class Net::IMAP

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality. The protocol is described in [IMAP].

IMAP Overview

An IMAP client connects to a server, and then authenticates itself using either authenticate() or login(). Having authenticated itself, there is a range of commands available to it. Most work with mailboxes, which may be arranged in an hierarchical namespace, and each of which contains zero or more messages. How this is implemented on the server is implementation-dependent; on a UNIX server, it will frequently be implemented as files in mailbox format within a hierarchy of directories.

To work on the messages within a mailbox, the client must first select that mailbox, using either select() or (for read-only access) examine(). Once the client has successfully selected a mailbox, they enter selected state, and that mailbox becomes the current mailbox, on which mail-item related commands implicitly operate.

Messages have two sorts of identifiers: message sequence numbers and UIDs.

Message sequence numbers number messages within a mailbox from 1 up to the number of items in the mailbox. If a new message arrives during a session, it receives a sequence number equal to the new size of the mailbox. If messages are expunged from the mailbox, remaining messages have their sequence numbers “shuffled down” to fill the gaps.

UIDs, on the other hand, are permanently guaranteed not to identify another message within the same mailbox, even if the existing message is deleted. UIDs are required to be assigned in ascending (but not necessarily sequential) order within a mailbox; this means that if a non-IMAP client rearranges the order of mailitems within a mailbox, the UIDs have to be reassigned. An IMAP client thus cannot rearrange message orders.

Examples of Usage

List sender and subject of all recent messages in the default mailbox

imap = Net::IMAP.new('mail.example.com')
imap.authenticate('LOGIN', 'joe_user', 'joes_password')
imap.examine('INBOX')
imap.search(["RECENT"]).each do |message_id|
  envelope = imap.fetch(message_id, "ENVELOPE")[0].attr["ENVELOPE"]
  puts "#{envelope.from[0].name}: \t#{envelope.subject}"
end

Move all messages from April 2003 from “Mail/sent-mail” to “Mail/sent-apr03”

imap = Net::IMAP.new('mail.example.com')
imap.authenticate('LOGIN', 'joe_user', 'joes_password')
imap.select('Mail/sent-mail')
if not imap.list('Mail/', 'sent-apr03')
  imap.create('Mail/sent-apr03')
end
imap.search(["BEFORE", "30-Apr-2003", "SINCE", "1-Apr-2003"]).each do |message_id|
  imap.copy(message_id, "Mail/sent-apr03")
  imap.store(message_id, "+FLAGS", [:Deleted])
end
imap.expunge

Thread Safety

Net::IMAP supports concurrent threads. For example,

imap = Net::IMAP.new("imap.foo.net", "imap2")
imap.authenticate("cram-md5", "bar", "password")
imap.select("inbox")
fetch_thread = Thread.start { imap.fetch(1..-1, "UID") }
search_result = imap.search(["BODY", "hello"])
fetch_result = fetch_thread.value
imap.disconnect

This script invokes the FETCH command and the SEARCH command concurrently.

Errors

An IMAP server can send three different types of responses to indicate failure:

NO

the attempted command could not be successfully completed. For instance, the username/password used for logging in are incorrect; the selected mailbox does not exist; etc.

BAD

the request from the client does not follow the server's understanding of the IMAP protocol. This includes attempting commands from the wrong client state; for instance, attempting to perform a SEARCH command without having SELECTed a current mailbox. It can also signal an internal server failure (such as a disk crash) has occurred.

BYE

the server is saying goodbye. This can be part of a normal logout sequence, and can be used as part of a login sequence to indicate that the server is (for some reason) unwilling to accept your connection. As a response to any other command, it indicates either that the server is shutting down, or that the server is timing out the client connection due to inactivity.

These three error response are represented by the errors Net::IMAP::NoResponseError, Net::IMAP::BadResponseError, and Net::IMAP::ByeResponseError, all of which are subclasses of Net::IMAP::ResponseError. Essentially, all methods that involve sending a request to the server can generate one of these errors. Only the most pertinent instances have been documented below.

Because the IMAP class uses Sockets for communication, its methods are also susceptible to the various errors that can occur when working with sockets. These are generally represented as Errno errors. For instance, any method that involves sending a request to the server and/or receiving a response from it could raise an Errno::EPIPE error if the network connection unexpectedly goes down. See the socket(7), ip(7), tcp(7), socket(2), connect(2), and associated man pages.

Finally, a Net::IMAP::DataFormatError is thrown if low-level data is found to be in an incorrect format (for instance, when converting between UTF-8 and UTF-16), and Net::IMAP::ResponseParseError is thrown if a server response is non-parseable.

References

[IMAP]
  1. Crispin, “INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1”,

RFC 2060, December 1996. (Note: since obsoleted by RFC 3501)

[LANGUAGE-TAGS]

Alvestrand, H., “Tags for the Identification of Languages”, RFC 1766, March 1995.

[MD5]

Myers, J., and M. Rose, “The Content-MD5 Header Field”, RFC 1864, October 1995.

[MIME-IMB]

Freed, N., and N. Borenstein, “MIME (Multipurpose Internet Mail Extensions) Part One: Format of Internet Message Bodies”, RFC 2045, November 1996.

[RFC-822]

Crocker, D., “Standard for the Format of ARPA Internet Text Messages”, STD 11, RFC 822, University of Delaware, August 1982.

[RFC-2087]

Myers, J., “IMAP4 QUOTA extension”, RFC 2087, January 1997.

[RFC-2086]

Myers, J., “IMAP4 ACL extension”, RFC 2086, January 1997.

[RFC-2195]

Klensin, J., Catoe, R., and Krumviede, P., “IMAP/POP AUTHorize Extension for Simple Challenge/Response”, RFC 2195, September 1997.

[SORT-THREAD-EXT]

Crispin, M., “INTERNET MESSAGE ACCESS PROTOCOL - SORT and THREAD Extensions”, draft-ietf-imapext-sort, May 2003.

[OSSL]

www.openssl.org

[RSSL]

savannah.gnu.org/projects/rubypki

[UTF7]

Goldsmith, D. and Davis, M., “UTF-7: A Mail-Safe Transformation Format of Unicode”, RFC 2152, May 1997.

Constants

ANSWERED

Flag indicating a message has been answered.

DATE_MONTH
DELETED

Flag indicating a message has been marked for deletion. This will occur when the mailbox is closed or expunged.

DRAFT

Flag indicating a message is only a draft or work-in-progress version.

FLAGGED

Flag indicating a message has been flagged for special or urgent attention.

MARKED

Flag indicating that a mailbox has been marked “interesting” by the server; this commonly indicates that the mailbox contains new messages.

NOINFERIORS

Flag indicating that a mailbox context name cannot contain children.

NOSELECT

Flag indicating that a mailbox is not selected.

RECENT

Flag indicating that the message is “recent,” meaning that this session is the first session in which the client has been notified of this message.

SEEN

Flag indicating a message has been seen.

UNMARKED

Flag indicating that the mailbox does not contains new messages.

Attributes

client_thread[RW]

The thread to receive exceptions.

greeting[R]

Returns an initial greeting response from the server.

response_handlers[R]

Returns all response handlers.

responses[R]

Returns recorded untagged responses. For example:

imap.select("inbox")
p imap.responses["EXISTS"][-1]
#=> 2
p imap.responses["UIDVALIDITY"][-1]
#=> 968263756

Public Class Methods

add_authenticator(auth_type, authenticator) click to toggle source

Adds an authenticator for #authenticate. auth_type is the type of authentication this authenticator supports (for instance, “LOGIN”). The authenticator is an object which defines a process() method to handle authentication with the server. See Net::IMAP::LoginAuthenticator, Net::IMAP::CramMD5Authenticator, and Net::IMAP::DigestMD5Authenticator for examples.

If auth_type refers to an existing authenticator, it will be replaced by the new one.

# File lib/net/imap.rb, line 295
def self.add_authenticator(auth_type, authenticator)
  @@authenticators[auth_type] = authenticator
end
debug() click to toggle source

Returns the debug mode.

# File lib/net/imap.rb, line 265
def self.debug
  return @@debug
end
debug=(val) click to toggle source

Sets the debug mode.

# File lib/net/imap.rb, line 270
def self.debug=(val)
  return @@debug = val
end
decode_utf7(s) click to toggle source

Decode a string from modified UTF-7 format to UTF-8.

UTF-7 is a 7-bit encoding of Unicode [UTF7]. IMAP uses a slightly modified version of this to encode mailbox names containing non-ASCII characters; see [IMAP] section 5.1.3.

Net::IMAP does not automatically encode and decode mailbox names to and from UTF-7.

# File lib/net/imap.rb, line 992
def self.decode_utf7(s)
  return s.gsub(/&([^-]+)?-/n) {
    if $1
      ($1.tr(",", "/") + "===").unpack("m")[0].encode(Encoding::UTF_8, Encoding::UTF_16BE)
    else
      "&"
    end
  }
end
default_imap_port()
Alias for: default_port
default_imaps_port()
Alias for: default_tls_port
default_port() click to toggle source

The default port for IMAP connections, port 143

# File lib/net/imap.rb, line 300
def self.default_port
  return PORT
end
Also aliased as: default_imap_port
default_ssl_port()
Alias for: default_tls_port
default_tls_port() click to toggle source

The default port for IMAPS connections, port 993

# File lib/net/imap.rb, line 305
def self.default_tls_port
  return SSL_PORT
end
encode_utf7(s) click to toggle source

Encode a string from UTF-8 format to modified UTF-7.

# File lib/net/imap.rb, line 1003
def self.encode_utf7(s)
  return s.gsub(/(&)|[^\x20-\x7e]+/) {
    if $1
      "&-"
    else
      base64 = [$&.encode(Encoding::UTF_16BE)].pack("m0")
      "&" + base64.delete("=").tr("/", ",") + "-"
    end
  }.force_encoding("ASCII-8BIT")
end
format_date(time) click to toggle source

Formats time as an IMAP-style date.

# File lib/net/imap.rb, line 1015
def self.format_date(time)
  return time.strftime('%d-%b-%Y')
end
format_datetime(time) click to toggle source

Formats time as an IMAP-style date-time.

# File lib/net/imap.rb, line 1020
def self.format_datetime(time)
  return time.strftime('%d-%b-%Y %H:%M %z')
end
max_flag_count() click to toggle source

Returns the max number of flags interned to symbols.

# File lib/net/imap.rb, line 275
def self.max_flag_count
  return @@max_flag_count
end
max_flag_count=(count) click to toggle source

Sets the max number of flags interned to symbols.

# File lib/net/imap.rb, line 280
def self.max_flag_count=(count)
  @@max_flag_count = count
end
Net::IMAP.new(host, options = {}) click to toggle source

Creates a new Net::IMAP object and connects it to the specified host.

options is an option hash, each key of which is a symbol.

The available options are:

port

Port number (default value is 143 for imap, or 993 for imaps)

ssl

If options is true, then an attempt will be made to use SSL (now TLS) to connect to the server. For this to work OpenSSL [OSSL] and the Ruby OpenSSL [RSSL] extensions need to be installed. If options is a hash, it's passed to OpenSSL::SSL::SSLContext#set_params as parameters.

The most common errors are:

Errno::ECONNREFUSED

Connection refused by host or an intervening firewall.

Errno::ETIMEDOUT

Connection timed out (possibly due to packets being dropped by an intervening firewall).

Errno::ENETUNREACH

There is no route to that network.

SocketError

Hostname not known or other socket error.

Net::IMAP::ByeResponseError

The connected to the host was successful, but it immediately said goodbye.

Calls superclass method MonitorMixin.new
# File lib/net/imap.rb, line 1062
def initialize(host, port_or_options = {},
               usessl = false, certs = nil, verify = true)
  super()
  @host = host
  begin
    options = port_or_options.to_hash
  rescue NoMethodError
    # for backward compatibility
    options = {}
    options[:port] = port_or_options
    if usessl
      options[:ssl] = create_ssl_params(certs, verify)
    end
  end
  @port = options[:port] || (options[:ssl] ? SSL_PORT : PORT)
  @tag_prefix = "RUBY"
  @tagno = 0
  @parser = ResponseParser.new
  @sock = TCPSocket.open(@host, @port)
  begin
    if options[:ssl]
      start_tls_session(options[:ssl])
      @usessl = true
    else
      @usessl = false
    end
    @responses = Hash.new([].freeze)
    @tagged_responses = {}
    @response_handlers = []
    @tagged_response_arrival = new_cond
    @continuation_request_arrival = new_cond
    @idle_done_cond = nil
    @logout_command_tag = nil
    @debug_output_bol = true
    @exception = nil

    @greeting = get_response
    if @greeting.nil?
      raise Error, "connection closed"
    end
    if @greeting.name == "BYE"
      raise ByeResponseError, @greeting
    end

    @client_thread = Thread.current
    @receiver_thread = Thread.start {
      begin
        receive_responses
      rescue Exception
      end
    }
    @receiver_thread_terminating = false
  rescue Exception
    @sock.close
    raise
  end
end

Public Instance Methods

add_response_handler(handler = Proc.new) click to toggle source

Adds a response handler. For example, to detect when the server sends a new EXISTS response (which normally indicates new messages being added to the mailbox), add the following handler after selecting the mailbox:

imap.add_response_handler { |resp|
  if resp.kind_of?(Net::IMAP::UntaggedResponse) and resp.name == "EXISTS"
    puts "Mailbox now has #{resp.data} messages"
  end
}
# File lib/net/imap.rb, line 899
def add_response_handler(handler = Proc.new)
  @response_handlers.push(handler)
end
append(mailbox, message, flags = nil, date_time = nil) click to toggle source

Sends a APPEND command to append the message to the end of the mailbox. The optional flags argument is an array of flags initially passed to the new message. The optional date_time argument specifies the creation time to assign to the new message; it defaults to the current time. For example:

imap.append("inbox", <<EOF.gsub(/\n/, "\r\n"), [:Seen], Time.now)
Subject: hello
From: shugo@ruby-lang.org
To: shugo@ruby-lang.org

hello world
EOF

A Net::IMAP::NoResponseError is raised if the mailbox does not exist (it is not created automatically), or if the flags, date_time, or message arguments contain errors.

