Module:Redirect: Difference between revisions

Module:Redirect (edit)

Revision as of 05:11, 11 June 2014

357 bytes added , 10 years ago

add getTarget and isRedirect functions, format comments

Anonymous user

wikipedia>Mr. Stradivarius

@@ 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)
-    -- 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
 return p