Modul:URLutil

---

--[=[ URLutil 2013-05-06
Utilities for URL etc. on www.
* getAuthority()
* getHost()
* getPort()
* getScheme()
* isAuthority()
* isDomain()
* isHost()
* isIP()
* isIPv4()
* isIPv6()
* isMailAddress()
* isMailLink()
* isProtocolDialog
* isProtocolWiki
* isResourceURL()
* isSuspiciousURL()
* isUnescapedURL()
* isWebURL()
Only [[dotted decimal]] notation for IPv4 supported.
Does not support dotted hexadecimal, dotted octal, or single-number formats.
IPv6 URL (bracketed) not yet implemented; might need Wikintax escaping anyway.
]=]



-- table for export
local URLutil = {}



URLutil.getAuthority = function ( url )
    if type( url ) == "string" then
        local host, colon, port = mw.ustring.match( url .. "/", "^%s*%w*:?//([%w.%%-]+)(:?)([%d]*)/" )
        if URLutil.isHost( host ) then
            host = mw.ustring.lower( host )
            if colon == ":" then
                if port:find( "^[1-9]" ) then
                    return ( host .. ":" .. port )
                end
            elseif #port == 0 then
                return host
            end
        end
    end
    return false
end -- URLutil.getAuthority()



URLutil.getHost = function ( url )
    local auth = URLutil.getAuthority( url )
    if auth then
        return mw.ustring.match( auth, "^([%w%.%%-]+):?[%d]*$" )
    end
    return false
end -- URLutil.getHost()



URLutil.getPort = function ( url )
    url = URLutil.getAuthority( url )
    if url then
        url = url:match( ":([1-9][0-9]*)$" )
        if type( url ) == "string" then
            return tonumber( url )
        end
    end
    return false
end -- URLutil.getPort()



URLutil.getScheme = function ( url )
    if type( url ) == "string" then
        local prot, colon, slashes = url:match( "^%s*([a-zA-Z]*)(:?)(//)" )
        if slashes == "//" then
            if colon == ":" then
                if #prot > 2 then
                    return prot:lower() .. "://"
                end
            elseif #prot == 0 then
                return "//"
            end
        end
    end
    return false
end -- URLutil.getScheme()



URLutil.isAuthority = function ( s )
    if type( s ) == "string" then
        local host, colon, port = mw.ustring.match( s, "^%s*([%w%.%%-]+)(:?)(%d*)%s*$" )
        if colon == ":" then
            port = port:match( "^[1-9][0-9]*$" )
            if type( port ) ~= "string" then
                return false
            end
        elseif port ~= "" then
            return false
        end
        return URLutil.isHost( host )
    end
    return false
end -- URLutil.isAuthority()



URLutil.isDomain = function ( s )
    if type( s ) == "string" then
        s = mw.ustring.match( s, "^%s*([%w%.%%-]+%w)%.[a-zA-Z][a-zA-Z]+%s*$" )
        if type( s ) == "string" then
            if mw.ustring.find( s, "^%w" ) then
                if mw.ustring.find( s, "..", 1, true ) then
                    return false
                else
                    return true
                end
            end
        end
    end
    return false
end -- URLutil.isDomain()



URLutil.isHost = function ( s )
    return URLutil.isDomain( s ) or URLutil.isIP( s )
end -- URLutil.isHost()



URLutil.isIP = function ( s )
    return URLutil.isIPv4( s ) and 4 or URLutil.isIPv6( s ) and 6
end -- URLutil.isIP()



URLutil.isIPv4 = function ( s )
    local function legal( n )
              return ( tonumber( n ) < 256 )
          end
    if type( s ) == "string" then
        local p1, p2, p3, p4 = s:match( "^%s*([12][0-9]?[0-9]?)%.([012][0-9]?[0-9]?)%.([012][0-9]?[0-9]?)%.([012][0-9]?[0-9]?)%s*$" )
        if p1 and p2 and p3 and p4 then
            return legal( p1 ) and legal( p2 ) and legal( p3 ) and legal( p4 )
        end
    end
    return false
end -- URLutil.isIPv4()



URLutil.isIPv6 = function ( s )
    local dcolon, groups
    if type( s ) ~= "string"
        or s:len() == 0
        or s:find( "[^:%x]" ) -- only colon and hex digits are legal chars
        or s:find( "^:[^:]" ) -- can begin or end with :: but not with single :
        or s:find( "[^:]:$" )
        or s:find( ":::" )
    then
        return false
    end
    s = mw.text.trim( s )
    s, dcolon = s:gsub( "::", ":" )
    if dcolon > 1 then
        return false
    end -- at most one ::
    s = s:gsub( "^:?", ":" ) -- prepend : if needed, upper
    s, groups = s:gsub( ":%x%x?%x?%x?", "" ) -- remove valid groups, and count them
    return ( ( dcolon == 1 and groups < 8 ) or
             ( dcolon == 0 and groups == 8 ) )
        and ( s:len() == 0 or ( dcolon == 1 and s == ":" ) ) -- might be one dangling : if original ended with ::
end -- URLutil.isIPv6()



URLutil.isMailAddress = function ( s )
    if type( s ) == "string" then
        s = mw.ustring.match( s, "^%s*[%w%.%%_-]+@([%w%.%%-]+)%s*$" )
        return URLutil.isDomain( s )
    end
    return false
end -- URLutil.isMailAddress()



