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--[[
$Id$
Copyright © 2007-2016 the VideoLAN team
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
--]]
-- Helper function to get a parameter's value in a URL
function get_url_param( url, name )
local _, _, res = string.find( url, "[&?]"..name.."=([^&]*)" )
return res
end
-- Helper function to copy a parameter when building a new URL
function copy_url_param( url, name )
local value = get_url_param( url, name )
return ( value and "&"..name.."="..value or "" ) -- Ternary operator
end
function get_arturl()
local iurl = get_url_param( vlc.path, "iurl" )
if iurl then
return iurl
end
local video_id = get_url_param( vlc.path, "v" )
if not video_id then
return nil
end
return vlc.access.."://img.youtube.com/vi/"..video_id.."/default.jpg"
end
-- Pick the most suited format available
function get_fmt( fmt_list )
local prefres = vlc.var.inherit(nil, "preferred-resolution")
if prefres < 0 then
return nil
end
local fmt = nil
for itag,height in string.gmatch( fmt_list, "(%d+)/%d+x(%d+)/[^,]+" ) do
-- Apparently formats are listed in quality
-- order, so we take the first one that works,
-- or fallback to the lowest quality
fmt = itag
if tonumber(height) <= prefres then
break
end
end
return fmt
end
-- Buffering iterator to parse through the HTTP stream several times
-- without making several HTTP requests
function buf_iter( s )
s.i = s.i + 1
local line = s.lines[s.i]
if not line then
-- Put back together statements split across several lines,
-- otherwise we won't be able to parse them
repeat
local l = s.stream:readline()
if not l then break end
line = line and line..l or l -- Ternary operator
until string.match( line, "};$" )
if line then
s.lines[s.i] = line
end
end
return line
end
-- Helper to search and extract code from javascript stream
function js_extract( js, pattern )
js.i = 0 -- Reset to beginning
for line in buf_iter, js do
local ex = string.match( line, pattern )
if ex then
return ex
end
end
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
return nil
end
-- Descramble the URL signature using the javascript code that does that
-- in the web page
function js_descramble( sig, js_url )
-- Fetch javascript code
local js = { stream = vlc.stream( js_url ), lines = {}, i = 0 }
if not js.stream then
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
return sig
end
-- Look for the descrambler function's name
-- c&&a.set("signature",br(c));
local descrambler = js_extract( js, "%.set%(\"signature\",(.-)%(" )
if not descrambler then
vlc.msg.dbg( "Couldn't extract youtube video URL signature descrambling function name" )
return sig
end
-- Fetch the code of the descrambler function
-- Go=function(a){a=a.split("");Fo.sH(a,2);Fo.TU(a,28);Fo.TU(a,44);Fo.TU(a,26);Fo.TU(a,40);Fo.TU(a,64);Fo.TR(a,26);Fo.sH(a,1);return a.join("")};
local rules = js_extract( js, "^"..descrambler.."=function%([^)]*%){(.-)};" )
if not rules then
vlc.msg.dbg( "Couldn't extract youtube video URL signature descrambling rules" )
return sig
end
-- Get the name of the helper object providing transformation definitions
local helper = string.match( rules, ";(..)%...%(" )
if not helper then
vlc.msg.dbg( "Couldn't extract youtube video URL signature transformation helper name" )
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
return sig
end
-- Fetch the helper object code
-- var Fo={TR:function(a){a.reverse()},TU:function(a,b){var c=a[0];a[0]=a[b%a.length];a[b]=c},sH:function(a,b){a.splice(0,b)}};
local transformations = js_extract( js, "[ ,]"..helper.."={(.-)};" )
if not transformations then
vlc.msg.dbg( "Couldn't extract youtube video URL signature transformation code" )
return sig
end
-- Parse the helper object to map available transformations
local trans = {}
for meth,code in string.gmatch( transformations, "(..):function%([^)]*%){([^}]*)}" ) do
-- a=a.reverse()
