Do you have a content type that you’d like to be able to offer as Comma Separated Value (CSV)/Excel download? Python can create both formats pretty easily (using either the standard csv library, or xlwt) and you can write a view for your content type that will create the file and return it to the user as a file download.

At Plone.org, Martin Aspeli covers this process as a part of the five.grok documentation. I’d already created my product without using five.grok, and I didn’t figure this one use case was enough reason to switch. So here’s what I came up with:

First, register the view in browser/configure.zcml

...
    <browser:view
      for="my.product.interfaces.IMyContentType"
      name="csv_view"
      class=".mycontenttypeview.MyContentTypeCsvView"
      permission="zope.Public"
      />
...

I added the view to browser/myContentType.py under the default view.

...
class MyContentTypeCsvView(BrowserView):
    """
    Download the content type as a CSV file.
    """
    
    def __call__(self):
        """
	Build a CSV from the content type.
	"""
	out = StringIO()
	writer = csv.writer(out)

        ...
        # make the CSV file
        ...

	filename = "%s.csv" % context.id

	self.request.response.setHeader('Content-Type', 'text/csv')
	self.request.response.setHeader('Content-Disposition', 'attachment; filename="%s"' % filename)

        return out.getvalue()

Now you should be able to link to http://mysite.com/mycontenttype/csv_view and initiate a file download.