index.js

var fs = require('fs');
var parse = require('url').parse;
var uid = require('uid2');
var express = require('express');
var phantomjs = require('phantom');

var app = express();
app.use(express.logger('dev'));

phantomjs.create(function(p) {
  app.get('/', function(req, res) {
    var url = req.query.url || 'http://www.yahoo.co.jp/';
    try {
      var parsed = parse(url);
    } catch (e) {
      return res.send(400, e);
    }
    p.createPage(function(page) {
      page.open(url, function(status) {
        var uniqid = parsed.hostname + '-' + uid(32) + '.pdf';
        page.render(uniqid, function() {
          var stream = fs.createReadStream(uniqid);
          stream.pipe(res);
        });
      });
    });
  });
});

app.listen(process.env.PORT || 3000);

package.json

{
  "name": "phantom-pdf",
  "version": "0.0.0",
  "dependencies": {
    "phantomjs": "~1.9.2-4",
    "express": "~3.4.4",
    "phantom": "~0.5.4",
    "uid2": "0.0.3"
  }
}