# File lib/net/imap.rb, line 692
def append(mailbox, message, flags = nil, date_time = nil)
  args = []
  if flags
    args.push(flags)
  end
  args.push(date_time) if date_time
  args.push(Literal.new(message))
  send_command("APPEND", mailbox, *args)
end
authenticate(auth_type, *args) click to toggle source

Sends an AUTHENTICATE command to authenticate the client. The auth_type parameter is a string that represents the authentication mechanism to be used. Currently Net::IMAP supports the authentication mechanisms:

LOGIN:: login using cleartext user and password.
CRAM-MD5:: login with cleartext user and encrypted password
           (see [RFC-2195] for a full description).  This
           mechanism requires that the server have the user's
           password stored in clear-text password.

For both of these mechanisms, there should be two args: username and (cleartext) password. A server may not support one or the other of these mechanisms; check capability() for a capability of the form “AUTH=LOGIN” or “AUTH=CRAM-MD5”.

Authentication is done using the appropriate authenticator object: see @@authenticators for more information on plugging in your own authenticator.

For example:

imap.authenticate('LOGIN', user, password)

A Net::IMAP::NoResponseError is raised if authentication fails.

# File lib/net/imap.rb, line 410
def authenticate(auth_type, *args)
  auth_type = auth_type.upcase
  unless @@authenticators.has_key?(auth_type)
    raise ArgumentError,
      format('unknown auth type - "%s"', auth_type)
  end
  authenticator = @@authenticators[auth_type].new(*args)
  send_command("AUTHENTICATE", auth_type) do |resp|
    if resp.instance_of?(ContinuationRequest)
      data = authenticator.process(resp.data.text.unpack("m")[0])
      s = [data].pack("m0")
      send_string_data(s)
      put_string(CRLF)
    end
  end
end
capability() click to toggle source

Sends a CAPABILITY command, and returns an array of capabilities that the server supports. Each capability is a string. See [IMAP] for a list of possible capabilities.

Note that the Net::IMAP class does not modify its behaviour according to the capabilities of the server; it is up to the user of the class to ensure that a certain capability is supported by a server before using it.

# File lib/net/imap.rb, line 352
def capability
  synchronize do
    send_command("CAPABILITY")
    return @responses.delete("CAPABILITY")[-1]
  end
end
check() click to toggle source

Sends a CHECK command to request a checkpoint of the currently selected mailbox. This performs implementation-specific housekeeping; for instance, reconciling the mailbox's in-memory and on-disk state.

# File lib/net/imap.rb, line 706
def check
  send_command("CHECK")
end
close() click to toggle source

Sends a CLOSE command to close the currently selected mailbox. The CLOSE command permanently removes from the mailbox all messages that have the Deleted flag set.

# File lib/net/imap.rb, line 713
def close
  send_command("CLOSE")
end
copy(set, mailbox) click to toggle source

Sends a COPY command to copy the specified message(s) to the end of the specified destination mailbox. The set parameter is a number, an array of numbers, or a Range object. The number is a message sequence number.

# File lib/net/imap.rb, line 846
def copy(set, mailbox)
  copy_internal("COPY", set, mailbox)
end
create(mailbox) click to toggle source

Sends a CREATE command to create a new mailbox.

A Net::IMAP::NoResponseError is raised if a mailbox with that name cannot be created.

# File lib/net/imap.rb, line 473
def create(mailbox)
  send_command("CREATE", mailbox)
end
delete(mailbox) click to toggle source

Sends a DELETE command to remove the mailbox.

A Net::IMAP::NoResponseError is raised if a mailbox with that name cannot be deleted, either because it does not exist or because the client does not have permission to delete it.

# File lib/net/imap.rb, line 482
def delete(mailbox)
  send_command("DELETE", mailbox)
end
disconnect() click to toggle source

Disconnects from the server.

# File lib/net/imap.rb, line 316
def disconnect
  begin
    begin
      # try to call SSL::SSLSocket#io.
      @sock.io.shutdown
    rescue NoMethodError
      # @sock is not an SSL::SSLSocket.
      @sock.shutdown
    end
  rescue Errno::ENOTCONN
    # ignore `Errno::ENOTCONN: Socket is not connected' on some platforms.
  rescue Exception => e
    @receiver_thread.raise(e)
  end
  @receiver_thread.join
  synchronize do
    @sock.close
  end
  raise e if e
end
disconnected?() click to toggle source

Returns true if disconnected from the server.

# File lib/net/imap.rb, line 338
def disconnected?
  return @sock.closed?
end
examine(mailbox) click to toggle source

Sends a EXAMINE command to select a mailbox so that messages in the mailbox can be accessed. Behaves the same as select(), except that the selected mailbox is identified as read-only.

A Net::IMAP::NoResponseError is raised if the mailbox does not exist or is for some reason non-examinable.

# File lib/net/imap.rb, line 462
def examine(mailbox)
  synchronize do
    @responses.clear
    send_command("EXAMINE", mailbox)
  end
end
expunge() click to toggle source

Sends a EXPUNGE command to permanently remove from the currently selected mailbox all messages that have the Deleted flag set.

# File lib/net/imap.rb, line 719
def expunge
  synchronize do
    send_command("EXPUNGE")
    return @responses.delete("EXPUNGE")
  end
end
fetch(set, attr) click to toggle source

Sends a FETCH command to retrieve data associated with a message in the mailbox.

The set parameter is a number or a range between two numbers, or an array of those. The number is a message sequence number, where -1 represents a '*' for use in range notation like 100..-1 being interpreted as '100:*'. Beware that the exclude_end? property of a Range object is ignored, and the contents of a range are independent of the order of the range endpoints as per the protocol specification, so 1…5, 5..1 and 5…1 are all equivalent to 1..5.

attr is a list of attributes to fetch; see the documentation for Net::IMAP::FetchData for a list of valid attributes.

The return value is an array of Net::IMAP::FetchData or nil (instead of an empty array) if there is no matching message.

For example:

p imap.fetch(6..8, "UID")
#=> [#<Net::IMAP::FetchData seqno=6, attr={"UID"=>98}>, \\
     #<Net::IMAP::FetchData seqno=7, attr={"UID"=>99}>, \\
     #<Net::IMAP::FetchData seqno=8, attr={"UID"=>100}>]
p imap.fetch(6, "BODY[HEADER.FIELDS (SUBJECT)]")
#=> [#<Net::IMAP::FetchData seqno=6, attr={"BODY[HEADER.FIELDS (SUBJECT)]"=>"Subject: test\r\n\r\n"}>]
data = imap.uid_fetch(98, ["RFC822.SIZE", "INTERNALDATE"])[0]
p data.seqno
#=> 6
p data.attr["RFC822.SIZE"]
#=> 611
p data.attr["INTERNALDATE"]
#=> "12-Oct-2000 22:40:59 +0900"
p data.attr["UID"]
#=> 98
# File lib/net/imap.rb, line 810
def fetch(set, attr)
  return fetch_internal("FETCH", set, attr)
end
getacl(mailbox) click to toggle source

Send the GETACL command along with a specified mailbox. If this mailbox exists, an array containing objects of Net::IMAP::MailboxACLItem will be returned.

# File lib/net/imap.rb, line 632
def getacl(mailbox)
  synchronize do
    send_command("GETACL", mailbox)
    return @responses.delete("ACL")[-1]
  end
end
getquota(mailbox) click to toggle source

Sends the GETQUOTA command along with specified mailbox. If this mailbox exists, then an array containing a Net::IMAP::MailboxQuota object is returned. This command is generally only available to server admin.

# File lib/net/imap.rb, line 596
def getquota(mailbox)
  synchronize do
    send_command("GETQUOTA", mailbox)
    return @responses.delete("QUOTA")
  end
end
getquotaroot(mailbox) click to toggle source

Sends the GETQUOTAROOT command along with the specified mailbox. This command is generally available to both admin and user. If this mailbox exists, it returns an array containing objects of type Net::IMAP::MailboxQuotaRoot and Net::IMAP::MailboxQuota.

# File lib/net/imap.rb, line 582
def getquotaroot(mailbox)
  synchronize do
    send_command("GETQUOTAROOT", mailbox)
    result = []
    result.concat(@responses.delete("QUOTAROOT"))
    result.concat(@responses.delete("QUOTA"))
    return result
  end
end
idle(timeout = nil, &response_handler) click to toggle source

Sends an IDLE command that waits for notifications of new or expunged messages. Yields responses from the server during the IDLE.

Use idle_done() to leave IDLE.

If timeout is given, this method returns after timeout seconds passed. timeout can be used for keep-alive. For example, the following code checks the connection for each 60 seconds.

loop do
  imap.idle(60) do |res|
    ...
  end
end
# File lib/net/imap.rb, line 945
def idle(timeout = nil, &response_handler)
  raise LocalJumpError, "no block given" unless response_handler

  response = nil

  synchronize do
    tag = Thread.current[:net_imap_tag] = generate_tag
    put_string("#{tag} IDLE#{CRLF}")

    begin
      add_response_handler(response_handler)
      @idle_done_cond = new_cond
      @idle_done_cond.wait(timeout)
      @idle_done_cond = nil
      if @receiver_thread_terminating
        raise Net::IMAP::Error, "connection closed"
      end
    ensure
      unless @receiver_thread_terminating
        remove_response_handler(response_handler)
        put_string("DONE#{CRLF}")
        response = get_tagged_response(tag, "IDLE")
      end
    end
  end

  return response
end
idle_done() click to toggle source

Leaves IDLE.

# File lib/net/imap.rb, line 975
def idle_done
  synchronize do
    if @idle_done_cond.nil?
      raise Net::IMAP::Error, "not during IDLE"
    end
    @idle_done_cond.signal
  end
end
list(refname, mailbox) click to toggle source

Sends a LIST command, and returns a subset of names from the complete set of all names available to the client. refname provides a context (for instance, a base directory in a directory-based mailbox hierarchy). mailbox specifies a mailbox or (via wildcards) mailboxes under that context. Two wildcards may be used in mailbox: '*', which matches all characters including the hierarchy delimiter (for instance, '/' on a UNIX-hosted directory-based mailbox hierarchy); and '%', which matches all characters except the hierarchy delimiter.

If refname is empty, mailbox is used directly to determine which mailboxes to match. If mailbox is empty, the root name of refname and the hierarchy delimiter are returned.

The return value is an array of Net::IMAP::MailboxList. For example:

imap.create("foo/bar")
imap.create("foo/baz")
p imap.list("", "foo/%")
#=> [#<Net::IMAP::MailboxList attr=[:Noselect], delim="/", name="foo/">, \\
     #<Net::IMAP::MailboxList attr=[:Noinferiors, :Marked], delim="/", name="foo/bar">, \\
     #<Net::IMAP::MailboxList attr=[:Noinferiors], delim="/", name="foo/baz">]
# File lib/net/imap.rb, line 539
def list(refname, mailbox)
  synchronize do
    send_command("LIST", refname, mailbox)
    return @responses.delete("LIST")
  end
end
login(user, password) click to toggle source

Sends a LOGIN command to identify the client and carries the plaintext password authenticating this user. Note that, unlike calling authenticate() with an auth_type of “LOGIN”, login() does not use the login authenticator.

A Net::IMAP::NoResponseError is raised if authentication fails.

# File lib/net/imap.rb, line 433
def login(user, password)
  send_command("LOGIN", user, password)
end
logout() click to toggle source

Sends a LOGOUT command to inform the server that the client is done with the connection.

# File lib/net/imap.rb, line 366
def logout
  send_command("LOGOUT")
end
lsub(refname, mailbox) click to toggle source

Sends a LSUB command, and returns a subset of names from the set of names that the user has declared as being “active” or “subscribed.” refname and mailbox are interpreted as for list(). The return value is an array of Net::IMAP::MailboxList.

# File lib/net/imap.rb, line 644
def lsub(refname, mailbox)
  synchronize do
    send_command("LSUB", refname, mailbox)
    return @responses.delete("LSUB")
  end
end
move(set, mailbox) click to toggle source

Sends a MOVE command to move the specified message(s) to the end of the specified destination mailbox. The set parameter is a number, an array of numbers, or a Range object. The number is a message sequence number. The IMAP MOVE extension is described in [RFC-6851].

# File lib/net/imap.rb, line 860
def move(set, mailbox)
  copy_internal("MOVE", set, mailbox)
end
noop() click to toggle source

Sends a NOOP command to the server. It does nothing.

