Class: MailCatcher::Smtp

Inherits:
EventMachine::Protocols::SmtpServer
  • Object
show all
Defined in:
lib/mail_catcher/smtp.rb

Direct Known Subclasses

SmtpTls

Constant Summary collapse

@@active_connections = 
0

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(*args) ⇒ Smtp

Returns a new instance of Smtp.



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# File 'lib/mail_catcher/smtp.rb', line 16

def initialize(*args)
  @transcript_entries = []
  @session_id = SecureRandom.uuid
  @connection_started_at = Time.now
  @data_started = false
  @last_message_id = nil
  super
end

Class Method Details

.connection_count ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 12

def self.connection_count
  @@active_connections
end

Instance Method Details

#current_message ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 135

def current_message
  @current_message ||= {}
end

#get_server_capabilities ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 149

def get_server_capabilities
  # Advertise SMTP capabilities per RFC standards
  # SIZE: RFC 1870 - Message size extension
  # 8BITMIME: RFC 6152 - 8bit MIME transport
  # SMTPUTF8: RFC 6531 - UTF-8 support in SMTP
  ["8BITMIME", "SMTPUTF8"]
end

#log_transcript(type, direction, message) ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 69

def log_transcript(type, direction, message)
  @transcript_entries << {
    timestamp: Time.now.utc.iso8601(3),
    type: type,
    direction: direction,
    message: message
  }
rescue => e
  $stderr.puts "Error logging transcript: #{e.message}"
end

#post_init ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 25

def post_init
  @@active_connections += 1

  # Get connection details
  begin
    peer_sockaddr = get_peername
    if peer_sockaddr
      port, client_ip = Socket.unpack_sockaddr_in(peer_sockaddr)
      @client_ip = client_ip
      @client_port = port
    end
  rescue => e
    $stderr.puts "Error getting peer info: #{e.message}"
  end

  begin
    local_sockaddr = get_sockname
    if local_sockaddr
      port, server_ip = Socket.unpack_sockaddr_in(local_sockaddr)
      @server_ip = server_ip
      @server_port = port
    end
  rescue => e
    $stderr.puts "Error getting local info: #{e.message}"
  end

  log_transcript('connection', 'server', "Connection established from #{@client_ip}:#{@client_port}")

  super
end

#process_mail_from(sender) ⇒ Object

We override EM’s mail from processing to allow multiple mail-from commands per [RFC 2821](tools.ietf.org/html/rfc2821#section-4.1.1.2)



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# File 'lib/mail_catcher/smtp.rb', line 125

def process_mail_from sender
  if @state.include? :mail_from
    @state -= [:mail_from, :rcpt, :data]

    receive_reset
  end

  super
end

#process_starttls ⇒ Object

Override to log STARTTLS command and TLS negotiation



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# File 'lib/mail_catcher/smtp.rb', line 255

def process_starttls
  log_transcript('tls', 'client', 'STARTTLS')
  result = super

  # Log TLS info after negotiation
  if @tls_started
    begin
      protocol = get_cipher_protocol
      cipher = get_cipher_name
      log_transcript('tls', 'server', "TLS negotiation completed (#{protocol}, #{cipher})")
    rescue
      log_transcript('tls', 'server', "TLS negotiation completed")
    end
  end

  result
end

#process_unknown(command, data) ⇒ Object

Override to log unknown/invalid commands



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# File 'lib/mail_catcher/smtp.rb', line 288

def process_unknown(command, data)
  log_transcript('command', 'client', "#{command} #{data}".strip)
  result = super

  log_transcript('response', 'server', '500 5.5.1 Command not recognized')

  result
end

#receive_data_chunk(lines) ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 186

def receive_data_chunk(lines)
  # Log DATA command on first chunk only
  if !@data_started
    @data_started = true
    log_transcript('command', 'client', 'DATA')
    log_transcript('response', 'server', '354 Start mail input; end with <CRLF>.<CRLF>')
  end

  current_message[:source] ||= +""

  lines.each do |line|
    current_message[:source] << line << "\r\n"
  end

  true
end

#receive_ehlo_domain(domain) ⇒ Object

Override to log EHLO/HELO command



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# File 'lib/mail_catcher/smtp.rb', line 236

def receive_ehlo_domain(domain)
  log_transcript('command', 'client', "EHLO #{domain}")

