Module: Sisimai::RFC3464

Defined in:

lib/sisimai/rfc3464.rb,
lib/sisimai/rfc3464/thirdparty.rb

Overview

Sisimai::RFC3464 - bounce mail decoder class for Fallback.

Defined Under Namespace

Modules: ThirdParty

Constant Summary

Indicators =

Sisimai::Lhost.INDICATORS

Boundaries =

[
  # When the new value added, the part of the value should be listed in delimiters variable
  # defined at Sisimai::RFC2045.makeFlat() method
  "Content-Type: message/rfc822",
  "Content-Type: text/rfc822-headers",
  "Content-Type: message/partial",
  "Content-Disposition: inline", # See lhost-amavis-*.eml, lhost-facebook-*.eml
].freeze

StartingOf =

{message: ["Content-Type: message/delivery-status"]}.freeze

FieldTable =

Sisimai::RFC1894.FIELDTABLE

Class Method Summary

• .description ⇒ Object
• .inquire(mhead, mbody) ⇒ Hash, Nil

  Decode a bounce mail which have fields defined in RFC3464.

Class Method Details

.description ⇒ Object

# File 'lib/sisimai/rfc3464.rb', line 271

def description; 'RFC3464'; end

.inquire(mhead, mbody) ⇒ Hash, Nil

Decode a bounce mail which have fields defined in RFC3464

Parameters:

• mhead (Hash) —

  Message headers of a bounce email

• mbody (String) —

  Message body of a bounce email

Returns:

• (Hash) —

  Bounce data list and message/rfc822 part

• (Nil) —

  it failed to decode or the arguments are missing

# File 'lib/sisimai/rfc3464.rb', line 31

def inquire(mhead, mbody)
  # There is no "Content-Type: message/rfc822" line in the message body
  if Boundaries.any? { |a| mbody.include?(a) } == false
    # Insert "Content-Type: message/rfc822" before "Return-Path:" of the original message
    p0 = mbody.index("\n\nReturn-Path:")
    mbody = sprintf("%s%s%s", mbody[0, p0], Boundaries[0], mbody[p0 + 1, mbody.size]) if p0
  end

  permessage = {}
  dscontents = [Sisimai::Lhost.DELIVERYSTATUS]; v = nil
  alternates = Sisimai::Lhost.DELIVERYSTATUS
  emailparts = Sisimai::RFC5322.part(mbody, Boundaries)
  readslices = [""]
  readcursor = 0      # (Integer) Points the current cursor position
  recipients = 0      # (Integer) The number of 'Final-Recipient' header
  beforemesg = ""     # (String) String before StartingOf[:message]
  goestonext = false  # (Bool) Flag: do not append the line into beforemesg
  isboundary = [Sisimai::RFC2045.boundary(mhead["content-type"], 0)]; isboundary[0] ||= ""

  while emailparts[0].index('@').nil? do
    # There is no email address in the first element of emailparts
    # There is a bounce message inside of message/rfc822 part at lhost-x5-*
    p0 = -1 # The index of the boundary string found first
    p1 =  0 # Offset position of the message body after the boundary string
    ct = "" # Boundary string found first such as "Content-Type: message/rfc822"

    Boundaries.each do |e|
      # Look for a boundary string from the message body
      p0 = mbody.index(e + "\n"); next if p0.nil?
      p1 = p0 + e.size + 2
      ct = e; break
    end
    break if p0.nil?

    cx = mbody[p1, mbody.size]
    p2 = cx.index("\n\n")
    cv = cx[p2 + 2, mbody.size]
    emailparts = Sisimai::RFC5322.part(cv, [ct], 0)
    break
  end

  if emailparts[0].index(StartingOf[:message][0]) == nil
    # There is no "Content-Type: message/delivery-status" line in the message body
    # Insert "Content-Type: message/delivery-status" before "Reporting-MTA:" field
    cv = "\nReporting-MTA:"
    e0 = emailparts[0]
    p0 = e0.index(cv)
    emailparts[0] = sprintf("%s\n\n%s%s", e0[0, p0], StartingOf[:message][0], e0[p0, e0.size]) if p0
  end

