Module:Namespace detect

This Lua module is used on approximately 9,900,000 pages, or roughly 3640% 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.

This module allows you to output different text depending on the namespace that a given page is in. It is a Lua implementation of the {{namespace detect}} template, with a few improvements: all namespaces and all namespace aliases are supported, and namespace names are detected automatically for the local wiki.

Usage

{{#invoke: Namespace detect | main
| page              = <!-- page to detect namespace for, if not the current page -->
| main              = <!-- text to return for the main namespace -->
| talk              = <!-- text to return for talk namespaces -->

<!-- text to return for specific subject namespaces -->
| portal            = 
| category          = 
| user 	            = 
| wikipedia         = 
| wp                = 
| education program = 
| mediawiki         = 
| book              = 
| timedtext         = 
| template          = 
| special           = 
| media             = 
| file              = 
| image             = 
| help 	            = 
| module            = 

| other             = <!-- text to return for unspecified namespaces -->
| demospace         = <!-- namespace to display text for -->

| subjectns         = <!-- set to "yes" to treat talk pages as the corresponding subject page -->
}}

Parameters

main - text to return if the page is in the main namespace.
talk - text to return if the page is in a talk namespace. This can be any talk namespace - it will match any of "Talk:", "Wikipedia talk:", "User talk:", etc.
Subject namespace parameters, e.g. wikipedia, user, file... - the text to return if the page is in the corresponding namespace. This module accepts all subject namespaces as parameters, including namespace aliases and virtual namespaces. See below for a list of supported values.
other - text to return if no parameters for the page's namespace were specified. This text is also returned if |demospace= is set to an invalid namespace value.
subjectns - if on a talk page, use the corresponding subject page. Can be set with values of "yes", "y", "true" or "1".
demopage - specifies a page to detect the namespace of. If not specified, and if the |demospace= parameter is not set, then the module uses the current page.
demospace - force the module to behave as if the page was in the specified namespace. Often used for demonstrations.

Namespace parameters

Possible values for subject namespace parameters are as follows:

Namespace	Aliases
`main`
`module`
`story`
`media`
`special`
`help`
`topic`
`newsletter`
`timedtext`
`portal`
`user`
`flow test`
`wikipedia`	`project`, `wp`
`event`
`draft`
`talk`
`config`
`mos`
`category`
`file`	`image`
`mediawiki`
`template`	`tm`

Table function

Use the following to display a table with the different possible namespace parameters:

{{#invoke:Namespace detect|table|talk=yes}}

To include the parameter for talk namespaces, use |talk=yes.

Porting to different wikis

This module is designed to be portable. To use it on a different wiki, all you need to do is to change the values in Module:Namespace detect/config. Instructions are available on that page.

Technical details

The module uses a data page at Module:Namespace detect/data. This page is loaded with mw.loadData, which means it is processed once per page rather than once per #invoke. This was done for performance reasons.

----------------------------------------------------------------------------------------------------
--                                                                                                --
--                                           NAMESPACE DETECT                                     --
--                                                                                                --
--      This module implements the {{namespace detect}} template in Lua, with a few               --
--      improvements: all namespaces and all namespace aliases are supported, and namespace       --
--      names are detected automatically for the local wiki. The module can also use the          --
--      corresponding subject namespace value if it is used on a talk page. Parameter names       --
--      can be configured for different wikis by altering the values in the "cfg" table.          --
--                                                                                                --
----------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------
--                                          Configuration data                                    --
--      Language-specific parameter names can be set here.                                        --
----------------------------------------------------------------------------------------------------

local cfg = {}

-- This parameter displays content for the main namespace:
cfg.main = 'main'

-- This parameter displays in talk namespaces:
cfg.talk = 'talk'

-- This parameter displays content for "other" namespaces (namespaces for which
-- parameters have not been specified, or for when cfg.demospace is set to cfg.other):
cfg.other = 'other'

-- This parameter makes talk pages behave as though they are the corresponding subject namespace.
-- Note that this parameter is used with [[Module:Yesno]]. Edit that module to change
-- the default values of "yes", "no", etc.
cfg.subjectns = 'subjectns'

-- This parameter sets a demonstration namespace:
cfg.demospace = 'demospace'

-- This parameter sets a specific page to compare:
cfg.page = 'page'

-- The header for the namespace column in the wikitable containing the list of possible subject-space parameters.
cfg.wikitableNamespaceHeader = 'Namespace'

-- The header for the wikitable containing the list of possible subject-space parameters.
cfg.wikitableAliasesHeader = 'Aliases'