URLutil.isMailLink = function ( s )
    if type( s ) == "string" then
        local addr
        s, addr = mw.ustring.match( s, "^%s([Mm][Aa][Ii][Ll][Tt][Oo]):(%S[%w%.%%_-]*@[%w%.%%-]+)%s$*" )
        if type( s ) == "string" then
            if s:lower() == "mailto" then
                return URLutil.isMailAddress( addr )
            end
        end
    end
    return false
end -- URLutil.isMailLink()



local function isProtocolAccepted( prot, supplied )
    if type( prot ) == "string" then
        local scheme, colon, slashes = mw.ustring.match( prot, "^%s*([a-zA-Z]*)(:?)(/?/?)%s*$" )
        if slashes ~= "/" then
            if scheme == "" then
                if colon ~= ":" and slashes == "//" then
                    return true
                end
             elseif colon == ":" or slashes == "" then
                local s = supplied:match( " " .. scheme:lower() .. " " )
                if type( s ) == "string" then
                    return true
                end
            end
        end
    end
    return false
end -- isProtocolAccepted()



URLutil.isProtocolDialog = function ( prot )
    return isProtocolAccepted( prot, " mailto irc ircs telnet " )
end -- URLutil.isProtocolDialog()



URLutil.isProtocolWiki = function ( prot )
    return isProtocolAccepted( prot,
                               " ftp git http https nntp svn worldwind " )
end -- URLutil.isProtocolWiki()



URLutil.isResourceURL = function ( url )
    local scheme = URLutil.getScheme( url )
    if scheme then
        local s = " // http:// https:// ftp:// "
        s = s:find( " " .. scheme .. " " )
        if s then
            if URLutil.getAuthority( url ) then
                if not url:match( "%S%s+%S" ) then
                    return true
                end
            end
        end
    end
    return false
end -- URLutil.isResourceURL()



URLutil.isSuspiciousURL = function ( url )
    if URLutil.isResourceURL( url ) then
        local s = URLutil.getAuthority( url )
        local pat = "[%[|%]" ..
                    mw.ustring.char( 8201, 45, 8207, 8234, 45, 8239, 8288 )
                    .. "]"
        if s:find( "@" )
           or url:find( "''" )
           or url:find( pat )
           or url:find( "[%.,]$" ) then
            return true
        end
        -- TODO  zero width character
        return false
    end
    return true
end -- URLutil.isSuspiciousURL()



URLutil.isUnescapedURL = function ( url, trailing )
    if type( trailing ) ~= "string" then
        if URLutil.isWebURL( url ) then
            if url:match( "[%[|%]]" ) then
                return true
            end
        end
    end
    return false
end -- URLutil.isUnescapedURL()



URLutil.isWebURL = function ( url )
    if URLutil.getScheme( url ) and URLutil.getAuthority( url ) then
        if not url:match( "%S%s+%S" ) then
            return true
        end
    end
    return false
end -- URLutil.isWebURL()



-- Provide template access and expose URLutil table to require

local p = {}

function p.getAuthority( frame )
    return URLutil.getAuthority( frame.args[ 1 ] ) or ""
end
function p.getHost( frame )
    return URLutil.getHost( frame.args[ 1 ] ) or ""
end
function p.getPort( frame )
    return URLutil.getPort( frame.args[ 1 ] ) or ""
end
function p.getScheme( frame )
    return URLutil.getScheme( frame.args[ 1 ] ) or ""
end
function p.isAuthority( frame )
    return URLutil.isAuthority( frame.args[ 1 ] ) and "1" or ""
end
function p.isDomain( frame )
    return URLutil.isDomain( frame.args[ 1 ] ) and "1" or ""
end
function p.isHost( frame )
    return URLutil.isHost( frame.args[ 1 ] ) and "1" or ""
end
function p.isIP( frame )
    return URLutil.isIP( frame.args[ 1 ] ) or ""
end
function p.isIPv4( frame )
    return URLutil.isIPv4( frame.args[ 1 ] ) and "1" or ""
end
function p.isIPv6( frame )
    return URLutil.isIPv6( frame.args[ 1 ] ) and "1" or ""
end
function p.isMailAddress( frame )
    return URLutil.isMailAddress( frame.args[ 1 ] ) and "1" or ""
end
function p.isMailLink( frame )
    return URLutil.isMailLink( frame.args[ 1 ] ) and "1" or ""
end
function p.isProtocolDialog( frame )
    return URLutil.isProtocolDialog( frame.args[ 1 ] ) and "1" or ""
end
function p.isProtocolWiki( frame )
    return URLutil.isProtocolWiki( frame.args[ 1 ] ) and "1" or ""
end
function p.isResourceURL( frame )
    return URLutil.isResourceURL( frame.args[ 1 ] ) and "1" or ""
end
function p.isSuspiciousURL( frame )
    return URLutil.isSuspiciousURL( frame.args[ 1 ] ) and "1" or ""
end
function p.isUnescapedURL( frame )
    return URLutil.isUnescapedURL( frame.args[ 1 ], frame.args[ 2 ] ) and "1" or ""
end
function p.isWebURL( frame )
    return URLutil.isWebURL( frame.args[ 1 ] ) and "1" or ""
end
function p.URLutil()
    return URLutil
end

return p