if string.match( code, "%.reverse%(" ) then
trans[meth] = "reverse"
-- a.splice(0,b)
elseif string.match( code, "%.splice%(") then
trans[meth] = "slice"
-- var c=a[0];a[0]=a[b%a.length];a[b]=c
elseif string.match( code, "var c=" ) then
trans[meth] = "swap"
else
vlc.msg.warn("Couldn't parse unknown youtube video URL signature transformation")
end
end
-- Parse descrambling rules, map them to known transformations
-- and apply them on the signature
local missing = false
for meth,idx in string.gmatch( rules, "..%.(..)%([^,]+,(%d+)%)" ) do
idx = tonumber( idx )
if trans[meth] == "reverse" then
sig = string.reverse( sig )
elseif trans[meth] == "slice" then
sig = string.sub( sig, idx + 1 )
elseif trans[meth] == "swap" then
if idx > 1 then
sig = string.gsub( sig, "^(.)("..string.rep( ".", idx - 1 )..")(.)(.*)$", "%3%2%1%4" )
elseif idx == 1 then
sig = string.gsub( sig, "^(.)(.)", "%2%1" )
end
else
vlc.msg.dbg("Couldn't apply unknown youtube video URL signature transformation")
missing = true
end
end
if missing then
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
end
return sig
end
-- Parse and pick our video URL
function pick_url( url_map, fmt, js_url )
local path = nil
for stream in string.gmatch( url_map, "[^,]+" ) do
-- Apparently formats are listed in quality order,
-- so we can afford to simply take the first one
local itag = string.match( stream, "itag=(%d+)" )
if not fmt or not itag or tonumber( itag ) == tonumber( fmt ) then
local url = string.match( stream, "url=([^&,]+)" )
if url then
url = vlc.strings.decode_uri( url )
local sig = string.match( stream, "sig=([^&,]+)" )
if not sig then
-- Scrambled signature
sig = string.match( stream, "s=([^&,]+)" )
if sig then
vlc.msg.dbg( "Found "..string.len( sig ).."-character scrambled signature for youtube video URL, attempting to descramble... " )
if js_url then
sig = js_descramble( sig, js_url )
else
vlc.msg.err( "Couldn't process youtube video URL, please check for updates to this script" )
end
end
end
local signature = ""
if sig then
signature = "&signature="..sig
end
path = url..signature
break
end
end
end
return path
end
-- Probe function.
function probe()
return ( ( vlc.access == "http" or vlc.access == "https" )
and string.match( vlc.path, "^www%.youtube%.com/" )
and (
string.match( vlc.path, "/watch%?" ) -- the html page
or string.match( vlc.path, "/live$" ) -- user live stream html page
or string.match( vlc.path, "/live%?" ) -- user live stream html page
or string.match( vlc.path, "/get_video_info%?" ) -- info API
or string.match( vlc.path, "/v/" ) -- video in swf player
or string.match( vlc.path, "/embed/" ) -- embedded player iframe
) )
end
-- Parse function.
function parse()
if string.match( vlc.path, "/watch%?" )
or string.match( vlc.path, "/live$" )
or string.match( vlc.path, "/live%?" )
then -- This is the HTML page's URL
-- fmt is the format of the video
-- (cf. http://en.wikipedia.org/wiki/YouTube#Quality_and_formats)
fmt = get_url_param( vlc.path, "fmt" )
while true do
-- Try to find the video's title
line = vlc.readline()
if not line then break end
if string.match( line, "<meta property=\"og:title\"" ) then
_,_,name = string.find( line, "content=\"(.-)\"" )
name = vlc.strings.resolve_xml_special_chars( name )
name = vlc.strings.resolve_xml_special_chars( name )
end
if not description then
description = string.match( line, "<p id=\"eow%-description\"[^>]*>(.-)</p>" )
if description then
description = vlc.strings.resolve_xml_special_chars( description )
end
end
if string.match( line, "<meta property=\"og:image\"" ) then
_,_,arturl = string.find( line, "content=\"(.-)\"" )
arturl = vlc.strings.resolve_xml_special_chars( arturl )
end
if string.match(line, "\"author\": *\"(.-)\"") then
_,_,artist = string.find(line, "\"author\": *\"(.-)\"")
end
-- JSON parameters, also formerly known as "swfConfig",
-- "SWF_ARGS", "swfArgs", "PLAYER_CONFIG", "playerConfig" ...
