jcfergus/phantom-workers

Run phantom script in managed workers

#phantom-workers

Run phantom scripts in multiple managed reusable workers

Running a script in phantom can soon become performance bottleneck when it comes to scale. Starting phantomjs process is not a cheap operation and you cannot start hundred of them at once. This package provides solution using phantomjs webserver and multiple phantomjs processes running in parallel.

##First create a phantomjs script wrapped in webserver

//every worker gets unique port, get it from a process environment variables
var system = require("system");
var port = system.env['PHANTOM_WORKER_PORT'];
var host = system.env['PHANTOM_WORKER_HOST'];

require('webserver').create().listen(host + ':' + port, function (req, res) {
	//standard phantomjs script which get input parametrs from request
	var page = require('webpage').create();
	page.open(JSON.parse(req.post).url, function(status) {
    var title = page.evaluate(function() {
	    return document.title;
	});

	//write the result to the response
	res.statusCode = 200;
    res.write({ title: title });
    res.close();
});

##Start phantomjs workers

var phantom = require("phantom-workers")({
	pathToPhantomScript: "script.js",
	timeout: 5000,
	numberOfWorkers: 10
});

phantom.start(function() {
	phantom.execute({ url: "http://jsreport.net" }, function(err, res) {
		console.log(res.title);
	});
});

##Options

pathToPhantomScript (required) - absolute path to the phantom script
timeout - execution timeout in ms
numberOfWorkers - number of phantomjs instances
host - ip or hostname where to start listening phantomjs web service, default 127.0.0.1
portLeftBoundary - don't specify if you just want to take any random free port
portRightBoundary - don't specify if you just want to take any random free port
hostEnvVarName - customize the name of the environment variable passed to the phantom script that specifies the worker host. defaults to PHANTOM_WORKER_HOST
portEnvVarName - customize the name of the environment variable passed to the phantom script that specifies the worker port. defaults to PHANTOM_WORKER_PORT
phantomPath - path to the phantomjs library. If not specified, this will use the version of phantom declared in the optionalDependencies in package.json

##License See license