Module:Portal

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This module has two functions, portal and image. The portal produces a box with links to a portal or to multiple portals, and is used by the {{portal}} template. It is most often used in the "See also" section of an article. The image function produces the name of the image used by the specified portal.

Portal function

The portal function produces a box of portal links.

Usage

Basic usage

{{#invoke:Portal|portal |Portal 1 |Portal 2 |Portal 3 |... }}

All options

{{#invoke:Portal|portal
 | Portal 1
 | Portal 2
 | Portal 3
 | ... 
 | left = 
 | margin = 
 | break = 
 | boxsize = 
}}

Location

Within articles, the output of the portal function is meant to be placed at the bottom of the article in the See also section. If there is no See also section, you can put it in the External links section instead; there is no need to create a new section just to house this template. If there is no External links section either, just put it below the article text in the place that seems most appropriate.

There are no particular rules about the placement of portals on other kinds of pages.

Image

The portal image names are stored in subpages of Module:Portal/images, organised by the first letter of the portal name. For example, the first letter of Portal:Fishing is "F", so the image name is stored at Module:Portal/images/f. If there is an entry for a portal on the correct page then the corresponding image will be shown next to the portal link. If no image is found then File:Portal-puzzle.svg will be shown instead.

It is also possible to specify aliases for portal images. For example, the code {{portal|Detroit}} produces the same image as the code {{portal|Metro Detroit}}. The "Detroit" alias is found on the page Module:Portal/images/aliases.

The image-detection algorithm is case-insensitive. For example, the code {{portal|Detroit}} will produce the same image as the code {{portal|detroit}} (although the portal links will be different). Portal names are stored in lower case in the image subpages, and input is converted to lower case before being checked.

To add new images to the list, please make a protected edit request at Template talk:Portal to get an administrator to edit the correct subpage for you. Portal images must be either in the public domain or available under a free license that allows commercial reuse and derivative works; fair-use images are not acceptable. The template {{Portal icon demonstration}} may be of use when deciding whether an image is suitable for use as a portal icon; it formats an image using the same size and style that the {{portal}} template uses by default.

Example

Code	Result
{{#invoke:Portal|portal|Science}}

Parameters

Name	Value	Description
1, 2, 3 ...	The portal name, e.g. Literature	The positional parameters specify the portals to be displayed.
left	yes	If set to yes, the portal appears on the left side of the page instead of the right.
margin	CSS margin value, e.g. 1.2em 3em 0.5em 1em	This allows you to set a custom margin. All valid CSS margin values are accepted.
break	yes	If set to yes, a line break is inserted after the portal name and before the word portal.
boxsize	Size in pixels, e.g. 300	This sets a custom box width in pixels.

Maintenance

The following tracking category lists instances where the module is used incorrectly:

• Category:Portal templates without a parameter

Image function

The image function produces the name of the image used by the specified portal.

Usage

{{#invoke:Portal|image|portal}}

Example

• {{#invoke:Portal|image|Art}} → Ballerina-icon.jpg

Image dupes function

The image dupes function returns a list of all images that are being used by more than one portal (aliases are not included). This can be helpful in identifying image entries that should be changed to use aliases.

Usage

{{#invoke:Portal|imageDupes}}

Display all function

The display all function returns a box containing all portals that have images. This is used for maintenance, and should not be displayed in articles, because a) there are around 1500 portals with images, and displaying 1500 images on one page takes up a lot of server resources, and b) the module has no way to know the correct capitalisation of a portal name, so some links to portals will be broken. This function can be seen at Template:Portal/doc/all.

Usage

{{#invoke:Portal|displayAll}}

--[==[ This module is a Lua implementation of the old {{Portal}} template. As of August 2013 it is used on nearly 5,000,000 articles.
-- Please take care when updating it! It outputs two functions: p.portal, which generates a table of portals, and p.image, which
-- produces the image name for an individual portal.

