Class: Net::SMTP

Inherits:
Object
  • Object
show all
Defined in:
lib/net/smtp.rb

Overview

Net::SMTP

What is This Library?

This library provides functionality to send internet mail via SMTP, the Simple Mail Transfer Protocol. For details of SMTP itself, see [RFC2821] (www.ietf.org/rfc/rfc2821.txt).

What is This Library NOT?

This library does NOT provide functions to compose internet mails. You must create them by yourself. If you want better mail support, try RubyMail or TMail. You can get both libraries from RAA. (www.ruby-lang.org/en/raa.html)

FYI: the official documentation on internet mail is: [RFC2822] (www.ietf.org/rfc/rfc2822.txt).

Examples

Sending Messages

You must open a connection to an SMTP server before sending messages. The first argument is the address of your SMTP server, and the second argument is the port number. Using SMTP.start with a block is the simplest way to do this. This way, the SMTP connection is closed automatically after the block is executed.

require 'net/smtp'
Net::SMTP.start('your.smtp.server', 25) do |smtp|
  # Use the SMTP object smtp only in this block.
end

Replace 'your.smtp.server' with your SMTP server. Normally your system manager or internet provider supplies a server for you.

Then you can send messages.

msgstr = <<END_OF_MESSAGE
From: Your Name <[email protected]>
To: Destination Address <[email protected]>
Subject: test message
Date: Sat, 23 Jun 2001 16:26:43 +0900
Message-Id: <[email protected]>

This is a test message.
END_OF_MESSAGE

require 'net/smtp'
Net::SMTP.start('your.smtp.server', 25) do |smtp|
  smtp.send_message msgstr,
                    '[email protected]',
                    '[email protected]'
end

Closing the Session

You MUST close the SMTP session after sending messages, by calling the #finish method:

# using SMTP#finish
smtp = Net::SMTP.start('your.smtp.server', 25)
smtp.send_message msgstr, '[email protected]', '[email protected]'
smtp.finish

You can also use the block form of SMTP.start/SMTP#start. This closes the SMTP session automatically:

# using block form of SMTP.start
Net::SMTP.start('your.smtp.server', 25) do |smtp|
  smtp.send_message msgstr, '[email protected]', '[email protected]'
end

I strongly recommend this scheme. This form is simpler and more robust.

HELO domain

In almost all situations, you must provide a third argument to SMTP.start/SMTP#start. This is the domain name which you are on (the host to send mail from). It is called the “HELO domain”. The SMTP server will judge whether it should send or reject the SMTP session by inspecting the HELO domain.

Net::SMTP.start('your.smtp.server', 25,
                'mail.from.domain') { |smtp| ... }

SMTP Authentication

The Net::SMTP class supports three authentication schemes; PLAIN, LOGIN and CRAM MD5. (SMTP Authentication: [RFC2554]) To use SMTP authentication, pass extra arguments to SMTP.start/SMTP#start.

# PLAIN
Net::SMTP.start('your.smtp.server', 25, 'mail.from.domain',
                'Your Account', 'Your Password', :plain)
# LOGIN
Net::SMTP.start('your.smtp.server', 25, 'mail.from.domain',
                'Your Account', 'Your Password', :login)

# CRAM MD5
Net::SMTP.start('your.smtp.server', 25, 'mail.from.domain',
                'Your Account', 'Your Password', :cram_md5)

Constant Summary collapse

Revision =
%q$Revision: 10709 $.split[1]

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(address, port = nil) ⇒ SMTP

Creates a new Net::SMTP object.

address is the hostname or ip address of your SMTP server. port is the port to connect to; it defaults to port 25.

This method does not open the TCP connection. You can use SMTP.start instead of SMTP.new if you want to do everything at once. Otherwise, follow SMTP.new with SMTP#start.


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# File 'lib/net/smtp.rb', line 222

def initialize(address, port = nil)
  @address = address
  @port = (port || SMTP.default_port)
  @esmtp = true
  @socket = nil
  @started = false
  @open_timeout = 30
  @read_timeout = 60
  @error_occured = false
  @debug_output = nil
  @use_tls = SMTP.use_tls?
  @certs = SMTP.certs
  @verify = SMTP.verify      
end

Instance Attribute Details

#addressObject (readonly)

The address of the SMTP server to connect to.


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# File 'lib/net/smtp.rb', line 283

def address
  @address
end

#open_timeoutObject

Seconds to wait while attempting to open a connection. If the connection cannot be opened within this time, a TimeoutError is raised.


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# File 'lib/net/smtp.rb', line 291

def open_timeout
  @open_timeout
end

#portObject (readonly)

The port number of the SMTP server to connect to.


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# File 'lib/net/smtp.rb', line 286

def port
  @port
end

#read_timeoutObject

Seconds to wait while reading one block (by one read(2) call). If the read(2) call does not complete within this time, a TimeoutError is raised.


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# File 'lib/net/smtp.rb', line 296

def read_timeout
  @read_timeout
end

Class Method Details

.certsObject


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# File 'lib/net/smtp.rb', line 207

def SMTP.certs
  @certs
end

.default_portObject

The default SMTP port, port 25.


