module Sisimai::Lhost::GSuite

Sisimai::Lhost::GSuite parses a bounce email which created by G Suite. Methods in the module are called from only Sisimai::Message.

Constants

Indicators
MarkingsOf
MessagesOf
ReBackbone

Public Class Methods

description() click to toggle source
# File lib/sisimai/lhost/gsuite.rb, line 197
def description; return 'G Suite: https://gsuite.google.com'; end
make(mhead, mbody) click to toggle source

Parse bounce messages from G Suite (Transfer from G Suite to a destinaion host) @param [Hash] mhead Message headers of a bounce email @param [String] mbody Message body of a bounce email @return [Hash] Bounce data list and message/rfc822 part @return [Nil] it failed to parse or the arguments are missing

# File lib/sisimai/lhost/gsuite.rb, line 27
def make(mhead, mbody)
  return nil unless mhead['from'].end_with?('<mailer-daemon@googlemail.com>')
  return nil unless mhead['subject'].start_with?('Delivery Status Notification')
  return nil unless mhead['x-gm-message-state']

  require 'sisimai/rfc1894'
  fieldtable = Sisimai::RFC1894.FIELDTABLE
  permessage = {}     # (Hash) Store values of each Per-Message field

  dscontents = [Sisimai::Lhost.DELIVERYSTATUS]
  emailsteak = Sisimai::RFC5322.fillet(mbody, ReBackbone)
  bodyslices = emailsteak[0].split("\n")
  readcursor = 0      # (Integer) Points the current cursor position
  recipients = 0      # (Integer) The number of 'Final-Recipient' header
  endoferror = false  # (Integer) Flag for a blank line after error messages
  anotherset = {}     # (Hash) Another error information
  emptylines = 0      # (Integer) The number of empty lines
  v = nil

  while e = bodyslices.shift do
    # Read error messages and delivery status lines from the head of the email
    # to the previous line of the beginning of the original message.
    if readcursor == 0
      # Beginning of the bounce message or message/delivery-status part
      readcursor |= Indicators[:deliverystatus] if e =~ MarkingsOf[:message]
    end
    next if (readcursor & Indicators[:deliverystatus]) == 0

    if f = Sisimai::RFC1894.match(e)
      # "e" matched with any field defined in RFC3464
      next unless o = Sisimai::RFC1894.field(e)
      v = dscontents[-1]

      if o[-1] == 'addr'
        # Final-Recipient: rfc822; kijitora@example.jp
        # X-Actual-Recipient: rfc822; kijitora@example.co.jp
        if o[0] == 'final-recipient'
          # Final-Recipient: rfc822; kijitora@example.jp
          if v['recipient']
            # There are multiple recipient addresses in the message body.
            dscontents << Sisimai::Lhost.DELIVERYSTATUS
            v = dscontents[-1]
          end
          v['recipient'] = o[2]
          recipients += 1
        else
          # X-Actual-Recipient: rfc822; kijitora@example.co.jp
          v['alias'] = o[2]
        end
      elsif o[-1] == 'code'
        # Diagnostic-Code: SMTP; 550 5.1.1 <userunknown@example.jp>... User Unknown
        v['spec'] = o[1]
        v['diagnosis'] = o[2]
      else
        # Other DSN fields defined in RFC3464
        next unless fieldtable[o[0]]
        v[fieldtable[o[0]]] = o[2]

        if fieldtable[o[0]] == 'lhost'
          # Do not set an email address as a hostname in "lhost" value
          v['lhost'] = '' if v['lhost'].include?('@')
        end

        next unless f == 1
        permessage[fieldtable[o[0]]] = o[2]
      end
    else
      # The line does not begin with a DSN field defined in RFC3464
      # Append error messages continued from the previous line
      if endoferror == false && v && ! v['diagnosis'].to_s.empty?
        endoferror ||= true if e.empty?

        next if endoferror
        next unless e.start_with?(' ')
        v['diagnosis'] << e

      elsif e =~ MarkingsOf[:error]
        # Detect SMTP session error or connection error
        # The response from the remote server was:
        anotherset['diagnosis'] << e
      else
        # ** Address not found **
        #
        # Your message wasn't delivered to * because the address couldn't be found.
        # Check for typos or unnecessary spaces and try again.
        #
        # The response from the remote server was:
        # 550 #5.1.0 Address rejected.
        next if e =~ MarkingsOf[:html]

        if anotherset['diagnosis']
          # Continued error messages from the previous line like
          # "550 #5.1.0 Address rejected."
          next if e =~ /\AContent-Type:/
          next if emptylines > 5
          if e.empty?
            # Count and next()
            emptylines += 1
            next
          end
          anotherset['diagnosis'] << ' ' << e
        else
          # ** Address not found **
          #
          # Your message wasn't delivered to * because the address couldn't be found.
          # Check for typos or unnecessary spaces and try again.
          next if e.empty?
          next unless e =~ MarkingsOf[:message]
          anotherset['diagnosis'] = e
        end
      end
    end
  end
  return nil unless recipients > 0

  dscontents.each do |e|
    # Set default values if each value is empty.
    e['lhost'] ||= permessage['rhost']
    permessage.each_key { |a| e[a] ||= permessage[a] || '' }

    if anotherset['diagnosis']
      # Copy alternative error message
      e['diagnosis'] = anotherset['diagnosis'] unless e['diagnosis']

      if e['diagnosis'] =~ /\A\d+\z/
        e['diagnosis'] = anotherset['diagnosis']
      else
        # More detailed error message is in "anotherset"
        as = nil  # status
        ar = nil  # replycode

        e['status']    ||= ''
        e['replycode'] ||= ''

        if e['status'] == '' || e['status'].start_with?('4.0.0', '5.0.0')
          # Check the value of D.S.N. in anotherset
          as = Sisimai::SMTP::Status.find(anotherset['diagnosis'])
          if as && as[-3, 3] != '0.0'
            # The D.S.N. is neither an empty nor *.0.0
            e['status'] = as
          end
        end

        if e['replycode'].empty? || e['replycode'].start_with?('400', '500')
          # Check the value of SMTP reply code in anotherset
          ar = Sisimai::SMTP::Reply.find(anotherset['diagnosis'])
          if ar && ar[-2, 2].to_i != 0
            # The SMTP reply code is neither an empty nor *00
            e['replycode'] = ar
          end
        end

        if (as || ar) && (anotherset['diagnosis'].size > e['diagnosis'].size)
          # Update the error message in e['diagnosis']
          e['diagnosis'] = anotherset['diagnosis']
        end
      end
    end

    e['diagnosis'] = Sisimai::String.sweep(e['diagnosis'])
    MessagesOf.each_key do |r|
      # Guess an reason of the bounce
      next unless MessagesOf[r].any? { |a| e['diagnosis'].include?(a) }
      e['reason'] = r
      break
    end
  end

  return { 'ds' => dscontents, 'rfc822' => emailsteak[1] }
end