Module:Redirect: Difference between revisions

add getTarget and isRedirect functions, format comments
(handle apostrophes and other characters escaped by {{TALKPAGENAME}}, per protected edit request by User:Jackmcbarn)
(add getTarget and isRedirect functions, format comments)
Line 1:
-- This module provides functions for getting the target of a redirect page.
-- 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.
 
-- Thus these are roughly the same:
-- [[{{#invoke:redirect|main|redirect-page-name}}]] and {{#invoke:redirect|main|redirect-page-name|bracket=yes}}
 
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})
-- If called via #invoke, use the args passed into the invoking
return p.luaMain(args[1], args.bracket) or ''
-- template, or the args passed to #invoke if any exist. Otherwise
end
-- assume args are being passed directly in from the debug console
-- 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
 
-- Returns "yes" if the specified page is a redirect, and the blank string
local redirect = mw.ustring.match(rpage:getContent() or "", "^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]]-)%]%]" )
-- otherwise.
if redirect then
function p.isRedirect(frame)
-- Decode html entities and percent encodings.
local args = require('Module:Arguments').getArgs(frame, {frameOnly = true})
redirect = mw.text.decode(redirect, true)
local titleObj = getTitle(args[1])
redirect = mw.uri.decode(redirect, 'WIKI')
if not titleObj then
return mw.ustring.format(bracket, redirect)
return ''
else
end
return mw.ustring.format('<span class="error">[[Module:redirect]] error: could not parse redirect - [[%s]]</span>', rname)
if titleObj.isRedirect then
end
return 'yes'
else
return ''
end
end