pdf.js

var spawn = require('child_process').spawn;
var fs = require('fs');
var path = require('path');
var os = require('os');
var request = require('request');

function waitForJavaScript() {
  if(window.MathJax) {
    // Amazon EC2: fix TeX font detection
    MathJax.Hub.Register.StartupHook("HTML-CSS Jax Startup",function () {
      var HTMLCSS = MathJax.OutputJax["HTML-CSS"];
      HTMLCSS.Font.checkWebFont = function (check,font,callback) {
        if (check.time(callback)) {
          return;
        }
        if (check.total === 0) {
          HTMLCSS.Font.testFont(font);
          setTimeout(check,200);
        } else {
          callback(check.STATUS.OK);
        }
      };
    });
    MathJax.Hub.Queue(function () {
      window.status = 'done';
    });
  }
  else {
    setTimeout(function() {
      window.status = 'done';
    }, 2000);
  }
}

var authorizedPageSizes = [
  'A3',
  'A4',
  'Legal',
  'Letter'
];

exports.export = function(req, res, next) {
  function onError(err) {
    next(err);
  }
  function onUnknownError() {
    res.statusCode = 400;
    res.end('Unknown error');
  }
  function onUnauthorizedError() {
    res.statusCode = 401;
    res.end('Unauthorized');
  }
  function onTimeout() {
    res.statusCode = 408;
    res.end('Request timeout');
  }
  request({
    uri: 'https://monetizejs.com/api/payments',
    qs: {
      access_token: req.query.token
    },
    json: true
  }, function (err, paymentsRes, payments) {
    var authorized = payments && payments.app == 'ESTHdCYOi18iLhhO' && (
      (payments.chargeOption && payments.chargeOption.alias == 'once') ||
      (payments.subscriptionOption && payments.subscriptionOption.alias == 'yearly'));
    if(err || paymentsRes.statusCode != 200 || !authorized) {
      return onUnauthorizedError();
    }
    var options, params = [];
    try {
      options = JSON.parse(req.query.options);
    }
    catch(e) {
      options = {};
    }

    // Margins
    var marginTop = parseInt(options.marginTop);
    params.push('-T', isNaN(marginTop) ? 25 : marginTop);
    var marginRight = parseInt(options.marginRight);
    params.push('-R', isNaN(marginRight) ? 25 : marginRight);
    var marginBottom = parseInt(options.marginBottom);
    params.push('-B', isNaN(marginBottom) ? 25 : marginBottom);
    var marginLeft = parseInt(options.marginLeft);
    params.push('-L', isNaN(marginLeft) ? 25 : marginLeft);

    // Header
    options.headerCenter && params.push('--header-center', options.headerCenter);
    options.headerLeft && params.push('--header-left', options.headerLeft);
    options.headerRight && params.push('--header-left', options.headerRight);
    options.headerFontName && params.push('--header-font-name ', options.headerFontName);
    options.headerFontSize && params.push('--header-font-size ', options.headerFontSize);

    // Footer
    options.footerCenter && params.push('--footer-center', options.footerCenter);
    options.footerLeft && params.push('--footer-left', options.footerLeft);
    options.footerRight && params.push('--footer-left', options.footerRight);
    options.footerFontName && params.push('--footer-font-name ', options.footerFontName);
    options.footerFontSize && params.push('--footer-font-size ', options.footerFontSize);

    // Page size
    params.push('--page-size', authorizedPageSizes.indexOf(options.pageSize) === -1 ? 'A4' : options.pageSize);

    // Use a temp file as wkhtmltopdf can't access /dev/stdout on Amazon EC2 for some reason
    var filePath = path.join(os.tmpDir(), Date.now() + '.pdf');
    var binPath = process.env.WKHTMLTOPDF_PATH || 'wkhtmltopdf';
    params.push('--run-script', waitForJavaScript.toString() + 'waitForJavaScript()');
    params.push('--window-status', 'done');
    var wkhtmltopdf = spawn(binPath, params.concat('-', filePath), {
      stdio: [
        'pipe',
        'ignore',
        'ignore'
      ]
    });
    var timeoutId = setTimeout(function() {
      timeoutId = undefined;
      wkhtmltopdf.kill();
    }, 30000);
    wkhtmltopdf.on('error', onError);
    wkhtmltopdf.stdin.on('error', onError);
    wkhtmltopdf.on('close', function(code) {
      if(!timeoutId) {
        return onTimeout();
      }
      clearTimeout(timeoutId);
      if(code) {
        return onUnknownError();
      }
      var readStream = fs.createReadStream(filePath);
      readStream.on('open', function() {
        readStream.pipe(res);
      });
      readStream.on('close', function() {
        fs.unlink(filePath, function() {
        });
      });
      readStream.on('error', onUnknownError);
    });
    req.pipe(wkhtmltopdf.stdin);
  });
};