Creating Zope Products - Finishing Touches (
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Though the person.py file is complete, Zope still will not acknowledge our new Zope Product. This is because there is a bit more work left to do. We have to tell Zope exactly where our Zope Product is located and how to go about adding the Product—what methods are required to create the Product and what-not.
Thankfully, though, this is a pretty simple process. Zope looks around in the Products directory for __init__.py files. These files contain instructions on what Zope should do to add the particular Product with which the file is associated. Go ahead and create a file named __init__.py and place it in the directory with the person.py file.
import person
def initialize(context):
"Instructions for creating an object."
context.registerClass(person.Person, constructors =
(person.addForm,person.addProduct))
If you followed everything closely, then you should now be ready to test out the Product we created. Simply restart Zope and select our new Product from the drop-down list in the Zope Management Interface.
There is one additional thing I would like to explain. Though generating all the required HTML in the Python of a Product is perfectly possible, it's not completely practical. A better solution might be to create DTML files and then return those to the user instead. We'll modify our person.py file. The first thing you need to do is import Globals:
import Globals
...
Next, you need to add an attribute to Person and assign it to the DTML page. We'll use the page dtml_page.dtml here:
...
dtml_page = Globals.HTMLFile('dtml_page', globals())
...
Finally, we must create the DTML page. Put it in the same directory as person.py and name it dtml_page.dtml (even though we don't use the extension in Globals.HTMLFile, the extension is required):
<html>
<head>
<title><dtml-var title></title>
</head>
<body>
This is a DTML page for <dtml-var title>.
</body>
</html>
Conclusion
From here, there are a lot of paths you can take. Try experimenting with Zope Products a bit more and familiarizing yourself with them. Simple ones aren't difficult to create, as this article has illustrated with the Person Product. You can use them to simplify complex logic that can't be organized using traditional methods. I know that many Python scripters feel that creating numerous Zope objects and attempting to force them to interact is a bit cumbersome, but Zope Products can get around this as well.
Of course, this article only explains a very small fraction of the inner workings of Zope Products. Products are pretty complex creatures that allow much more customization and functionality than a simple article like this can explain. However, I do hope that this article has introduced you to the very basics of Products so that you can decide where to go next.
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