Issue #384: Add view option to public printing interface

Adds a 'View' button along with Print and Cancel buttons on the
list of print jobs for a user.  Opens in a new browser window.
Access is limited to the user who owns the print job

This is especially helpful now that we can do automated PDF conversion;
users may want to verify that their file rendered right before paying
to print it.

Author: Ian Walls

lib/Libki/Controller/Public/API/User.pm

@@ -47,6 +47,54 @@ sub funds : Local Args(0) {
     $c->forward( $c->view('JSON') );
 }
 
+
+=head2 view_print_job
+
+Returns the PDF of a given print job.
+
+=cut
+
+sub view_print_job : Local : Args(0) {
+    my ( $self, $c ) = @_;
+
+    if ( !$c->user_exists ) {
+        $c->response->body('Unauthorized');
+        $c->response->status(401);
+        return;
+    }
+
+    my $id = $c->request->params->{id};
+
+    my $user = $c->user();
+    my $instance = $c->instance;
+    my $print_job = $c->model('DB::PrintJob')->find($id);
+
+    if ( $user->id != $print_job->user_id ) {
+        $c->response->body('Forbidden');
+        $c->response->status(403);
+        return;
+    }
+
+    if ($print_job) {
+        my $print_file = $c->model('DB::PrintFile')->find( $print_job->print_file_id );
+        if ($print_file) {
+            my $filename = $print_file->filename;
+
+            $c->response->body( $print_file->data );
+            $c->response->content_type('application/pdf');
+            $c->response->header( 'Content-Disposition', "inline; filename=$filename" );
+        }
+        else {
+            $c->stash( success => 0, error => 'PRINT_FILE_NOT_FOUND' );
+            $c->forward( $c->view('JSON') );
+        }
+    }
+    else {
+        $c->stash( success => 0, error => 'PRINT_JOB_NOT_FOUND' );
+        $c->forward( $c->view('JSON') );
+    }
+}
+
 =head2 release_print_job
 
 Sends the given print job to the actual print management backend.

root/dynamic/includes/index/printing.tt

@@ -215,6 +215,8 @@ $(document).ready(function() {
                   const not_held = row["status"] !== "Held";
 
                   let html = "<div class='btn-group' role='group' aria-label='Print actions'>";
+                  html += `<a id="view-btn-${print_job_id}" class="btn btn-info print-view" onclick="window.open('/public/api/user/view_print_job?id=${print_job_id}', '_blank' )" href="#" role="button"><i class="fa fa-eye"></i> View</a>`;
+
                   [% IF public_print_release != "disabled" %]
                   if (not_held || user_funds < row["7"]) {
                     html += `<a id="print-btn-${print_job_id}" data-jobid="${print_job_id}" class="btn btn-primary print-release disabled" disabled aria-disabled="true" href="#" role="button"><i class="fa fa-print"></i> Print</a>`;