71 行
1.9 KiB
Crystal
71 行
1.9 KiB
Crystal
def fetch_decrypt_function(id = "CvFH_6DNRCY")
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client = make_client(YT_URL)
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document = client.get("/watch?v=#{id}&gl=US&hl=en&disable_polymer=1").body
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url = document.match(/src="(?<url>\/yts\/jsbin\/player_ias-.{9}\/en_US\/base.js)"/).not_nil!["url"]
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player = client.get(url).body
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function_name = player.match(/^(?<name>[^=]+)=function\(a\){a=a\.split\(""\)/m).not_nil!["name"]
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function_body = player.match(/^#{Regex.escape(function_name)}=function\(a\){(?<body>[^}]+)}/m).not_nil!["body"]
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function_body = function_body.split(";")[1..-2]
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var_name = function_body[0][0, 2]
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var_body = player.delete("\n").match(/var #{Regex.escape(var_name)}={(?<body>(.*?))};/).not_nil!["body"]
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operations = {} of String => String
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var_body.split("},").each do |operation|
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op_name = operation.match(/^[^:]+/).not_nil![0]
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op_body = operation.match(/\{[^}]+/).not_nil![0]
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case op_body
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when "{a.reverse()"
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operations[op_name] = "a"
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when "{a.splice(0,b)"
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operations[op_name] = "b"
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else
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operations[op_name] = "c"
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end
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end
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decrypt_function = [] of {name: String, value: Int32}
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function_body.each do |function|
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function = function.lchop(var_name).delete("[].")
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op_name = function.match(/[^\(]+/).not_nil![0]
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value = function.match(/\(a,(?<value>[\d]+)\)/).not_nil!["value"].to_i
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decrypt_function << {name: operations[op_name], value: value}
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end
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return decrypt_function
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end
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def decrypt_signature(fmt, code)
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if !fmt["s"]?
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return ""
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end
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a = fmt["s"]
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a = a.split("")
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code.each do |item|
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case item[:name]
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when "a"
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a.reverse!
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when "b"
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a.delete_at(0..(item[:value] - 1))
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when "c"
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a = splice(a, item[:value])
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end
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end
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signature = a.join("")
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return "&#{fmt["sp"]?}=#{signature}"
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end
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def splice(a, b)
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c = a[0]
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a[0] = a[b % a.size]
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a[b % a.size] = c
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return a
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end
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