class Net::SMTP
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 <your@mail.address> To: Destination Address <someone@example.com> Subject: test message Date: Sat, 23 Jun 2001 16:26:43 +0900 Message-Id: <unique.message.id.string@example.com> This is a test message. END_OF_MESSAGE require 'net/smtp' Net::SMTP.start('your.smtp.server', 25) do |smtp| smtp.send_message msgstr, 'your@mail.address', 'his_addess@example.com' 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, 'from@address', 'to@address' 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, 'from@address', 'to@address' 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)
Constants
- Revision
Attributes
The address of the SMTP
server to connect to.
Seconds to wait while attempting to open a connection. If the connection cannot be opened within this time, a TimeoutError is raised.
The port number of the SMTP
server to connect to.
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.
Public Class Methods
# File lib/net/smtp.rb, line 207 def SMTP.certs @certs end
The default SMTP
port, port 25.
# File lib/net/smtp.rb, line 173 def SMTP.default_port 25 end
Disable SSL for all new instances.
# File lib/net/smtp.rb, line 193 def SMTP.disable_tls @use_tls = nil @verify = nil @certs = nil end
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.
# 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
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
.
# 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
Creates a new Net::SMTP
object and connects to the server.
This method is equivalent to:
Net::SMTP.new(address, port).start(helo_domain, account, password, authtype)
Example¶ ↑
Net::SMTP.start('your.smtp.server') do |smtp| smtp.send_message msgstr, 'from@example.com', ['dest@example.com'] 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:
-
IOError
-
TimeoutError
# 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
# File lib/net/smtp.rb, line 199 def SMTP.use_tls? @use_tls end
# File lib/net/smtp.rb, line 203 def SMTP.verify @verify end
Public Instance Methods
# File lib/net/smtp.rb, line 276 def disable_tls @use_tls = false @verify = nil @certs = nil end
method to send helo or ehlo based on defaults and to retry with helo if server doesn't like ehlo.
# 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
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.
# 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
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).
# File lib/net/smtp.rb, line 254 def esmtp=(bool) @esmtp = bool end
true
if the SMTP
object uses ESMTP (which it does by default).
# File lib/net/smtp.rb, line 243 def esmtp? @esmtp end
Finishes the SMTP
session and closes TCP connection. Raises IOError if not started.
# File lib/net/smtp.rb, line 522 def finish raise IOError, 'not yet started' unless started? do_finish end
Provide human-readable stringification of class state.
# File lib/net/smtp.rb, line 238 def inspect "#<#{self.class} #{@address}:#{@port} started=#{@started}>" end
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('from@example.com', ['dest@example.com']) do |f| f.puts 'From: from@example.com' f.puts 'To: dest@example.com' f.puts 'Subject: test message' f.puts f.puts 'This is a test message.' end end
Errors¶ ↑
This method may raise:
-
IOError
-
TimeoutError
# 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
Set the number of seconds to wait until timing-out a read(2) call.
# File lib/net/smtp.rb, line 300 def read_timeout=(sec) @socket.read_timeout = sec if @socket @read_timeout = sec end
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, 'from@example.com', ['dest@example.com', 'dest2@example.com'] end
Errors¶ ↑
This method may raise:
-
IOError
-
TimeoutError
# 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
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
# File lib/net/smtp.rb, line 319 def set_debug_output(arg) @debug_output = arg end
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, account, password, authtype) do |smtp| smtp.send_message msgstr, 'from@example.com', ['dest@example.com'] 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:
-
IOError
-
TimeoutError
# 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
true
if the SMTP
session has been started.
# File lib/net/smtp.rb, line 382 def started? @started end
does this instance use SSL?