-- The portal image data is kept in submodules of [[Module:Portal/images]], listed below:
-- [[Module:Portal/images/a]]		- for portal names beginning with "A".
-- [[Module:Portal/images/b]]		- for portal names beginning with "B".
-- [[Module:Portal/images/c]]		- for portal names beginning with "C".
-- [[Module:Portal/images/d]]		- for portal names beginning with "D".
-- [[Module:Portal/images/e]]		- for portal names beginning with "E".
-- [[Module:Portal/images/f]]		- for portal names beginning with "F".
-- [[Module:Portal/images/g]]		- for portal names beginning with "G".
-- [[Module:Portal/images/h]]		- for portal names beginning with "H".
-- [[Module:Portal/images/i]]		- for portal names beginning with "I".
-- [[Module:Portal/images/j]]		- for portal names beginning with "J".
-- [[Module:Portal/images/k]]		- for portal names beginning with "K".
-- [[Module:Portal/images/l]]		- for portal names beginning with "L".
-- [[Module:Portal/images/m]]		- for portal names beginning with "M".
-- [[Module:Portal/images/n]]		- for portal names beginning with "N".
-- [[Module:Portal/images/o]]		- for portal names beginning with "O".
-- [[Module:Portal/images/p]]		- for portal names beginning with "P".
-- [[Module:Portal/images/q]]		- for portal names beginning with "Q".
-- [[Module:Portal/images/r]]		- for portal names beginning with "R".
-- [[Module:Portal/images/s]]		- for portal names beginning with "S".
-- [[Module:Portal/images/t]]		- for portal names beginning with "T".
-- [[Module:Portal/images/u]]		- for portal names beginning with "U".
-- [[Module:Portal/images/v]]		- for portal names beginning with "V".
-- [[Module:Portal/images/w]]		- for portal names beginning with "W".
-- [[Module:Portal/images/x]]		- for portal names beginning with "X".
-- [[Module:Portal/images/y]]		- for portal names beginning with "Y".
-- [[Module:Portal/images/z]]		- for portal names beginning with "Z".
-- [[Module:Portal/images/other]]	- for portal names beginning with any other letters. This includes numbers,
-- 									  letters with diacritics, and letters in non-Latin alphabets.
-- [[Module:Portal/images/aliases]]	- for adding aliases for existing portal names. Use this page for variations
-- 									  in spelling and diacritics, etc., no matter what letter the portal begins with.
--
-- The images data pages are separated by the first letter to reduce server load when images are added, changed, or removed.
-- Previously all the images were on one data page at [[Module:Portal/images]], but this had the disadvantage that all
-- 5,000,000 pages using this module needed to be refreshed every time an image was added or removed.
]==]

local p = {}

local function matchImagePage(s)
	-- Finds the appropriate image subpage given a lower-case
	-- portal name plus the first letter of that portal name.
	if type(s) ~= 'string' or #s < 1 then return end
	local firstLetter = mw.ustring.sub(s, 1, 1)
	local imagePage
	if mw.ustring.find(firstLetter, '^[a-z]') then
		imagePage = 'Module:Portal/images/' .. firstLetter
	else
		imagePage = 'Module:Portal/images/other'
	end
	return mw.loadData(imagePage)[s]
end

local function getAlias(s)
	-- Gets an alias from the image alias data page.
	local aliasData = mw.loadData('Module:Portal/images/aliases')
	for portal, aliases in pairs(aliasData) do
		for _, alias in ipairs(aliases) do
			if alias == s then
				return portal
			end
		end
	end
end

local function getImageName(s)
	-- Gets the image name for a given string.
	if type(s) ~= 'string' or #s < 1 then
		return 'Portal-puzzle.svg'
	end
	s = mw.ustring.lower(s)
	return matchImagePage(s) or matchImagePage(getAlias(s)) or 'Portal-puzzle.svg'
end

function p._portal(portals, args)
	-- This function builds the portal box used by the {{portal}} template.
	local root = mw.html.create('div')
		:addClass('noprint portal')
		:addClass(args.left and 'tleft' or 'tright')
		:css('border', 'solid #aaa 1px')
		:css('margin', args.margin or (args.left == 'yes' and '0.5em 1em 0.5em 0') or '0.5em 0 0.5em 1em')
		:newline()

	-- Start the table. This corresponds to the start of the wikitext table in the old [[Template:Portal]].
	local tableroot = root:tag('table')
		:css('background', '#f9f9f9')
		:css('font-size', '85%')
		:css('line-height', '110%')
		:css('max-width', '175px')
		:css('width', type(args.boxsize) == 'string' and (args.boxsize .. 'px') or nil)

	-- If no portals have been specified, display an error and add the page to a tracking category.
	if not portals[1] then
		tableroot:wikitext('<strong class="error">No portals specified: please specify at least one portal</strong>[[Category:Portal templates without a parameter]]')
	end

