refactor: move lib/postal/received_header to app/lib/received_header

app/lib/received_header.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class ReceivedHeader
+
+  OUR_HOSTNAMES = {
+    smtp: Postal.config.dns.smtp_server_hostname,
+    http: Postal.config.web.host
+  }.freeze
+
+  class << self
+
+    def generate(server, helo, ip_address, method)
+      our_hostname = OUR_HOSTNAMES[method]
+      if our_hostname.nil?
+        raise Error, "`method` is invalid (must be one of #{OUR_HOSTNAMES.join(', ')})"
+      end
+
+      header = "by #{our_hostname} with #{method.to_s.upcase}; #{Time.now.utc.rfc2822}"
+
+      if server.nil? || server.privacy_mode == false
+        hostname = DNSResolver.local.ip_to_hostname(ip_address)
+        header = "from #{helo} (#{hostname} [#{ip_address}]) #{header}"
+      end
+
+      header
+    end
+
+  end
+
+end

app/lib/smtp_server/client.rb

@@ -366,8 +366,8 @@ module SMTPServer
       @headers = {}
       @receiving_headers = true
 
-      received_header = Postal::ReceivedHeader.generate(@credential&.server, @helo_name, @ip_address, :smtp)
-                                              .force_encoding("BINARY")
+      received_header = ReceivedHeader.generate(@credential&.server, @helo_name, @ip_address, :smtp)
+                                      .force_encoding("BINARY")
 
       @data << "Received: #{received_header}\r\n"
       @headers["received"] = [received_header]

app/models/incoming_message_prototype.rb

@@ -95,7 +95,7 @@ class IncomingMessagePrototype
           content: attachment[:data]
         }
       end
-      mail.header["Received"] = Postal::ReceivedHeader.generate(@server, @source_type, @ip, :http)
+      mail.header["Received"] = ReceivedHeader.generate(@server, @source_type, @ip, :http)
       mail.to_s
     end
   end

app/models/outgoing_message_prototype.rb

@@ -177,7 +177,7 @@ class OutgoingMessagePrototype
           content: attachment[:data]
         }
       end
-      mail.header["Received"] = Postal::ReceivedHeader.generate(@server, @source_type, @ip, :http)
+      mail.header["Received"] = ReceivedHeader.generate(@server, @source_type, @ip, :http)
       mail.message_id = "<#{@message_id}>"
       mail.to_s
     end