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# File 'lib/net/smtp.rb', line 173

def SMTP.default_port
  25
end

.disable_tlsObject

Disable SSL for all new instances.


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# File 'lib/net/smtp.rb', line 193

def SMTP.disable_tls
  @use_tls = nil
  @verify = nil
  @certs = nil
end

.enable_tls(verify = OpenSSL::SSL::VERIFY_PEER, certs = nil) ⇒ Object

Enable SSL for all new instances. verify is the type of verification to do on the Server Cert; Defaults to OpenSSL::SSL::VERIFY_PEER. certs is a file or directory holding CA certs to use to verify the server cert; Defaults to nil.


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

def SMTP.enable_tls(verify = OpenSSL::SSL::VERIFY_PEER, certs = nil)
  @use_tls = true
  @verify = verify
  @certs = certs  
end

.start(address, port = nil, helo = 'localhost.localdomain', user = nil, secret = nil, authtype = nil, &block) ⇒ Object

Creates a new Net::SMTP object and connects to the server.

This method is equivalent to:

Net::SMTP.new(address, port).start(helo_domain, , password, authtype)

Example

Net::SMTP.start('your.smtp.server') do |smtp|
  smtp.send_message msgstr, '[email protected]', ['[email protected]']
end

Block Usage

If called with a block, the newly-opened Net::SMTP object is yielded to the block, and automatically closed when the block finishes. If called without a block, the newly-opened Net::SMTP object is returned to the caller, and it is the caller's responsibility to close it when finished.

Parameters

address is the hostname or ip address of your smtp server.

port is the port to connect to; it defaults to port 25.

helo is the HELO domain provided by the client to the server (see overview comments); it defaults to 'localhost.localdomain'.

The remaining arguments are used for SMTP authentication, if required or desired. user is the account name; secret is your password or other authentication token; and authtype is the authentication type, one of :plain, :login, or :cram_md5. See the discussion of SMTP Authentication in the overview notes.

Errors

This method may raise:

  • Net::SMTPAuthenticationError

  • Net::SMTPServerBusy

  • Net::SMTPSyntaxError

  • Net::SMTPFatalError

  • Net::SMTPUnknownError

  • IOError

  • TimeoutError


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# File 'lib/net/smtp.rb', line 375

def SMTP.start(address, port = nil, helo = 'localhost.localdomain',
               user = nil, secret = nil, authtype = nil,
               &block)   # :yield: smtp
  new(address, port).start(helo, user, secret, authtype, &block)
end

.use_tls?Boolean

Returns:

  • (Boolean)

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# File 'lib/net/smtp.rb', line 199

def SMTP.use_tls?
  @use_tls
end

.verifyObject


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

def SMTP.verify
  @verify
end

Instance Method Details

#disable_tlsObject


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# File 'lib/net/smtp.rb', line 276

def disable_tls
  @use_tls = false
  @verify = nil
  @certs = nil
end

#do_helo(helodomain) ⇒ Object

method to send helo or ehlo based on defaults and to retry with helo if server doesn't like ehlo.


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# File 'lib/net/smtp.rb', line 502

def do_helo(helodomain)
   begin
    if @esmtp
      ehlo helodomain
    else
      helo helodomain
    end
  rescue ProtocolError
    if @esmtp
      @esmtp = false
      @error_occured = false
      retry
    end
    raise
  end
end

#enable_tls(verify = OpenSSL::SSL::VERIFY_PEER, certs = nil) ⇒ Object

Enables STARTTLS for this instance. verify is the type of verification to do on the Server Cert; Defaults to OpenSSL::SSL::VERIFY_PEER. certs is a file or directory holding CA certs to use to verify the server cert; Defaults to nil.


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# File 'lib/net/smtp.rb', line 270

def enable_tls(verify = OpenSSL::SSL::VERIFY_PEER, certs = nil)
  @use_tls = true
  @verify = verify
  @certs = certs
end

#esmtp=(bool) ⇒ Object

Set whether to use ESMTP or not. This should be done before calling #start. Note that if #start is called in ESMTP mode, and the connection fails due to a ProtocolError, the SMTP object will automatically switch to plain SMTP mode and retry (but not vice versa).


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# File 'lib/net/smtp.rb', line 254

def esmtp=(bool)
  @esmtp = bool
end

#esmtp?Boolean Also known as: esmtp

true if the SMTP object uses ESMTP (which it does by default).

Returns:

  • (Boolean)

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# File 'lib/net/smtp.rb', line 243

def esmtp?
  @esmtp
end

#finishObject

Finishes the SMTP session and closes TCP connection. Raises IOError if not started.

Raises:

  • (IOError)

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# File 'lib/net/smtp.rb', line 522

def finish
  raise IOError, 'not yet started' unless started?
  do_finish
end

#inspectObject

Provide human-readable stringification of class state.


