Having trouble running Phantomjs + node on Heroku

Question

I've successfully got Phantomjs to work on Heroku but now I'm hitting issues with the phantomjs-node interface for node.js (see https://github.com/sgentle/phantomjs-node).

When I'm attempting to initialize Phantom I'm seeing a 10-15 second delay and then:

> phantom stdout: ReferenceError: Can't find variable: socket

phantom stdout:   phantomjs://webpage.evaluate():1
  phantomjs://webpage.evaluate():1
  phantomjs://webpage.evaluate():1

You can reproduce the problem with the following steps or by pulling down my test app at https://github.com/matellis/phantom-test

git init phantom-test
cd phantom-test
heroku apps:create
# create node app as per Heroku instructions here https://devcenter.heroku.com/articles/nodejs
# copy bin and lib folders from http://phantomjs.googlecode.com/files/phantomjs-1.6.1-linux-x86_64-dynamic.tar.bz2 into root of your new project
# if you don't do this step you'll get an error "phantom stderr: execvp(): No such file or directory"
git add .
git commit -m "init"
git push heroku

Test your app has come up, the third to last line will tell you the URL, it should read like:

http://fathomless-ravine-5563.herokuapp.com deployed to Heroku

If successful you should see Hello World! in your browser.

Now from the same folder as your Heroku application run:

heroku run node

At the node prompt try the following:

phantom = require('phantom');
x = phantom.create();

Wait 10-15 seconds and you should see the error. Nothing works from this point on.

This should output file foo.png:

x = phantom.create(function(ph){ph.createPage(function(page){ page.open('http://bbcnews.com', function(status){ page.render('foo.png', function(result) {ph.exit()}); }); }); });

To validate Phantomjs is working fine on Heroku, try the following using my test project:

>heroku run bash
Running `bash` attached to terminal... up, run.1
~ $ phantomjs test.js http://bbcnews.com foo.png
~ $ ls *.png
foo.png

I cannot reproduce any of these problems locally but there are other issues reported where folks may have hit this issue locally.

The problem seems to originate in shim.js line 1637:

s.on('request', function(req) {
  var evil;
  evil = "function(){socket.emit('message', " + (JSON.stringify(JSON.stringify(req))) + " + '\\n');}";
  return controlPage.evaluate(evil);
});

I've tried variations of versions of node, phantom, etc. with no luck.

I've also tried a custom buildpack that sets the DYLD variable, see http://github.com/tecnh/heroku-buildpack-nodejs with no luck either.

Anyone who has got Phantom + Node playing together nicely on Heroku please let me know. There are several references to this on Stackoverflow but nobody is saying "I got it to work, here's how".

Answer 1

I've never used the phantomjs node module, but I do have an app running both node and phantomjs on Heroku.

You need to use custom buildpacks in order to get this to work. My .buildpacks file looks like

http://github.com/heroku/heroku-buildpack-nodejs.git
http://github.com/stomita/heroku-buildpack-phantomjs.git

You should then be able to run phantomjs scripts in a child process:

var script = app.get('root') + '/scripts/rasterize.js' //the phantomjs script to run
  , bin = app.get('phantom') //normally this would just be the string "phantomjs"
  , spawn = require('child_process').spawn;

// set up args to the phantom cli
// (run the phantomjs command in your terminal to see options/format)
var args = [];
// ...

var phntm = spawn(bin, args);

phntm.stdout.on('data', function (data) { /* do something */ });
phntm.stderr.on('data', function (data) { /* do something */ });
phntm.on('exit', function (code) { /* handle exit */ });