[Zope] Button to pack data base

I would like to include a button or link on a Zope site that would allow a user with the right privileges ( what privileges do they need -- can I restrict their "management" capability to just the pack function?) to pack the data base. I would like to have it use the appearance of the website, not the ZMI. Any idea of how to do this? Directions to code that does this in the ZMI that I could examine?