Only add signature if stream has decrypted signature

src/helpers.cr

@@ -183,21 +183,26 @@ def swap(a, b)
 end
 
 def decrypt_signature(a, base)
-  if a && base
     a = a.split("")
 
-    if base == "vflG9lb96"
+  case base
+  when "vflG9lb96"
       a = swap(a, 26)
       a.reverse!
       a = swap(a, 8)
       a = swap(a, 61)
-    elsif base == "vflxuxnEY"
+  when "vflxuxnEY"
       a.delete_at(0..2)
       a.reverse!
       c = a[0]
       a[0] = a[49 % a.size]
       a[49] = c
-    elsif base == "vflAXQwEj"
+  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)
@@ -208,7 +213,6 @@ def decrypt_signature(a, base)
 
     return a.join("")
   end
-end
 
 def rank_videos(db, n)
   top = [] of {Float64, String}

src/invidious.cr

@@ -176,24 +176,26 @@ get "/watch" do |env|
       base = video.html.xpath_node(%q(//script[@name="player_ias/base"]))
     end
 
-    if base
+    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
 
-  begin
       fmt_stream.each do |fmt|
-      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)}"
+    if base
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], base)
     end
-  rescue ex
-    error_message = ex
-    next templated "error"
   end
 
   # We want lowest quality first
@@ -207,7 +209,9 @@ get "/watch" do |env|
   end
 
       adaptive_fmts.each do |fmt|
-    fmt["url"] = "#{fmt["url"]}&signature=#{decrypt_signature(fmt["s"]?, base)}"
+    if base
+      fmt["url"] += "&signature=" + decrypt_signature(fmt["s"], base)
+    end
   end
 
   rvs = [] of Hash(String, String)