----------------------------------------------------------------------------------------------------
--                                       End configuration data                                   --
----------------------------------------------------------------------------------------------------

local yesno = require('Module:Yesno')

local p = {}

function p.getPageObject(page)
	-- Get the page object, passing the function through pcall in case we are over the expensive function count limit.
	if page then
		local noError, pageObject = pcall(mw.title.new, page)
		if not noError then
			return nil
		else
			return pageObject
		end
	else
		return mw.title.getCurrentTitle()
	end
end

function p.getParamMappings()
	--[[ Returns a table of how parameter names map to namespace names. The keys are the actual namespace 
	  names, in lower case, and the values are the possible parameter names for that namespace, also in
	  lower case. The table entries are structured like this:
		{
			[''] = {'main'},
			['wikipedia'] = {'wikipedia', 'project', 'wp'},
			...
		}
	]] 
	local mappings = {}
	mappings[mw.ustring.lower(mw.site.namespaces[0].name)] = {cfg.main}
	mappings[cfg.talk] = {cfg.talk}
	for nsid, ns in pairs(mw.site.subjectNamespaces) do
		if nsid ~= 0 then -- Exclude main namespace.
			local nsname = mw.ustring.lower(ns.name)
			local canonicalName = mw.ustring.lower(ns.canonicalName)
			mappings[nsname] = {nsname}
			if canonicalName ~= nsname then
				table.insert(mappings[nsname], canonicalName)
			end
			for _, alias in ipairs(ns.aliases) do
				table.insert(mappings[nsname], mw.ustring.lower(alias))
			end
		end
	end
	return mappings
end

local function getNamespace(args)
	-- Gets the namespace name from the page object.
	local page = args[cfg.page]
	local demospace = args[cfg.demospace]
	local subjectns = args[cfg.subjectns]
	local ret
	if demospace then
		-- Handle "demospace = main" properly.
		if mw.ustring.lower(demospace) == cfg.main then
			ret = mw.site.namespaces[0].name
		else
			ret = demospace
		end
	else
		local pageObject = p.getPageObject(page)
		if pageObject then
			if pageObject.isTalkPage then
				-- If cfg.subjectns is set, get the subject namespace, otherwise use cfg.talk.
				if yesno(subjectns) then
					ret = mw.site.namespaces[pageObject.namespace].subject.name
				else
					ret = cfg.talk
				end
			else
				ret = pageObject.nsText
			end
		else
			return nil -- return nil if the page object doesn't exist.
		end
	end
	ret = mw.ustring.gsub(ret, '_', ' ')
	return mw.ustring.lower(ret)
end

function p._main(args)
	-- Get the namespace to compare the parameters to, and the parameter mapping table.
	local namespace = getNamespace(args)
	local mappings = p.getParamMappings()
	-- Check for any matches in the namespace arguments. The order we check them doesn't matter,
	-- as there can only be one match.
	for ns, params in pairs(mappings) do
		if ns == namespace then
			-- Check all aliases for matches. The default local namespace is checked first, as
			-- {{namespace detect}} checked these before alias names.
			for _, param in ipairs(params) do
				if args[param] ~= nil then
					return args[param]
				end
			end
		end
	end
	-- If there were no matches, return parameters for other namespaces. This happens if there
	-- was no text specified for the namespace that was detected or if the demospace parameter
	-- is not a valid namespace. Note that the parameter for the detected namespace must be
	-- completely absent for this to happen, not merely blank.
	if args[cfg.other] ~= nil then
		return args[cfg.other]
	end
end

function p.main(frame)
	-- If called via #invoke, use the args passed into the invoking template, or the args
	-- passed to #invoke if any exist. Otherwise assume args are being passed directly in.
	local origArgs
	if frame == mw.getCurrentFrame() then
		origArgs = frame:getParent().args
		for k, v in pairs(frame.args) do
			origArgs = frame.args
			break
		end
	else
		origArgs = frame
	end
	-- Trim whitespace and remove blank arguments for demospace and page parameters.
	local args = {}
	for k, v in pairs(origArgs) do
		if type(v) == 'string' then
			v = mw.text.trim(v) -- Trim whitespace.
		end
		if k == cfg.demospace or k == cfg.page then
			if v ~= '' then
				args[k] = v
			end
		else
			args[k] = v
		end
	end
	return p._main(args)
end

function p.table(frame)
	--[[ Create a wikitable of all subject namespace parameters, for documentation purposes. The talk 
	  parameter is optional, in case it needs to be excluded in the documentation.
	]]
	local useTalk = type(frame) == 'table' and type(frame.args) == 'table' and frame.args.talk == 'yes' -- Whether to use the talk parameter.
	local mappings = p.getParamMappings()
	-- Start the wikitable.
	local ret = '{| class="wikitable"'
		.. '\n|-'
		.. '\n! ' .. cfg.wikitableNamespaceHeader
		.. '\n! ' .. cfg.wikitableAliasesHeader
	
	-- Generate the row for the main namespace, as we want this to be first in the list.
	ret = ret .. '\n|-'
		.. '\n| <code>' .. cfg.main .. '</code>'
		.. '\n|'
	if useTalk then
		ret = ret .. '\n|-'
			.. '\n| <code>' .. cfg.talk .. '</code>'
			.. '\n|'
	end
	-- Enclose all parameter names in <code> tags.
	for ns, params in pairs(mappings) do
		if ns ~= mw.site.namespaces[0].name then
			for i, param in ipairs(params) do
				mappings[ns][i] = '<code>' .. param .. '</code>'
			end
		end
	end
	-- Generate the other wikitable rows.
	for ns, params in pairs(mappings) do
		if ns ~= mw.site.namespaces[0].name then -- Ignore the main namespace.
			ret = ret .. '\n|-'
				.. '\n| ' .. params[1]
				.. '\n| ' .. table.concat(params, ', ', 2)
		end
	end
	-- End the wikitable.
	ret = ret .. '\n|-'
		.. '\n|}'
	return ret
end

return p