Module:Redirect/sandbox

This is the module sandbox page for Module:Redirect (diff).
See also the companion subpage for test cases (run).
-- 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 = {}

function warOnGsub(text, repl)
	if repl then
		text = mw.ustring.gsub(text, "%%", "%%%%")
	else
	    text = mw.ustring.gsub(text, "([%?%^%$%(%)%%%.%[%]%*%+%-%]])", "%%%1")
	end
	return text
end

function getArgs(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 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
    return args
end

function getRedirect(rname)
    -- Get the title object, passing the function through pcall 
    -- in case we are over the expensive function count limit.
    -- returning nil indicates the redirect did not parse, but nonexistent or non-redirect pages are not nil.
    local noError, rpage = pcall(mw.title.new, rname)
    if not noError or noError and not rpage or not rpage.isRedirect then
        -- mw.title.new failed, or the page is not a redirect, so use the passed page name.
        return rname
    end

    local redirect = mw.ustring.match(rpage:getContent() or "", "^%s*#[Rr][Ee][Dd][Ii][Rr][Ee][Cc][Tt]%s*:?%s*%[%[([^%[%]]-)%]%]" )
    if redirect then
        -- Decode html entities and percent encodings.
        redirect = mw.text.decode(redirect, true)
        redirect = mw.uri.decode(redirect, 'WIKI')
    end
    return redirect
end

function p.main(frame)

    local args = getArgs(frame)
    local rname, bracket = args[1], args.bracket
    bracket = bracket and "[[%s]]" or "%s"
    if type(rname) ~= "string" or not mw.ustring.match(rname, "%S") then return end
    rname = mw.ustring.match(rname, "%[%[(.+)%]%]") or rname

    local redirect = getRedirect(rname)

    if redirect then
        return mw.ustring.format(bracket, redirect)
    else
        return mw.ustring.format('<span class="error">[[Module:redirect]] error: could not parse redirect - [[%s]]</span>', rname)
    end
end

function getPage(sourceName)

    if type(sourceName) ~= "string" or not mw.ustring.match(sourceName, "%S") then return end
    -- the following delink doesn't make as much sense for this usage but is done for consistency.
    sourceName = mw.ustring.match(sourceName, "%[%[(.+)%]%]") or sourceName

    local noError, title = pcall(mw.title.new, sourceName)
    if not noError then
        text = nil -- should be anyway; nil means error
    else
    	text = title:getContent()
    end
    return text
    
end

function nowikize(frame, text, nowiki, default)
	if (default or nowiki) and (nowiki ~= 'no') then
		text = frame:preprocess('<pre><nowiki>'..text..'</nowiki></pre>')
	end
	return text
end

function p.block(frame)
    -- this feature takes an initial page as an argument.  It obtains all the links from that page 
    -- starting from the first instance of some link named as start=, and replaces every link after
    -- that which is a redirect with the non-redirected canonical name, up until pcall throws an error
    -- due to expense.  Finally, it returns the substituted page.

    local args = getArgs(frame)
    local sourceName, start, text, pipe, nowiki = args[1], args[2], args.text, args.pipe, args.nowiki
    if type(sourceName) == "string" then sourceName = mw.text.trim(sourceName) or sourceName end
    if type(start) == "string" then start = mw.text.trim(start) or start end
    if type(pipe) == "string" then pipe = mw.text.trim(pipe) or pipe end
    
    if type(text) ~= "string" then 
        text = getPage(sourceName)-- we're getting text = the contents of the page at args[1]
    end

    if not(text) then -- nothing to work from
        return -- optional error here
    end
    
    local originalText = text -- I don't want to even think about conflicts...
    local nextLink = mw.ustring.gmatch(originalText, "%[%[([^%]|]*)|?([^%]]-)%]%]")
    local link = " " -- true
    local display = "" -- false
    while link do
        if not(start) and link ~= " " then
            newLink = getRedirect(link)
            -- if the page does redirect, do it if "pipe" isn't set or a pipe is present or absent as specified
            if newLink and (newLink ~= link) and ((not pipe) or (pipe == 'make') or (display and (pipe == 'yes')) or (not display and (pipe == 'no'))) then
            	if pipe == 'make' and (not display) then
            		-- if we're changing the link and there's no |something, create |the old name in the link.
            		newLink = newLink .. "|" .. link
            	end
                link = warOnGsub(link, nil)
            	newLink = warOnGsub(newLink, true)
            	text = mw.ustring.gsub(text, link, newLink, 1) or text -- no sense looking past 1, we'll be back...
            end
        end

        link, display = nextLink()
        if display then
        	display = mw.ustring.match(display, "(%S+)") -- nil if no non-space
        end
        if link then link = mw.text.trim(link) or link end
        
        if start and link then
            if start == link then
                start = nil
            else
                link = " " -- discard all links before the one to start with
            end
        end
    end
    return nowikize(frame, text, nowiki, true)
                
end

return p
Module:Redirect/sandbox

Main

Examples

LuaMain

IsRedirect

Examples

LuaIsRedirect

GetTarget

See also
