index.js

const Koa = require("koa");
const puppeteer = require("puppeteer");
const chalk = require("chalk");
const qs = require("koa-qs");
const dotenv = require('dotenv').config();

/**
 * Launches Puppeteer.
 * We found this hinting mode to be the most reliable
 * when working with client fonts.
 */
async function boot() {
  const browser = await puppeteer.launch({
    args: [
      "--no-proxy-server",
      "--no-sandbox",
      "--font-render-hinting=none"],
    pipe: true
  });
  return browser;
}

/**
 * Returns a simple Koa instance, with koa-qs injected.
 * On the app instance lies our puppeteer instance.
 */
async function launch() {
  const app = new Koa();
  qs(app, "first");
  app.context.chrome = await boot();
  return app;
}

/**
 * Helpers to reject, return a successful PDF, an auth failure.
 */
const reject = (response, message) => {
  response.type = 'text/plain';
  response.body = message;
  response.status = 400;
};

const printed = (response, pdf) => {
  response.type = 'application/pdf';
  response.body = pdf;
  response.status = 201;
}

const rendered = (response, htmlOutput) => {
  response.type = 'text/html';
  response.body = htmlOutput;
  response.status = 200;
}

const unauthorized = (response, message) => {
  response.type = 'text/plain';
  response.body = message;
  response.status = 401;
}

/**
 * Docs.
 */
const doc = `
 Our only route.
 Accepts a GET request with the form
 http(s?)://service-url?
 url={url:base64 string} the URL to render, as a base64 string.
 &format={format:string} a paper format. Defaults to "A4".
 &range={range:range} the page range to print. Defaults to printing only the first page.
 &orientation={orientation:string} either "portrait" or "landscape", defaults to being portrait.
 &width={width::dimension+unit} dimensions with units. Is overriden by the "format" parameter.
 &height={height:dimension+unit} dimensions with units. Is overriden by the "format" parameter.
 &background={background:bool-like} bool-like : pass 0 or 1 as a string, defaults to true
 &token={token:string?} optional : if you'd like to compare against a PRINTSERVER_TOKEN env var.
 `;

launch().then((app) => {
  app.use(async ({ request, response }) => {
    if (process.env.PRINTSERVER_TOKEN) {
      if (!request.query.token || request.query.token !== process.env.PRINTSERVER_TOKEN) {
        return unauthorized(response, `Unauthorized.`);
      }
    }
    if (!request.query.url) {
      return reject(response, `Bad request, \n ${doc}`);
    }
    let outputMode = 'pdf';
    if (request.query.output) {
      outputMode = request.query.output === 'pdf' ? 'pdf' : 'html';
    }

    const page = await app.context.chrome.newPage();
    const u = Buffer.from(request.query.url, "base64").toString("binary");
    await page.setViewport({ width: 1440, height: 900 });

    // Wait until all network activity is idle.
    // This should be changed if you expect ads or do not control the target page.
    await page.goto(u, { waitUntil: 'networkidle0' });
    console.log('networkIdle');
    if (outputMode === 'pdf') {
      let params = {
        format: "A4",
        landscape: false,
        printBackground: true,
        pageRanges: "1"
      };

      if (request.query.format) {
        params.format = request.query.format;
      } else {
        params.width = request.query.width;
        params.height = request.query.height;
      }

      if (request.query.range) {
        params.pageRanges = request.query.range;
      }

      params.landscape = request.query.orientation && request.query.orientation === 'landscape';
      params.printBackground = request.query.background && !!parseInt(request.query.background, 10);
      return printed(response, await page.pdf(params))
    } else {
      const html = await page.content();
      return rendered(response, html);
    }
  });

  const port = process.env.PRINTSERVER_PORT || 3468;
  app.listen(port);
  console.log(`Listening on port ${port}`);
});