Zope Management Interface know-how for better Plone development

Question

As a typical 'integrator' programmer customising Plone, what should I know about the ZMI to help me code more effectively? What are the settings, tools, pitfalls, shortcuts and dark corners that will save me time and help me write better code?

Edit: take it as read that I am coding on the filesystem, using GenericSetup profiles to make settings changes. I know making changes in the ZMI is a bad idea and generally steer clear. But occasionally the ZMI sure is useful: for inspecting a workflow, or examining a content item's permissions, or installing only one part of a profile via portal_setup. Is there really nothing worth knowing about the ZMI? Or are there other useful little tidbits in there?

Answer 1

There are a few places in the ZMI that I find myself returning to for diagnostic information:

• /Control_Panel/Database: Select a ZODB mountpoint. Cache Parameters tab shows how much of your designated ZODB cache size has been used. Activity tab shows how many objects are being loaded to cache and written over time.

• /Control_Panel/DebugInfo/manage: Lots of info, including showing what request each thread is serving at the current moment. The 'Cache detail' and 'Cache extreme detail' links give info on what classes of objects are currently in the ZODB cache.

• Components tab of the Plone site root: Quick way to see what local adapters and utilities are registered. DON'T HIT THE APPLY BUTTON!

• Undo tab of most objects: See who has committed transactions affecting the object lately.

• Security tab: See what permissions are actually in effect for an object. You really don't want to change permissions here 90% of the time; it's too hard to keep track of where permissions are set and they are liable to be reset by workflow. Use the Sharing tab in the Plone UI to assign local roles instead. (The one exception is that I often find it handy to enable the add permission for a particular type in specific contexts.) In Zope 2.12, there is a new feature on this tab to enter a username and see what permissions and roles would be in effect for that user, which is handy.

• Catalog tab of portal_catalog: See what index data and metadata is stored for a particular path. (Can also remove bogus entries from the index.)

• Index tab of portal_catalog: Select an index, then click its Browse tab to get an overview of what keys are indexed and which items are associated with each key.

Answer 2

The key thing to know is that while many ZMI tools provide quick, through-the-web customization, the customizations that you make this way are hard to export out of the database. So, they don't move easily from development to production environments or from one deployment to another.

Ideally, a new developer should use the ZMI to explore and find points of intervention. Then, learn how to implement the same changes in policy add ons (products) that move from one deployment to another much more reproducibly.