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