  # Call parent to handle the EHLO response
  result = super

  # Log the capabilities after they're sent
  capabilities = get_server_capabilities
  capabilities_str = capabilities.map { |cap| "250-#{cap}" }.join("\r\n")
  # Replace first 250- with 250 followed by a space
  if capabilities_str.start_with?("250-")
    capabilities_str = "250 " + capabilities_str[4..-1]
  end
  log_transcript('response', 'server', capabilities_str)

  result
end

#receive_message ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 203

def receive_message
  message_size = current_message[:source].length
  log_transcript('data', 'client', "Message complete (#{message_size} bytes)")
  log_transcript('response', 'server', '250 OK: Message accepted')

  begin
    message_id = MailCatcher::Mail.add_message current_message
    @last_message_id = message_id
  rescue => e
    $stderr.puts "Error in add_message: #{e.message}"
    $stderr.puts e.backtrace.join("\n")
    message_id = nil
  end

  MailCatcher::Mail.delete_older_messages!

  # Don't save transcript here - save it when connection closes (in unbind)
  # This ensures "Connection closed" entry is included

  true
rescue => exception
  log_transcript('error', 'server', "Exception: #{exception.class} - #{exception.message}")
  MailCatcher.log_exception("Error receiving message", @current_message, exception)

  # Don't save transcript here - save it when connection closes (in unbind)

  false
ensure
  @current_message = nil
  @data_started = false
end

#receive_plain_auth(user, password) ⇒ Object

Override to log AUTH attempts (without logging credentials)



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# File 'lib/mail_catcher/smtp.rb', line 274

def receive_plain_auth(user, password)
  log_transcript('command', 'client', "AUTH PLAIN [credentials hidden]")
  result = super

  if result
    log_transcript('response', 'server', '235 2.7.0 Authentication successful')
  else
    log_transcript('response', 'server', '535 5.7.8 Authentication credentials invalid')
  end

  result
end

#receive_recipient(recipient) ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 175

def receive_recipient(recipient)
  log_transcript('command', 'client', "RCPT TO:<#{recipient}>")

  current_message[:recipients] ||= []
  current_message[:recipients] << recipient

  log_transcript('response', 'server', '250 OK')

  true
end

#receive_reset ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 139

def receive_reset
  log_transcript('command', 'client', 'RSET')
  log_transcript('response', 'server', '250 OK')

  @current_message = nil
  @data_started = false

  true
end

#receive_sender(sender) ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 157

def receive_sender(sender)
  # Log the full MAIL FROM command with ESMTP parameters
  log_transcript('command', 'client', "MAIL FROM:<#{sender}>")

  # EventMachine SMTP advertises size extensions [https://tools.ietf.org/html/rfc1870]
  # and other SMTP parameters via the MAIL FROM command
  # Strip potential " SIZE=..." and "BODY=..." suffixes from senders
  sender_cleaned = sender.gsub(/ (?:SIZE|BODY)=\S+/i, "")

  log_transcript('response', 'server', '250 OK')

  current_message[:sender] = sender_cleaned
  # Store the original sender line to track if 8BIT was specified
  current_message[:sender_line] = sender_cleaned

  true
end

#save_transcript(message_id) ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 80

def save_transcript(message_id)
  return if @transcript_entries.empty?

  begin
    tls_enabled = @tls_started ? 1 : 0
    tls_protocol = nil
    tls_cipher = nil

    if @tls_started
      begin
        tls_protocol = get_cipher_protocol
      rescue
        # TLS info not available
      end
      begin
        tls_cipher = get_cipher_name
      rescue
        # TLS info not available
      end
    end

    MailCatcher::Mail.add_smtp_transcript(
      message_id: message_id,
      session_id: @session_id,
      client_ip: @client_ip,
      client_port: @client_port,
      server_ip: @server_ip,
      server_port: @server_port,
      tls_enabled: tls_enabled,
      tls_protocol: tls_protocol,
      tls_cipher: tls_cipher,
      connection_started_at: @connection_started_at,
      connection_ended_at: @connection_ended_at || Time.now,
      entries: @transcript_entries
    )

    @transcript_entries = []
  rescue => e
    $stderr.puts "Error saving SMTP transcript: #{e.message}"
    $stderr.puts e.backtrace.join("\n")
  end
end

#unbind ⇒ Object 



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# File 'lib/mail_catcher/smtp.rb', line 56

def unbind
  @@active_connections -= 1

  @connection_ended_at = Time.now
  log_transcript('connection', 'server', "Connection closed")

  # Save transcript with the last message if available, otherwise without message_id
  # This ensures "Connection closed" is included in the transcript
  save_transcript(@last_message_id) if @transcript_entries.any?

  super
end