# File lib/net/imap.rb, line 360
def noop
  send_command("NOOP")
end
remove_response_handler(handler) click to toggle source

Removes the response handler.

# File lib/net/imap.rb, line 904
def remove_response_handler(handler)
  @response_handlers.delete(handler)
end
rename(mailbox, newname) click to toggle source

Sends a RENAME command to change the name of the mailbox to newname.

A Net::IMAP::NoResponseError is raised if a mailbox with the name mailbox cannot be renamed to newname for whatever reason; for instance, because mailbox does not exist, or because there is already a mailbox with the name newname.

# File lib/net/imap.rb, line 493
def rename(mailbox, newname)
  send_command("RENAME", mailbox, newname)
end
select(mailbox) click to toggle source

Sends a SELECT command to select a mailbox so that messages in the mailbox can be accessed.

After you have selected a mailbox, you may retrieve the number of items in that mailbox from @responses[-1], and the number of recent messages from @responses[-1]. Note that these values can change if new messages arrive during a session; see add_response_handler() for a way of detecting this event.

A Net::IMAP::NoResponseError is raised if the mailbox does not exist or is for some reason non-selectable.

# File lib/net/imap.rb, line 449
def select(mailbox)
  synchronize do
    @responses.clear
    send_command("SELECT", mailbox)
  end
end
setacl(mailbox, user, rights) click to toggle source

Sends the SETACL command along with mailbox, user and the rights that user is to have on that mailbox. If rights is nil, then that user will be stripped of any rights to that mailbox. The IMAP ACL commands are described in [RFC-2086].

# File lib/net/imap.rb, line 621
def setacl(mailbox, user, rights)
  if rights.nil?
    send_command("SETACL", mailbox, user, "")
  else
    send_command("SETACL", mailbox, user, rights)
  end
end
setquota(mailbox, quota) click to toggle source

Sends a SETQUOTA command along with the specified mailbox and quota. If quota is nil, then quota will be unset for that mailbox. Typically one needs to be logged in as a server admin for this to work. The IMAP quota commands are described in [RFC-2087].

# File lib/net/imap.rb, line 608
def setquota(mailbox, quota)
  if quota.nil?
    data = '()'
  else
    data = '(STORAGE ' + quota.to_s + ')'
  end
  send_command("SETQUOTA", mailbox, RawData.new(data))
end
sort(sort_keys, search_keys, charset) click to toggle source

Sends a SORT command to sort messages in the mailbox. Returns an array of message sequence numbers. For example:

p imap.sort(["FROM"], ["ALL"], "US-ASCII")
#=> [1, 2, 3, 5, 6, 7, 8, 4, 9]
p imap.sort(["DATE"], ["SUBJECT", "hello"], "US-ASCII")
#=> [6, 7, 8, 1]

See [SORT-THREAD-EXT] for more details.

# File lib/net/imap.rb, line 878
def sort(sort_keys, search_keys, charset)
  return sort_internal("SORT", sort_keys, search_keys, charset)
end
starttls(options = {}, verify = true) click to toggle source

Sends a STARTTLS command to start TLS session.

# File lib/net/imap.rb, line 371
def starttls(options = {}, verify = true)
  send_command("STARTTLS") do |resp|
    if resp.kind_of?(TaggedResponse) && resp.name == "OK"
      begin
        # for backward compatibility
        certs = options.to_str
        options = create_ssl_params(certs, verify)
      rescue NoMethodError
      end
      start_tls_session(options)
    end
  end
end
status(mailbox, attr) click to toggle source

Sends a STATUS command, and returns the status of the indicated mailbox. attr is a list of one or more attributes whose statuses are to be requested. Supported attributes include:

MESSAGES:: the number of messages in the mailbox.
RECENT:: the number of recent messages in the mailbox.
UNSEEN:: the number of unseen messages in the mailbox.

The return value is a hash of attributes. For example:

p imap.status("inbox", ["MESSAGES", "RECENT"])
#=> {"RECENT"=>0, "MESSAGES"=>44}

A Net::IMAP::NoResponseError is raised if status values for mailbox cannot be returned; for instance, because it does not exist.

# File lib/net/imap.rb, line 667
def status(mailbox, attr)
  synchronize do
    send_command("STATUS", mailbox, attr)
    return @responses.delete("STATUS")[-1].attr
  end
end
store(set, attr, flags) click to toggle source

Sends a STORE command to alter data associated with messages in the mailbox, in particular their flags. The set parameter is a number, an array of numbers, or a Range object. Each number is a message sequence number. attr is the name of a data item to store: 'FLAGS' will replace the message's flag list with the provided one, '+FLAGS' will add the provided flags, and '-FLAGS' will remove them. flags is a list of flags.

The return value is an array of Net::IMAP::FetchData. For example:

p imap.store(6..8, "+FLAGS", [:Deleted])
#=> [#<Net::IMAP::FetchData seqno=6, attr={"FLAGS"=>[:Seen, :Deleted]}>, \\
     #<Net::IMAP::FetchData seqno=7, attr={"FLAGS"=>[:Seen, :Deleted]}>, \\
     #<Net::IMAP::FetchData seqno=8, attr={"FLAGS"=>[:Seen, :Deleted]}>]
# File lib/net/imap.rb, line 833
def store(set, attr, flags)
  return store_internal("STORE", set, attr, flags)
end
subscribe(mailbox) click to toggle source

Sends a SUBSCRIBE command to add the specified mailbox name to the server's set of “active” or “subscribed” mailboxes as returned by lsub().

A Net::IMAP::NoResponseError is raised if mailbox cannot be subscribed to; for instance, because it does not exist.

# File lib/net/imap.rb, line 503
def subscribe(mailbox)
  send_command("SUBSCRIBE", mailbox)
end
thread(algorithm, search_keys, charset) click to toggle source

Similar to search(), but returns message sequence numbers in threaded format, as a Net::IMAP::ThreadMember tree. The supported algorithms are:

ORDEREDSUBJECT

split into single-level threads according to subject, ordered by date.

REFERENCES

split into threads by parent/child relationships determined by which message is a reply to which.

Unlike search(), charset is a required argument. US-ASCII and UTF-8 are sample values.

See [SORT-THREAD-EXT] for more details.

# File lib/net/imap.rb, line 921
def thread(algorithm, search_keys, charset)
  return thread_internal("THREAD", algorithm, search_keys, charset)
end
uid_copy(set, mailbox) click to toggle source

Similar to copy(), but set contains unique identifiers.

# File lib/net/imap.rb, line 851
def uid_copy(set, mailbox)
  copy_internal("UID COPY", set, mailbox)
end
uid_fetch(set, attr) click to toggle source

Similar to fetch(), but set contains unique identifiers.

# File lib/net/imap.rb, line 815
def uid_fetch(set, attr)
  return fetch_internal("UID FETCH", set, attr)
end
uid_move(set, mailbox) click to toggle source

Similar to move(), but set contains unique identifiers.

# File lib/net/imap.rb, line 865
def uid_move(set, mailbox)
  copy_internal("UID MOVE", set, mailbox)
end
uid_sort(sort_keys, search_keys, charset) click to toggle source

Similar to sort(), but returns an array of unique identifiers.

# File lib/net/imap.rb, line 883
def uid_sort(sort_keys, search_keys, charset)
  return sort_internal("UID SORT", sort_keys, search_keys, charset)
end
uid_store(set, attr, flags) click to toggle source

Similar to store(), but set contains unique identifiers.

# File lib/net/imap.rb, line 838
def uid_store(set, attr, flags)
  return store_internal("UID STORE", set, attr, flags)
end
uid_thread(algorithm, search_keys, charset) click to toggle source

Similar to thread(), but returns unique identifiers instead of message sequence numbers.

# File lib/net/imap.rb, line 927
def uid_thread(algorithm, search_keys, charset)
  return thread_internal("UID THREAD", algorithm, search_keys, charset)
end
unsubscribe(mailbox) click to toggle source

Sends a UNSUBSCRIBE command to remove the specified mailbox name from the server's set of “active” or “subscribed” mailboxes.

A Net::IMAP::NoResponseError is raised if mailbox cannot be unsubscribed from; for instance, because the client is not currently subscribed to it.

# File lib/net/imap.rb, line 513
def unsubscribe(mailbox)
  send_command("UNSUBSCRIBE", mailbox)
end
xlist(refname, mailbox) click to toggle source

Sends a XLIST command, and returns a subset of names from the complete set of all names available to the client. refname provides a context (for instance, a base directory in a directory-based mailbox hierarchy). mailbox specifies a mailbox or (via wildcards) mailboxes under that context. Two wildcards may be used in mailbox: '*', which matches all characters including the hierarchy delimiter (for instance, '/' on a UNIX-hosted directory-based mailbox hierarchy); and '%', which matches all characters except the hierarchy delimiter.

If refname is empty, mailbox is used directly to determine which mailboxes to match. If mailbox is empty, the root name of refname and the hierarchy delimiter are returned.

The XLIST command is like the LIST command except that the flags returned refer to the function of the folder/mailbox, e.g. :Sent

The return value is an array of Net::IMAP::MailboxList. For example:

imap.create("foo/bar")
imap.create("foo/baz")
p imap.xlist("", "foo/%")
#=> [#<Net::IMAP::MailboxList attr=[:Noselect], delim="/", name="foo/">, \\
     #<Net::IMAP::MailboxList attr=[:Noinferiors, :Marked], delim="/", name="foo/bar">, \\
     #<Net::IMAP::MailboxList attr=[:Noinferiors], delim="/", name="foo/baz">]
# File lib/net/imap.rb, line 571
def xlist(refname, mailbox)
  synchronize do
    send_command("XLIST", refname, mailbox)
    return @responses.delete("XLIST")
  end
end

Private Instance Methods

copy_internal(cmd, set, mailbox) click to toggle source
# File lib/net/imap.rb, line 1415
def copy_internal(cmd, set, mailbox)
  send_command(cmd, MessageSet.new(set), mailbox)
end
create_ssl_params(certs = nil, verify = true) click to toggle source
# File lib/net/imap.rb, line 1454
def create_ssl_params(certs = nil, verify = true)
  params = {}
  if certs
    if File.file?(certs)
      params[:ca_file] = certs
    elsif File.directory?(certs)
      params[:ca_path] = certs
    end
  end
  if verify
    params[:verify_mode] = VERIFY_PEER
  else
    params[:verify_mode] = VERIFY_NONE
  end
  return params
end
fetch_internal(cmd, set, attr) click to toggle source
# File lib/net/imap.rb, line 1387
def fetch_internal(cmd, set, attr)
  case attr
  when String then
    attr = RawData.new(attr)
  when Array then
    attr = attr.map { |arg|
      arg.is_a?(String) ? RawData.new(arg) : arg
    }
  end

  synchronize do
    @responses.delete("FETCH")
    send_command(cmd, MessageSet.new(set), attr)
    return @responses.delete("FETCH")
  end
end
generate_tag() click to toggle source
# File lib/net/imap.rb, line 1257
def generate_tag
  @tagno += 1
  return format("%s%04d", @tag_prefix, @tagno)
end
get_response() click to toggle source
# File lib/net/imap.rb, line 1202
    def get_response
      buff = String.new
      while true
        s = @sock.gets(CRLF)
        break unless s
        buff.concat(s)
        if /\{(\d+)\}\r\n/n =~ s
          s = @sock.read($1.to_i)
          buff.concat(s)
        else
          break
        end
      end
      return nil if buff.length == 0
      if @@debug
        $stderr.print(buff.gsub(/^/n, "S: "))
      end
      return @parser.parse(buff)
    end

    def record_response(name, data)
      unless @responses.has_key?(name)
        @responses[name] = []
      end
      @responses[name].push(data)
    end

    def send_command(cmd, *args, &block)
      synchronize do
        args.each do |i|
          validate_data(i)
        end
        tag = generate_tag
        put_string(tag + " " + cmd)
        args.each do |i|
          put_string(" ")
          send_data(i)
        end
        put_string(CRLF)
        if cmd == "LOGOUT"
          @logout_command_tag = tag
        end
        if block
          add_response_handler(block)
        end
        begin
          return get_tagged_response(tag, cmd)
        ensure
          if block
            remove_response_handler(block)
          end
        end
      end
    end

    def generate_tag
      @tagno += 1
      return format("%s%04d", @tag_prefix, @tagno)
    end

    def put_string(str)
      @sock.print(str)
      if @@debug
        if @debug_output_bol
          $stderr.print("C: ")
        end
        $stderr.print(str.gsub(/\n(?!\z)/n, "\nC: "))
        if /\r\n\z/n.match(str)
          @debug_output_bol = true
        else
          @debug_output_bol = false
        end
      end
    end

    def validate_data(data)
      case data
      when nil
      when String
      when Integer
        NumValidator.ensure_number(data)
      when Array
        data.each do |i|
          validate_data(i)
        end
      when Time
      when Symbol
      else
        data.validate
      end
    end

    def send_data(data)
      case data
      when nil
        put_string("NIL")
      when String
        send_string_data(data)
      when Integer
        send_number_data(data)
      when Array
        send_list_data(data)
      when Time
        send_time_data(data)
      when Symbol
        send_symbol_data(data)
      else
        data.send_data(self)
      end
    end

    def send_string_data(str)
      case str
      when ""
        put_string('""')
      when /[\x80-\xff\r\n]/n
        # literal
        send_literal(str)
      when /[(){ \x00-\x1f\x7f%*"\\]/n
        # quoted string
        send_quoted_string(str)
      else
        put_string(str)
      end
    end

    def send_quoted_string(str)
      put_string('"' + str.gsub(/["\\]/n, "\\\\\\&") + '"')
    end

    def send_literal(str)
      put_string("{" + str.bytesize.to_s + "}" + CRLF)
      @continuation_request_arrival.wait
      raise @exception if @exception
      put_string(str)
    end

    def send_number_data(num)
      put_string(num.to_s)
    end

    def send_list_data(list)
      put_string("(")
      first = true
      list.each do |i|
        if first
          first = false
        else
          put_string(" ")
        end
        send_data(i)
      end
      put_string(")")
    end

