README.md

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+Download a McGraw Hill Education eTextbook
+---
+If you purchase a textbook from McGraw Hill, the website to view it is clunky and only works on some devices.
+You can't go to specific page numbers, the search is super slow, etc.
+That's why I wrote this script to download the textbook as an ePub file for your own viewing.
+Using this script is 100% legal. McGraw Hill publicly hosts their ebooks online in order for their web client to,
+download it. Moreover, to use it, you must already have purchased the book you would like to download, so it is
+legally yours to use as you please. **However, it IS illegal to use this for piracy purposes.DO NOT DISTRIBUTE
+ANY TEXTBOOKS YOU DOWNLOAD USING THIS SCRIPT.**
+
+## Instructions
+1. Open your textbook in the McGraw-Hill Connect website (how you normally open it)
+2. 

source.js

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+import('https://cdnjs.cloudflare.com/ajax/libs/jszip/3.2.2/jszip.min.js').then(async () => {
+  alert('This is the McGraw-Hill Education Textbook Downloader. Click OK to start downloading the files.');
+  const IMPORT_URL = (await (await fetch('https://player-api.mheducation.com/lti', { credentials: 'include' })).json()).custom_epub_url;
+  const epub = new JSZip();
+  const metaInf = epub.folder('META-INF');
+  metaInf.file('container.xml', await (await fetch(IMPORT_URL + 'META-INF/container.xml', { credentials: 'include' })).text());
+  const epubData = epub.folder('OPS');
+  const opfString = await (await fetch(IMPORT_URL + 'OPS/content.opf', { credentials: 'include' })).text();
+  epubData.file('content.opf', opfString);
+  const opf = new DOMParser().parseFromString(opfString, 'application/xml');
+  for (let item of opf.querySelector('manifest').children) {
+    const href = item.getAttribute('href');
+    try {
+      const data = await (await fetch(`${IMPORT_URL}OPS/${href}`, { credentials: 'include' })).arrayBuffer();
+      epubData.file(href, data);
+      console.log('Finished downloading', href);
+     } catch(e) {
+       throw `Failed to download ${href}: ${e}`;
+     }
+  }
+  alert('Finished downloading data! Click OK to start compression.');
+  window.__savedTextbook = epub;
+  let highestPercent = 0;
+  const data = await epub.generateInternalStream({ type: 'blob' }).accumulate(({ percent }) => {
+    const intPercent = Math.floor(percent);
+    if (intPercent > highestPercent) {
+      console.log(intPercent+'% complete');
+      highestPercent = intPercent
+    }
+  });
+  alert('Finished compressing textbook! Click OK to start download.');
+  window.__savedTextbookEpub = data;
+  const url = URL.createObjectURL(data);
+  const tmpLink = document.createElement('a');
+  tmpLink.href = url;
+  const possibleTitle = opf.querySelector('metadata title');
+  const titleString = possibleTitle ? possibleTitle.innerHTML : 'textbook';
+  tmpLink.download = titleString + '.epub';
+  tmpLink.click();
+  URL.revokeObjectURL(url);
+}).catch(err => alert('Textbook download failed because an error occurred: '+err));