  %w[Final-Recipient Original-Recipient].each do |e|
    # Fix the malformed field "Final-Recipient: <kijitora@example.jp>"
    cv = "\n" + e + ": "
    cx = cv + "<"
    p0 = emailparts[0].index(cx); next if p0.nil?

    emailparts[0] = emailparts[0].sub(": <", ": rfc822; ")
    p1 = emailparts[0].index(">\n", p0 + 2); emailparts[0][p1, 1] = ""
  end

  bodyslices = emailparts[0].scrub('?').split("\n")
  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.
    readslices << e # Save the current line for the next loop

    if readcursor == 0
      # Beginning of the bounce message or delivery status part
      readcursor |= Indicators[:deliverystatus] if e.start_with?(StartingOf[:message][0])

      while true do
        # Append each string before startingof["message"][0] except the following patterns
        # for the later reference
        break if e.empty?   # Blank line
        break if goestonext # Skip if the part is text/html, image/icon, in multipart/*

        # This line is a boundary kept in "multiparts" as a string, when the end of the boundary
        # appeared, the condition above also returns true.
        if isboundary.any? { |a| e == a } then goestonext = false; break; end
        if e.start_with?("Content-Type:")
          # Content-Type: field in multipart/*
          case
            # Content-Type: multipart/alternative; boundary=aa00220022222222ffeebb
            # Pick the boundary string and store it into "isboucdary"
            when e.include?("multipart/") then isboundary << Sisimai::RFC2045.boundary(e, 0)
            when e.include?("text/plain") then goestonext = false
            else goestonext = true # Other types: for example, text/html, image/jpg, and so on
          end
          break
        end

        break if e.start_with?("Content-")        # Content-Disposition, ...
        break if e.start_with?("This is a MIME")  # This is a MIME-formatted message.
        break if e.start_with?("This is a multi") # This is a multipart message in MIME format
        break if e.start_with?("This is an auto") # This is an automatically generated ...
        break if e.start_with?("This multi-part") # This multi-part MIME message contains...
        break if e.start_with?("###")             # A frame like #####
        break if e.start_with?("***")             # A frame like *****
        break if e.start_with?("--")              # Boundary string
        break if e.include?("--- The follow")     # ----- The following addresses had delivery problems -----
        break if e.include?("--- Transcript")     # ----- Transcript of session follows -----
        beforemesg += "#{e} "; break
      end
      next
    end
    next if (readcursor & Indicators[:deliverystatus]) == 0 || e.empty?

    f = Sisimai::RFC1894.match(e)
    if f > 0
      # "e" matched with any field defined in RFC3464
      next unless o = Sisimai::RFC1894.field(e)
      v = dscontents[-1]

      case o[3]
      when "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
          # Final-Recipient: x400; /PN=...
          cv = Sisimai::Address.s3s4(o[2]); next if Sisimai::Address.is_emailaddress(cv) == false
          cw = dscontents.size;             next if cw > 0 && cv == dscontents[cw - 1]["recipient"]

          if v["recipient"] != ""
            # There are multiple recipient addresses in the message body.
            dscontents << Sisimai::Lhost.DELIVERYSTATUS
            v = dscontents[-1]
          end
          v["recipient"] = cv
          recipients += 1
        else
          # X-Actual-Recipient: rfc822; kijitora@example.co.jp
          v["alias"] = o[2]
        end
      when "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
        if o[4].size > 0
          # There are other error messages as a comment such as the following:
          # Status: 5.0.0 (permanent failure)
          # Status: 4.0.0 (cat.example.net: host name lookup failure)
          v["diagnosis"] += " #{o[4]} "
        end
        next if FieldTable[o[0]].nil?
        next if o[3] == "host" && Sisimai::RFC1123.is_internethost(o[2]) == false
        v[FieldTable[o[0]]] = o[2]

