Chrome extensions for silent print?

Question

I have made a silent print web application that prints a PDF file. The key was to add JavaScript to the PDF file that silently print itself.

To do this I open the PDF with acrobat reader in chrome, that allow me to execute the script (with the proper permissions).

But as it was announced this solution won't work after chrome 45 because the npapi issue.

I guess a possible solution could be to use the recently release printProvider of chrome extensions.

Nevertheless I can't imagine how to fire any of the printProvider events. So the question is: Is ok to think in chrome extensions to make a silent print web application, and how can I fire and handle a print job for an embedded PDF of a HTML Page.

Answer 1

Finally I reached an acceptable solution for this problem, as I couldn't find it out there, but read to many post with the same issue I will leave my solution here.

So first you need to add your printer to the Google Cloud Print and then you will need to add a proyect to the Google Developers Console

Then add this script and any time you need to print something execute the print() function. This method will print the document indicated in the content

The application will ask for your permission once to manage your printers.

function auth() {
  gapi.auth.authorize({
    'client_id': 'YOUR_GOOGLE_API_CLIENT_ID',
    'scope': 'https://www.googleapis.com/auth/cloudprint',
    'immediate': true
  });

}

function print() {
  var xhr = new XMLHttpRequest();
  var q = new FormData()
  q.append('xsrf', gapi.auth.getToken().access_token);
  q.append('printerid', 'YOUR_GOOGLE_CLOUD_PRINTER_ID');
  q.append('jobid', '');
  q.append('title', 'silentPrintTest');
  q.append('contentType', 'url');
  q.append('content',"http://www.pdf995.com/samples/pdf.pdf");
  q.append('ticket', '{ "version": "1.0", "print": {}}');


  xhr.open('POST', 'https://www.google.com/cloudprint/submit');
  xhr.setRequestHeader('Authorization', 'Bearer ' + gapi.auth.getToken().access_token);
  xhr.onload = function () {
    try {
      var r = JSON.parse(xhr.responseText);
      console.log(r.message)
    } catch (e) {
      console.log(xhr.responseText)
    }
  }

  xhr.send(q)

}

window.addEventListener('load', auth);

<script src="https://apis.google.com/js/client.js"></script>

Anyway this script throw a 'Access-Control-Allow-Origin' error, even though this appears in the documentation... I couldn't make it work :(

Google APIs support requests and responses using Cross-origin Resource Sharing (CORS). You do not need to load the complete JavaScript client library to use CORS. If you want your application to access a user's personal information, however, it must still work with Google's OAuth 2.0 mechanism. To make this possible, Google provides the standalone auth client — a subset of the JavaScript client.

So to go throw this I had to install this chrome extension CORS. I'm sure that some one will improve this script to avoid this chrome extension.

Answer 2

You can register an Application to a URI Scheme to trigger the local application to print silently. The setting is pretty easy and straightforward. It's a seamless experience. I have posted the solution here with full example:

https://stackoverflow.com/a/37601807/409319