I'm looking for a way to stream temporary files and make sure they are deleted after they are sent.
With Mongrel I can do something like this
Tempfile.open('ue-basket-') do |zip| Zip::ZipOutputStream.open(zip.path) do |zos| items.each do |item| zos.put_next_entry(item.filename) zos.write(item.data) end end
send_file zip.path, :type => 'application/zip', :filename => item.filename
zip.unlink end
By Unix filesystem semantics, zip.unlink does not free the blocks (inodes) that make up the file. As long as there still is a reference to it, the file still exists. However, the directory entry for the file is deleted. The nice effect is that the file is no longer visible, but can still be streamed. As soon as the last file descriptor referencing it is closed, the file is finally deleted for good.
This doesn't work anymore, when serving files is offloaded to the web- server. The default Rails 3 (Rack-)middleware detects that a file is being send (respond_to?(:to_path)), adds the file's path as a special header, which in turn is interpreted by the web server to serve that particular file. Of course this can only work if the file is still visible in the filesystem. Therefore the unlink trick doesn't apply.
As a last resort, I can set up a cron job that removes temporary files after they've reached a certain age. I'm still hoping for a more elegant solution. Say, a hook that is executed after the server has finished sending the file.
I'm using apache 2.2 and mod_xsendfile 0.9.
Michael
