phrase

Wikibase Phrase Entity, Viewing

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This entry is part 7 of 7 in the series Wikibase Entities

In my previous post, we got to the point of being able to create a new Wikibase Entity, it is stored in the MediaWiki database as a page, however we can’t actually view it via any interface currently.

In this post, we will work through another set of code changes, tackling each issue as we see it arise, until we can see the entity represented in the various places that users might expect.

Viewing the page

The provided entity serialization is neither legacy nor current

When clicking on one of the links on Special:RecentChanges to a phrase page that we have created, we get our first error.

/wiki/Phrase:Phrase66900b01937842.29097733 MWContentSerializationException: The provided entity serialization is neither legacy nor current
from /var/www/html/w/extensions/Wikibase/lib/includes/Store/EntityContentDataCodec.php(253)Code language: JavaScript (javascript)

The full stack trace is a little large, but you can find it in a paste bin.

This error is very similar to an issue we saw in the creation blog post, but this time the codec class can not deserialize what we have stored in the database, as we have not registered a deserializer for phrases.

Adding a deserializer to the entity registration file is very simple:

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Wikibase Phrase Entity, Creation

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This entry is part 6 of 7 in the series Wikibase Entities

Finally, after a long lead up of discussing what an entity is, looking at some examples of entity extensions, and one extension that chose not to make use of the Wikibase Entity system & EntityDocument. What does it take to create a new type of data entity within Wikibase that implements the EntityDocument interface and makes use of the various integrations that have evolved over the past 10+ years?

I slapped together a very rough branch exploring this in 2022, but it’s hard to follow at best, and doesn’t really discuss any of the challenges that crop up along the way. This post, and those following are the redo, with much more context. And with any luck, it will work mostly as before (as Wikibase hasn’t changed much internally when it comes to how Entities are handled in the last 2 years)

If you want to follow along, you’ll need a development environment, and for that I would recommend the mwcli walkthrough that I wrote in the past weeks.

Where to start

I have a slight advantage here, as the closest thing that comes to documentation around how to add a new entity type to Wikibase is the documentation of the various fields that make up the entity registration system.

Beyond that, your only way in would likely be to start looking at one of the extensions that already provides an additional entity type, such as WikibaseMediaInfo, and the entity type registration that it makes. But each of these extensions come with their own complexity to muddle your view.

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