From 1d301a5055328881f348b61ac10b74d175a54a3c Mon Sep 17 00:00:00 2001
From: Omar Roth <omarroth@hotmail.com>
Date: Sun, 11 Feb 2018 22:06:29 -0600
Subject: [PATCH] Add support for different signature functions

---
 src/helpers.cr   | 39 ++++++++++++++++++++++++++++++++-------
 src/invidious.cr | 33 +++++++++++++++++++++++++--------
 2 files changed, 57 insertions(+), 15 deletions(-)

diff --git a/src/helpers.cr b/src/helpers.cr
index b260ec9b..4ac08f9e 100644
--- a/src/helpers.cr
+++ b/src/helpers.cr
@@ -175,14 +175,39 @@ def search(query, client)
   end
 end
 
-def decrypt_signature(a)
-  a = a.split("")
-  a.delete_at(0..2)
-  a = a.reverse
+def swap(a, b)
   c = a[0]
-  a[0] = a[49 % a.size]
-  a[49] = c
-  return a.join("")
+  a[0] = a[b % a.size]
+  a[b % a.size] = c
+  return a
+end
+
+def decrypt_signature(a, base)
+  if a && base
+    a = a.split("")
+
+    if base == "vflG9lb96"
+      a = swap(a, 26)
+      a.reverse!
+      a = swap(a, 8)
+      a = swap(a, 61)
+    elsif base == "vflxuxnEY"
+      a.delete_at(0..2)
+      a.reverse!
+      c = a[0]
+      a[0] = a[49 % a.size]
+      a[49] = c
+    elsif base == "vflAXQwEj"
+      a = swap(a, 26)
+      a.reverse!
+      a = swap(a, 8)
+      a = swap(a, 61)
+    else
+      raise "Could not decrypt signature for player #{base}"
+    end
+
+    return a.join("")
+  end
 end
 
 def rank_videos(db, n)
diff --git a/src/invidious.cr b/src/invidious.cr
index b7bbc5af..2a5ff4e0 100644
--- a/src/invidious.cr
+++ b/src/invidious.cr
@@ -168,12 +168,32 @@ get "/watch" do |env|
     fmt_stream << HTTP::Params.parse(string)
   end
 
-  if fmt_stream[0]?
-    if fmt_stream[0]["s"]?
+  base = nil
+  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
+      base = base["src"]
+      base = base.split("/")[3].split("-")[1]
+    end
+  end
+
+  begin
       fmt_stream.each do |fmt|
-        fmt["url"] = "#{fmt["url"]}&signature=#{decrypt_signature(fmt["s"])}"
+      if fmt["s"]? && !base
+        File.write("info/#{id}.html", video.html)
+        raise "Could not find signature for #{video.id}"
       end
+
+      fmt["url"] = "#{fmt["url"]}&signature=#{decrypt_signature(fmt["s"]?, base)}"
     end
+  rescue ex
+    error_message = ex
+    next templated "error"
   end
 
   # We want lowest quality first
@@ -186,12 +206,8 @@ get "/watch" do |env|
     end
   end
 
-  if adaptive_fmts[0]?
-    if adaptive_fmts[0]["s"]?
       adaptive_fmts.each do |fmt|
-        fmt["url"] = "#{fmt["url"]}&signature=#{decrypt_signature(fmt["s"])}"
-      end
-    end
+    fmt["url"] = "#{fmt["url"]}&signature=#{decrypt_signature(fmt["s"]?, base)}"
   end
 
   rvs = [] of Hash(String, String)
@@ -209,6 +225,7 @@ get "/watch" do |env|
   rating = video.info["avg_rating"].to_f64
 
   engagement = ((video.dislikes.to_f + video.likes.to_f)/video.views * 100)
+
   if video.likes > 0 || video.dislikes > 0
     calculated_rating = (video.likes.to_f/(video.likes.to_f + video.dislikes.to_f) * 4 + 1)
   else