A platform for running scripts on many browsers
A platform for running scripts on many browsers.
Queen is a server which is capable of brokering socketed communication between browsers which are connected to it and other applications or scripts. You can think of the Queen Server as a pool of browsers which you can execute code on. Taking the abstraction further, you can think of Queen Server as distributed execution platform using browsers as computation nodes.
Let's say you want to play a "game" where you write down a number and others try to guess it. You gather some friends and tell them to start giving numbers at you. Your friends keep giving you random numbers until one of them gets it right.
Now imagine your friends are browsers, and the game is a script which tells browsers how to play, and waits for the right number to be guessed. This makes you the Queen Server. The Queen Servers allows you to perform distributed tasks on many browsers -- a platform for running scripts on many browsers.
Let's run the example:
npm install -g queen(use sudo on mac and linux).
queen -c localhost:9300 http://queenjs.com/server-example.js
Here's what happened:
You need two scripts to run a job on Queen: a client-side script which will run on browsers, and a server-side script which all of the client-side scripts will communicate with. Here's an example of two such scripts:
//// queenSocket is a global variable queen injects in// to this context// The queenSocket.onMessage hook executes whenever the server-side script// sends a message.// Wait one second, then send the number + 1 back// to the server-side scriptsetTimeout// Sending something in to the queenSocket function sends// it to the server-side scriptqueenSocketnumber + 1;1000;;
//var config =run: ''// This tells queen to run this script on any// browsers which are connected now and in the futurepopulate: "continuous"// By default, queen will kill a workforce (i.e. this job)// if there are no browsers connected, this tells queen// that it's ok to idle and wait for browsers to connect.killOnStop: false// This function gets called right before a browser starts// running the client script.// Worker can be thought of as the browser.workeron'message'queen.logworkerprovider + " is at " + num + "\n";// If the browser has pinged us 10 times, kill it.ifnum === 10workerkill;else// Echo the number back to the workerworkernum;;// Tell the worker to start at 0worker0;// queen is a global variable of the running queen instancequeenconfig;;
To run this example, run this command in your terminal:
queen -c localhost:9300 http://queenjs.com/ping-server.js.
This tells queen to run the server script, and listen for browsers on port 9300. Now if you navigate to
http://localhost:9300/capture.html, you'll add that browser as a worker,
and queen will automatically push the client-side script to the browser to run the test.
The examples above are single-user scenarios, and don't do justice to the scale Queen affords. Queen is intended to act as a browser pool. In real use, you should have one Queen server with many browsers connected to it, allowing anyone in your network to execute scripts on it through queen-remote.
Queen gives each client-side script it's own iframe, so, many scripts can run on the same browser simultaneously. If you're using an automatic populator (such as Selenium) Queen will automatically restart browsers which crash.
Queen can be executed through the command line as
queen [options] [filepath].
The only thing you cannot configure through the command line is populators, you'll need a
Queen config file to define those.
Examples for these commands are available at the command line options wiki page.
This can either be a local file path, or a URL. The file can either be a Queen config file, or a server-side Queen script.
If the file is a Queen config file, it will be used to configure this queen instance.
If the file is a Queen server-side script, queen will disable it's remote server and execute the server-side script.
The host to bind the remote server to. This is the address queen-remote clients will connect to.
The address to bind the capture server to. Browsers will navigate to the url + "/capture.html" to connect to Queen.
Milliseconds clients have to send a heartbeat until they're considered unresponsive.
Enable debug logging.
Please see the wiki for more information about Queen.