    DATE_MONTH = %w(Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)

    def send_time_data(time)
      t = time.dup.gmtime
      s = format('"%2d-%3s-%4d %02d:%02d:%02d +0000"',
                 t.day, DATE_MONTH[t.month - 1], t.year,
                 t.hour, t.min, t.sec)
      put_string(s)
    end

    def send_symbol_data(symbol)
      put_string("\\" + symbol.to_s)
    end

    def search_internal(cmd, keys, charset)
      if keys.instance_of?(String)
        keys = [RawData.new(keys)]
      else
        normalize_searching_criteria(keys)
      end
      synchronize do
        if charset
          send_command(cmd, "CHARSET", charset, *keys)
        else
          send_command(cmd, *keys)
        end
        return @responses.delete("SEARCH")[-1]
      end
    end

    def fetch_internal(cmd, set, attr)
      case attr
      when String then
        attr = RawData.new(attr)
      when Array then
        attr = attr.map { |arg|
          arg.is_a?(String) ? RawData.new(arg) : arg
        }
      end

      synchronize do
        @responses.delete("FETCH")
        send_command(cmd, MessageSet.new(set), attr)
        return @responses.delete("FETCH")
      end
    end

    def store_internal(cmd, set, attr, flags)
      if attr.instance_of?(String)
        attr = RawData.new(attr)
      end
      synchronize do
        @responses.delete("FETCH")
        send_command(cmd, MessageSet.new(set), attr, flags)
        return @responses.delete("FETCH")
      end
    end

    def copy_internal(cmd, set, mailbox)
      send_command(cmd, MessageSet.new(set), mailbox)
    end

    def sort_internal(cmd, sort_keys, search_keys, charset)
      if search_keys.instance_of?(String)
        search_keys = [RawData.new(search_keys)]
      else
        normalize_searching_criteria(search_keys)
      end
      normalize_searching_criteria(search_keys)
      synchronize do
        send_command(cmd, sort_keys, charset, *search_keys)
        return @responses.delete("SORT")[-1]
      end
    end

    def thread_internal(cmd, algorithm, search_keys, charset)
      if search_keys.instance_of?(String)
        search_keys = [RawData.new(search_keys)]
      else
        normalize_searching_criteria(search_keys)
      end
      normalize_searching_criteria(search_keys)
      send_command(cmd, algorithm, charset, *search_keys)
      return @responses.delete("THREAD")[-1]
    end

    def normalize_searching_criteria(keys)
      keys.collect! do |i|
        case i
        when -1, Range, Array
          MessageSet.new(i)
        else
          i
        end
      end
    end

    def create_ssl_params(certs = nil, verify = true)
      params = {}
      if certs
        if File.file?(certs)
          params[:ca_file] = certs
        elsif File.directory?(certs)
          params[:ca_path] = certs
        end
      end
      if verify
        params[:verify_mode] = VERIFY_PEER
      else
        params[:verify_mode] = VERIFY_NONE
      end
      return params
    end

    def start_tls_session(params = {})
      unless defined?(OpenSSL::SSL)
        raise "SSL extension not installed"
      end
      if @sock.kind_of?(OpenSSL::SSL::SSLSocket)
        raise RuntimeError, "already using SSL"
      end
      begin
        params = params.to_hash
      rescue NoMethodError
        params = {}
      end
      context = SSLContext.new
      context.set_params(params)
      if defined?(VerifyCallbackProc)
        context.verify_callback = VerifyCallbackProc
      end
      @sock = SSLSocket.new(@sock, context)
      @sock.sync_close = true
      @sock.connect
      if context.verify_mode != VERIFY_NONE
        @sock.post_connection_check(@host)
      end
    end

    class RawData # :nodoc:
      def send_data(imap)
        imap.send(:put_string, @data)
      end

      def validate
      end

      private

      def initialize(data)
        @data = data
      end
    end

    class Atom # :nodoc:
      def send_data(imap)
        imap.send(:put_string, @data)
      end

      def validate
      end

      private

      def initialize(data)
        @data = data
      end
    end

    class QuotedString # :nodoc:
      def send_data(imap)
        imap.send(:send_quoted_string, @data)
      end

      def validate
      end

      private

      def initialize(data)
        @data = data
      end
    end

    class Literal # :nodoc:
      def send_data(imap)
        imap.send(:send_literal, @data)
      end

      def validate
      end

      private

      def initialize(data)
        @data = data
      end
    end

    class MessageSet # :nodoc:
      def send_data(imap)
        imap.send(:put_string, format_internal(@data))
      end

      def validate
        validate_internal(@data)
      end

      private

      def initialize(data)
        @data = data
      end

      def format_internal(data)
        case data
        when "*"
          return data
        when Integer
          if data == -1
            return "*"
          else
            return data.to_s
          end
        when Range
          return format_internal(data.first) +
            ":" + format_internal(data.last)
        when Array
          return data.collect {|i| format_internal(i)}.join(",")
        when ThreadMember
          return data.seqno.to_s +
            ":" + data.children.collect {|i| format_internal(i).join(",")}
        end
      end

      def validate_internal(data)
        case data
        when "*"
        when Integer
          NumValidator.ensure_nz_number(data)
        when Range
        when Array
          data.each do |i|
            validate_internal(i)
          end
        when ThreadMember
          data.children.each do |i|
            validate_internal(i)
          end
        else
          raise DataFormatError, data.inspect
        end
      end
    end

    # Common validators of number and nz_number types
    module NumValidator # :nodoc
      class << self
        # Check is passed argument valid 'number' in RFC 3501 terminology
        def valid_number?(num)
          # [RFC 3501]
          # number          = 1*DIGIT
          #                    ; Unsigned 32-bit integer
          #                    ; (0 <= n < 4,294,967,296)
          num >= 0 && num < 4294967296
        end

        # Check is passed argument valid 'nz_number' in RFC 3501 terminology
        def valid_nz_number?(num)
          # [RFC 3501]
          # nz-number       = digit-nz *DIGIT
          #                    ; Non-zero unsigned 32-bit integer
          #                    ; (0 < n < 4,294,967,296)
          num != 0 && valid_number?(num)
        end

        # Ensure argument is 'number' or raise DataFormatError
        def ensure_number(num)
          return if valid_number?(num)

          msg = "number must be unsigned 32-bit integer: #{num}"
          raise DataFormatError, msg
        end

        # Ensure argument is 'nz_number' or raise DataFormatError
        def ensure_nz_number(num)
          return if valid_nz_number?(num)

          msg = "nz_number must be non-zero unsigned 32-bit integer: #{num}"
          raise DataFormatError, msg
        end
      end
    end

    # Net::IMAP::ContinuationRequest represents command continuation requests.
    #
    # The command continuation request response is indicated by a "+" token
    # instead of a tag.  This form of response indicates that the server is
    # ready to accept the continuation of a command from the client.  The
    # remainder of this response is a line of text.
    #
    #   continue_req    ::= "+" SPACE (resp_text / base64)
    #
    # ==== Fields:
    #
    # data:: Returns the data (Net::IMAP::ResponseText).
    #
    # raw_data:: Returns the raw data string.
    ContinuationRequest = Struct.new(:data, :raw_data)

    # Net::IMAP::UntaggedResponse represents untagged responses.
    #
    # Data transmitted by the server to the client and status responses
    # that do not indicate command completion are prefixed with the token
    # "*", and are called untagged responses.
    #
    #   response_data   ::= "*" SPACE (resp_cond_state / resp_cond_bye /
    #                       mailbox_data / message_data / capability_data)
    #
    # ==== Fields:
    #
    # name:: Returns the name, such as "FLAGS", "LIST", or "FETCH".
    #
    # data:: Returns the data such as an array of flag symbols,
    #        a ((<Net::IMAP::MailboxList>)) object.
    #
    # raw_data:: Returns the raw data string.
    UntaggedResponse = Struct.new(:name, :data, :raw_data)

    # Net::IMAP::TaggedResponse represents tagged responses.
    #
    # The server completion result response indicates the success or
    # failure of the operation.  It is tagged with the same tag as the
    # client command which began the operation.
    #
    #   response_tagged ::= tag SPACE resp_cond_state CRLF
    #
    #   tag             ::= 1*<any ATOM_CHAR except "+">
    #
    #   resp_cond_state ::= ("OK" / "NO" / "BAD") SPACE resp_text
    #
    # ==== Fields:
    #
    # tag:: Returns the tag.
    #
    # name:: Returns the name, one of "OK", "NO", or "BAD".
    #
    # data:: Returns the data. See ((<Net::IMAP::ResponseText>)).
    #
    # raw_data:: Returns the raw data string.
    #
    TaggedResponse = Struct.new(:tag, :name, :data, :raw_data)

    # Net::IMAP::ResponseText represents texts of responses.
    # The text may be prefixed by the response code.
    #
    #   resp_text       ::= ["[" resp_text_code "]" SPACE] (text_mime2 / text)
    #                       ;; text SHOULD NOT begin with "[" or "="
    #
    # ==== Fields:
    #
    # code:: Returns the response code. See ((<Net::IMAP::ResponseCode>)).
    #
    # text:: Returns the text.
    #
    ResponseText = Struct.new(:code, :text)

    # Net::IMAP::ResponseCode represents response codes.
    #
    #   resp_text_code  ::= "ALERT" / "PARSE" /
    #                       "PERMANENTFLAGS" SPACE "(" #(flag / "\*") ")" /
    #                       "READ-ONLY" / "READ-WRITE" / "TRYCREATE" /
    #                       "UIDVALIDITY" SPACE nz_number /
    #                       "UNSEEN" SPACE nz_number /
    #                       atom [SPACE 1*<any TEXT_CHAR except "]">]
    #
    # ==== Fields:
    #
    # name:: Returns the name, such as "ALERT", "PERMANENTFLAGS", or "UIDVALIDITY".
    #
    # data:: Returns the data, if it exists.
    #
    ResponseCode = Struct.new(:name, :data)

    # Net::IMAP::MailboxList represents contents of the LIST response.
    #
    #   mailbox_list    ::= "(" #("\Marked" / "\Noinferiors" /
    #                       "\Noselect" / "\Unmarked" / flag_extension) ")"
    #                       SPACE (<"> QUOTED_CHAR <"> / nil) SPACE mailbox
    #
    # ==== Fields:
    #
    # attr:: Returns the name attributes. Each name attribute is a symbol
    #        capitalized by String#capitalize, such as :Noselect (not :NoSelect).
    #
    # delim:: Returns the hierarchy delimiter.
    #
    # name:: Returns the mailbox name.
    #
    MailboxList = Struct.new(:attr, :delim, :name)

    # Net::IMAP::MailboxQuota represents contents of GETQUOTA response.
    # This object can also be a response to GETQUOTAROOT.  In the syntax
    # specification below, the delimiter used with the "#" construct is a
    # single space (SPACE).
    #
    #    quota_list      ::= "(" #quota_resource ")"
    #
    #    quota_resource  ::= atom SPACE number SPACE number
    #
    #    quota_response  ::= "QUOTA" SPACE astring SPACE quota_list
    #
    # ==== Fields:
    #
    # mailbox:: The mailbox with the associated quota.
    #
    # usage:: Current storage usage of the mailbox.
    #
    # quota:: Quota limit imposed on the mailbox.
    #
    MailboxQuota = Struct.new(:mailbox, :usage, :quota)

    # Net::IMAP::MailboxQuotaRoot represents part of the GETQUOTAROOT
    # response. (GETQUOTAROOT can also return Net::IMAP::MailboxQuota.)
    #
    #    quotaroot_response ::= "QUOTAROOT" SPACE astring *(SPACE astring)
    #
    # ==== Fields:
    #
    # mailbox:: The mailbox with the associated quota.
    #
    # quotaroots:: Zero or more quotaroots that affect the quota on the
    #              specified mailbox.
    #
    MailboxQuotaRoot = Struct.new(:mailbox, :quotaroots)

    # Net::IMAP::MailboxACLItem represents the response from GETACL.
    #
    #    acl_data        ::= "ACL" SPACE mailbox *(SPACE identifier SPACE rights)
    #
    #    identifier      ::= astring
    #
    #    rights          ::= astring
    #
    # ==== Fields:
    #
    # user:: Login name that has certain rights to the mailbox
    #        that was specified with the getacl command.
    #
    # rights:: The access rights the indicated user has to the
    #          mailbox.
    #
    MailboxACLItem = Struct.new(:user, :rights, :mailbox)

