Youtube Playlist Parser for VLC Media Player

playlist_youtube.lua

--[[
 Youtube playlist importer for VLC media player 1.1 and 2.0
 Copyright 2012 Guillaume Le Maout
 
 Authors:  Guillaume Le Maout
 Contact: http://addons.videolan.org/messages/?action=newmessage&username=exebetche
 
 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.
--]]
 
--[[
 MODified by Kai Gillmann, 19.01.2013, kaigillmann@googlemail.com:
 VLC HAS already a youtube importer, but not for playlists. IMO this mentioned one is
 better than this one, because it opens the video in the best possible video resolution.
 So i decided to remove all parts of the code which is not responsible for list handling.
 Now this lua script parses the list, as wanted, but for each video opened, the vlc default
 Youtube script is used, so the videos will be displayed properly.
--]]
 
-- 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
 
-- Probe function.
function probe()
     if vlc.access ~= "http" and vlc.access ~= "https" then
	     return false
     end
	     
     return string.match(vlc.path:match("([^/]+)"),"%w+.youtube.com") and (string.match(vlc.path, "list="))
end
 
-- Parse function.
function parse()
	if string.match( vlc.path, "list=" ) then
		local playlist_parsed, playlistData, line, s, item
		local p = {}
		local id_ref = {}
		local index = 1
		local playlistID = get_url_param( vlc.path, "list" )
		local videoID = get_url_param( vlc.path, "v" )
		local playlistURL = "http://www.youtube.com/list_ajax?action_get_list=1&style=xml&list="..playlistID

		while true do
			playlistData = ""
			line = ""
			s = nil
			s = vlc.stream(playlistURL.."&index="..index)
			while line do
				playlistData = playlistData..line
				line = s:readline()
			end

			playlist_parsed = nil
			playlist_parsed = parse_xml(playlistData).root.video
			
			for i, video in ipairs(playlist_parsed) do
				vlc.msg.err(i.." "..video.encrypted_id.CDATA)
				if id_ref[video.encrypted_id.CDATA] 
				and id_ref[video.encrypted_id.CDATA] == i
				then
					return p
				else
					id_ref[video.encrypted_id.CDATA] = i
				end
				
				item = nil
				item = {}
				item.path = "http://www.youtube.com/watch?v="..video.encrypted_id.CDATA
				item.title = video.title.CDATA
				item.artist = video.author.CDATA
				item.arturl = video.thumbnail.CDATA
				--~ item.description = video.description
				--~ item.rating = video.rating
				table.insert (p, item)
			end
			if #playlist_parsed == 100 then
				index = index +100
			else
				return p
			end
		end
	end
end
 
 
function parse_xml(data)
	local tree = {}
	local stack = {}
	local tmp = {}
	local tmpTag = ""
	local level = 0

	table.insert(stack, tree)

	for op, tag, attr, empty, val in string.gmatch(
		data, 
		"<(%p?)([^%s>/]+)([^>]-)(%/?)>[%s\r\n\t]*([^<]*)[%s\r\n\t]*") do
		if op=="?" then
			--~ DOCTYPE
		elseif op=="/" then
			if level>0 then
			level = level - 1
			table.remove(stack)
			end
		else
		level = level + 1

		if op=="!" then
			stack[level]['CDATA'] = vlc.strings.resolve_xml_special_chars(
			string.gsub(tag..attr, "%[CDATA%[(.+)%]%]", "%1"))
			attr = ""
			level = level - 1
		elseif type(stack[level][tag]) == "nil" then
			stack[level][tag] = {}
			table.insert(stack, stack[level][tag])
		else
			if type(stack[level][tag][1]) == "nil" then
			 tmp = nil
			 tmp = stack[level][tag]
			 stack[level][tag] = nil
			 stack[level][tag] = {}
			 table.insert(stack[level][tag], tmp)
			end
			tmp = nil
			tmp = {}
			table.insert(stack[level][tag], tmp)
			table.insert(stack, tmp)
			end

			if val~="" then
			stack[level][tag]['CDATA'] = {}
			stack[level][tag]['CDATA'] = vlc.strings.resolve_xml_special_chars(val)
			end

			if attr ~= "" then
			stack[level][tag]['ATTR'] = {}
				string.gsub(attr, 
				"(%w+)=([\"'])(.-)%2", 
				function (name, _, value)
				 stack[level][tag]['ATTR'][name] = value
				end)
			end

			if empty ~= "" then
				level = level - 1
				table.remove(stack)
			end
		end
	end
	return tree
end