[Grok-dev] declaring catalog indexes
faassen at startifact.com
Sat Apr 14 12:38:40 EDT 2007
The current way to set up catalog indexes in Grok looks like this:
catalog['a_index'] = FieldIndex('a_attribute',
catalog['b_index'] = TextIndex('b_attribute',
provides=ICatalog, name='my_catalog', setup=setup_catalog)
This will index everything providing ISomeInterface. We can also set up
an adapter from our own objects to ISomeInterface and this will result
in those objects being indexed as well.
This approach is pretty powerful. If I have an extension object that
wants to be indexed, I merely have to implement the right interface on
my object, or provide some adapter from my object to that interface.
The main drawback to this approach is that all indexes are set up
centrally. Of course you can write code to adjust the catalog later (and
have no setup_catalog), but are there patterns we can come up with to
make the creation of indexes more easy?
Let's translate the above in another proposal:
grok.local_utility(Catalog, provides=ICatalog, name='my_catalog')
The indexes are grokked automatically and get created in the catalog
when 'App' is created using a subscriber. This allows an extension
modules to create new indexes in the core. Of course the app would still
need to be reinstalled to enable those indexes, but with some clever
event registration (IApplicationSetup event?) we might be able to handle
that quite nicely as well.
One issue that this approach has is if indexes take other parameters
than the three I know about (attribute name, interface, boolean on
whether to call attribute or not). How do we pass them in? Does anyone
have experience with indexes that can use extra information?
What do people think?
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