// ==UserScript== // @name Google Scholar to free PDF // @namespace ScholarToSciHub // @version 1.4 // @description Adds Sci-Hub, LibGen, LibSTC and Anna's Archive buttons to Google Scholar results // @author Bui Quoc Dung // @include https://scholar.google.*/* // @license AGPL-3.0-or-later // @grant GM_xmlhttpRequest // @downloadURL none // ==/UserScript== const SCIHUB_URL = 'https://www.tesble.com/'; const LIBGEN_URL = 'https://libgen.li/index.php?req='; const LIBSTC_BASE_URL = 'https://hub.libstc.cc/'; const ANNA_URL = 'https://annas-archive.org/scidb/'; const ANNA_CHECK_URL = 'https://annas-archive.org/search?index=journals&q='; const DOI_REGEX = /\b(10\.\d{4,}(?:\.\d+)*\/(?:(?!["&'<>])\S)+)\b/gi; function addLink(textContent, href, buttonContainer) { const link = document.createElement('a'); link.textContent = textContent; link.href = href; link.target = '_blank'; buttonContainer.appendChild(link); return link; } function extractYear(element) { const yearMatch = element.textContent.match(/\d{4}/); return yearMatch ? parseInt(yearMatch[0]) : 0; } function checkLibGenPDF(title, buttonContainer) { GM_xmlhttpRequest({ method: 'GET', url: LIBGEN_URL + encodeURIComponent(title), onload: function(response) { const parser = new DOMParser(); const doc = parser.parseFromString(response.responseText, 'text/html'); const hasTable = doc.querySelector('.table.table-striped') !== null; addLink(hasTable ? '[PDF] LibGen' : '[No] LibGen', LIBGEN_URL + encodeURIComponent(title), buttonContainer); }, onerror: function(error) { console.error('Error checking LibGen:', error); addLink('[No] LibGen', LIBGEN_URL + encodeURIComponent(title), buttonContainer); } }); } function checkSciHubPDF(url, buttonContainer) { GM_xmlhttpRequest({ method: 'GET', url: SCIHUB_URL + url, onload: function(response) { const hasPDF = /iframe|pdf|embed/.test(response.responseText); addLink(hasPDF ? '[PDF] Sci-Hub' : '[No] Sci-Hub', SCIHUB_URL + url, buttonContainer); }, onerror: function(error) { console.error('Error checking Sci-Hub:', error); addLink('[No] Sci-Hub', SCIHUB_URL + url, buttonContainer); } }); } function checkAnnaPDF(doi, buttonContainer) { const checkUrl = ANNA_CHECK_URL + encodeURIComponent(doi); GM_xmlhttpRequest({ method: 'GET', url: checkUrl, onload: function(response) { const parser = new DOMParser(); const doc = parser.parseFromString(response.responseText, 'text/html'); // Check for the new class combination const hasPDF = doc.querySelector('.mt-4.uppercase.text-xs.text-gray-500') !== null; addLink( hasPDF ? '[PDF] Anna' : '[No] Anna', ANNA_URL + doi, buttonContainer ); }, onerror: function(error) { console.error('Error checking Anna’s Archive:', error); addLink('[No] Anna', ANNA_URL + doi, buttonContainer); } }); } function checkLibSTCPDF(firstDOI, buttonContainer) { const pdfURL = LIBSTC_BASE_URL + firstDOI + '.pdf'; GM_xmlhttpRequest({ method: 'HEAD', url: pdfURL, onload: function(response) { const isPDF = response.status === 200 && response.responseHeaders.toLowerCase().includes('application/pdf'); addLink(isPDF ? '[PDF] LibSTC' : '[No] LibSTC', pdfURL, buttonContainer); }, onerror: function() { addLink('[No] LibSTC', pdfURL, buttonContainer); } }); } function fetchDOI(titleLink, callback) { GM_xmlhttpRequest({ method: 'GET', url: titleLink.href, onload: function(response) { const matches = response.responseText.match(DOI_REGEX); matches && matches.length ? callback(matches[0]) : callback(null); }, onerror: function(error) { console.error('Error fetching DOI:', error); callback(null); } }); } function addButtons() { document.querySelectorAll('#gs_res_ccl_mid .gs_r.gs_or.gs_scl').forEach(result => { const titleLink = result.querySelector('.gs_rt a'); const yearElement = result.querySelector('.gs_a'); if (!titleLink || !yearElement) return; let buttonContainer = result.querySelector('.gs_or_ggsm'); if (!buttonContainer) { const div = document.createElement('div'); div.className = 'gs_ggs gs_fl'; div.innerHTML = '
'; result.insertBefore(div, result.firstChild); buttonContainer = div.querySelector('.gs_or_ggsm'); // Add basic links checkSciHubPDF(titleLink.href, buttonContainer); checkLibGenPDF(titleLink.textContent, buttonContainer); // DOI-based links fetchDOI(titleLink, (doi) => { if (doi) { // Always add Anna's Archive checkAnnaPDF(doi, buttonContainer); // Add LibSTC only for recent papers if (extractYear(yearElement) > 2020) { checkLibSTCPDF(doi, buttonContainer); } } }); } }); } // Initial setup and mutation observer addButtons(); new MutationObserver((mutations) => { mutations.forEach((mutation) => mutation.addedNodes.length && addButtons()); }).observe(document.body, {childList: true, subtree: true});