Module:Redirect: Difference between revisions

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Module:Redirect (edit)

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45 revisions imported from wikipedia:Module:Redirect: see Topic:Vtixlm0q28eo6jtf

Ondo

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- ---- This module 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 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).
+-- This module provides functions for getting the target of a redirect page.
-p={}
+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 name of a page that a redirect leads to, or nil if it isn't a
+-- redirect.
+function p.getTargetFromText(text)
+	local target = string.match(
+		text,
+		"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)%]%]"
+	) or string.match(
+		text,
+		"^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]|]-)|[^%[%]]-%]%]"
+	)
+	return target and mw.uri.decode(target, 'PATH')
+end
+-- Gets the target of a redirect. If the page specified is not a redirect,
+-- returns nil.
+function p.getTarget(page, fulltext)
+	-- 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 = p.getTargetFromText(titleObj:getContent() or "")
+	if target then
+		local targetTitle = getTitle(target)
+		if targetTitle then
+			if fulltext then
+				return targetTitle.fullText
+			else
+				return targetTitle.prefixedText
+			end
+		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"',
+			fulltext and titleObj.fullText or 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, fulltext)
+	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, fulltext)
+	local ret = target or rname
+	ret = getTitle(ret)
+	if ret then
+		if fulltext then
+			ret = ret.fullText
+		else
+			ret = ret.prefixedText
+		end
+		return bracket:format(ret)
+	else
+		return nil
+	end
+end
+-- Provides access to the luaMain function from wikitext.
 function p.main(frame)
-   args=frame.args
+	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
-   parent=frame.getParent(frame)
+	return p.luaMain(args[1], args.bracket, args.fulltext) or ''
-   if parent then pargs = parent.args else pargs={} end
+end
-   local rname=args[1] or pargs[1] or ""
-   if redirect then
+-- Returns true if the specified page is a redirect, and false otherwise.
-       if mw.ustring.gsub(redirect,"%s","") == "" then return "" end
+function p.luaIsRedirect(page)
-       else return "" end
+	local titleObj = getTitle(page)
-   local rpage=mw.title.new(rname)
+	if not titleObj then
-   local err=""
+		return false
-   if rpage then -- avoid possibly expensive FileExists if we don't have anything
+	end
-      if rpage.id ~= 0 then
+	if titleObj.isRedirect then
-       --  if rpage.fileExists then
+		return true
-            if rpage.isRedirect then
+	else
-               return (tostring(mw.ustring.match(tostring(rpage.getContent(rpage)),"REDIRECT.-%[%[(.-)%]%]")) or [=[<span style="text-color:red;">[[Module:redirect]] error: failed to understand - [[]=] .. rname .. [=[]]</span]=])
+		return false
-            else return rname -- not a redirect so leave the original text (for some general-purpose template use)
+	end
-            end
+end
-      --   else err="File does not exist: "
-      --   end
+-- Provides access to the luaIsRedirect function from wikitext, returning 'yes'
-      else err="File not found (id=0): "
+-- if the specified page is a redirect, and the blank string otherwise.
-      end
+function p.isRedirect(frame)
-   else err="File not found (mw.title.new failed)"
+	local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
-   end
+	if p.luaIsRedirect(args[1]) then
-   return [=[<span style="text-color:red;">[[Module:redirect]] error: ]=] .. err .. [=[ - [[]=] .. rname .. [=[]]</span>]=]
+		return 'yes'
+	else
+		return ''
+	end
 end
 return p