	-- Display the portals specified in the positional arguments.
	for _, portal in ipairs(portals) do
		local image = getImageName(portal)

		-- Generate the html for the image and the portal name.
		tableroot
			:newline()
			:tag('tr')
				:css('vertical-align', 'middle')
				:tag('td')
					:css('text-align', 'center')
					:wikitext(string.format('[[File:%s|32x28px|alt=Portal icon|class=noviewer]]', image))
					:done()
				:tag('td')
					:css('padding', '0 0.2em')
					:css('vertical-align', 'middle')
					:css('font-style', 'italic')
					:css('font-weight', 'bold')
					:wikitext(string.format('[[Portal:%s|%s%sportal]]', portal, portal, args['break'] and '<br />' or ' '))
	end
	return tostring(root)
end

function p._image(portals)

	-- Wrapper function to allow getImageName() to be accessed through #invoke.
	return getImageName(portals[1])
end

local function getAllImageTables()
	-- Returns an array containing all image subpages (minus aliases) as loaded by mw.loadData.
	local images = {}
	for i, subpage in ipairs{'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'other'} do
		images[i] = mw.loadData('Module:Portal/images/' .. subpage)
	end
	return images
end

function p._displayAll(portals, args)
	-- This function displays all portals that have portal images. This function is for maintenance purposes and should not be used in
	-- articles, for two reasons: 1) there are over 1500 portals with portal images, and 2) the module doesn't record how the portal
	-- names are capitalized, so the portal links may be broken.
	local lang = mw.language.getContentLanguage()
	local count = 1
	for _, imageTable in ipairs(getAllImageTables()) do
		for portal in pairs(imageTable) do
			portals[count] = lang:ucfirst(portal)
			count = count + 1
		end
	end
	return p._portal(portals, args)
end

function p._imageDupes()
	-- This function searches the image subpages to find duplicate images. If duplicate images exist, it is not necessarily a bad thing,
	-- as different portals might just happen to choose the same image. However, this function is helpful in identifying images that
	-- should be moved to a portal alias for ease of maintenance.
	local exists, dupes = {}, {}
	for _, imageTable in ipairs(getAllImageTables()) do
		for portal, image in pairs(imageTable) do
			if not exists[image] then
				exists[image] = portal
			else
				table.insert(dupes, string.format('The image "[[:File:%s|%s]]" is used for both portals "%s" and "%s".', image, image, exists[image], portal))
			end
		end
	end
	if #dupes < 1 then
		return 'No duplicate images found.'
	else
		return 'The following duplicate images were found:\n* ' .. table.concat(dupes, '\n* ')
	end
end

local function processPortalArgs(args)
	-- This function processes a table of arguments and returns two tables: an array of portal names for processing by ipairs, and a table of
	-- the named arguments that specify style options, etc. We need to use ipairs because we want to list all the portals in the order
	-- they were passed to the template, but we also want to be able to deal with positional arguments passed explicitly, for example
	-- {{portal|2=Politics}}. The behaviour of ipairs is undefined if nil values are present, so we need to make sure they are all removed.
	args = type(args) == 'table' and args or {}
	local portals = {}
	local namedArgs = {}
	for k, v in pairs(args) do
		if type(k) == 'number' and type(v) == 'string' then -- Make sure we have no non-string portal names.
			table.insert(portals, k)
		elseif type(k) ~= 'number' then
			namedArgs[k] = v
		end
	end
	table.sort(portals)
	for i, v in ipairs(portals) do
		portals[i] = args[v]
	end
	return portals, namedArgs
end

local function makeWrapper(funcName)
	-- Processes external arguments and sends them to the other functions.
	return function (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 from the debug console
		-- or from another Lua module.
		local origArgs
		if type(frame.getParent) == 'function' 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.
		local args = {}
		for k, v in pairs(origArgs) do
			if type(v) == 'string' then
				v = mw.text.trim(v)
			end
			if v ~= '' then
				args[k] = v
			end
		end
		return p[funcName](processPortalArgs(args)) -- passes two tables to func: an array of portal names, and a table of named arguments.
	end
end

for _, funcName in ipairs{'portal', 'image', 'imageDupes', 'displayAll'} do
	p[funcName] = makeWrapper('_' .. funcName)
end

return p