fix handle_response, fix signature, fix exception message

lib/cryptomus/configuration.rb

@@ -6,6 +6,7 @@ class Configuration
                   :merchant_id,
                   :user_agent,
                   :connection_config,
+                  :handle_response,
                   :on_error,
                   :logger
 

lib/cryptomus/errors.rb

@@ -11,13 +11,14 @@ class ApiError < Error
       # @!method response_body [Hash,nil]
       attr_reader :response, :status, :response_body
 
-      # @param msg [String]
       # @param response [Faraday::Response,nil]
-      def initialize(msg, response = nil)
+      # @param msg [String,nil]
+      def initialize(response, msg = nil)
         @response = response
         @status = response&.status
         @response_body = response&.body
-        super(msg)
+        msg ||= "Response #{status}, #{response_body}" if response
+        super(msg || self.class.name)
       end
     end
   end

lib/cryptomus/signature.rb

@@ -11,7 +11,7 @@ module Signature
     # @param raw_body [String]
     # @return [String]
     def generate(raw_body)
-      raw_body_encoded = Base64.encode64(raw_body || '')
+      raw_body_encoded = Base64.strict_encode64(raw_body || '')
       Digest::MD5.hexdigest("#{raw_body_encoded}#{Cryptomus.config.api_key}")
     end
   end