Print a list of PDF files to Client's printer

Question

I am writing a web application that will, amongst a lot of other things, produce a list of PDF files:

public JsonResult BulkPrintExemptions()
        {
            List<FileContentResult> retValues = new List<FileContentResult>();
            var results = db.Permits.Where(m => m.Year == DateTime.Now.Year).Where(e => e.RecordDeleted == false).ToList();
            foreach (var result in results)
            {
                retValues.Add(GetPDF(result, "Exemption"));
            }
            return Json(retValues, JsonRequestBehavior.AllowGet);
        }

The list will be a minimum of about 400 PDF documents, and the user wants to automatically print them without any interaction on her part.

Once I return that List of FileContentResults, how do I automagically send it to the user's default printer?

I am fairly certain I just need to loop through the list and call Acrobat Reader for each one; I'm just at a loss as to how to do that through javascript.

How do I do that? Or, alternatively, I'm open to better options.

Full disclosure, to assist with options:

This is an MVC application in C#. The enduser has Adobe Acrobat Reader (at least) installed, as it's a default on the "Office Desktop" image.

Edit to add: The PDF files are coming from SSRS, if that makes any difference.

Does this answer your question? [Print PDF directly from JavaScript](https://stackoverflow.com/questions/16239513/print-pdf-directly-from-javascript) — Heretic Monkey, Dec 18 '19 at 18:34
This is not a great solution for many reasons, the simplest of which is that printing 400 documents via a web browser is going to tie up that browser window for a LONG time. And depending on what browser manufacturers do or don't decide, printing without user interaction may or may not continue to work in future browser releases. A more robust solution, IMO, would be to have your `BulkPrintExemptions` call queue up the PDFs to be printed somewhere (e.g. a DB table), and then on each client PC have a Windows service running that polls that queue and sends everything in it to the system printer. — Ian Kemp, Dec 18 '19 at 22:49

score 1 · Answer 1 · answered Dec 18 '19 at 18:31

First, that sounds like a terrible idea on your user's part. This could potentially lead to locking up her computer while it processes that many print requests.

Second, it is possible. This SO question has some options listed, and it looks like Print.js is probably your best bet. Some comments there said it didn't open the print dialog, so it may not require interaction on your user's part; but I sincerely hope it does, because allowing a website unlimited access to a printer with no user interaction sounds like a terrible idea.

Alternatively, if it prompts for every single one of those 400+ PDFs, if you can concatenate them into one 400+ page document then you'd only have one print dialog. Still probably slow/lock up her PC while processing that request.

score 0 · Answer 2 · answered Dec 18 '19 at 18:01

There are strict limits regarding what your WebPage can do on/to the Computer showing the WebPage. We used to be more lax. It was abused the heck out off. So it was fixed. But I doubt anyone was mad enough to ever allow JavaScript to send Print orders.

That being said it should be possible, using a Progamm or possibly even a Addon/Extension installed on the Client side.

You can register Programms with specific Protocolls, same way you would with File Extensions. Indeed that is how those Steam Links on the Desktop work - they are URL's with the custom "steam:" Protocoll. And all browser register both the common Filenames and the common Protocolls.

That is about the best answer I can give you with such a broad question.

Print a list of PDF files to Client's printer

2 Answers2