Download PDF resource from PHP to Javascript via Ajax

Question

So I will explain the problem:

Steps:

1) client (browser javascript) sends an Ajax request to the server that hits a controller method called download.

2) the controller's method creates a PDF resource(without saving on the filesystem), and returns a response with the PDF binary stream back to the client.

3) the client receives the PDF binary stream and download it on the client's computer. Is that possible?

Code: Things I have already tried -

Client-side:

<script>
    (function($) {

        var button; // some random DOM button

        button.on('click', function(e) {
            e.preventDefault();

            $.ajax({
                url: "/download/:userId"
                method: "POST",
                dataType: "json"
                success: function(response) {
                    var reader = new FileReader;
                    var file = new Blob([response.pdf_stream], 'application/pdf');

                    // create a generic download link
                    var a = $('<a/>', {
                        href: file,
                        download: response.filename
                    });

                    // trigger click event on that generic link.
                    a.get(0).click(); 
                }
            });
        }

    })(jQuery);


</script>

On the server-side:

class Controller
{
     public function download($userId)
     {
         // fetching the user from the database
         $user = User::find($userId);

         // creating a pdf file using barry pdfdom package
         // this will actually parse an HTML view and give us the PDF blob.
         $pdf = PDF::loadView('pdf.view')->output();

         // using Laravel helper function
         return response()->json([
             'pdf_stream' => utf8_encode($pdf),
             'filename' => 'blahblah.pdf"
         ]);

        // Or if you will in native PHP, just in case you don't use laravel.
        echo json_encode([
             'pdf_stream' => utf8_encode($pdf),
             'filename' => 'blahblah.pdf"
        ]);
     }
}

Any Idea what am I doing wrong here? How could I download that PDF file without saving it to the system (security and space concerns).

Any help would be appreciated.

Eden

Victor Fedorenko · Answer 1 · 2018-06-06T19:49:55.817

0

If you want download pdf on client side, just open this pdf in new window. Use GET request for that things, like in RESTfull application (e.g. download/user/:id or somehow like that).

Could be useful: Download and open pdf file using Ajax

edited Jun 06 '18 at 19:49

answered Jun 06 '18 at 19:37

Victor Fedorenko

331
2
13

This is more of a comment since the sever side code outputs JSON rather than an pdf. – Musa Jun 06 '18 at 19:48
@Victor thanks for the answer, can you please give code example? Do you mean window.open(file); ? Will that work? file is a blob (the file is not located on my server system) – Eden Reich Jun 06 '18 at 19:49
`window.open(route)` - on client side and generate appropriate pdf on server-side by this route – Victor Fedorenko Jun 06 '18 at 19:52
Interesting, your comment lead me to the answer going to try this out: https://stackoverflow.com/questions/21729451/pdf-blob-pop-up-window-not-showing-content – Eden Reich Jun 06 '18 at 19:55
ah yes, you also have to output pdf on server side, not json as @Musa noticed – Victor Fedorenko Jun 06 '18 at 19:56
var fileURL = URL.createObjectURL(file); winow.open(fileURL); – Eden Reich Jun 06 '18 at 20:01

score 0 · Answer 2 · answered Jun 07 '18 at 07:27

The main problem is the returned response from controller. Try this:

public function download($userId)
     {
      // fetching the user from the database
      $user = User::find($userId);

      // creating a pdf file using barry pdfdom package
      // this will actually parse an HTML view and give us the PDF blob.
      $pdf = PDF::loadView('pdf.view')->output();
      return response($pdf, 200,
        [
          'Content-Type'   => 'application/pdf',
          'Content-Length' =>  strlen($pdf),
          'Cache-Control'  => 'private, max-age=0, must-revalidate',
          'Pragma'         => 'public'
        ]
      );

About calling the route which executes download($userid) method:

You do not have to use Ajax. Easy way:

<a href="/path/to/download/1" target="_blank">Click view PDF</a>

thank for the solution, I tried many times with ajax and for some decode and encode problem between PHP to Javascript it did not work. So eventually I have decided to go with a full http request like you suggested and now it works. Thanks again! — Eden Reich, Jun 07 '18 at 09:10

Download PDF resource from PHP to Javascript via Ajax

2 Answers2