CKAN: Ticket Query

#3014: Crash when deleting a non-empty vocabulary

seanh — Tue, 13 Nov 2012 10:50:08 GMT

From Knud Möller:

when I try to delete a non-empty tag vocabulary via the API (through HTTP), I get an internal server error. Checking the logs, this turns out to be a consistency error raised by sqlalchemy:

Error - <class 'sqlalchemy.exc.IntegrityError?'>: (IntegrityError?) update or delete on table "vocabulary" violates foreign key constraint "tag_vocabulary_id_fkey" on table "tag" DETAIL: Key (id)=(21421955-7560-467c-af30-9f790b73e6ae) is still referenced from table "tag".

'DELETE FROM vocabulary WHERE vocabulary.id = %(id)s' {'id': u'21421955-7560-467c-af30-9f790b73e6ae'}

URL: http://33.33.33.10:5000/api/action/vocabulary_delete

The error makes sense, but I'm wondering if it would be useful to extend the API to also allow the deletion of non-empty vocabularies, possibly via a parameter (not sure what best practice in API design is). At the very least, it would be cool if the error message coming back in the response had more information in it.

#1789: Implement a tag_update() logic action function

seanh — Thu, 09 Feb 2012 16:36:53 GMT

So users can rename a tag and/or move it between vocabularies using the API.

Currently we have create_tag() and delete_tag(), but if you were to 'update' a tag by deleting it and then recreating it all the datasets that had that tag will have lost it and you'll have to re-add it to them all.

What should happen to datasets that have the tag, if the tag gets moved between vocabularies? All the datasets just keep the tag with the new vocabulary? This will become a problem if/when we support 'radio button'-style vocabularies (where each dataset can only have one tag from the vocabulary).

#1824: Add vocabulary pages

seanh — Tue, 21 Feb 2012 17:24:49 GMT

For a free tag foo you can visit the page at /tag/foo and see a list of all the datasets that have the tag foo, and when the tag appears on dataset view pages etc. it's linked to this tag page.

We should do the same thing for vocabulary tags. A tag bar in vocabulary baz should be hyperlinked to a page /tag/baz/bar, or perhaps /vocab/baz/bar.

#2200: Add vocabulary_id option to tag_show() logic action function

seanh — Wed, 29 Feb 2012 16:41:18 GMT

Currently tag_show() only works with free tags, it's not possible to get a tag_show for a vocabulary tag.

#2961: Preview plugin endpoint

dominik — Mon, 08 Oct 2012 11:39:27 GMT

Users could write ckan extensions that offer previews for a certain datatype.

Advantages:

We can say that you can add your own previews
Every preview would have to define it's own dependencies
External development (community creates new extensions?)

Questions to answer:

Specification of the interface
Precedence of previews for the same data types
Plugins only define the datatype that they are responsible for or do we call a function that returns whether the extension is responsible.

As far as I can see, this should be fairly easy to implement by following these instructions: http://docs.ckan.org/en/latest/writing-extensions.html#writing-a-plugin-interface