Difference between revisions of "Module:Redirect"

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test>Mr. Stradivarius
(handle apostrophes and other characters escaped by {{TALKPAGENAME}}, per protected edit request by User:Jackmcbarn)
test>Mr. Stradivarius
(add getTarget and isRedirect functions, format comments)
Line 1: Line 1:
-- Given a single page name determines what page it redirects to and returns the target page name, or the
+
-- This module provides functions for getting the target of a redirect page.
-- passed page name when not a redirect. The passed page name can be given as plain text or as a page link.
 
-- Returns page name as plain text, or when the bracket parameter is given, as a page link. Returns an
 
-- error message when page does not exist or the redirect target cannot be determined for some reason.
 
  
-- Thus these are roughly the same:
+
local p = {}
-- [[{{#invoke:redirect|main|redirect-page-name}}]] and {{#invoke:redirect|main|redirect-page-name|bracket=yes}}
+
 
 +
-- Gets a mw.title object, using pcall to avoid generating script errors if we
 +
-- are over the expensive function count limit (among other possible causes).
 +
local function getTitle(...)
 +
local success, titleObj = pcall(mw.title.new, ...)
 +
if success then
 +
return titleObj
 +
else
 +
return nil
 +
end
 +
end
 +
 
 +
-- Gets the target of a redirect. If the page specified is not a redirect,
 +
-- returns nil.
 +
function p.getTarget(page)
 +
-- Get the title object. Both page names and title objects are allowed
 +
-- as input.
 +
local titleObj
 +
if type(page) == 'string' or type(page) == 'number' then
 +
titleObj = getTitle(page)
 +
elseif type(page) == 'table' and type(page.getContent) == 'function' then
 +
titleObj = page
 +
else
 +
error(string.format(
 +
"bad argument #1 to 'getTarget'"
 +
.. " (string, number, or title object expected, got %s)",
 +
type(page)
 +
), 2)
 +
end
 +
if not titleObj or not titleObj.isRedirect then
 +
return nil
 +
end
 +
 +
-- Find the target by using string matching on the page content.
 +
local target = string.match(
 +
titleObj:getContent() or "",
 +
"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]]-)%]%]"
 +
)
 +
if target then
 +
local targetTitle = getTitle(target)
 +
if targetTitle then
 +
return targetTitle.prefixedText
 +
else
 +
return nil
 +
end
 +
else
 +
-- The page is a redirect, but matching failed. This indicates a bug in
 +
-- the redirect matching pattern, so throw an error.
 +
error(string.format(
 +
'could not parse redirect on page "%s"',
 +
titleObj.prefixedText
 +
))
 +
end
 +
end
  
local p = {}
+
--[[
 +
-- Given a single page name determines what page it redirects to and returns the
 +
-- target page name, or the passed page name when not a redirect. The passed
 +
-- page name can be given as plain text or as a page link.
 +
--
 +
-- Returns page name as plain text, or when the bracket parameter is given, as a
 +
-- page link. Returns an error message when page does not exist or the redirect
 +
-- target cannot be determined for some reason.
 +
--]]
 +
function p.luaMain(rname, bracket)
 +
if type(rname) ~= "string" or not rname:find("%S") then
 +
return nil
 +
end
 +
bracket = bracket and "[[%s]]" or "%s"
 +
rname = rname:match("%[%[(.+)%]%]") or rname
 +
local target = p.getTarget(rname)
 +
local ret = target or rname
 +
ret = getTitle(ret)
 +
if ret then
 +
ret = ret.prefixedText
 +
return bracket:format(ret)
 +
else
 +
return nil
 +
end
 +
end
  
 +
-- Provides access to the luaMain function from wikitext.
 
function p.main(frame)
 
function p.main(frame)
    -- If called via #invoke, use the args passed into the invoking
+
local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
    -- template, or the args passed to #invoke if any exist. Otherwise
+
return p.luaMain(args[1], args.bracket) or ''
    -- assume args are being passed directly in from the debug console
+
end
    -- or from another Lua module.
 
    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.
 
    local args = {}
 
    for k, v in pairs( origArgs ) do
 
        v = mw.text.trim( v )
 
        if v ~= '' then
 
            args[k] = v
 
        end
 
    end
 
    local rname, bracket = args[1], args.bracket
 
   
 
    if type(rname) ~= "string" or not mw.ustring.match(rname, "%S") then return end
 
    bracket = bracket and "[[%s]]" or "%s"
 
    rname = mw.ustring.match(rname, "%[%[(.+)%]%]") or rname
 
   
 
    -- Get the title object, passing the function through pcall
 
    -- in case we are over the expensive function count limit.
 
    local noError, rpage = pcall(mw.title.new, rname)
 
    if not noError or not rpage then
 
    -- mw.title.new failed, so use the passed page name.
 
    return mw.ustring.format(bracket, rname)
 
    elseif not rpage.isRedirect then
 
        -- the page is not a redirect, so use the normalized name of the page we
 
        -- were given.
 
        return mw.ustring.format(bracket, rpage.prefixedText)
 
    end
 
  
    local redirect = mw.ustring.match(rpage:getContent() or "", "^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]]-)%]%]" )
+
-- Returns "yes" if the specified page is a redirect, and the blank string
    if redirect then
+
-- otherwise.
        -- Decode html entities and percent encodings.
+
function p.isRedirect(frame)
        redirect = mw.text.decode(redirect, true)
+
local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
        redirect = mw.uri.decode(redirect, 'WIKI')
+
local titleObj = getTitle(args[1])
        return mw.ustring.format(bracket, redirect)
+
if not titleObj then
    else
+
return ''
        return mw.ustring.format('<span class="error">[[Module:redirect]] error: could not parse redirect - [[%s]]</span>', rname)
+
end
    end
+
if titleObj.isRedirect then
 +
return 'yes'
 +
else
 +
return ''
 +
end
 
end
 
end
  
 
return p
 
return p

Revision as of 05:11, 11 June 2014

This module contains functions to find the target of a redirect page.

