimeout(() => {
        window.URL.revokeObjectURL(url);
        document.body.removeChild(a);
    }, 0);
};

})();