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# File 'lib/net/smtp.rb', line 238

def inspect
  "#<#{self.class} #{@address}:#{@port} started=#{@started}>"
end

#open_message_stream(from_addr, *to_addrs, &block) ⇒ Object Also known as: ready

Opens a message writer stream and gives it to the block. The stream is valid only in the block, and has these methods:

puts(str = '')

outputs STR and CR LF.

print(str)

outputs STR.

printf(fmt, *args)

outputs sprintf(fmt,*args).

write(str)

outputs STR and returns the length of written bytes.

<<(str)

outputs STR and returns self.

If a single CR (“r”) or LF (“n”) is found in the message, it is converted to the CR LF pair. You cannot send a binary message with this method.

Parameters

from_addr is a String representing the source mail address.

to_addr is a String or Strings or Array of Strings, representing the destination mail address or addresses.

Example

Net::SMTP.start('smtp.example.com', 25) do |smtp|
  smtp.open_message_stream('[email protected]', ['[email protected]']) do |f|
    f.puts 'From: [email protected]'
    f.puts 'To: [email protected]'
    f.puts 'Subject: test message'
    f.puts
    f.puts 'This is a test message.'
  end
end

Errors

This method may raise:

  • Net::SMTPServerBusy

  • Net::SMTPSyntaxError

  • Net::SMTPFatalError

  • Net::SMTPUnknownError

  • IOError

  • TimeoutError


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# File 'lib/net/smtp.rb', line 626

def open_message_stream(from_addr, *to_addrs, &block)   # :yield: stream
  send0(from_addr, to_addrs.flatten) {
    @socket.write_message_by_block(&block)
  }
end

#send_message(msgstr, from_addr, *to_addrs) ⇒ Object Also known as: send_mail, sendmail

Sends msgstr as a message. Single CR (“r”) and LF (“n”) found in the msgstr, are converted into the CR LF pair. You cannot send a binary message with this method. msgstr should include both the message headers and body.

from_addr is a String representing the source mail address.

to_addr is a String or Strings or Array of Strings, representing the destination mail address or addresses.

Example

Net::SMTP.start('smtp.example.com') do |smtp|
  smtp.send_message msgstr,
                    '[email protected]',
                    ['[email protected]', '[email protected]']
end

Errors

This method may raise:

  • Net::SMTPServerBusy

  • Net::SMTPSyntaxError

  • Net::SMTPFatalError

  • Net::SMTPUnknownError

  • IOError

  • TimeoutError


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# File 'lib/net/smtp.rb', line 573

def send_message(msgstr, from_addr, *to_addrs)
  send0(from_addr, to_addrs.flatten) {
    @socket.write_message msgstr
  }
end

#set_debug_output(arg) ⇒ Object

WARNING: This method causes serious security holes. Use this method for only debugging.

Set an output stream for debug logging. You must call this before #start.

# example
smtp = Net::SMTP.new(addr, port)
smtp.set_debug_output $stderr
smtp.start do |smtp|
  ....
end

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# File 'lib/net/smtp.rb', line 319

def set_debug_output(arg)
  @debug_output = arg
end

#start(helo = 'localhost.localdomain', user = nil, secret = nil, authtype = nil) ⇒ Object

Opens a TCP connection and starts the SMTP session.

Parameters

helo is the HELO domain that you'll dispatch mails from; see the discussion in the overview notes.

If both of user and secret are given, SMTP authentication will be attempted using the AUTH command. authtype specifies the type of authentication to attempt; it must be one of :login, :plain, and :cram_md5. See the notes on SMTP Authentication in the overview.

Block Usage

When this methods is called with a block, the newly-started SMTP object is yielded to the block, and automatically closed after the block call finishes. Otherwise, it is the caller's responsibility to close the session when finished.

Example

This is very similar to the class method SMTP.start.

require 'net/smtp' 
smtp = Net::SMTP.new('smtp.mail.server', 25)
smtp.start(helo_domain, , password, authtype) do |smtp|
  smtp.send_message msgstr, '[email protected]', ['[email protected]']
end

The primary use of this method (as opposed to SMTP.start) is probably to set debugging (#set_debug_output) or ESMTP (#esmtp=), which must be done before the session is started.

Errors

If session has already been started, an IOError will be raised.

This method may raise:

  • Net::SMTPAuthenticationError

  • Net::SMTPServerBusy

  • Net::SMTPSyntaxError

  • Net::SMTPFatalError

  • Net::SMTPUnknownError

  • IOError

  • TimeoutError


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# File 'lib/net/smtp.rb', line 436

def start(helo = 'localhost.localdomain',
          user = nil, secret = nil, authtype = nil)   # :yield: smtp
  if block_given?
    begin
      do_start(helo, user, secret, authtype)
      return yield(self)
    ensure
      do_finish
    end
  else
    do_start(helo, user, secret, authtype)
    return self
  end
end

#started?Boolean

true if the SMTP session has been started.

Returns:

  • (Boolean)

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# File 'lib/net/smtp.rb', line 382

def started?
  @started
end

#use_tls?Boolean

does this instance use SSL?

Returns:

  • (Boolean)

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# File 'lib/net/smtp.rb', line 261

def use_tls?
  @use_tls
end