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class 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 or search for alternatives in RubyGems.org or The Ruby Toolbox.
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 ::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_address@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 ::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 ::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 ::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
- CRAM_BUFSIZE
- DEFAULT_AUTH_TYPE
-
Authentication
- IMASK
- OMASK
- 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 Net::OpenTimeout is raised. The default value is 30 seconds.
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 Net::ReadTimeout is raised. The default value is 60 seconds.
Public Class Methods
# File lib/net/smtp.rb, line 174
def SMTP.default_port
25
end
The default SMTP port number, 25.
# File lib/net/smtp.rb, line 192
def SMTP.default_ssl_context
OpenSSL::SSL::SSLContext.new
end
# File lib/net/smtp.rb, line 179
def SMTP.default_submission_port
587
end
The default mail submission port number, 587.
# File lib/net/smtp.rb, line 184
def SMTP.default_tls_port
465
end
The default SMTPS port number, 465.
# File lib/net/smtp.rb, line 207
def initialize(address, port = nil)
@address = address
@port = (port || SMTP.default_port)
@esmtp = true
@capabilities = nil
@socket = nil
@started = false
@open_timeout = 30
@read_timeout = 60
@error_occurred = false
@debug_output = nil
@tls = false
@starttls = false
@ssl_context = nil
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 ::start instead of ::new if you want to do everything at once. Otherwise, follow ::new with #start.
# File lib/net/smtp.rb, line 451
def SMTP.start(address, port = nil, helo = 'localhost',
user = nil, secret = nil, authtype = nil,
&block) # :yield: smtp
new(address, port).start(helo, user, secret, authtype, &block)
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'.
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:
Public Instance Methods
# File lib/net/smtp.rb, line 750
def auth_cram_md5(user, secret)
check_auth_args user, secret
res = critical {
res0 = get_response('AUTH CRAM-MD5')
check_auth_continue res0
crammed = cram_md5_response(secret, res0.cram_md5_challenge)
get_response(base64_encode("#{user} #{crammed}"))
}
check_auth_response res
res
end
# File lib/net/smtp.rb, line 739
def auth_login(user, secret)
check_auth_args user, secret
res = critical {
check_auth_continue get_response('AUTH LOGIN')
check_auth_continue get_response(base64_encode(user))
get_response(base64_encode(secret))
}
check_auth_response res
res
end
# File lib/net/smtp.rb, line 730
def auth_plain(user, secret)
check_auth_args user, secret
res = critical {
get_response('AUTH PLAIN ' + base64_encode("\0#{user}\0#{secret}"))
}
check_auth_response res
res
end
# File lib/net/smtp.rb, line 724
def authenticate(user, secret, authtype = DEFAULT_AUTH_TYPE)
check_auth_method authtype
check_auth_args user, secret
send auth_method(authtype), user, secret
end
# File lib/net/smtp.rb, line 279
def capable_auth_types
return [] unless @capabilities
return [] unless @capabilities['AUTH']
@capabilities['AUTH']
end
Returns supported authentication methods on this server. You cannot get valid value before opening SMTP session.
# File lib/net/smtp.rb, line 266
def capable_cram_md5_auth?
auth_capable?('CRAM-MD5')
end
true if server advertises AUTH CRAM-MD5. You cannot get valid value before opening SMTP session.
# File lib/net/smtp.rb, line 260
def capable_login_auth?
auth_capable?('LOGIN')
end
true if server advertises AUTH LOGIN. You cannot get valid value before opening SMTP session.
# File lib/net/smtp.rb, line 254
def capable_plain_auth?
auth_capable?('PLAIN')
end
true if server advertises AUTH PLAIN. You cannot get valid value before opening SMTP session.
# File lib/net/smtp.rb, line 242
def capable_starttls?
capable?('STARTTLS')
end
true if server advertises STARTTLS. You cannot get valid value before opening SMTP session.
