From 13ef4440d01b606e07c5e96f0f0117ead2ba9f1c Mon Sep 17 00:00:00 2001
From: Omar Roth <omarroth@hotmail.com>
Date: Thu, 22 Feb 2018 13:01:37 -0600
Subject: [PATCH] Replace signature function with generic catchall

---
 src/helpers.cr   | 50 ++++++++++--------------------------------------
 src/invidious.cr | 39 +++++++++----------------------------
 2 files changed, 19 insertions(+), 70 deletions(-)

diff --git a/src/helpers.cr b/src/helpers.cr
index 9ce527a7..d3c89e03 100644
--- a/src/helpers.cr
+++ b/src/helpers.cr
@@ -175,54 +175,24 @@ def search(query, client)
   end
 end
 
-def swap(a, b)
+def splice(a, b)
   c = a[0]
   a[0] = a[b % a.size]
   a[b % a.size] = c
   return a
 end
 
-def decrypt_signature(a, base)
+def decrypt_signature(a)
   a = a.split("")
 
-  case base
-  when "vflG9lb96"
-    a = swap(a, 26)
-    a.reverse!
-    a = swap(a, 8)
-    a = swap(a, 61)
-  when "vflxuxnEY"
-    a.delete_at(0..2)
-    a.reverse!
-    c = a[0]
-    a[0] = a[49 % a.size]
-    a[49] = c
-  when "vflAXQwEj"
-    a = swap(a, 26)
-    a.reverse!
-    a = swap(a, 8)
-    a = swap(a, 61)
-  when "vflNpPGQq"
-    a = swap(a, 26)
-    a.reverse!
-    a = swap(a, 8)
-    a = swap(a, 61)
-  when "vflCCoUi2"
-    a = swap(a, 26)
-    a.reverse!
-    a = swap(a, 8)
-    a = swap(a, 61)
-  when "vflg4IfMn"
-    a = swap(a, 6)
-    a = swap(a, 64)
-    a = swap(a, 25)
-    a = swap(a, 53)
-    a.delete_at(0..1)
-    a.reverse!
-    a.delete_at(0..2)
-  else
-    raise "Could not decrypt signature for player #{base}"
-  end
+  a.delete_at(0..1)
+  a = splice(a, 2)
+  a = splice(a, 51)
+  a = splice(a, 9)
+  a.delete_at(0..1)
+  a.reverse!
+  a = splice(a, 15)
+  a.delete_at(0..2)
 
   return a.join("")
 end
diff --git a/src/invidious.cr b/src/invidious.cr
index cb95647c..ae9e0978 100644
--- a/src/invidious.cr
+++ b/src/invidious.cr
@@ -177,34 +177,9 @@ get "/watch" do |env|
     fmt_stream << HTTP::Params.parse(string)
   end
 
-  base = nil
+  signature = false
   if fmt_stream[0]? && fmt_stream[0]["s"]?
-    base = video.html.xpath_node(%q(//script[@name="player/base"]))
-
-    if !base
-      base = video.html.xpath_node(%q(//script[@name="player_ias/base"]))
-    end
-
-    if !base
-      error_message = "Could not find signature for #{video.id}"
-      next templated "error"
-    end
-
-    base = base["src"]
-    base = base.split("/")[3].split("-")[1]
-
-    begin
-      decrypt_signature(fmt_stream[0]["s"], base)
-    rescue ex
-      error_message = ex.message
-      next templated "error"
-    end
-  end
-
-  fmt_stream.each do |fmt|
-    if base
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], base)
-    end
+    signature = true
   end
 
   # We want lowest quality first
@@ -217,9 +192,13 @@ get "/watch" do |env|
     end
   end
 
-  adaptive_fmts.each do |fmt|
-    if base
-      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], base)
+  if signature
+    adaptive_fmts.each do |fmt|
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
+    end
+
+    fmt_stream.each do |fmt|
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"])
     end
   end