2 # Copyright Michael Orlitzky
4 # http://michael.orlitzky.com/
6 # This program is free software: you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation, either version 3 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful,
12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 # GNU General Public License for more details.
16 # http://www.fsf.org/licensing/licenses/gpl.html
22 class Youtube
< Website
24 VALID_YOUTUBE_URL_REGEX
= /^(http:\/\
/)?([a-z0-9]+\.)?youtube\.com\/((watch
\?v
=)|(v\
/)|([a-z]+\#[a-z]\/[a-z
]\
/[0-9]\/))[a-z0-9_\
-]+
(\
&.*)?\
#?$/i
26 def self.owns_url
?(url
)
27 return url
=~ VALID_YOUTUBE_URL_REGEX
34 # The @format variable just caches the format of the video we're
35 # downloading. Storing it will prevent us from having to calculate
42 video_id
= self.parse_video_id()
44 # The video's URL (the "page data" URL) may be different from the
45 # URL that was passed to the program. We support the /v/video_id
46 # URL format, but that is *not* the main video page where we can
47 # retrieve the "t" parameter. We can only get that from the
48 # /watch?v=video_id form.
49 page_data_url
= "http://www.youtube.com/watch?v=#{video_id}"
50 page_data
= self.get_page_data(page_data_url
)
52 # Get the URL map from the page.
53 fmt_url_map
= get_format_url_map(page_data
)
55 # Figure out which formats are available, and if any are,
56 # choose the best one.
57 available_formats
= fmt_url_map
.keys()
58 desired_format
= get_desired_format(available_formats
)
60 # First we cache the format so that when we're asked for the
61 # video filename later, we don't have to recompute the format.
62 @format = desired_format
64 # And then use whatever URL is available for the desired format.
65 # We assume that all available formats will have an entry in the
67 video_url
= fmt_url_map
[desired_format
]
73 def get_video_filename()
74 # The format -> extension mapping is available on Wikipedia:
76 # http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs
78 # The default extension is .flv.
81 if [18, 22, 35, 37].include?(@format)
87 return (self.parse_video_id() + extension
)
93 # Get the video id from the URL. Should be relatively easy,
94 # unless Youtube supports some URL formats of which I'm unaware.
96 # Both URLs are fairly easy to parse if you handle
97 # them one at a time. The only tricky situation is when
98 # parameters like "&hl=en" are tacked on to the end.
99 # We'll call /watch?v=video_id the "first form."
100 first_form_video_id_regex
= /v=([0-9a-z_\-]+)/i
101 first_form_matches
= first_form_video_id_regex
.match(@url)
102 return first_form_matches
[1] if not (first_form_matches
.nil? ||
103 first_form_matches
.length
< 2)
105 # First form didn't work? Try the second.
106 second_form_video_id_regex
= /\/v\
/([0-9a-z_\-]+)/i
107 second_form_matches
= second_form_video_id_regex
.match(@url)
108 return second_form_matches
[1] if not (second_form_matches
.nil? ||
109 second_form_matches
.length
< 2)
112 third_form_video_id_regex
= /\/([[:alnum:]]+
)$/i
113 third_form_matches
= third_form_video_id_regex
.match(@url)
114 return third_form_matches
[1] if not (third_form_matches
.nil? ||
115 third_form_matches
.length
< 2)
117 # If we made it here, we couldn't figure out the video id. Yes,
118 # this is fatal, since we don't know where the video file is
120 raise StandardError
.new("Could not parse the video id.")
125 def get_format_url_map(page_data
)
126 # Youtube has implemented a new fmt_url_map that (perhaps
127 # unsurprisingly) maps formats to video URLs. This makes it
128 # easyish to parse the video URLs.
130 url_map_regex
= /fmt_url_map=([^&\"]+)/
132 matches
= url_map_regex
.match(page_data
)
134 if (matches
.nil? || matches
.length
< 1)
135 raise StandardError
.new("Could not parse the fmt_url_map Flash variable.")
138 # The map is stored entirely in one Flash variable. The format is
139 # key|value,key|value,...
140 maptext
= CGI
::unescape(matches
[1])
141 entries
= maptext
.split(',')
142 entries
.each
do |entry
|
143 key
= entry
.split('|')[0].to_i
144 value
= entry
.split('|')[1]
148 if (url_map
.length
< 1)
149 raise StandardError
.new("Could not find any valid format URLs.")
156 def get_desired_format(available_formats
)
157 # Check for the presence of formats, in order of preference
158 # (quality). That is, we check for the best formats first. As soon
159 # as a format is found to be available, we return it as the
160 # desired format, since the first format we find is going to be
161 # the best available format.
162 return 37 if available_formats
.include?(37)
163 return 22 if available_formats
.include?(22)
164 return 35 if available_formats
.include?(35)
165 return 18 if available_formats
.include?(18)
166 return 34 if available_formats
.include?(34)
167 return 17 if available_formats
.include?(17)
169 # Available formats can't be empty (we would have raised an error
170 # in get_available_formats), so if there's some unknown format
171 # here we might as well return it as a last resort.
172 return available_formats
[0]