Merge pull request #15 from omarroth/extract-signature

Add ability to automatically extract video signature funtion
6 years ago · 9c3bf5fd27
parent e1ec1b6837 0bb07e55f5
commit 9c3bf5fd27
2 changed files with 73 additions and 10 deletions
--- a/src/invidious.cr
+++ b/src/invidious.cr
@ -173,7 +173,6 @@ video_threads.times do |i|
 end

 top_videos = [] of Video
-
 spawn do
  if CONFIG.dl_api_key
    DetectLanguage.configure do |config|
@ -213,6 +212,20 @@ spawn do
  end
 end

+# Refresh decrypt function
+decrypt_function = [] of {name: String, value: Int32}
+spawn do
+  loop do
+    begin
+      client = make_client(YT_URL)
+      decrypt_function = update_decrypt_function(client)
+    rescue ex
+    end
+
+    Fiber.yield
+  end
+end
+
 before_all do |env|
  if env.request.cookies.has_key? "SID"
    headers = HTTP::Headers.new
@ -296,11 +309,11 @@ get "/watch" do |env|

  if adaptive_fmts[0]? && adaptive_fmts[0]["s"]?
    adaptive_fmts.each do |fmt|
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], decrypt_function)
    end

    fmt_stream.each do |fmt|
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], decrypt_function)
    end
  end

@ -433,11 +446,11 @@ get "/embed/:id" do |env|

  if adaptive_fmts[0]? && adaptive_fmts[0]["s"]?
    adaptive_fmts.each do |fmt|
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], decrypt_function)
    end

    fmt_stream.each do |fmt|
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], decrypt_function)
    end
  end

@ -1044,7 +1057,7 @@ get "/api/manifest/dash/id/:id" do |env|

  if adaptive_fmts[0]? && adaptive_fmts[0]["s"]?
    adaptive_fmts.each do |fmt|
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], decrypt_function)
    end
  end

--- a/src/invidious/helpers.cr
+++ b/src/invidious/helpers.cr
@ -324,16 +324,66 @@ def splice(a, b)
  return a
 end

-def decrypt_signature(a)
+def decrypt_signature(a, code)
  a = a.split("")

-  a.reverse!
-  a.delete_at(0..0)
-  a = splice(a, 11)
+  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 update_decrypt_function(client)
+  # Video with signature
+  document = client.get("/watch?v=CvFH_6DNRCY").body
+  url = document.match(/src="(?<url>\/yts\/jsbin\/player-.{9}\/en_US\/base.js)"/).not_nil!["url"]
+  player = client.get(url).body
+
+  function_name = player.match(/\(b\|\|\(b="signature"\),d.set\(b,(?<name>[a-zA-Z]{2})\(c\)\)\)/).not_nil!["name"]
+  function_body = player.match(/#{function_name}=function\(a\){(?<body>[^}]+)}/).not_nil!["body"]
+  function_body = function_body.split(";")[1..-2]
+
+  var_name = function_body[0][0, 2]
+
+  operations = {} of String => String
+  matches = player.delete("\n").match(/var #{var_name}={((?<op1>[a-zA-Z]{2}:[^}]+})),((?<op2>[a-zA-Z]{2}:[^}]+})),((?<op3>[a-zA-Z]{2}:[^}]+}))};/).not_nil!
+  3.times do |i|
+    operation = matches["op#{i + 1}"]
+    op_name = operation[0, 2]
+
+    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 + ".")
+    op_name = function[0, 2]
+
+    function = function.lchop(op_name + "(a,")
+    value = function.rchop(")").to_i
+
+    decrypt_function << {name: operations[op_name], value: value}
+  end
+
+  return decrypt_function
+end
+
 def rank_videos(db, n, filter, url)
  top = [] of {Float64, String}