# File lib/net/smtp.rb, line 261 def use_tls? @use_tls end
Private Instance Methods
# File lib/net/smtp.rb, line 691 def auth_cram_md5(user, secret) # CRAM-MD5: [RFC2195] res = nil critical { res = check_response(get_response('AUTH CRAM-MD5'), true) challenge = res.split(/ /)[1].unpack('m')[0] secret = Digest::MD5.digest(secret) if secret.size > 64 isecret = secret + "\0" * (64 - secret.size) osecret = isecret.dup 0.upto(63) do |i| c = isecret[i].ord ^ 0x36 isecret[i] = c.chr c = osecret[i].ord ^ 0x5c osecret[i] = c.chr end tmp = Digest::MD5.digest(isecret + challenge) tmp = Digest::MD5.hexdigest(osecret + tmp) res = get_response(base64_encode(user + ' ' + tmp)) } raise SMTPAuthenticationError, res unless /\A2../ === res end
# File lib/net/smtp.rb, line 682 def auth_login(user, secret) res = critical { check_response(get_response('AUTH LOGIN'), true) check_response(get_response(base64_encode(user)), true) get_response(base64_encode(secret)) } raise SMTPAuthenticationError, res unless /\A2../ === res end
# File lib/net/smtp.rb, line 676 def auth_plain(user, secret) res = critical { get_response('AUTH PLAIN %s', base64_encode("\0#{user}\0#{secret}")) } raise SMTPAuthenticationError, res unless /\A2../ === res end
# File lib/net/smtp.rb, line 672 def authenticate(user, secret, authtype) __send__("auth_#{authtype || 'cram_md5'}", user, secret) end
# File lib/net/smtp.rb, line 715 def base64_encode(str) # expects "str" may not become too long [str].pack('m').gsub(/\s+/, '') end
auth
# File lib/net/smtp.rb, line 664 def check_auth_args(user, secret, authtype) raise ArgumentError, 'both user and secret are required'\ unless user and secret auth_method = "auth_#{authtype || 'cram_md5'}" raise ArgumentError, "wrong auth type #{authtype}"\ unless respond_to?(auth_method, true) end
# File lib/net/smtp.rb, line 778 def check_response(res, allow_continue = false) return res if /\A2/ === res return res if allow_continue and /\A3/ === res err = case res when /\A4/ then SMTPServerBusy when /\A50/ then SMTPSyntaxError when /\A55/ then SMTPFatalError else SMTPUnknownError end raise err, res end
# File lib/net/smtp.rb, line 790 def critical(&block) return '200 dummy reply code' if @error_occured begin return yield() rescue Exception @error_occured = true raise end end
# File lib/net/smtp.rb, line 527 def do_finish quit if @socket and not @socket.closed? and not @error_occured ensure @started = false @error_occured = false @socket.close if @socket and not @socket.closed? @socket = nil end
# File lib/net/smtp.rb, line 451 def do_start(helodomain, user, secret, authtype) raise IOError, 'SMTP session already started' if @started check_auth_args user, secret, authtype if user or secret s = timeout(@open_timeout) { TCPSocket.open(@address, @port) } @socket = InternetMessageIO.new(s) logging "SMTP session opened: #{@address}:#{@port}" @socket.read_timeout = @read_timeout @socket.debug_output = @debug_output check_response(critical { recv_response() }) do_helo(helodomain) if @use_tls raise 'openssl library not installed' unless defined?(OpenSSL) context = OpenSSL::SSL::SSLContext.new context.verify_mode = @verify if @certs if File.file?(@certs) context.ca_file = @certs elsif File.directory?(@certs) context.ca_path = @certs else raise ArgumentError, "certs given but is not file or directory: #{@certs}" end end s = OpenSSL::SSL::SSLSocket.new(s, context) s.sync_close = true starttls s.connect logging 'TLS started' @socket = InternetMessageIO.new(s) @socket.read_timeout = @read_timeout @socket.debug_output = @debug_output # helo response may be different after STARTTLS do_helo(helodomain) end authenticate user, secret, authtype if user @started = true ensure unless @started # authentication failed, cancel connection. s.close if s and not s.closed? @socket = nil end end
# File lib/net/smtp.rb, line 730 def ehlo(domain) getok('EHLO %s', domain) end
# File lib/net/smtp.rb, line 763 def get_response(fmt, *args) @socket.writeline sprintf(fmt, *args) recv_response() end
row level library
# File lib/net/smtp.rb, line 755 def getok(fmt, *args) res = critical { @socket.writeline sprintf(fmt, *args) recv_response() } return check_response(res) end
SMTP
command dispatcher
# File lib/net/smtp.rb, line 726 def helo(domain) getok('HELO %s', domain) end
# File lib/net/smtp.rb, line 800 def logging(msg) @debug_output << msg + "\n" if @debug_output end
# File lib/net/smtp.rb, line 734 def mailfrom(fromaddr) getok('MAIL FROM:<%s>', fromaddr) end
# File lib/net/smtp.rb, line 742 def quit getok('QUIT') end
# File lib/net/smtp.rb, line 738 def rcptto(to) getok('RCPT TO:<%s>', to) end
# File lib/net/smtp.rb, line 768 def recv_response res = '' while true line = @socket.readline res << line << "\n" break unless line[3] == ?- # "210-PIPELINING" end res end
# File lib/net/smtp.rb, line 636 def send0(from_addr, to_addrs) raise IOError, 'closed session' unless @socket raise ArgumentError, 'mail destination not given' if to_addrs.empty? if $SAFE > 0 raise SecurityError, 'tainted from_addr' if from_addr.tainted? to_addrs.each do |to| raise SecurityError, 'tainted to_addr' if to.tainted? end end mailfrom from_addr to_addrs.each do |to| rcptto to end res = critical { check_response(get_response('DATA'), true) yield recv_response() } check_response(res) end
# File lib/net/smtp.rb, line 746 def starttls getok('STARTTLS') end