if string.match( line, "ytplayer%.config" ) then
local js_url = string.match( line, "\"js\": *\"(.-)\"" )
if js_url then
js_url = string.gsub( js_url, "\\/", "/" )
js_url = string.gsub( js_url, "^//", vlc.access.."://" )
end
if not fmt then
fmt_list = string.match( line, "\"fmt_list\": *\"(.-)\"" )
if fmt_list then
fmt_list = string.gsub( fmt_list, "\\/", "/" )
fmt = get_fmt( fmt_list )
end
end
url_map = string.match( line, "\"url_encoded_fmt_stream_map\": *\"(.-)\"" )
if url_map then
-- FIXME: do this properly
url_map = string.gsub( url_map, "\\u0026", "&" )
path = pick_url( url_map, fmt, js_url )
end
if not path then
-- If this is a live stream, the URL map will be empty
-- and we get the URL from this field instead
local hlsvp = string.match( line, "\"hlsvp\": *\"(.-)\"" )
if hlsvp then
hlsvp = string.gsub( hlsvp, "\\/", "/" )
path = hlsvp
end
end
-- There is also another version of the parameters, encoded
-- differently, as an HTML attribute of an <object> or <embed>
-- tag; but we don't need it now
end
end
if not path then
local video_id = get_url_param( vlc.path, "v" )
if video_id then
-- Passing no "el" parameter to /get_video_info seems to
-- let it default to "embedded", and both known values
-- of "embedded" and "detailpage" are wrong and fail for
-- various restricted videos, so we pass a different value
path = vlc.access.."://www.youtube.com/get_video_info?video_id="..video_id.."&el=detail"..copy_url_param( vlc.path, "fmt" )
vlc.msg.warn( "Couldn't extract video URL, falling back to alternate youtube API" )
end
end
if not path then
vlc.msg.err( "Couldn't extract youtube video URL, please check for updates to this script" )
return { }
end
if not arturl then
arturl = get_arturl()
end
return { { path = path; name = name; description = description; artist = artist; arturl = arturl } }
elseif string.match( vlc.path, "/get_video_info%?" ) then -- video info API
local line = vlc.readline() -- data is on one line only
local fmt = get_url_param( vlc.path, "fmt" )
if not fmt then
local fmt_list = string.match( line, "&fmt_list=([^&]*)" )
if fmt_list then
fmt_list = vlc.strings.decode_uri( fmt_list )
fmt = get_fmt( fmt_list )
end
end
local url_map = string.match( line, "&url_encoded_fmt_stream_map=([^&]*)" )
if url_map then
url_map = vlc.strings.decode_uri( url_map )
path = pick_url( url_map, fmt )
end
if not path then
-- If this is a live stream, the URL map will be empty
-- and we get the URL from this field instead
local hlsvp = string.match( line, "&hlsvp=([^&]*)" )
if hlsvp then
hlsvp = vlc.strings.decode_uri( hlsvp )
path = hlsvp
end
end
if not path then
vlc.msg.err( "Couldn't extract youtube video URL, please check for updates to this script" )
return { }
end
local title = string.match( line, "&title=([^&]*)" )
if title then
title = string.gsub( title, "+", " " )
title = vlc.strings.decode_uri( title )
end
local artist = string.match( line, "&author=([^&]*)" )
if artist then
artist = string.gsub( artist, "+", " " )
artist = vlc.strings.decode_uri( artist )
end
local arturl = string.match( line, "&thumbnail_url=([^&]*)" )
if arturl then
arturl = vlc.strings.decode_uri( arturl )
end
return { { path = path, title = title, artist = artist, arturl = arturl } }
else -- Other supported URL formats
local video_id = string.match( vlc.path, "/[^/]+/([^?]*)" )
if not video_id then
vlc.msg.err( "Couldn't extract youtube video URL" )
return { }
end
return { { path = vlc.access.."://www.youtube.com/watch?v="..video_id..copy_url_param( vlc.path, "fmt" ) } }
end
end