    # Net::IMAP::StatusData represents the contents of the STATUS response.
    #
    # ==== Fields:
    #
    # mailbox:: Returns the mailbox name.
    #
    # attr:: Returns a hash. Each key is one of "MESSAGES", "RECENT", "UIDNEXT",
    #        "UIDVALIDITY", "UNSEEN". Each value is a number.
    #
    StatusData = Struct.new(:mailbox, :attr)

    # Net::IMAP::FetchData represents the contents of the FETCH response.
    #
    # ==== Fields:
    #
    # seqno:: Returns the message sequence number.
    #         (Note: not the unique identifier, even for the UID command response.)
    #
    # attr:: Returns a hash. Each key is a data item name, and each value is
    #        its value.
    #
    #        The current data items are:
    #
    #        [BODY]
    #           A form of BODYSTRUCTURE without extension data.
    #        [BODY[<section>]<<origin_octet>>]
    #           A string expressing the body contents of the specified section.
    #        [BODYSTRUCTURE]
    #           An object that describes the [MIME-IMB] body structure of a message.
    #           See Net::IMAP::BodyTypeBasic, Net::IMAP::BodyTypeText,
    #           Net::IMAP::BodyTypeMessage, Net::IMAP::BodyTypeMultipart.
    #        [ENVELOPE]
    #           A Net::IMAP::Envelope object that describes the envelope
    #           structure of a message.
    #        [FLAGS]
    #           A array of flag symbols that are set for this message. Flag symbols
    #           are capitalized by String#capitalize.
    #        [INTERNALDATE]
    #           A string representing the internal date of the message.
    #        [RFC822]
    #           Equivalent to BODY[].
    #        [RFC822.HEADER]
    #           Equivalent to BODY.PEEK[HEADER].
    #        [RFC822.SIZE]
    #           A number expressing the [RFC-822] size of the message.
    #        [RFC822.TEXT]
    #           Equivalent to BODY[TEXT].
    #        [UID]
    #           A number expressing the unique identifier of the message.
    #
    FetchData = Struct.new(:seqno, :attr)

    # Net::IMAP::Envelope represents envelope structures of messages.
    #
    # ==== Fields:
    #
    # date:: Returns a string that represents the date.
    #
    # subject:: Returns a string that represents the subject.
    #
    # from:: Returns an array of Net::IMAP::Address that represents the from.
    #
    # sender:: Returns an array of Net::IMAP::Address that represents the sender.
    #
    # reply_to:: Returns an array of Net::IMAP::Address that represents the reply-to.
    #
    # to:: Returns an array of Net::IMAP::Address that represents the to.
    #
    # cc:: Returns an array of Net::IMAP::Address that represents the cc.
    #
    # bcc:: Returns an array of Net::IMAP::Address that represents the bcc.
    #
    # in_reply_to:: Returns a string that represents the in-reply-to.
    #
    # message_id:: Returns a string that represents the message-id.
    #
    Envelope = Struct.new(:date, :subject, :from, :sender, :reply_to,
                          :to, :cc, :bcc, :in_reply_to, :message_id)

    #
    # Net::IMAP::Address represents electronic mail addresses.
    #
    # ==== Fields:
    #
    # name:: Returns the phrase from [RFC-822] mailbox.
    #
    # route:: Returns the route from [RFC-822] route-addr.
    #
    # mailbox:: nil indicates end of [RFC-822] group.
    #           If non-nil and host is nil, returns [RFC-822] group name.
    #           Otherwise, returns [RFC-822] local-part.
    #
    # host:: nil indicates [RFC-822] group syntax.
    #        Otherwise, returns [RFC-822] domain name.
    #
    Address = Struct.new(:name, :route, :mailbox, :host)

    #
    # Net::IMAP::ContentDisposition represents Content-Disposition fields.
    #
    # ==== Fields:
    #
    # dsp_type:: Returns the disposition type.
    #
    # param:: Returns a hash that represents parameters of the Content-Disposition
    #         field.
    #
    ContentDisposition = Struct.new(:dsp_type, :param)

    # Net::IMAP::ThreadMember represents a thread-node returned
    # by Net::IMAP#thread.
    #
    # ==== Fields:
    #
    # seqno:: The sequence number of this message.
    #
    # children:: An array of Net::IMAP::ThreadMember objects for mail
    #            items that are children of this in the thread.
    #
    ThreadMember = Struct.new(:seqno, :children)

    # Net::IMAP::BodyTypeBasic represents basic body structures of messages.
    #
    # ==== Fields:
    #
    # media_type:: Returns the content media type name as defined in [MIME-IMB].
    #
    # subtype:: Returns the content subtype name as defined in [MIME-IMB].
    #
    # param:: Returns a hash that represents parameters as defined in [MIME-IMB].
    #
    # content_id:: Returns a string giving the content id as defined in [MIME-IMB].
    #
    # description:: Returns a string giving the content description as defined in
    #               [MIME-IMB].
    #
    # encoding:: Returns a string giving the content transfer encoding as defined in
    #            [MIME-IMB].
    #
    # size:: Returns a number giving the size of the body in octets.
    #
    # md5:: Returns a string giving the body MD5 value as defined in [MD5].
    #
    # disposition:: Returns a Net::IMAP::ContentDisposition object giving
    #               the content disposition.
    #
    # language:: Returns a string or an array of strings giving the body
    #            language value as defined in [LANGUAGE-TAGS].
    #
    # extension:: Returns extension data.
    #
    # multipart?:: Returns false.
    #
    class BodyTypeBasic < Struct.new(:media_type, :subtype,
                                     :param, :content_id,
                                     :description, :encoding, :size,
                                     :md5, :disposition, :language,
                                     :extension)
      def multipart?
        return false
      end

      # Obsolete: use +subtype+ instead.  Calling this will
      # generate a warning message to +stderr+, then return
      # the value of +subtype+.
      def media_subtype
        $stderr.printf("warning: media_subtype is obsolete.\n")
        $stderr.printf("         use subtype instead.\n")
        return subtype
      end
    end

    # Net::IMAP::BodyTypeText represents TEXT body structures of messages.
    #
    # ==== Fields:
    #
    # lines:: Returns the size of the body in text lines.
    #
    # And Net::IMAP::BodyTypeText has all fields of Net::IMAP::BodyTypeBasic.
    #
    class BodyTypeText < Struct.new(:media_type, :subtype,
                                    :param, :content_id,
                                    :description, :encoding, :size,
                                    :lines,
                                    :md5, :disposition, :language,
                                    :extension)
      def multipart?
        return false
      end

      # Obsolete: use +subtype+ instead.  Calling this will
      # generate a warning message to +stderr+, then return
      # the value of +subtype+.
      def media_subtype
        $stderr.printf("warning: media_subtype is obsolete.\n")
        $stderr.printf("         use subtype instead.\n")
        return subtype
      end
    end

    # Net::IMAP::BodyTypeMessage represents MESSAGE/RFC822 body structures of messages.
    #
    # ==== Fields:
    #
    # envelope:: Returns a Net::IMAP::Envelope giving the envelope structure.
    #
    # body:: Returns an object giving the body structure.
    #
    # And Net::IMAP::BodyTypeMessage has all methods of Net::IMAP::BodyTypeText.
    #
    class BodyTypeMessage < Struct.new(:media_type, :subtype,
                                       :param, :content_id,
                                       :description, :encoding, :size,
                                       :envelope, :body, :lines,
                                       :md5, :disposition, :language,
                                       :extension)
      def multipart?
        return false
      end

      # Obsolete: use +subtype+ instead.  Calling this will
      # generate a warning message to +stderr+, then return
      # the value of +subtype+.
      def media_subtype
        $stderr.printf("warning: media_subtype is obsolete.\n")
        $stderr.printf("         use subtype instead.\n")
        return subtype
      end
    end

    # Net::IMAP::BodyTypeAttachment represents attachment body structures
    # of messages.
    #
    # ==== Fields:
    #
    # media_type:: Returns the content media type name.
    #
    # subtype:: Returns +nil+.
    #
    # param:: Returns a hash that represents parameters.
    #
    # multipart?:: Returns false.
    #
    class BodyTypeAttachment < Struct.new(:media_type, :subtype,
                                          :param)
      def multipart?
        return false
      end
    end

    # Net::IMAP::BodyTypeMultipart represents multipart body structures
    # of messages.
    #
    # ==== Fields:
    #
    # media_type:: Returns the content media type name as defined in [MIME-IMB].
    #
    # subtype:: Returns the content subtype name as defined in [MIME-IMB].
    #
    # parts:: Returns multiple parts.
    #
    # param:: Returns a hash that represents parameters as defined in [MIME-IMB].
    #
    # disposition:: Returns a Net::IMAP::ContentDisposition object giving
    #               the content disposition.
    #
    # language:: Returns a string or an array of strings giving the body
    #            language value as defined in [LANGUAGE-TAGS].
    #
    # extension:: Returns extension data.
    #
    # multipart?:: Returns true.
    #
    class BodyTypeMultipart < Struct.new(:media_type, :subtype,
                                         :parts,
                                         :param, :disposition, :language,
                                         :extension)
      def multipart?
        return true
      end

      # Obsolete: use +subtype+ instead.  Calling this will
      # generate a warning message to +stderr+, then return
      # the value of +subtype+.
      def media_subtype
        $stderr.printf("warning: media_subtype is obsolete.\n")
        $stderr.printf("         use subtype instead.\n")
        return subtype
      end
    end

    class BodyTypeExtension < Struct.new(:media_type, :subtype,
                                         :params, :content_id,
                                         :description, :encoding, :size)
      def multipart?
        return false
      end
    end

    class ResponseParser # :nodoc:
      def initialize
        @str = nil
        @pos = nil
        @lex_state = nil
        @token = nil
        @flag_symbols = {}
      end

      def parse(str)
        @str = str
        @pos = 0
        @lex_state = EXPR_BEG
        @token = nil
        return response
      end

      private

      EXPR_BEG          = :EXPR_BEG
      EXPR_DATA         = :EXPR_DATA
      EXPR_TEXT         = :EXPR_TEXT
      EXPR_RTEXT        = :EXPR_RTEXT
      EXPR_CTEXT        = :EXPR_CTEXT

      T_SPACE   = :SPACE
      T_NIL     = :NIL
      T_NUMBER  = :NUMBER
      T_ATOM    = :ATOM
      T_QUOTED  = :QUOTED
      T_LPAR    = :LPAR
      T_RPAR    = :RPAR
      T_BSLASH  = :BSLASH
      T_STAR    = :STAR
      T_LBRA    = :LBRA
      T_RBRA    = :RBRA
      T_LITERAL = :LITERAL
      T_PLUS    = :PLUS
      T_PERCENT = :PERCENT
      T_CRLF    = :CRLF
      T_EOF     = :EOF
      T_TEXT    = :TEXT

      BEG_REGEXP = /\G(?:\
(?# 1:  SPACE   )( +)|\
(?# 2:  NIL     )(NIL)(?=[\x80-\xff(){ \x00-\x1f\x7f%*"\\\[\]+])|\
(?# 3:  NUMBER  )(\d+)(?=[\x80-\xff(){ \x00-\x1f\x7f%*"\\\[\]+])|\
(?# 4:  ATOM    )([^\x80-\xff(){ \x00-\x1f\x7f%*"\\\[\]+]+)|\
(?# 5:  QUOTED  )"((?:[^\x00\r\n"\\]|\\["\\])*)"|\
(?# 6:  LPAR    )(\()|\
(?# 7:  RPAR    )(\))|\
(?# 8:  BSLASH  )(\\)|\
(?# 9:  STAR    )(\*)|\
(?# 10: LBRA    )(\[)|\
(?# 11: RBRA    )(\])|\
(?# 12: LITERAL )\{(\d+)\}\r\n|\
(?# 13: PLUS    )(\+)|\
(?# 14: PERCENT )(%)|\
(?# 15: CRLF    )(\r\n)|\
(?# 16: EOF     )(\z))/ni

      DATA_REGEXP = /\G(?:\
(?# 1:  SPACE   )( )|\
(?# 2:  NIL     )(NIL)|\
(?# 3:  NUMBER  )(\d+)|\
(?# 4:  QUOTED  )"((?:[^\x00\r\n"\\]|\\["\\])*)"|\
(?# 5:  LITERAL )\{(\d+)\}\r\n|\
(?# 6:  LPAR    )(\()|\
(?# 7:  RPAR    )(\)))/ni

      TEXT_REGEXP = /\G(?:\
(?# 1:  TEXT    )([^\x00\r\n]*))/ni

      RTEXT_REGEXP = /\G(?:\
(?# 1:  LBRA    )(\[)|\
(?# 2:  TEXT    )([^\x00\r\n]*))/ni

