import a class and use the method python

Question

I have a file structure like this: products

-product
  - content
    - MyContent.py
  - Tool.py

In Tool.py, I have

from AccessControl import ClassSecurityInfo
from OFS.SimpleItem import SimpleItem
from Products.CMFCore.utils import UniqueObject

class Tool(PropertyManager, UniqueObject, SimpleItem):

    @staticmethod
    security.declarePublic('convert_to_lower')
    def convert_to_lower(data):
        return data.lower()

In MyContent.py, I Tool access this class method, so I did:

from Product.Tool import Tool
from Product.Content.ATContentTypes.content.base import ATCTContent
class MyContent(BaseContent):
      def new_definition(self):
          print Tool.convert_to_lower("ABCD")

I can't seem to find what I am doing wrong here. I instantiate the object of MyContent with:

mycontent = MyContent()
mycontent.new_definition()

But, when I run it, it gives me error saying that the method convert_to_lower is not defined. Note: the convert_to_lower() is just a simple example of what I am trying to do.

Answer 1

• You probably made a typo in your example; the correct spelling would be @staticmethod, not @staticclass. Since the latter would produce a name error I'm sure you knew that already. :-)

• There is no point in putting a security declaration on a static method, that's only applicable to class methods (the declaration is stored on the class, not the method).

• The decorator is being applied to the result of the security declaration line, not the function definition below it. In other words, you now have a None static method on your class.

The usual way to provide such utility methods in Plone is to use a ZCA utility registration though, not a static method.

Answer 2

The approach above appears weird. Your tool uses PropertyManager, UniqueObject, SimpleItem as base classes - this implies that your tool is a persistent object. So you want to get hold of the tool by using

my_tool = getToolByName(self, tool_name)
result = my_tool.my_method()

Or you implement your functionality as a Zope utility and look it up using getUtility().

However writing a persistent tool and then trying to just important the tool does not make much sense. If your code does not deal with persistent object or is just a utility method having nothing in mind with core Zope or Plone functionality: make it a "normal" class without the base classes above and import it they you are trying to do.