Module:ResolveEntityId

This module is rated as beta, and is ready for widespread use. It is still new and should be used with some caution to ensure the results are as expected.

This Lua module is used on approximately 2,380,000 pages, or roughly 11140% of all pages.
To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Consider discussing changes on the talk page before implementing them.

Usage

Functions similarly to mw.wikibase.resolvePropertyId, but for Wikidata entities instead of properties.

Returns an entity id for the given label or id. This allows using the entity's labels instead of ids in all places. If no entity was found for the label or id, or if the label is ambiguous, a nil value is returned.

When attempting to resolve a label, only entities with English Wikipedia sitelinks are considered in the search. If a label exists in Wikidata, but does not have the requisite language sitelink, a nil value is returned.

Call from within a module (_id)

Example calls within a module might look like the following:


Code	Result	Notes
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Q42')	`id` = `Q42`	"Q42" is a valid Wikidata ID, and a Wikidata items exists with that Id, so it is therefore returned intact
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Q0')	`id` = `nil`	"Q0" is not a valid Wikidata ID, and while the Wikipedia article Q0 exists, it is a disambiguation page, so `nil` is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Q404')	`id` = `Q404`	"Q404" is a Wikidata redirect to Q395, so the latter is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Q2147483647')	`id` = `nil`	Q2147483647 is a valid Wikidata ID, but no entity exists with that ID, so `nil` is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Douglas Adams')	`id` = `nil`	The article Douglas Adams exists and has the Wikidata ID "Q42", so that is returned.
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('ThisIsNotARealWikidataItem')	`id` = `nil`	"ThisIsNotARealWikidataItem" is not a valid Wikidata ID, and no Wikipedia article exists at ThisIsNotARealWikidataItem, so `nil` is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('ThisIsNotARealWikidataItem', 'Wikidata ID not found!')	`id` = `'Wikidata ID not found!'`	Same as above, but the custom error message `Wikidata ID not found!` is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Douglas adams')	`id` = `nil`	"Douglas adams" is not a valid Wikidata ID, and while Douglas adams (with a lower-case "a") exists, it is a redirect to Douglas Adams. Therefore the Wikidata ID for the latter page is returned
local resolveEntityId = require( "Module:ResolveEntityId" )._id id = resolveEntityId('Wikipedia:Village pump (technical)/Archive 1')	`id` = `nil`	"Wikipedia:Village pump (technical)/Archive 1" is not a valid Wikidata ID, and while Wikipedia:Village pump (technical)/Archive 1 exists, it does not have a Wikidata ID, so `nil` is returned

Use from within a template (entityid)

The following will return the entity id (or nothing if the ID doesn't exist): {{#invoke:ResolveEntityId|entityid|id}}

The following will return the entity id (or the alternate text if the ID doesn't exist): {{#invoke:ResolveEntityId|entityid|id|alternate text if id is nil}}

Former _entityid function

The _entityid function, which required that the frame be passed as the first argument, has been removed from the module because workarounds are no longer needed for phab:T143970.

local p = {}

function p._id(idOrTitle, alt)
	local function checkId(id)
		if id and mw.wikibase.entityExists(id) then
			local sitelink = mw.wikibase.getSitelink(id)
			if sitelink then
				return mw.wikibase.getEntityIdForTitle(sitelink) or mw.wikibase.getEntity(id).id
			end
			return mw.wikibase.getEntity(id).id
		else
			return alt
		end
	end

	if type(idOrTitle) == 'string' then
		idOrTitle = mw.ustring.upper(mw.ustring.sub(idOrTitle, 1, 1)) .. mw.ustring.sub(idOrTitle, 2)
		if mw.wikibase.isValidEntityId(idOrTitle) then
			-- idOrTitle is in the proper format for a Wikidata entity ID
			return checkId(idOrTitle)
		else
			local eid = mw.wikibase.getEntityIdForTitle(idOrTitle)
			if eid then
				-- idOrTitle is a title that matches a Wikidata entity
				local instanceOf = mw.wikibase.getBestStatements(eid, 'P31')[1] --instance of
				if not instanceOf or instanceOf.mainsnak.datavalue.value.id ~= 'Q4167410' then
					-- instance-of value is missing or is not "disambiguation"
					return checkId(eid)
				end
			else
				-- idOrTitle is a title, but no wikidata item exists for that title
				local page = mw.title.new(idOrTitle)
				if page then -- valid title
					local rtarget = page.redirectTarget
					if rtarget then	-- title is a Wikipedia redirect
						return p._id(rtarget.fullText, alt)
					end
				end
			end
		end
	end
	return alt
end

function p.entityid(frame)
	return p._id(frame.args[1], frame.args[2])
end

return p