How to draw print from a web page using backend rails?

You can use the html2canvas library to save an image. I've prepared the following demo for you:

HTML:

<div id="welcome">
    <h1>Hello world!</h1>
</div>

<hr>

<div id="screenshot"></div>

JavaScript:

var content = document.getElementById('welcome')
    , screenshot = document.getElementById('screenshot');

html2canvas(content, {
    onrendered: function(canvas) {
        screenshot.appendChild(canvas);
    }
});

jsFiddle to view.

The technique is very simple: #welcome is the element you want to capture a screenshot; #screenshot is where it will be displayed.

To achieve the effect you want, you must work in complicity with Rails. You said the following:

  

I point to a page for my application, and it saves an image of the indicated page. A print.

So, by my interpretation, you want to take the photo of a whole page. For this, you will need to consume the body of that page (element body ) and use it as a reference in the html2canvas (in this case, the variable content (in JavaScript) is responsible for this). See:

uri = URI.parse("http://yourapp.com")

http = Net::HTTP.new(uri.host, uri.port)

request = Net::HTTP::Post.new(uri.request_uri)

response = http.request(request)

render json: response.body

The above code, based on here , will consume all body requested page. Then, using render json: response.body , you will be sending this body to JSON for who to request.

In summary, with a scenario:

The line you should follow is more or less this. There are some adaptations you can make along the way, but the idea has been given.

The answer to your question is too complex to be detailed, you need to use a task management service such as SideKiq and integrate it with the gem PhantomJS GEM , remembering that for this you will need to have PhantomJS . PhantomJS will allow you to capture these screens and for more information, see: Screen Capture Doc

Then through GEM you can interact using:

require 'phantomjs'
Phantomjs.run('./path/to/script.js') # => retorna stdout