javascript - Default filename when saving from html2canvas or save as dialogue? - php

Question

A friend of mine configured h2ml2canvas for me as I don't understand javascript. When saving using h2ml2canvas it generates a random filename e.g.
df0e604b2962492165eb8f2b31578171
Is there a way to specify a filename prefix? e.g. soccer then generate a random 3-4 digit number? Alternatively is there a way to open a save as dialogue instead of downloading an image on click? My download.php file.
<?php
$file = trim($_GET['path']);
// force user to download the image
if (file_exists($file)) {
header('Content-Description: File Transfer');
header('Content-Type: image/png');
header('Content-Disposition: attachment; filename='.basename($file));
header('Content-Transfer-Encoding: binary');
header('Expires: 0');
header('Cache-Control: must-revalidate, post-check=0, pre-check=0');
header('Pragma: public');
header('Content-Length: ' . filesize($file));
ob_clean();
flush();
readfile($file);
unlink($file);
exit;
}
else {
echo "error not found";
}
?>

Answer 1

The filename in your case is actually generated (or not) by the PHP server-side, not the JavaScript you've quoted. When it returns the data to send back, it's including a Content-Disposition header, probably one that looks like this:
Content-Disposition: attachment
It's possible to suggest a filename to the browser by adding to that header:
Content-Disposition: attachment; filename=soccer123.xyz
In the PHP somewhere, you should find:
header("Content-Disposition", "attachment");
or similar. You can change it to:
header("Content-Disposition", "attachment; filename=soccer-" . rand(100,999) . ".xyz");
(Probably best to make the .xyz an appropriate extension for the type of image, e.g. .png or .jpg...)
Re your edit, you can replace:
header('Content-Disposition: attachment; filename='.basename($file));
with
header('Content-Disposition: attachment; filename=soccer-'.rand(100,999).'.xyz');
again you'll want a correct extension instead of .xyz.