# File lib/net/smtp.rb, line 890
def data(msgstr = nil, &block) #:yield: stream
if msgstr and block
raise ArgumentError, "message and block are exclusive"
end
unless msgstr or block
raise ArgumentError, "message or block is required"
end
res = critical {
check_continue get_response('DATA')
socket_sync_bak = @socket.io.sync
begin
@socket.io.sync = false
if msgstr
@socket.write_message msgstr
else
@socket.write_message_by_block(&block)
end
ensure
@socket.io.flush
@socket.io.sync = socket_sync_bak
end
recv_response()
}
check_response res
res
end
This method sends a message. If msgstr
is given, sends it as a message. If block is given, yield a message writer stream. You must write message before the block is closed.
# Example 1 (by string)
smtp.data(<<EndMessage)
From: john@example.com
To: betty@example.com
Subject: I found a bug
Check vm.c:58879.
EndMessage
# Example 2 (by block)
smtp.data {|f|
f.puts "From: john@example.com"
f.puts "To: betty@example.com"
f.puts "Subject: I found a bug"
f.puts ""
f.puts "Check vm.c:58879."
}
# File lib/net/smtp.rb, line 392
def debug_output=(arg)
@debug_output = arg
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 350
def disable_starttls
@starttls = false
@ssl_context = nil
end
Disables SMTP/TLS (STARTTLS) for this object. Must be called before the connection is established to have any effect.
# File lib/net/smtp.rb, line 306
def disable_tls
@tls = false
@ssl_context = nil
end
Disables SMTP/TLS for this object. Must be called before the connection is established to have any effect.
# File lib/net/smtp.rb, line 828
def ehlo(domain)
getok("EHLO #{domain}")
end
# File lib/net/smtp.rb, line 332
def enable_starttls(context = SMTP.default_ssl_context)
raise 'openssl library not installed' unless defined?(OpenSSL)
raise ArgumentError, "SMTPS and STARTTLS is exclusive" if @tls
@starttls = :always
@ssl_context = context
end
Enables SMTP/TLS (STARTTLS) for this object. context
is a OpenSSL::SSL::SSLContext object.
# File lib/net/smtp.rb, line 341
def enable_starttls_auto(context = SMTP.default_ssl_context)
raise 'openssl library not installed' unless defined?(OpenSSL)
raise ArgumentError, "SMTPS and STARTTLS is exclusive" if @tls
@starttls = :auto
@ssl_context = context
end
Enables SMTP/TLS (STARTTLS) for this object if server accepts. context
is a OpenSSL::SSL::SSLContext object.
# File lib/net/smtp.rb, line 295
def enable_tls(context = SMTP.default_ssl_context)
raise 'openssl library not installed' unless defined?(OpenSSL)
raise ArgumentError, "SMTPS and STARTTLS is exclusive" if @starttls
@tls = true
@ssl_context = context
end
Enables SMTP/TLS (SMTPS: SMTP over direct TLS connection) for this object. Must be called before the connection is established to have any effect. context
is a OpenSSL::SSL::SSLContext object.
# File lib/net/smtp.rb, line 824
def helo(domain)
getok("HELO #{domain}")
end
# File lib/net/smtp.rb, line 224
def inspect
"#<#{self.class} #{@address}:#{@port} started=#{@started}>"
end
Provide human-readable stringification of class state.
# File lib/net/smtp.rb, line 832
def mailfrom(from_addr)
if $SAFE > 0
raise SecurityError, 'tainted from_addr' if from_addr.tainted?
end
getok("MAIL FROM:<#{from_addr}>")
end
# File lib/net/smtp.rb, line 708
def open_message_stream(from_addr, *to_addrs, &block) # :yield: stream
raise IOError, 'closed session' unless @socket
mailfrom from_addr
rcptto_list(to_addrs) {data(&block)}
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:
# File lib/net/smtp.rb, line 917
def quit
getok('QUIT')
end
# File lib/net/smtp.rb, line 860
def rcptto(to_addr)
if $SAFE > 0
raise SecurityError, 'tainted to_addr' if to_addr.tainted?
end
getok("RCPT TO:<#{to_addr}>")
end
# File lib/net/smtp.rb, line 839
def rcptto_list(to_addrs)
raise ArgumentError, 'mail destination not given' if to_addrs.empty?
