bandcamp-download-from-release-page.user.js

// ==UserScript==
// @name         bandcamp-download-from-release-page
// @version      1.0.0
// @description  turns the "You own this" BC link into an actually useful download link
// @author       jammy
// @match        https://*.bandcamp.com/*
// @grant        none
// ==/UserScript==

(function () {
  'use strict';

  const ownsProduct = document.querySelector('.you-own-this-link')
  if (ownsProduct) {
    const dataObject = document.querySelector('[data-tralbum-collect-info*="fan_id"]');
    const userData = dataObject?.dataset?.tralbumCollectInfo;
    const albumData = dataObject?.dataset?.tralbum;

    if (!userData) return;
    const uid = JSON.parse(userData)?.fan_id;
    const albumId = JSON.parse(albumData)?.id;
    const releaseName = document.querySelector('h2.trackTitle').innerText.trim();
    fetch('/api/fancollection/1/search_items', {
      method: 'POST',
      body: JSON.stringify({
        fan_id: uid,
        search_key: releaseName,
        search_type: 'collection'
      })
    }).then(a => a.json()).then(res => {
      const release = res.tralbums.find(a => a.item_id === albumId || a.album_id === albumId)
      if (!release) return;
      const dlUrl = res?.redownload_urls?.[release.sale_item_type + release.sale_item_id];
      if (!dlUrl) return;
      const dlBtn = document.createElement('a')
      dlBtn.innerText = '☁️ Download'
      dlBtn.style.fontSize = '16px';
      dlBtn.href = dlUrl;
      const useless = document.querySelector('h3.you-own-this');
      useless.innerHTML = '';
      useless.appendChild(dlBtn);
    })
  }
})();