      CTEXT_REGEXP = /\G(?:\
(?# 1:  TEXT    )([^\x00\r\n\]]*))/ni

      Token = Struct.new(:symbol, :value)

      def response
        token = lookahead
        case token.symbol
        when T_PLUS
          result = continue_req
        when T_STAR
          result = response_untagged
        else
          result = response_tagged
        end
        while lookahead.symbol == T_SPACE
          # Ignore trailing space for Microsoft Exchange Server
          shift_token
        end
        match(T_CRLF)
        match(T_EOF)
        return result
      end

      def continue_req
        match(T_PLUS)
        match(T_SPACE)
        return ContinuationRequest.new(resp_text, @str)
      end

      def response_untagged
        match(T_STAR)
        match(T_SPACE)
        token = lookahead
        if token.symbol == T_NUMBER
          return numeric_response
        elsif token.symbol == T_ATOM
          case token.value
          when /\A(?:OK|NO|BAD|BYE|PREAUTH)\z/ni
            return response_cond
          when /\A(?:FLAGS)\z/ni
            return flags_response
          when /\A(?:LIST|LSUB|XLIST)\z/ni
            return list_response
          when /\A(?:QUOTA)\z/ni
            return getquota_response
          when /\A(?:QUOTAROOT)\z/ni
            return getquotaroot_response
          when /\A(?:ACL)\z/ni
            return getacl_response
          when /\A(?:SEARCH|SORT)\z/ni
            return search_response
          when /\A(?:THREAD)\z/ni
            return thread_response
          when /\A(?:STATUS)\z/ni
            return status_response
          when /\A(?:CAPABILITY)\z/ni
            return capability_response
          else
            return text_response
          end
        else
          parse_error("unexpected token %s", token.symbol)
        end
      end

      def response_tagged
        tag = atom
        match(T_SPACE)
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return TaggedResponse.new(tag, name, resp_text, @str)
      end

      def response_cond
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return UntaggedResponse.new(name, resp_text, @str)
      end

      def numeric_response
        n = number
        match(T_SPACE)
        token = match(T_ATOM)
        name = token.value.upcase
        case name
        when "EXISTS", "RECENT", "EXPUNGE"
          return UntaggedResponse.new(name, n, @str)
        when "FETCH"
          shift_token
          match(T_SPACE)
          data = FetchData.new(n, msg_att(n))
          return UntaggedResponse.new(name, data, @str)
        end
      end

      def msg_att(n)
        match(T_LPAR)
        attr = {}
        while true
          token = lookahead
          case token.symbol
          when T_RPAR
            shift_token
            break
          when T_SPACE
            shift_token
            next
          end
          case token.value
          when /\A(?:ENVELOPE)\z/ni
            name, val = envelope_data
          when /\A(?:FLAGS)\z/ni
            name, val = flags_data
          when /\A(?:INTERNALDATE)\z/ni
            name, val = internaldate_data
          when /\A(?:RFC822(?:\.HEADER|\.TEXT)?)\z/ni
            name, val = rfc822_text
          when /\A(?:RFC822\.SIZE)\z/ni
            name, val = rfc822_size
          when /\A(?:BODY(?:STRUCTURE)?)\z/ni
            name, val = body_data
          when /\A(?:UID)\z/ni
            name, val = uid_data
          else
            parse_error("unknown attribute `%s' for {%d}", token.value, n)
          end
          attr[name] = val
        end
        return attr
      end

      def envelope_data
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return name, envelope
      end

      def envelope
        @lex_state = EXPR_DATA
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          result = nil
        else
          match(T_LPAR)
          date = nstring
          match(T_SPACE)
          subject = nstring
          match(T_SPACE)
          from = address_list
          match(T_SPACE)
          sender = address_list
          match(T_SPACE)
          reply_to = address_list
          match(T_SPACE)
          to = address_list
          match(T_SPACE)
          cc = address_list
          match(T_SPACE)
          bcc = address_list
          match(T_SPACE)
          in_reply_to = nstring
          match(T_SPACE)
          message_id = nstring
          match(T_RPAR)
          result = Envelope.new(date, subject, from, sender, reply_to,
                                to, cc, bcc, in_reply_to, message_id)
        end
        @lex_state = EXPR_BEG
        return result
      end

      def flags_data
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return name, flag_list
      end

      def internaldate_data
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        token = match(T_QUOTED)
        return name, token.value
      end

      def rfc822_text
        token = match(T_ATOM)
        name = token.value.upcase
        token = lookahead
        if token.symbol == T_LBRA
          shift_token
          match(T_RBRA)
        end
        match(T_SPACE)
        return name, nstring
      end

      def rfc822_size
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return name, number
      end

      def body_data
        token = match(T_ATOM)
        name = token.value.upcase
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
          return name, body
        end
        name.concat(section)
        token = lookahead
        if token.symbol == T_ATOM
          name.concat(token.value)
          shift_token
        end
        match(T_SPACE)
        data = nstring
        return name, data
      end

      def body
        @lex_state = EXPR_DATA
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          result = nil
        else
          match(T_LPAR)
          token = lookahead
          if token.symbol == T_LPAR
            result = body_type_mpart
          else
            result = body_type_1part
          end
          match(T_RPAR)
        end
        @lex_state = EXPR_BEG
        return result
      end

      def body_type_1part
        token = lookahead
        case token.value
        when /\A(?:TEXT)\z/ni
          return body_type_text
        when /\A(?:MESSAGE)\z/ni
          return body_type_msg
        when /\A(?:ATTACHMENT)\z/ni
          return body_type_attachment
        when /\A(?:MIXED)\z/ni
          return body_type_mixed
        else
          return body_type_basic
        end
      end

      def body_type_basic
        mtype, msubtype = media_type
        token = lookahead
        if token.symbol == T_RPAR
          return BodyTypeBasic.new(mtype, msubtype)
        end
        match(T_SPACE)
        param, content_id, desc, enc, size = body_fields
        md5, disposition, language, extension = body_ext_1part
        return BodyTypeBasic.new(mtype, msubtype,
                                 param, content_id,
                                 desc, enc, size,
                                 md5, disposition, language, extension)
      end

      def body_type_text
        mtype, msubtype = media_type
        match(T_SPACE)
        param, content_id, desc, enc, size = body_fields
        match(T_SPACE)
        lines = number
        md5, disposition, language, extension = body_ext_1part
        return BodyTypeText.new(mtype, msubtype,
                                param, content_id,
                                desc, enc, size,
                                lines,
                                md5, disposition, language, extension)
      end

      def body_type_msg
        mtype, msubtype = media_type
        match(T_SPACE)
        param, content_id, desc, enc, size = body_fields

        token = lookahead
        if token.symbol == T_RPAR
          # If this is not message/rfc822, we shouldn't apply the RFC822
          # spec to it.  We should handle anything other than
          # message/rfc822 using multipart extension data [rfc3501] (i.e.
          # the data itself won't be returned, we would have to retrieve it
          # with BODYSTRUCTURE instead of with BODY

          # Also, sometimes a message/rfc822 is included as a large
          # attachment instead of having all of the other details
          # (e.g. attaching a .eml file to an email)
          if msubtype == "RFC822"
            return BodyTypeMessage.new(mtype, msubtype, param, content_id,
                                       desc, enc, size, nil, nil, nil, nil,
                                       nil, nil, nil)
          else
            return BodyTypeExtension.new(mtype, msubtype,
                                         param, content_id,
                                         desc, enc, size)
          end
        end

        match(T_SPACE)
        env = envelope
        match(T_SPACE)
        b = body
        match(T_SPACE)
        lines = number
        md5, disposition, language, extension = body_ext_1part
        return BodyTypeMessage.new(mtype, msubtype,
                                   param, content_id,
                                   desc, enc, size,
                                   env, b, lines,
                                   md5, disposition, language, extension)
      end

      def body_type_attachment
        mtype = case_insensitive_string
        match(T_SPACE)
        param = body_fld_param
        return BodyTypeAttachment.new(mtype, nil, param)
      end

      def body_type_mixed
        mtype = "MULTIPART"
        msubtype = case_insensitive_string
        param, disposition, language, extension = body_ext_mpart
        return BodyTypeBasic.new(mtype, msubtype, param, nil, nil, nil, nil, nil, disposition, language, extension)
      end

      def body_type_mpart
        parts = []
        while true
          token = lookahead
          if token.symbol == T_SPACE
            shift_token
            break
          end
          parts.push(body)
        end
        mtype = "MULTIPART"
        msubtype = case_insensitive_string
        param, disposition, language, extension = body_ext_mpart
        return BodyTypeMultipart.new(mtype, msubtype, parts,
                                     param, disposition, language,
                                     extension)
      end

      def media_type
        mtype = case_insensitive_string
        token = lookahead
        if token.symbol != T_SPACE
          return mtype, nil
        end
        match(T_SPACE)
        msubtype = case_insensitive_string
        return mtype, msubtype
      end

      def body_fields
        param = body_fld_param
        match(T_SPACE)
        content_id = nstring
        match(T_SPACE)
        desc = nstring
        match(T_SPACE)
        enc = case_insensitive_string
        match(T_SPACE)
        size = number
        return param, content_id, desc, enc, size
      end

      def body_fld_param
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        end
        match(T_LPAR)
        param = {}
        while true
          token = lookahead
          case token.symbol
          when T_RPAR
            shift_token
            break
          when T_SPACE
            shift_token
          end
          name = case_insensitive_string
          match(T_SPACE)
          val = string
          param[name] = val
        end
        return param
      end

      def body_ext_1part
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return nil
        end
        md5 = nstring

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return md5
        end
        disposition = body_fld_dsp

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return md5, disposition
        end
        language = body_fld_lang

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return md5, disposition, language
        end

        extension = body_extensions
        return md5, disposition, language, extension
      end

      def body_ext_mpart
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return nil
        end
        param = body_fld_param

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return param
        end
        disposition = body_fld_dsp

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return param, disposition
        end
        language = body_fld_lang

        token = lookahead
        if token.symbol == T_SPACE
          shift_token
        else
          return param, disposition, language
        end

        extension = body_extensions
        return param, disposition, language, extension
      end

      def body_fld_dsp
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        end
        match(T_LPAR)
        dsp_type = case_insensitive_string
        match(T_SPACE)
        param = body_fld_param
        match(T_RPAR)
        return ContentDisposition.new(dsp_type, param)
      end

      def body_fld_lang
        token = lookahead
        if token.symbol == T_LPAR
          shift_token
          result = []
          while true
            token = lookahead
            case token.symbol
            when T_RPAR
              shift_token
              return result
            when T_SPACE
              shift_token
            end
            result.push(case_insensitive_string)
          end
        else
          lang = nstring
          if lang
            return lang.upcase
          else
            return lang
          end
        end
      end

      def body_extensions
        result = []
        while true
          token = lookahead
          case token.symbol
          when T_RPAR
            return result
          when T_SPACE
            shift_token
          end
          result.push(body_extension)
        end
      end

      def body_extension
        token = lookahead
        case token.symbol
        when T_LPAR
          shift_token
          result = body_extensions
          match(T_RPAR)
          return result
        when T_NUMBER
          return number
        else
          return nstring
        end
      end

      def section
        str = String.new
        token = match(T_LBRA)
        str.concat(token.value)
        token = match(T_ATOM, T_NUMBER, T_RBRA)
        if token.symbol == T_RBRA
          str.concat(token.value)
          return str
        end
        str.concat(token.value)
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
          str.concat(token.value)
          token = match(T_LPAR)
          str.concat(token.value)
          while true
            token = lookahead
            case token.symbol
            when T_RPAR
              str.concat(token.value)
              shift_token
              break
            when T_SPACE
              shift_token
              str.concat(token.value)
            end
            str.concat(format_string(astring))
          end
        end
        token = match(T_RBRA)
        str.concat(token.value)
        return str
      end

      def format_string(str)
        case str
        when ""
          return '""'
        when /[\x80-\xff\r\n]/n
          # literal
          return "{" + str.bytesize.to_s + "}" + CRLF + str
        when /[(){ \x00-\x1f\x7f%*"\\]/n
          # quoted string
          return '"' + str.gsub(/["\\]/n, "\\\\\\&") + '"'
        else
          # atom
          return str
        end
      end

      def uid_data
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return name, number
      end

      def text_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        @lex_state = EXPR_TEXT
        token = match(T_TEXT)
        @lex_state = EXPR_BEG
        return UntaggedResponse.new(name, token.value)
      end

      def flags_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return UntaggedResponse.new(name, flag_list, @str)
      end

      def list_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        return UntaggedResponse.new(name, mailbox_list, @str)
      end

      def mailbox_list
        attr = flag_list
        match(T_SPACE)
        token = match(T_QUOTED, T_NIL)
        if token.symbol == T_NIL
          delim = nil
        else
          delim = token.value
        end
        match(T_SPACE)
        name = astring
        return MailboxList.new(attr, delim, name)
      end

      def getquota_response
        # If quota never established, get back
        # `NO Quota root does not exist'.
        # If quota removed, get `()' after the
        # folder spec with no mention of `STORAGE'.
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        mailbox = astring
        match(T_SPACE)
        match(T_LPAR)
        token = lookahead
        case token.symbol
        when T_RPAR
          shift_token
          data = MailboxQuota.new(mailbox, nil, nil)
          return UntaggedResponse.new(name, data, @str)
        when T_ATOM
          shift_token
          match(T_SPACE)
          token = match(T_NUMBER)
          usage = token.value
          match(T_SPACE)
          token = match(T_NUMBER)
          quota = token.value
          match(T_RPAR)
          data = MailboxQuota.new(mailbox, usage, quota)
          return UntaggedResponse.new(name, data, @str)
        else
          parse_error("unexpected token %s", token.symbol)
        end
      end

      def getquotaroot_response
        # Similar to getquota, but only admin can use getquota.
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        mailbox = astring
        quotaroots = []
        while true
          token = lookahead
          break unless token.symbol == T_SPACE
          shift_token
          quotaroots.push(astring)
        end
        data = MailboxQuotaRoot.new(mailbox, quotaroots)
        return UntaggedResponse.new(name, data, @str)
      end

