Videos: Add support for attributed descriptions (#3701)
Samantaz Fox
2 years ago
commit
adc605024f
@ -1 +1 @@
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Subproject commit cb16e0343c8f94182615610bfe3c503db89717a7
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Subproject commit 11ec372f72747c09d48ffef04843f72be67d5b54
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@ -0,0 +1,105 @@
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require "json"
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require "uri"
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def parse_command(command : JSON::Any?, string : String) : String?
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on_tap = command.dig?("onTap", "innertubeCommand")
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# 3rd party URL, extract original URL from YouTube tracking URL
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if url_endpoint = on_tap.try &.["urlEndpoint"]?
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youtube_url = URI.parse url_endpoint["url"].as_s
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original_url = youtube_url.query_params["q"]?
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if original_url.nil?
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return ""
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else
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return "<a href=\"#{original_url}\">#{original_url}</a>"
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end
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# 1st party watch URL
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elsif watch_endpoint = on_tap.try &.["watchEndpoint"]?
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video_id = watch_endpoint["videoId"].as_s
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time = watch_endpoint["startTimeSeconds"].as_i
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url = "/watch?v=#{video_id}&t=#{time}s"
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# if string is a timestamp, use the string instead
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# this is a lazy regex for validating timestamps
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if /(?:\d{1,2}:){1,2}\d{2}/ =~ string
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return "<a href=\"#{url}\">#{string}</a>"
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else
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return "<a href=\"#{url}\">#{url}</a>"
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end
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# hashtag/other browse URLs
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elsif browse_endpoint = on_tap.try &.dig?("commandMetadata", "webCommandMetadata")
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url = browse_endpoint["url"].try &.as_s
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# remove unnecessary character in a channel name
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if browse_endpoint["webPageType"]?.try &.as_s == "WEB_PAGE_TYPE_CHANNEL"
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name = string.match(/@[\w\d.-]+/)
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if name.try &.[0]?
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return "<a href=\"#{url}\">#{name.try &.[0]}</a>"
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end
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end
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return "<a href=\"#{url}\">#{string}</a>"
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end
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return "(unknown YouTube desc command)"
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end
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private def copy_string(str : String::Builder, iter : Iterator, count : Int) : Int
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copied = 0
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while copied < count
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cp = iter.next
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break if cp.is_a?(Iterator::Stop)
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str << cp.chr
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# A codepoint from the SMP counts twice
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copied += 1 if cp > 0xFFFF
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copied += 1
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end
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return copied
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end
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def parse_description(desc : JSON::Any?) : String?
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return "" if desc.nil?
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content = desc["content"].as_s
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return "" if content.empty?
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commands = desc["commandRuns"]?.try &.as_a
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return content if commands.nil?
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# Not everything is stored in UTF-8 on youtube's side. The SMP codepoints
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# (0x10000 and above) are encoded as UTF-16 surrogate pairs, which are
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# automatically decoded by the JSON parser. It means that we need to count
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# copied byte in a special manner, preventing the use of regular string copy.
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iter = content.each_codepoint
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index = 0
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return String.build do |str|
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commands.each do |command|
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cmd_start = command["startIndex"].as_i
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cmd_length = command["length"].as_i
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# Copy the text chunk between this command and the previous if needed.
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length = cmd_start - index
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index += copy_string(str, iter, length)
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# We need to copy the command's text using the iterator
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# and the special function defined above.
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cmd_content = String.build(cmd_length) do |str2|
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copy_string(str2, iter, cmd_length)
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end
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str << parse_command(command, cmd_content)
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index += cmd_length
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end
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# Copy the end of the string (past the last command).
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remaining_length = content.size - index
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copy_string(str, iter, remaining_length) if remaining_length > 0
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end
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end
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