ok_users = []
unknown_users = []
to_addrs.flatten.each do |addr|
begin
rcptto addr
rescue SMTPAuthenticationError
unknown_users << addr.dump
else
ok_users << addr
end
end
raise ArgumentError, 'mail destination not given' if ok_users.empty?
ret = yield
unless unknown_users.empty?
raise SMTPAuthenticationError, "failed to deliver for #{unknown_users.join(', ')}"
end
ret
end
# File lib/net/smtp.rb, line 373
def read_timeout=(sec)
@socket.read_timeout = sec if @socket
@read_timeout = sec
end
Set the number of seconds to wait until timing-out a read(2) call.
# File lib/net/smtp.rb, line 816
def rset
getok('RSET')
end
Aborts the current mail transaction
# File lib/net/smtp.rb, line 655
def send_message(msgstr, from_addr, *to_addrs)
raise IOError, 'closed session' unless @socket
mailfrom from_addr
rcptto_list(to_addrs) {data msgstr}
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:
# File lib/net/smtp.rb, line 513
def start(helo = 'localhost',
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
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 ::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 ::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:
# File lib/net/smtp.rb, line 458
def started?
@started
end
true
if the SMTP session has been started.
# File lib/net/smtp.rb, line 820
def starttls
getok('STARTTLS')
end
# File lib/net/smtp.rb, line 316
def starttls?
@starttls
end
Returns truth value if this object uses STARTTLS. If this object always uses STARTTLS, returns :always. If this object uses STARTTLS when the server support TLS, returns :auto.
# File lib/net/smtp.rb, line 321
def starttls_always?
@starttls == :always
end
true if this object uses STARTTLS.
# File lib/net/smtp.rb, line 326
def starttls_auto?
@starttls == :auto
end
true if this object uses STARTTLS when server advertises STARTTLS.
# File lib/net/smtp.rb, line 286
def tls?
@tls
end
true if this object uses SMTP/TLS (SMTPS).
Private Instance Methods
# File lib/net/smtp.rb, line 270
def auth_capable?(type)
return nil unless @capabilities
return false unless @capabilities['AUTH']
@capabilities['AUTH'].include?(type)
end
# File lib/net/smtp.rb, line 770
def auth_method(type)
"auth_#{type.to_s.downcase}".intern
end
# File lib/net/smtp.rb, line 783
def base64_encode(str)
# expects "str" may not become too long
[str].pack('m0')
end
# File lib/net/smtp.rb, line 246
def capable?(key)
return nil unless @capabilities
@capabilities[key] ? true : false
end
# File lib/net/smtp.rb, line 774
def check_auth_args(user, secret, authtype = DEFAULT_AUTH_TYPE)
unless user
raise ArgumentError, 'SMTP-AUTH requested but missing user name'
end
unless secret
raise ArgumentError, 'SMTP-AUTH requested but missing secret phrase'
end
end
# File lib/net/smtp.rb, line 984
def check_auth_continue(res)
unless res.continue?
raise res.exception_class, res.message
end
end
# File lib/net/smtp.rb, line 764
def check_auth_method(type)
unless respond_to?(auth_method(type), true)
raise ArgumentError, "wrong authentication type #{type}"
end
end
# File lib/net/smtp.rb, line 978
def check_auth_response(res)
unless res.success?
raise SMTPAuthenticationError, res.message
end
end
# File lib/net/smtp.rb, line 972
def check_continue(res)
unless res.continue?
raise SMTPUnknownError, "could not get 3xx (#{res.status}: #{res.string})"
end
end
# File lib/net/smtp.rb, line 966
def check_response(res)
unless res.success?
