Presumably the Content-Disposition header is not used when the file has not finished downloading. This could be fixed by putting "collection.pdf" at the end of the path section of the URL, as a fake subpage of [[Special:Book]].

mhershberger wrote:

Unassigning default assignments. http://article.gmane.org/gmane.science.linguistics.wikipedia.technical/54734

Works every time for me... @tstarling, can you clarify what you meant here? Are we offering the file for download before it's actually ready?

It's reproducible in Firefox 38.

http://tstarling.com/stuff/slow-content-disposition.php

This script provides a link, and when you request the linked URL, the script sleeps for 10 seconds before sending a Content-Disposition header. When you right-click the link and select "save link as", Firefox waits for the headers for about 5 seconds, then gives up and uses the script filename instead.

I tested IE also, it waits for the whole 10 seconds for the headers to arrive, so the issue does not affect it.

The theory being that if you're on satellite or if our servers are slow or something, then PDF downloads may randomly hit Firefox's 5 second timeout and thus ignore the Content-Disposition header.

That's... interesting behaviour from Firefox. I reproduced it in Firefox 38 but not Chrome 44 with this script:

<?php
if ( isset( $_GET["download"] ) ) {
        header( "Content-Disposition: inline; filename=foo.bar" );
        sleep( 10 );
}
echo "<a href=\"?download=1\">Click here</a>";
?>

Can we make it send headers immediately? Perhaps via flush() or equivalent? That appears to resolve the issue in this code.