Django: Is there a way to prevent a view from being called twice simultaneously?
That is the best solution, however you could disable the button onclick by adding a disabled attribute to the button equalling 'true'
With jQuery:
$('#yourButtonId').attr("disabled", true);
There's some functionality on our Django app that displays a link to refresh some information from our version control system.  This is simply a link, and when they hit that URL the actions of going to version control, getting the information, checking it against the database and updating the database are performed. 
Recently we had a user click the 'refresh' button twice for one asset.  This resulted in the URL being hit twice, so the operations were performed twice and eventually a duplicate entry was created in our database.
We need to do something to remove the possibility of the user clicking that button twice.  Should we move from a link to a javascript button?  Should we set some flag in request.session as soon as the first click happens, then unset it upon completion, and always check that flag when performing a refresh?  Those are just two ideas that seem feasible, but I really don't know.