FakePublish

I find myself getting frustrated with trying to find where things are in the ZODB of a project that I'm working on. I'm working with other developers, and even though we're consistent and sensible enough about design, there are several places to hunt for what is publishing something - normal containment on the ZODB filesystem, ZClass? methods, and Python methods, with acquisition meaning that the URL isn't very helpful for locating something. When the Zope installation is 3000 miles away from my box & guarded by slow connectivity, slogging through several browser windows takes up too much time.

The only way to fly is to use the monitor or the debugger. See The Debugger Is Your Friend and Zope Deugging.

In order to see how something is published, we have to follow the process that the publisher takes. I stepped through the code and saw that the action (for my current Zope checkout, 2.2.x) is in

• /lib/python/ZPublisher/Publish.py(122)publish()
• /lib/python/ZPublisher/BaseRequest?.py(224)traverse()

but that doesn't help much. Almost everything is published by walking from the root to the leaf and, for each parent, calling getattr(parent, child) to get the child. If that doesn't work, we try parent[child] And we also look for a __bobo_traverse__ method, & try specific things at the end, like the default index_html attribute and calling the final object. getattr is overridden in a C extension, which I wasn't prepared to decipher. But, we can short-circuit acquisition, and find out if something is a method or a containee, and emulate the publishing process well enough that way.

Here's what I use - I call it from the monitor:

• FakePublishCode

It basically saves me from typing in the tests to find something:

• get the object from its URL by converting slashes to dots
• get a path to the object that it's acquired from by calling object.getPhysicalPath() on it, which returns a list of objects in the acquisition base's path
• each subset [0:i]? of this list gets us a parent object with unrestrictedTraverse(). For each of these objects, we want to know its relation to the child:
  • if the child isn't an attribute of the parent, it's reached by __bobo_traverse__ or some other complex method, and we'll have to be more thorough than this hack
  • else, if the child is in dir(parent), it's simple containment.
  • else, if the child is in the dictionary of the class of the parent, it's a method of a ZClass? or Python class.

It's not complete, but it saves time. I still have to find out if a parent is a ZClass? or a Python product.

If the parent is a ZClass? and the child is a method, I'd like to spit out an URL for that method so I can feed it to my browser, but I don't know if that's possible.