Plone: Overrides.zcml gets auto-included with z3c.autoinclude

Unsurprisingly, specifying a z3c.autoinclude entry point in your Plone product egg means your ZCML gets automatically included. That’s great because it means you don’t have to specify your product under the ZCML section of your instance in buildout. One thing that isn’t so obvious (it’s not mentioned that I can see on plone.org) is that if your package is marked for ZCML autoinclude, then Plone will automatically load an overrides.zcml file in your product.

Nothing hits you like a slippery wet fish in the face more than hitting this issue and having it …

in Plone · Tue 13 July 2010

Plone 4: Local Zeo blobs conflict with Plone instance

As the title suggests, there’s a conflict between a Zeo database instance being run together with a Plone 4/Zope instance, and them trying to share the same blob storage folder.  But, this only happens if you misunderstand or incorrectly set the option of  shared-blob = off, and blob-storage to be the same location as for Zeo in your buildout. If that previous set of (seemingly jumbled) thoughts doesn’t make any sense to you, then move along, nothing to see here.

By default, at the time of writing, blob support within Zeo runs with the bushylayout, and creates …

in Plone · Tue 06 July 2010

Plone: SiteManager leftovers; not the good kind

Leftovers are typically useful when they’re in your fridge at home. They mean you don’t have to mess around making lunch for the next day for work, and can just grab them, and walk right out the door. Now, leftovers in the zope.component SiteManager aren’t …

in Plone · Mon 28 June 2010

Plone, Dexterity, and Incorrect Widgets

A nice ‘gotcha’ is the distinction between Zope’s schema.Date and schema.Datetime. The difference is obvious and straightforward when the two terms are laid out side-by-side: one is for dates only and the other adds a time component. Where things fell down for me in my usage of these fields with a Dexterity-based content type in Plone is the human component. When these fields are mashed in together within a lot of other text/Python/names, it’s easy to miss those 4 little letters of ‘time’. This lead me trying to use a DatetimeFieldWidget when I really …

in Plone · Mon 21 June 2010

Plone/Zope: Using LDAPUserFolder with posixGroups

Due to various reasons, the Products.LDAPUserFolder package available for Plone and Zope doesn’t support POSIX groups.  The ‘official’ (ish) reason for this is because of the fact that these groups don’t store full distinguished names (DNs) for members.  It makes some degree of sense, because a user ID like ‘david.test’ isn’t strictly unique.  On the other hand, these types of groups are quite common in LDAP implementations; not supporting them without giving it at least half a shot to find the user seems a bit strange.

Here’s where a quick patch steps in. Thanks …

in Plone · Thu 03 June 2010

Virtualenv, Python 2.4, Plone 3.x and Lucid Lynx (Ubuntu 10.04)

These titles of my posts just keep getting longer and longer.  For those of you paying close attention (I know who you are), this is the next in my series of getting the above-mentioned tools working together. Previously, it was Centos 5.x, Jaunty (9.04), Karmic (9.10) and now Lucid (10.04).  Only subtly different, each of this distributions has pretty much called for its own post on the matter of getting a working Plone 3.x / Python 2.4 virtualenv installation going.  So, here goes this time around.

in Plone · Wed 12 May 2010

Good Morning World Plone Day!

Good morning from the land down under and welcome to World Plone Day 2010! It’s right on the hour (well, just after now) and 28 April 2010 — and yes, that’s World Plone Day to the uninitiated. To celebrate and to mark the occasion, I’ll be holding a bit of a discussion today about what Plone is, why it’s so useful, and what we, as users, are hanging out for in Plone 4 and above. But, what fun is that without sweets to eat?  And what’s potentially tastier than Plone?  Plone cupcakes!

Thanks to some great …

in Plone · Wed 28 April 2010

Plone and Dexterity: Working with computed fields

Today, we’re looking at how to utilise computed fields within a Dexterity-based content type. The specific use-case is that of having two separate fields (first name and surname, for a Person type, for example) generate the complete object title. The first part of this — having the title of the content displayed correctly — is pretty straight forward once you know what documentation to read and understand how things happen. The second part — having the ID of the content correctly generated to be first name/surname is slightly more complicated.

in Plone · Mon 19 April 2010

Plone/Zope: Utilising zope.testrecorder for unit testing

Writing unit tests (especial doctests) for your Plone product is reasonably time consuming. For us developers, having tested code is absolutely essential. This is especially true when clients are beating down your door looking for a fully functional product and you need to know what you’ve written works and isn’t going to fall over (just yet, anyway). Web apps are able to be tested using a multitude of frameworks, and whilst not the most fully featured (eg lacking Javascript support), Zope’s doctest machinery is right there within your Plone product. In order to write these, enter zope …

in Plone · Thu 25 March 2010

GenericSetup and “mismatched” tags in ZCML

Ever the issue-magnet, I’ve spent the better part of my morning trying to debug a mistmatched tag error from within some ZCML (aka XML for the non-initiated).  Essentially, the issue boiled down to the system telling me that it was certain that I had a mistmatched tag within my configuration, and presented me with the problematic XML tag (complete with line numbers).  However, life’s not always that simple.

The traceback looked like this:

Traceback (most recent call last):
zope.configuration.config.ConfigurationExecutionError: xml.parsers.expat.ExpatError: mismatched tag: line 6, column 70
in:
File "/home/david/buildout/src …

in Plone · Fri 12 March 2010