Banquo server

This repository is no longer being maintained. Please use https://github.com/mhkeller/banquo-server2.

Banquo server is a Node Express.js server set to run the Banquo library as a service.

Dependencies

You'll need Node.js and PhantomJS. If you're installing it on EC2 here are some good installation instructions. Make sure to change the version numbers to the current versions.

Node.js on EC2

PhantomJS on EC2

Installation

git clone https://github.com/ajam/banquo-server.git

Then

cd banquo-server && npm install

Configuring

To only allow traffic from whitelisted domains, enter the full path of the sites you are expecting to use this service in config.json. Whitelisting is disabled by default because it is difficult to test locally since you won't always get a value for req.headers.referer. Best to only enable this when you move to production.

You also have the option of uploading a png to S3 in addition to returning it as a base64 encoded string. To do this, fill out the fields in the config file.

Starting the service

Install Forever

npm install -g forever

cd to banquo server directory.

Start the server, default is port 3000 forever start app.js

Using the service

Let's say your server lives at banquo.com, the call has the following stucture:

http://banquo.com:3000/:url/:options

So

banquo.com:3000/america.aljazeera.com/viewport_width=1000&delay=1000&selector=#map-canvas&css_hide=.map-zoom`

That won't quite work, though, make sure you wrap your options with encodeURIComponent().

A full client set up would look something like this:

var url = 'america.aljazeera.com',
		options = 'viewport_width=1000&delay=1000&selector=#map-canvas&css_hide=.map-zoom';

function sendScreenshot(url, options){
	return $.ajax({
		url: 'http://banquo.com:3000/' + encodeURIComponent(url) + '/' + encodeURIComponent(options),
    dataType: 'JSONP',
    callback: 'callback'
	});

}

sendScreenshot(url, options)
	.done(function(response){
		console.log(response.image_data, response.timestamp);
	})
	.fail(function(err){
		console.log(err);
	})

Or, if you want to be fancy, store your options as an object and write a function that converts them to a & delimited string. But how you set up the client is whatever makes sense for you.

These are your options that you can pass to Banquo.

Key	Required	Default	Options	Description
url	yes	null	String	The website you want to screenshot.
viewport_width	no	1440	Number (pixels)	The desired browser width. Settings this to a higher number will increase processing time.
delay	no	1000	Number (milliseconds)	How long to wait after the page has loaded before taking the screenshot. PhantomJS apparently waits for the page to load but if you have a map or other data calculations going on, you'll need to specify a wait time.
selector	no	body	URI-component-encoded CSS selector	The div you want to screenshot.
css_hide	no	null	URI-component-encoded CSS selector	Any divs you want to hide, such as zoom buttons on map.

The response

Your Banquo Server should now be returning you a JSONP response of image data and a UNIX timestamp. The timestamp is useful if you've uploaded the image to S3 since it will bake out the image with the following format name: screenshot-1383626366826.png

Contact

Any questions? Contact me here:

michael.keller@aljazeera.net

@mhkeller

Pull requests welcome.