issue11980 has a patch that adds a method for writing a file into the ZIP archive.

But more flexible way is to add the support of the "w" mode to ZipFile.open(). This will allow to write a data that doesn't exist in memory at once, nor in disk, but is loaded by chunks from the pipe, or from the socket, or from other archive, or just generated on fly. I'm worked on this, but this feature needed to add support of some other features. For example writing to unseekable file (already implemented) or writing and reading a file without known size (not implemented still).

issue18595 has a proposition to add special methods for creating symlinks, directories etc.