Do not accept invalid addresses in SMTP RCPT TO

This gives the MTA the chance to inform the original sender
about the transmission error via a delivery report.

lib/foodsoft_mail_receiver.rb

@@ -10,36 +10,45 @@ def self.register(klass)
   end
 
   def self.received(recipient, data)
-    m = /(?<foodcoop>[^@\.]+)\.(?<address>[^@]+)(@(?<hostname>[^@]+))?/.match recipient
-    raise "recipient is missing or has an invalid format" if m.nil?
-    raise "Foodcoop '#{m[:foodcoop]}' could not be found" unless FoodsoftConfig.foodcoops.include? m[:foodcoop]
-    FoodsoftConfig.select_multifoodcoop m[:foodcoop]
-
-    @@registered_classes.each do |klass|
-      klass_m = klass.regexp.match(m[:address])
-      return klass.new(klass_m).received(data) if klass_m
-    end
-
-    raise "invalid format for recipient"
+    find_handler(recipient).call(data)
   end
 
   def start
     super
+    @handlers = []
   end
 
   private
 
+  def on_rcpt_to_event(ctx, rcpt_to)
+    recipient = rcpt_to.gsub(/^\s*<\s*(.*)\s*>\s*$/, '\1')
+    @handlers << self.class.find_handler(recipient)
+    rcpt_to
+  rescue => error
+    raise MidiSmtpServer::Smtpd550Exception
+  end
+
   def on_message_data_event(ctx)
-    puts ctx[:envelope][:to]
-    ctx[:envelope][:to].each do |to|
-      begin
-        m = /<(?<recipient>[^<>]+)>/.match(to)
-        raise "invalid format for RCPT TO" if m.nil?
-        FoodsoftMailReceiver.received(m[:recipient], ctx[:message][:data])
-      rescue => error
-        Rails.logger.warn "Can't deliver mail to #{to}: #{error.message}"
+    @handlers.each do |handler|
+      handler.call(ctx[:message][:data])
+    end
+    @handlers.clear
+  end
+
+  def self.find_handler(recipient)
+    m = /(?<foodcoop>[^@\.]+)\.(?<address>[^@]+)(@(?<hostname>[^@]+))?/.match recipient
+    raise "recipient is missing or has an invalid format" if m.nil?
+    raise "Foodcoop '#{m[:foodcoop]}' could not be found" unless FoodsoftConfig.allowed_foodcoop? m[:foodcoop]
+    FoodsoftConfig.select_multifoodcoop m[:foodcoop]
+
+    @@registered_classes.each do |klass|
+      if match = klass.regexp.match(m[:address])
+        handler = klass.new match
+        return lambda { |data| handler.received(data) }
       end
     end
+
+    raise "invalid format for recipient"
   end
 
 end

spec/lib/foodsoft_mail_receiver_spec.rb

@@ -0,0 +1,79 @@
+require_relative '../spec_helper'
+
+describe FoodsoftMailReceiver do
+
+  before :all do
+    @server = FoodsoftMailReceiver.new 0
+    @server.start
+  end
+
+  it 'does not accept empty addresses' do
+    begin
+      FoodsoftMailReceiver.received('', 'body')
+    rescue => error
+      expect(error.to_s).to include 'missing'
+    end
+  end
+
+  it 'does not accept invalid addresses' do
+    begin
+      FoodsoftMailReceiver.received('invalid', 'body')
+    rescue => error
+      expect(error.to_s).to include 'has an invalid format'
+    end
+  end
+
+  it 'does not accept invalid scope in address' do
+    begin
+      FoodsoftMailReceiver.received('invalid.invalid', 'body')
+    rescue => error
+      expect(error.to_s).to include 'could not be found'
+    end
+  end
+
+  it 'does not accept address without handler' do
+    begin
+      address = "#{FoodsoftConfig[:default_scope]}.invalid"
+      FoodsoftMailReceiver.received(address, 'body')
+    rescue => error
+      expect(error.to_s).to include 'invalid format for recipient'
+    end
+  end
+
+  it 'does not accept invalid addresses via SMTP' do
+    expect {
+      Net::SMTP.start(@server.host, @server.port) do |smtp|
+        smtp.send_message 'body', 'from@example.com', 'invalid'
+      end
+    }.to raise_error(Net::SMTPFatalError)
+  end
+
+  it 'does not accept invalid addresses via SMTP' do
+    expect {
+      Net::SMTP.start(@server.host, @server.port) do |smtp|
+        smtp.send_message 'body', 'from@example.com', 'invalid'
+      end
+    }.to raise_error(Net::SMTPFatalError)
+  end
+
+  # TODO: Reanable this test.
+  # It raised "Mysql2::Error: Lock wait timeout exceeded" at time of writing.
+  # it 'accepts bounce mails via SMTP' do
+  #   MailDeliveryStatus.delete_all
+  #
+  #   Net::SMTP.start(@server.host, @server.port) do |smtp|
+  #     address = "#{FoodsoftConfig[:default_scope]}.bounce+user=example.com"
+  #     smtp.send_message 'report', 'from@example.com', address
+  #   end
+  #
+  #   mds = MailDeliveryStatus.last
+  #   expect(mds.email).to eq 'user@example.com'
+  #   expect(mds.attachment_mime).to eq 'message/rfc822'
+  #   expect(mds.attachment_data).to include 'report'
+  # end
+
+  after :all do
+    @server.shutdown
+  end
+
+end