      def getacl_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        mailbox = astring
        data = []
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
          while true
            token = lookahead
            case token.symbol
            when T_CRLF
              break
            when T_SPACE
              shift_token
            end
            user = astring
            match(T_SPACE)
            rights = astring
            data.push(MailboxACLItem.new(user, rights, mailbox))
          end
        end
        return UntaggedResponse.new(name, data, @str)
      end

      def search_response
        token = match(T_ATOM)
        name = token.value.upcase
        token = lookahead
        if token.symbol == T_SPACE
          shift_token
          data = []
          while true
            token = lookahead
            case token.symbol
            when T_CRLF
              break
            when T_SPACE
              shift_token
            when T_NUMBER
              data.push(number)
            when T_LPAR
              # TODO: include the MODSEQ value in a response
              shift_token
              match(T_ATOM)
              match(T_SPACE)
              match(T_NUMBER)
              match(T_RPAR)
            end
          end
        else
          data = []
        end
        return UntaggedResponse.new(name, data, @str)
      end

      def thread_response
        token = match(T_ATOM)
        name = token.value.upcase
        token = lookahead

        if token.symbol == T_SPACE
          threads = []

          while true
            shift_token
            token = lookahead

            case token.symbol
            when T_LPAR
              threads << thread_branch(token)
            when T_CRLF
              break
            end
          end
        else
          # no member
          threads = []
        end

        return UntaggedResponse.new(name, threads, @str)
      end

      def thread_branch(token)
        rootmember = nil
        lastmember = nil

        while true
          shift_token    # ignore first T_LPAR
          token = lookahead

          case token.symbol
          when T_NUMBER
            # new member
            newmember = ThreadMember.new(number, [])
            if rootmember.nil?
              rootmember = newmember
            else
              lastmember.children << newmember
            end
            lastmember = newmember
          when T_SPACE
            # do nothing
          when T_LPAR
            if rootmember.nil?
              # dummy member
              lastmember = rootmember = ThreadMember.new(nil, [])
            end

            lastmember.children << thread_branch(token)
          when T_RPAR
            break
          end
        end

        return rootmember
      end

      def status_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        mailbox = astring
        match(T_SPACE)
        match(T_LPAR)
        attr = {}
        while true
          token = lookahead
          case token.symbol
          when T_RPAR
            shift_token
            break
          when T_SPACE
            shift_token
          end
          token = match(T_ATOM)
          key = token.value.upcase
          match(T_SPACE)
          val = number
          attr[key] = val
        end
        data = StatusData.new(mailbox, attr)
        return UntaggedResponse.new(name, data, @str)
      end

      def capability_response
        token = match(T_ATOM)
        name = token.value.upcase
        match(T_SPACE)
        data = []
        while true
          token = lookahead
          case token.symbol
          when T_CRLF
            break
          when T_SPACE
            shift_token
            next
          end
          data.push(atom.upcase)
        end
        return UntaggedResponse.new(name, data, @str)
      end

      def resp_text
        @lex_state = EXPR_RTEXT
        token = lookahead
        if token.symbol == T_LBRA
          code = resp_text_code
        else
          code = nil
        end
        token = match(T_TEXT)
        @lex_state = EXPR_BEG
        return ResponseText.new(code, token.value)
      end

      def resp_text_code
        @lex_state = EXPR_BEG
        match(T_LBRA)
        token = match(T_ATOM)
        name = token.value.upcase
        case name
        when /\A(?:ALERT|PARSE|READ-ONLY|READ-WRITE|TRYCREATE|NOMODSEQ)\z/n
          result = ResponseCode.new(name, nil)
        when /\A(?:PERMANENTFLAGS)\z/n
          match(T_SPACE)
          result = ResponseCode.new(name, flag_list)
        when /\A(?:UIDVALIDITY|UIDNEXT|UNSEEN)\z/n
          match(T_SPACE)
          result = ResponseCode.new(name, number)
        else
          token = lookahead
          if token.symbol == T_SPACE
            shift_token
            @lex_state = EXPR_CTEXT
            token = match(T_TEXT)
            @lex_state = EXPR_BEG
            result = ResponseCode.new(name, token.value)
          else
            result = ResponseCode.new(name, nil)
          end
        end
        match(T_RBRA)
        @lex_state = EXPR_RTEXT
        return result
      end

      def address_list
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        else
          result = []
          match(T_LPAR)
          while true
            token = lookahead
            case token.symbol
            when T_RPAR
              shift_token
              break
            when T_SPACE
              shift_token
            end
            result.push(address)
          end
          return result
        end
      end

      ADDRESS_REGEXP = /\G\
(?# 1: NAME     )(?:NIL|"((?:[^\x80-\xff\x00\r\n"\\]|\\["\\])*)") \
(?# 2: ROUTE    )(?:NIL|"((?:[^\x80-\xff\x00\r\n"\\]|\\["\\])*)") \
(?# 3: MAILBOX  )(?:NIL|"((?:[^\x80-\xff\x00\r\n"\\]|\\["\\])*)") \
(?# 4: HOST     )(?:NIL|"((?:[^\x80-\xff\x00\r\n"\\]|\\["\\])*)")\
\)/ni

      def address
        match(T_LPAR)
        if @str.index(ADDRESS_REGEXP, @pos)
          # address does not include literal.
          @pos = $~.end(0)
          name = $1
          route = $2
          mailbox = $3
          host = $4
          for s in [name, route, mailbox, host]
            if s
              s.gsub!(/\\(["\\])/n, "\\1")
            end
          end
        else
          name = nstring
          match(T_SPACE)
          route = nstring
          match(T_SPACE)
          mailbox = nstring
          match(T_SPACE)
          host = nstring
          match(T_RPAR)
        end
        return Address.new(name, route, mailbox, host)
      end

      FLAG_REGEXP = /\
(?# FLAG        )\\([^\x80-\xff(){ \x00-\x1f\x7f%"\\]+)|\
(?# ATOM        )([^\x80-\xff(){ \x00-\x1f\x7f%*"\\]+)/n

      def flag_list
        if @str.index(/\(([^)]*)\)/ni, @pos)
          @pos = $~.end(0)
          return $1.scan(FLAG_REGEXP).collect { |flag, atom|
            if atom
              atom
            else
              symbol = flag.capitalize.untaint.intern
              @flag_symbols[symbol] = true
              if @flag_symbols.length > IMAP.max_flag_count
                raise FlagCountError, "number of flag symbols exceeded"
              end
              symbol
            end
          }
        else
          parse_error("invalid flag list")
        end
      end

      def nstring
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        else
          return string
        end
      end

      def astring
        token = lookahead
        if string_token?(token)
          return string
        else
          return atom
        end
      end

      def string
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        end
        token = match(T_QUOTED, T_LITERAL)
        return token.value
      end

      STRING_TOKENS = [T_QUOTED, T_LITERAL, T_NIL]

      def string_token?(token)
        return STRING_TOKENS.include?(token.symbol)
      end

      def case_insensitive_string
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        end
        token = match(T_QUOTED, T_LITERAL)
        return token.value.upcase
      end

      def atom
        result = String.new
        while true
          token = lookahead
          if atom_token?(token)
            result.concat(token.value)
            shift_token
          else
            if result.empty?
              parse_error("unexpected token %s", token.symbol)
            else
              return result
            end
          end
        end
      end

      ATOM_TOKENS = [
        T_ATOM,
        T_NUMBER,
        T_NIL,
        T_LBRA,
        T_RBRA,
        T_PLUS
      ]

      def atom_token?(token)
        return ATOM_TOKENS.include?(token.symbol)
      end

      def number
        token = lookahead
        if token.symbol == T_NIL
          shift_token
          return nil
        end
        token = match(T_NUMBER)
        return token.value.to_i
      end

      def nil_atom
        match(T_NIL)
        return nil
      end

      def match(*args)
        token = lookahead
        unless args.include?(token.symbol)
          parse_error('unexpected token %s (expected %s)',
                      token.symbol.id2name,
                      args.collect {|i| i.id2name}.join(" or "))
        end
        shift_token
        return token
      end

      def lookahead
        unless @token
          @token = next_token
        end
        return @token
      end

      def shift_token
        @token = nil
      end

      def next_token
        case @lex_state
        when EXPR_BEG
          if @str.index(BEG_REGEXP, @pos)
            @pos = $~.end(0)
            if $1
              return Token.new(T_SPACE, $+)
            elsif $2
              return Token.new(T_NIL, $+)
            elsif $3
              return Token.new(T_NUMBER, $+)
            elsif $4
              return Token.new(T_ATOM, $+)
            elsif $5
              return Token.new(T_QUOTED,
                               $+.gsub(/\\(["\\])/n, "\\1"))
            elsif $6
              return Token.new(T_LPAR, $+)
            elsif $7
              return Token.new(T_RPAR, $+)
            elsif $8
              return Token.new(T_BSLASH, $+)
            elsif $9
              return Token.new(T_STAR, $+)
            elsif $10
              return Token.new(T_LBRA, $+)
            elsif $11
              return Token.new(T_RBRA, $+)
            elsif $12
              len = $+.to_i
              val = @str[@pos, len]
              @pos += len
              return Token.new(T_LITERAL, val)
            elsif $13
              return Token.new(T_PLUS, $+)
            elsif $14
              return Token.new(T_PERCENT, $+)
            elsif $15
              return Token.new(T_CRLF, $+)
            elsif $16
              return Token.new(T_EOF, $+)
            else
              parse_error("[Net::IMAP BUG] BEG_REGEXP is invalid")
            end
          else
            @str.index(/\S*/n, @pos)
            parse_error("unknown token - %s", $&.dump)
          end
        when EXPR_DATA
          if @str.index(DATA_REGEXP, @pos)
            @pos = $~.end(0)
            if $1
              return Token.new(T_SPACE, $+)
            elsif $2
              return Token.new(T_NIL, $+)
            elsif $3
              return Token.new(T_NUMBER, $+)
            elsif $4
              return Token.new(T_QUOTED,
                               $+.gsub(/\\(["\\])/n, "\\1"))
            elsif $5
              len = $+.to_i
              val = @str[@pos, len]
              @pos += len
              return Token.new(T_LITERAL, val)
            elsif $6
              return Token.new(T_LPAR, $+)
            elsif $7
              return Token.new(T_RPAR, $+)
            else
              parse_error("[Net::IMAP BUG] DATA_REGEXP is invalid")
            end
          else
            @str.index(/\S*/n, @pos)
            parse_error("unknown token - %s", $&.dump)
          end
        when EXPR_TEXT
          if @str.index(TEXT_REGEXP, @pos)
            @pos = $~.end(0)
            if $1
              return Token.new(T_TEXT, $+)
            else
              parse_error("[Net::IMAP BUG] TEXT_REGEXP is invalid")
            end
          else
            @str.index(/\S*/n, @pos)
            parse_error("unknown token - %s", $&.dump)
          end
        when EXPR_RTEXT
          if @str.index(RTEXT_REGEXP, @pos)
            @pos = $~.end(0)
            if $1
              return Token.new(T_LBRA, $+)
            elsif $2
              return Token.new(T_TEXT, $+)
            else
              parse_error("[Net::IMAP BUG] RTEXT_REGEXP is invalid")
            end
          else
            @str.index(/\S*/n, @pos)
            parse_error("unknown token - %s", $&.dump)
          end
        when EXPR_CTEXT
          if @str.index(CTEXT_REGEXP, @pos)
            @pos = $~.end(0)
            if $1
              return Token.new(T_TEXT, $+)
            else
              parse_error("[Net::IMAP BUG] CTEXT_REGEXP is invalid")
            end
          else
            @str.index(/\S*/n, @pos) #/
            parse_error("unknown token - %s", $&.dump)
          end
        else
          parse_error("invalid @lex_state - %s", @lex_state.inspect)
        end
      end

      def parse_error(fmt, *args)
        if IMAP.debug
          $stderr.printf("@str: %s\n", @str.dump)
          $stderr.printf("@pos: %d\n", @pos)
          $stderr.printf("@lex_state: %s\n", @lex_state)
          if @token
            $stderr.printf("@token.symbol: %s\n", @token.symbol)
            $stderr.printf("@token.value: %s\n", @token.value.inspect)
          end
        end
        raise ResponseParseError, format(fmt, *args)
      end
    end

    # Authenticator for the "LOGIN" authentication type.  See
    # #authenticate().
    class LoginAuthenticator
      def process(data)
        case @state
        when STATE_USER
          @state = STATE_PASSWORD
          return @user
        when STATE_PASSWORD
          return @password
        end
      end

      private

      STATE_USER = :USER
      STATE_PASSWORD = :PASSWORD

      def initialize(user, password)
        @user = user
        @password = password
        @state = STATE_USER
      end
    end
    add_authenticator "LOGIN", LoginAuthenticator

    # Authenticator for the "PLAIN" authentication type.  See
    # #authenticate().
    class PlainAuthenticator
      def process(data)
        return "\0#{@user}\0#{@password}"
      end

      private

      def initialize(user, password)
        @user = user
        @password = password
      end
    end
    add_authenticator "PLAIN", PlainAuthenticator

