Use zlib for compression when saving session cookie

Gemfile

@@ -7,3 +7,7 @@ gem "xxhash"
 gem "sequel"
 
 gem "json"
+
+gem "base64"
+
+gem "zlib"

session.rb

@@ -1,49 +1,62 @@
 require "base64"
+require "zlib"
 require "json"
 
-def set_session(request, response, key, val)
+def set_session(request, response, key, val, uid = nil)
   session = request.cookies["session"]
-  session = "e30=\n" if session.nil?
+  session = session.nil? ? "{}" : Zlib::Inflate.inflate(Base64.decode64(session))
-  session = JSON.parse(Base64.decode64(session))
+  session = JSON.parse(session)
   session[key] = val
-  session = Base64.encode64(JSON.generate(session))
+  compressed = Zlib::Deflate.deflate(JSON.generate(session))
+  encoded = Base64.encode64(compressed)
   response.set_cookie("session",
-                      value: session,
+                      value: encoded,
                       path: "/",
                       expires: Time.now + 360 * 24 * 60 * 60)
-rescue JSON::ParserError
+  begin
+    DB["UPDATE SignedInUsers SET last_used_at = CURRENT_TIMESTAMP WHERE code = ?", uid].update if uid
+  rescue Sequel::Error => e
+    File.write("log/main.log", "DB Error: #{e.message} when updating last_used_at for #{uid}\n", mode: "a")
+  end
+rescue JSON::ParserError, Zlib::Error
   response.delete_cookie("session")
 end
 
-def get_session(request, response, key)
+def get_session(request, response, key, uid = nil)
   session = request.cookies["session"]
-  session = "{}" if session.nil?
+  session = session.nil? ? "{}" : Zlib::Inflate.inflate(Base64.decode64(session))
-  session = JSON.parse(Base64.decode64(session))
+  session = JSON.parse(session)
+  begin
+    DB["UPDATE SignedInUsers SET last_used_at = CURRENT_TIMESTAMP WHERE code = ?", uid].update if uid
+  rescue Sequel::Error => e
+    File.write("log/main.log", "DB Error: #{e.message} when updating last_used_at for #{uid}\n", mode: "a")
+  end
   session[key]
-rescue JSON::ParserError
+rescue JSON::ParserError, Zlib::Error
   response.delete_cookie("session")
   ""
 end
 
 def get_session_all(request, response)
   session = request.cookies["session"]
-  session = "{}" if session.nil?
+  session = session.nil? ? "{}" : Zlib::Inflate.inflate(Base64.decode64(session))
-  JSON.parse(Base64.decode64(session))
+  JSON.parse(session)
-rescue JSON::ParserError
+rescue JSON::ParserError, Zlib::Error
   response.delete_cookie("session")
   ""
 end
 
 def rm_session(request, response, key)
   session = request.cookies["session"]
-  session = "{}" if session.nil?
+  session = session.nil? ? "{}" : Zlib::Inflate.inflate(Base64.decode64(session))
-  session = JSON.parse(Base64.decode64(session))
+  session = JSON.parse(session)
   session.delete(key)
-  session = Base64.encode64(JSON.generate(session))
+  compressed = Zlib::Deflate.deflate(JSON.generate(session))
+  encoded = Base64.encode64(compressed)
   response.set_cookie("session",
-                      value: session,
+                      value: encoded,
                       path: "/",
                       expires: Time.now + 360 * 24 * 60 * 60)
-rescue JSON::ParserError
+rescue JSON::ParserError, Zlib::Error
   response.delete_cookie("session")
 end