Phantomjs interprocess communication

Question

I am trying to implement a solution where by using PhantomJS a web location is open evaluated and the output is saved to a file for processing. Specifically the scanning for malicious scripts. I have been able to implement the solution using PhantomJS running once. For example this works perfectly...

var system = require('system');
var page = require('webpage').create();
var lastReceived = new Date().getTime();
var requestCount = 0;
var responseCount = 0;
var requestIds = [];
var fileSystem = require('fs');
var startTime = new Date().getTime();

page.onResourceReceived = function (response) {
    if(requestIds.indexOf(response.id) !== -1) {
        lastReceived = new Date().getTime();
        responseCount++;
        requestIds[requestIds.indexOf(response.id)] = null;
    }
};
page.onResourceRequested = function (request) {
    if(requestIds.indexOf(request.id) === -1) {
        requestIds.push(request.id);
        requestCount++;
    }
};

page.open('http://adserver.example.com/adserve/;ID=164857;size=300x250;setID=162909;type=iframe', function () {});

var checkComplete = function () {
    // We don't allow it to take longer than 5 seconds but
    // don't return until all requests are finished
    if((new Date().getTime() - lastReceived > 300 && requestCount === responseCount) || new Date().getTime() - startTime > 5000)  {
        clearInterval(checkCompleteInterval);
        console.log(page.content);
        phantom.exit();
    }
}

var checkCompleteInterval = setInterval(checkComplete, 1);

However, I have had immense difficulty trying to create and automated system that doesn't require PhantomJS to continually be restarted which has a fair bit of overhead. I tried using a named pipe to read from and then attempt to open the passed url, but for some reason it will not open properly. I would love and deeply appreciate any guidance on this.

Answer 1

One thing to mention is that PhantomJS excels in HTTP communications. That's why for advanced features & better performance, I always use resource pooling pattern + webserver module. This module is still tagged EXPERIMENTAL, but I have always found it quite stable until now.

So, I think the best in your case it's better to communicate via HTTP than via files IO.

Here is a very basic example :

var page = require('webpage').create();
var server = require('webserver').create();
var system = require('system');
var host, port;

if (system.args.length !== 2) {
    console.log('Usage: server.js <some port>');
    phantom.exit(1);
} else {
    port = system.args[1];
    var listening = server.listen(port, function (request, response) {
        var page=require('webpage').create();
        page.open(request.post.target, function(status){
            response.write("Hello "+page.title);
            response.close();
        });
    });
    if (!listening) {
        console.log("could not create web server listening on port " + port);
        phantom.exit();
    }

    //test only
    var url = "http://localhost:" + port + "/";
    console.log("SENDING REQUEST TO:");
    console.log(url);
    var data='target=http://stackoverflow.com/';
    page.open(url,'post', data, function (status) {
        if (status !== 'success') {
            console.log('FAIL to load the address');
        } else {
            console.log("GOT REPLY FROM SERVER:");
            console.log(page.content);
        }
        phantom.exit();
    });
}