raise res.exception_class, res.message
end
end
# File lib/net/smtp.rb, line 792
def cram_md5_response(secret, challenge)
tmp = Digest::MD5.digest(cram_secret(secret, IMASK) + challenge)
Digest::MD5.hexdigest(cram_secret(secret, OMASK) + tmp)
end
CRAM-MD5: [RFC2195]
# File lib/net/smtp.rb, line 799
def cram_secret(secret, mask)
secret = Digest::MD5.digest(secret) if secret.size > CRAM_BUFSIZE
buf = secret.ljust(CRAM_BUFSIZE, "\0")
0.upto(buf.size - 1) do |i|
buf[i] = (buf[i].ord ^ mask).chr
end
buf
end
# File lib/net/smtp.rb, line 956
def critical
return Response.parse('200 dummy reply code') if @error_occurred
begin
return yield()
rescue Exception
@error_occurred = true
raise
end
end
# File lib/net/smtp.rb, line 610
def do_finish
quit if @socket and not @socket.closed? and not @error_occurred
ensure
@started = false
@error_occurred = false
@socket.close if @socket
@socket = nil
end
# File lib/net/smtp.rb, line 598
def do_helo(helo_domain)
res = @esmtp ? ehlo(helo_domain) : helo(helo_domain)
@capabilities = res.capabilities
rescue SMTPError
if @esmtp
@esmtp = false
@error_occurred = false
retry
end
raise
end
# File lib/net/smtp.rb, line 541
def do_start(helo_domain, user, secret, authtype)
raise IOError, 'SMTP session already started' if @started
if user or secret
check_auth_method(authtype || DEFAULT_AUTH_TYPE)
check_auth_args user, secret
end
s = Timeout.timeout(@open_timeout, Net::OpenTimeout) do
tcp_socket(@address, @port)
end
logging "Connection opened: #{@address}:#{@port}"
@socket = new_internet_message_io(tls? ? tlsconnect(s) : s)
check_response critical { recv_response() }
do_helo helo_domain
if starttls_always? or (capable_starttls? and starttls_auto?)
unless capable_starttls?
raise SMTPUnsupportedCommand,
"STARTTLS is not supported on this server"
end
starttls
@socket = new_internet_message_io(tlsconnect(s))
# helo response may be different after STARTTLS
do_helo helo_domain
end
authenticate user, secret, (authtype || DEFAULT_AUTH_TYPE) if user
@started = true
ensure
unless @started
# authentication failed, cancel connection.
s.close if s
@socket = nil
end
end
# File lib/net/smtp.rb, line 940
def get_response(reqline)
validate_line reqline
@socket.writeline reqline
recv_response()
end
# File lib/net/smtp.rb, line 930
def getok(reqline)
validate_line reqline
res = critical {
@socket.writeline reqline
recv_response()
}
check_response res
res
end
# File lib/net/smtp.rb, line 1069
def logging(msg)
@debug_output << msg + "\n" if @debug_output
end
# File lib/net/smtp.rb, line 593
def new_internet_message_io(s)
InternetMessageIO.new(s, read_timeout: @read_timeout,
debug_output: @debug_output)
end
# File lib/net/smtp.rb, line 946
def recv_response
buf = ''.dup
while true
line = @socket.readline
buf << line << "\n"
break unless line[3,1] == '-' # "210-PIPELINING"
end
Response.parse(buf)
end
# File lib/net/smtp.rb, line 574
def ssl_socket(socket, context)
OpenSSL::SSL::SSLSocket.new socket, context
end
# File lib/net/smtp.rb, line 537
def tcp_socket(address, port)
TCPSocket.open address, port
end
# File lib/net/smtp.rb, line 578
def tlsconnect(s)
verified = false
s = ssl_socket(s, @ssl_context)
logging "TLS connection started"
s.sync_close = true
ssl_socket_connect(s, @open_timeout)
if @ssl_context.verify_mode != OpenSSL::SSL::VERIFY_NONE
s.post_connection_check(@address)
end
verified = true
s
ensure
s.close unless verified
end
# File lib/net/smtp.rb, line 923
def validate_line(line)
# A bare CR or LF is not allowed in RFC5321.
if /[\r\n]/ =~ line
raise ArgumentError, "A line must not contain CR or LF"
end
end
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Licensed under the Ruby License.
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Licensed under their own licenses.