        next if f != 1
        permessage[FieldTable[o[0]]] = o[2]
      end
    else
      # Check that the line is a continued line of the value of Diagnostic-Code: field or not
      if e.start_with?("X-") && e.include?(": ")
        # This line is a MTA-Specific fields begins with "X-"
        next if Sisimai::RFC3464::ThirdParty.is3rdparty(e) == false
        cv = Sisimai::RFC3464::ThirdParty.xfield(e)

        if cv.size > 0 && FieldTable[cv[0].downcase] == nil
          # Check the first element is a field defined in RFC1894 or not
          p1 = cv[4].index(":")
          v["reason"] = cv[4][p1 + 1, cv[4].size] if cv[4].start_with?("reason:")
        else
          # Set the value picked from "X-*" field to $dscontents when the current value is empty
          z = FieldTable[cv[0].downcase]; next if z.nil?
          v[z] ||=  cv[2]
        end
      else
        # The line may be a continued line of the value of the Diagnostic-Code: field
        if readslices[-2].start_with?("Diagnostic-Code:") == false
          # In the case of multiple "message/delivery-status" line
          next if e.start_with?("Content-") # Content-Disposition:, ...
          next if e.start_with?("--")       # Boundary string
          beforemesg += "#{e} "; next
        end

        # Diagnostic-Code: SMTP; 550-5.7.26 The MAIL FROM domain [email.example.jp]
        #    has an SPF record with a hard fail
        next if e.start_with?(" ") == false
        v["diagnosis"] += " " + e
      end
    end
  end

  while recipients == 0 do
    # There is no valid recipient address, Try to use the alias addaress as a final recipient
    break if dscontents[0]["alias"].nil? || dscontents[0]["alias"].empty?
    break if Sisimai::Address.is_emailaddress(dscontents[0]["alias"]) == false
    dscontents[0]["recipient"] = dscontents[0]["alias"]
    recipients += 1
  end
  return nil if recipients == 0

  require "sisimai/smtp/reply"
  require "sisimai/smtp/status"
  require "sisimai/smtp/command"

  if beforemesg != ""
    # Pick some values of $dscontents from the string before StartingOf[:message]
    beforemesg = beforemesg.split.join(" ")
    alternates["command"]   = Sisimai::SMTP::Command.find(beforemesg)
    alternates["replycode"] = Sisimai::SMTP::Reply.find(beforemesg, dscontents[0]["status"])
    alternates["status"]    = Sisimai::SMTP::Status.find(beforemesg, alternates["replycode"])
  end
  issuedcode = beforemesg.downcase

  dscontents.each do |e|
    # Set default values stored in "permessage" if each value in "dscontents" is empty.
    permessage.each_key { |a| e[a] ||= permessage[a] || '' }
    lowercased = e["diagnosis"].downcase

    if recipients == 1
      # Do not mix the error message of each recipient with "beforemesg" when there is
      # multiple recipient addresses in the bounce message
      if issuedcode.include?(lowercased)
        # beforemesg contains the entire strings of e["diagnosis"]
        e["diagnosis"] = beforemesg
      else
        # The value of e["diagnosis"] is not contained in $beforemesg
        # There may be an important error message in $beforemesg
        e["diagnosis"] = sprintf("%s %s", beforemesg, e["diagnosis"])
      end
    end
    e["command"]   = Sisimai::SMTP::Command.find(e["diagnosis"])
    e["command"]   = alternates["command"]   if e["command"].empty? 
    e["replycode"] = Sisimai::SMTP::Reply.find(e["diagnosis"], e["status"])
    e["replycode"] = alternates["replycode"] if e["replycode"].empty? 
    e["status"]    = Sisimai::SMTP::Status.find(e["diagnosis"], e["replycode"]) if e["status"].empty?
    e["status"]    = alternates["status"] if e["status"].empty?
  end

  if emailparts[1].nil? || emailparts[1].empty?
    # Set the recipient address as To: header in the original message part
    emailparts[1] = sprintf("To: <%s>\n", dscontents[0]["recipient"])
  end
  return { "ds" => dscontents, "rfc822" => emailparts[1] }
end