I haven't been able to find the following functionality in `dired-mode` with my Google-fu, but I suspect that someone has already written up a solution. When a PDF file exists on a remote server that is being accessed over an SSH connection and the file is displayed in a `dired-mode` buffer, I'd like to view the PDF locally in an external reader such as `xpdf` or `acroread` on linux (Ubuntu). It wouldn't be that difficult to write up a solution (e.g., download to a temporary directory, perhaps using something like `url-retrieve-synchronously`), but if a solution already exists, I'd like to start with that. Any ideas how that would be done would be greatly appreciated.