Main

The main function accepts the name of a single page. It determines if the page is a redirect; if so it looks up the page, extracts the target, and returns the target name as text. Its usage is {{#invoke:redirect|main|redirect-page-name}}.

The template normally neither takes nor gives square brackets, so to show the result as a link use [[{{#invoke:redirect|main|redirect-page-name}}]]. An error is produced if the redirect does not exist, but for versatility no error is given if the file is not a redirect (returns the original text) or if the file name is blank (returns blank).

However, if the parameter bracket is given a nonblank value, brackets will be passed on if present.

Examples

  • {{#invoke:redirect|main|WP:AFC}} → WP:AFC
  • {{#invoke:redirect|main|[[WP:AFD]]|bracket=yes}}WP:AFD
  • {{#invoke:redirect|main|Wikipedia:Articles for deletion}} → wikipedia:Articles for deletion

Note: WP:AFC and WP:AFD are both redirects, but Wikipedia:Articles for deletion is not.

LuaMain

If you want to use the main function from another Lua module, you may want to use the luaMain function. This provides the same functionality as the main function, but doesn't require that a frame object be available.

To use this, first load the module.

local mRedirect = require('Module:Redirect')

Then use the function with the following syntax:

mRedirect.luaMain(rname, bracket)

rname is the name of the redirect page, and if bracket is anything but false or nil, the module will produce a link rather than just a page name.

IsRedirect

The isRedirect function is used from wiki pages to find out if a given page is a redirect or not. If the page is a redirect, the function returns "yes", and if not the output is blank. Its usage is {{#invoke:redirect|isRedirect|redirect-page-name}}.

Examples

  • {{#invoke:redirect|isRedirect|WP:AFC}}
  • {{#invoke:redirect|isRedirect|Wikipedia:Articles for deletion}}

LuaIsRedirect

The isRedirect can be accessed from other Lua modules in the same way as the main function:

local mRedirect = require('Module:Redirect')
mRedirect.luaIsRedirect(rname)

GetTarget

The getTarget function fetches the target page name of a redirect page, and is only usable from Lua. If the page specified is a redirect, then the target is returned; otherwise the function returns nil.

To use it, first load the module.

local mRedirect = require('Module:Redirect')

Then use the function with the following syntax:

mRedirect.getTarget(page)

page can be either the name of the redirect page as a string, or a mw.title object.

See also


-- This module provides functions for getting the target of a redirect page.

local p = {}

-- Gets a mw.title object, using pcall to avoid generating script errors if we
-- are over the expensive function count limit (among other possible causes).
local function getTitle(...)
	local success, titleObj = pcall(mw.title.new, ...)
	if success then
		return titleObj
	else
		return nil
	end
end

-- Gets the target of a redirect. If the page specified is not a redirect,
-- returns nil.
function p.getTarget(page)
	-- Get the title object. Both page names and title objects are allowed
	-- as input.
	local titleObj
	if type(page) == 'string' or type(page) == 'number' then
		titleObj = getTitle(page)
	elseif type(page) == 'table' and type(page.getContent) == 'function' then
		titleObj = page
	else
		error(string.format(
			"bad argument #1 to 'getTarget'"
				.. " (string, number, or title object expected, got %s)",
			type(page)
		), 2)
	end
	if not titleObj or not titleObj.isRedirect then
		return nil
	end
	
	-- Find the target by using string matching on the page content.
	local target = string.match(
		titleObj:getContent() or "",
		"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]]-)%]%]"
	)
	if target then
		local targetTitle = getTitle(target)
		if targetTitle then
			return targetTitle.prefixedText
		else
			return nil
		end
	else
		-- The page is a redirect, but matching failed. This indicates a bug in
		-- the redirect matching pattern, so throw an error.
		error(string.format(
			'could not parse redirect on page "%s"',
			titleObj.prefixedText
		))
	end
end

--[[
-- Given a single page name determines what page it redirects to and returns the
-- target page name, or the passed page name when not a redirect. The passed
-- page name can be given as plain text or as a page link.
-- 
-- Returns page name as plain text, or when the bracket parameter is given, as a
-- page link. Returns an error message when page does not exist or the redirect
-- target cannot be determined for some reason.
--]]
function p.luaMain(rname, bracket)
	if type(rname) ~= "string" or not rname:find("%S") then
		return nil
	end
	bracket = bracket and "[[%s]]" or "%s"
	rname = rname:match("%[%[(.+)%]%]") or rname
	local target = p.getTarget(rname)
	local ret = target or rname
	ret = getTitle(ret)
	if ret then
		ret = ret.prefixedText
		return bracket:format(ret)
	else
		return nil
	end
end

-- Provides access to the luaMain function from wikitext.
function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
	return p.luaMain(args[1], args.bracket) or ''
end

-- Returns "yes" if the specified page is a redirect, and the blank string
-- otherwise.
function p.isRedirect(frame)
	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
	local titleObj = getTitle(args[1])
	if not titleObj then
		return ''
	end
	if titleObj.isRedirect then
		return 'yes'
	else
		return ''
	end
end

return p