Puppeteer to download Confluence PDF export

confluence-to-pdf.js

// PDF download hack taken from https://github.com/GoogleChrome/puppeteer/issues/610#issuecomment-340160025
const puppeteer = require("puppeteer");
const fs = require("fs");

(async () => {
  const browser = await puppeteer.launch({ headless: true });
  const page = await browser.newPage();
  await page.goto(
    "https://synopsys.atlassian.net/wiki/spaces/INTDOCS/pages/622678/Running+Black+Duck+Detect+with+Bamboo"
  );
  // await page.pdf({ path: "simple.pdf" });
  await page.click("#action-menu-link");
  await page.click("#action-export-pdf-link");
  await page.waitForSelector("#taskGreenBar[width='100%']");
  await page.exposeFunction("writeABString", async strbuf => {
    const str2ab = function _str2ab(str) {
      // Convert a UTF-8 String to an ArrayBuffer

      let buf = new ArrayBuffer(str.length); // 1 byte for each char
      let bufView = new Uint8Array(buf);

      for (let i = 0, strLen = str.length; i < strLen; i++) {
        bufView[i] = str.charCodeAt(i);
      }
      return buf;
    };

    return new Promise((resolve, reject) => {
      // Convert the ArrayBuffer string back to an ArrayBufffer, which in turn is converted to a Buffer
      let buf = Buffer.from(str2ab(strbuf));

      // Try saving the file.
      fs.writeFile("confluence.pdf", buf, (err, text) => {
        if (err) reject(err);
        else resolve();
      });
    });
  });

  await page.evaluate(async () => {
    function arrayBufferToString(buffer) {
      // Convert an ArrayBuffer to an UTF-8 String

      let bufView = new Uint8Array(buffer);
      let length = bufView.length;
      let result = "";
      let addition = Math.pow(2, 8) - 1;

      for (let i = 0; i < length; i += addition) {
        if (i + addition > length) {
          addition = length - i;
        }
        result += String.fromCharCode.apply(
          null,
          bufView.subarray(i, i + addition)
        );
      }
      return result;
    }

    let pdfURL = document.querySelector("#taskCurrentStatus a").href;

    return fetch(pdfURL, {
      credentials: "same-origin", // usefull when we are logged into a website and want to send cookies
      responseType: "arraybuffer" // get response as an ArrayBuffer
    })
      .then(response => response.arrayBuffer())
      .then(arrayBuffer => {
        let bufstring = arrayBufferToString(arrayBuffer);
        return window.writeABString(bufstring);
      })
      .catch(error => {
        console.log("Request failed: ", error);
      });
  });

  await browser.close();
})();