    # Authenticator for the "CRAM-MD5" authentication type.  See
    # #authenticate().
    class CramMD5Authenticator
      def process(challenge)
        digest = hmac_md5(challenge, @password)
        return @user + " " + digest
      end

      private

      def initialize(user, password)
        @user = user
        @password = password
      end

      def hmac_md5(text, key)
        if key.length > 64
          key = Digest::MD5.digest(key)
        end

        k_ipad = key + "\0" * (64 - key.length)
        k_opad = key + "\0" * (64 - key.length)
        for i in 0..63
          k_ipad[i] = (k_ipad[i].ord ^ 0x36).chr
          k_opad[i] = (k_opad[i].ord ^ 0x5c).chr
        end

        digest = Digest::MD5.digest(k_ipad + text)

        return Digest::MD5.hexdigest(k_opad + digest)
      end
    end
    add_authenticator "CRAM-MD5", CramMD5Authenticator

    # Authenticator for the "DIGEST-MD5" authentication type.  See
    # #authenticate().
    class DigestMD5Authenticator
      def process(challenge)
        case @stage
        when STAGE_ONE
          @stage = STAGE_TWO
          sparams = {}
          c = StringScanner.new(challenge)
          while c.scan(/(?:\s*,)?\s*(\w+)=("(?:[^\\"]+|\\.)*"|[^,]+)\s*/)
            k, v = c[1], c[2]
            if v =~ /^"(.*)"$/
              v = $1
              if v =~ /,/
                v = v.split(',')
              end
            end
            sparams[k] = v
          end

          raise DataFormatError, "Bad Challenge: '#{challenge}'" unless c.rest.size == 0
          raise Error, "Server does not support auth (qop = #{sparams['qop'].join(',')})" unless sparams['qop'].include?("auth")

          response = {
            :nonce => sparams['nonce'],
            :username => @user,
            :realm => sparams['realm'],
            :cnonce => Digest::MD5.hexdigest("%.15f:%.15f:%d" % [Time.now.to_f, rand, Process.pid.to_s]),
            :'digest-uri' => 'imap/' + sparams['realm'],
            :qop => 'auth',
            :maxbuf => 65535,
            :nc => "%08d" % nc(sparams['nonce']),
            :charset => sparams['charset'],
          }

          response[:authzid] = @authname unless @authname.nil?

          # now, the real thing
          a0 = Digest::MD5.digest( [ response.values_at(:username, :realm), @password ].join(':') )

          a1 = [ a0, response.values_at(:nonce,:cnonce) ].join(':')
          a1 << ':' + response[:authzid] unless response[:authzid].nil?

          a2 = "AUTHENTICATE:" + response[:'digest-uri']
          a2 << ":00000000000000000000000000000000" if response[:qop] and response[:qop] =~ /^auth-(?:conf|int)$/

          response[:response] = Digest::MD5.hexdigest(
            [
             Digest::MD5.hexdigest(a1),
             response.values_at(:nonce, :nc, :cnonce, :qop),
             Digest::MD5.hexdigest(a2)
            ].join(':')
          )

          return response.keys.map {|key| qdval(key.to_s, response[key]) }.join(',')
        when STAGE_TWO
          @stage = nil
          # if at the second stage, return an empty string
          if challenge =~ /rspauth=/
            return ''
          else
            raise ResponseParseError, challenge
          end
        else
          raise ResponseParseError, challenge
        end
      end

      def initialize(user, password, authname = nil)
        @user, @password, @authname = user, password, authname
        @nc, @stage = {}, STAGE_ONE
      end

      private

      STAGE_ONE = :stage_one
      STAGE_TWO = :stage_two

      def nc(nonce)
        if @nc.has_key? nonce
          @nc[nonce] = @nc[nonce] + 1
        else
          @nc[nonce] = 1
        end
        return @nc[nonce]
      end

      # some responses need quoting
      def qdval(k, v)
        return if k.nil? or v.nil?
        if %w"username authzid realm nonce cnonce digest-uri qop".include? k
          v.gsub!(/([\\"])/, "\\\1")
          return '%s="%s"' % [k, v]
        else
          return '%s=%s' % [k, v]
        end
      end
    end
    add_authenticator "DIGEST-MD5", DigestMD5Authenticator

    # Superclass of IMAP errors.
    class Error < StandardError
    end

    # Error raised when data is in the incorrect format.
    class DataFormatError < Error
    end

    # Error raised when a response from the server is non-parseable.
    class ResponseParseError < Error
    end

    # Superclass of all errors used to encapsulate "fail" responses
    # from the server.
    class ResponseError < Error

      # The response that caused this error
      attr_accessor :response

      def initialize(response)
        @response = response

        super @response.data.text
      end

    end

    # Error raised upon a "NO" response from the server, indicating
    # that the client command could not be completed successfully.
    class NoResponseError < ResponseError
    end

    # Error raised upon a "BAD" response from the server, indicating
    # that the client command violated the IMAP protocol, or an internal
    # server failure has occurred.
    class BadResponseError < ResponseError
    end

    # Error raised upon a "BYE" response from the server, indicating
    # that the client is not being allowed to login, or has been timed
    # out due to inactivity.
    class ByeResponseError < ResponseError
    end

    # Error raised when too many flags are interned to symbols.
    class FlagCountError < Error
    end
get_tagged_response(tag, cmd) click to toggle source
# File lib/net/imap.rb, line 1186
def get_tagged_response(tag, cmd)
  until @tagged_responses.key?(tag)
    raise @exception if @exception
    @tagged_response_arrival.wait
  end
  resp = @tagged_responses.delete(tag)
  case resp.name
  when /\A(?:NO)\z/ni
    raise NoResponseError, resp
  when /\A(?:BAD)\z/ni
    raise BadResponseError, resp
  else
    return resp
  end
end
normalize_searching_criteria(keys) click to toggle source
# File lib/net/imap.rb, line 1443
def normalize_searching_criteria(keys)
  keys.collect! do |i|
    case i
    when -1, Range, Array
      MessageSet.new(i)
    else
      i
    end
  end
end
put_string(str) click to toggle source
# File lib/net/imap.rb, line 1262
def put_string(str)
  @sock.print(str)
  if @@debug
    if @debug_output_bol
      $stderr.print("C: ")
    end
    $stderr.print(str.gsub(/\n(?!\z)/n, "\nC: "))
    if /\r\n\z/n.match(str)
      @debug_output_bol = true
    else
      @debug_output_bol = false
    end
  end
end
receive_responses() click to toggle source
# File lib/net/imap.rb, line 1120
def receive_responses
  connection_closed = false
  until connection_closed
    synchronize do
      @exception = nil
    end
    begin
      resp = get_response
    rescue Exception => e
      synchronize do
        @sock.close
        @exception = e
      end
      break
    end
    unless resp
      synchronize do
        @exception = EOFError.new("end of file reached")
      end
      break
    end
    begin
      synchronize do
        case resp
        when TaggedResponse
          @tagged_responses[resp.tag] = resp
          @tagged_response_arrival.broadcast
          if resp.tag == @logout_command_tag
            return
          end
        when UntaggedResponse
          record_response(resp.name, resp.data)
          if resp.data.instance_of?(ResponseText) &&
              (code = resp.data.code)
            record_response(code.name, code.data)
          end
          if resp.name == "BYE" && @logout_command_tag.nil?
            @sock.close
            @exception = ByeResponseError.new(resp)
            connection_closed = true
          end
        when ContinuationRequest
          @continuation_request_arrival.signal
        end
        @response_handlers.each do |handler|
          handler.call(resp)
        end
      end
    rescue Exception => e
      @exception = e
      synchronize do
        @tagged_response_arrival.broadcast
        @continuation_request_arrival.broadcast
      end
    end
  end
  synchronize do
    @receiver_thread_terminating = true
    @tagged_response_arrival.broadcast
    @continuation_request_arrival.broadcast
    if @idle_done_cond
      @idle_done_cond.signal
    end
  end
end
record_response(name, data) click to toggle source
# File lib/net/imap.rb, line 1222
def record_response(name, data)
  unless @responses.has_key?(name)
    @responses[name] = []
  end
  @responses[name].push(data)
end
search_internal(cmd, keys, charset) click to toggle source
# File lib/net/imap.rb, line 1371
def search_internal(cmd, keys, charset)
  if keys.instance_of?(String)
    keys = [RawData.new(keys)]
  else
    normalize_searching_criteria(keys)
  end
  synchronize do
    if charset
      send_command(cmd, "CHARSET", charset, *keys)
    else
      send_command(cmd, *keys)
    end
    return @responses.delete("SEARCH")[-1]
  end
end
send_command(cmd, *args, &block) click to toggle source
# File lib/net/imap.rb, line 1229
def send_command(cmd, *args, &block)
  synchronize do
    args.each do |i|
      validate_data(i)
    end
    tag = generate_tag
    put_string(tag + " " + cmd)
    args.each do |i|
      put_string(" ")
      send_data(i)
    end
    put_string(CRLF)
    if cmd == "LOGOUT"
      @logout_command_tag = tag
    end
    if block
      add_response_handler(block)
    end
    begin
      return get_tagged_response(tag, cmd)
    ensure
      if block
        remove_response_handler(block)
      end
    end
  end
end
send_data(data) click to toggle source
# File lib/net/imap.rb, line 1294
def send_data(data)
  case data
  when nil
    put_string("NIL")
  when String
    send_string_data(data)
  when Integer
    send_number_data(data)
  when Array
    send_list_data(data)
  when Time
    send_time_data(data)
  when Symbol
    send_symbol_data(data)
  else
    data.send_data(self)
  end
end
send_list_data(list) click to toggle source
# File lib/net/imap.rb, line 1343
def send_list_data(list)
  put_string("(")
  first = true
  list.each do |i|
    if first
      first = false
    else
      put_string(" ")
    end
    send_data(i)
  end
  put_string(")")
end
send_literal(str) click to toggle source
# File lib/net/imap.rb, line 1332
def send_literal(str)
  put_string("{" + str.bytesize.to_s + "}" + CRLF)
  @continuation_request_arrival.wait
  raise @exception if @exception
  put_string(str)
end
send_number_data(num) click to toggle source
# File lib/net/imap.rb, line 1339
def send_number_data(num)
  put_string(num.to_s)
end
send_quoted_string(str) click to toggle source
# File lib/net/imap.rb, line 1328
def send_quoted_string(str)
  put_string('"' + str.gsub(/["\\]/n, "\\\\\\&") + '"')
end
send_string_data(str) click to toggle source
# File lib/net/imap.rb, line 1313
def send_string_data(str)
  case str
  when ""
    put_string('""')
  when /[\x80-\xff\r\n]/n
    # literal
    send_literal(str)
  when /[(){ \x00-\x1f\x7f%*"\\]/n
    # quoted string
    send_quoted_string(str)
  else
    put_string(str)
  end
end
send_symbol_data(symbol) click to toggle source
# File lib/net/imap.rb, line 1367
def send_symbol_data(symbol)
  put_string("\\" + symbol.to_s)
end
send_time_data(time) click to toggle source
# File lib/net/imap.rb, line 1359
def send_time_data(time)
  t = time.dup.gmtime
  s = format('"%2d-%3s-%4d %02d:%02d:%02d +0000"',
             t.day, DATE_MONTH[t.month - 1], t.year,
             t.hour, t.min, t.sec)
  put_string(s)
end
sort_internal(cmd, sort_keys, search_keys, charset) click to toggle source
# File lib/net/imap.rb, line 1419
def sort_internal(cmd, sort_keys, search_keys, charset)
  if search_keys.instance_of?(String)
    search_keys = [RawData.new(search_keys)]
  else
    normalize_searching_criteria(search_keys)
  end
  normalize_searching_criteria(search_keys)
  synchronize do
    send_command(cmd, sort_keys, charset, *search_keys)
    return @responses.delete("SORT")[-1]
  end
end
start_tls_session(params = {}) click to toggle source
# File lib/net/imap.rb, line 1471
def start_tls_session(params = {})
  unless defined?(OpenSSL::SSL)
    raise "SSL extension not installed"
  end
  if @sock.kind_of?(OpenSSL::SSL::SSLSocket)
    raise RuntimeError, "already using SSL"
  end
  begin
    params = params.to_hash
  rescue NoMethodError
    params = {}
  end
  context = SSLContext.new
  context.set_params(params)
  if defined?(VerifyCallbackProc)
    context.verify_callback = VerifyCallbackProc
  end
  @sock = SSLSocket.new(@sock, context)
  @sock.sync_close = true
  @sock.connect
  if context.verify_mode != VERIFY_NONE
    @sock.post_connection_check(@host)
  end
end
store_internal(cmd, set, attr, flags) click to toggle source
# File lib/net/imap.rb, line 1404
def store_internal(cmd, set, attr, flags)
  if attr.instance_of?(String)
    attr = RawData.new(attr)
  end
  synchronize do
    @responses.delete("FETCH")
    send_command(cmd, MessageSet.new(set), attr, flags)
    return @responses.delete("FETCH")
  end
end
thread_internal(cmd, algorithm, search_keys, charset) click to toggle source
# File lib/net/imap.rb, line 1432
def thread_internal(cmd, algorithm, search_keys, charset)
  if search_keys.instance_of?(String)
    search_keys = [RawData.new(search_keys)]
  else
    normalize_searching_criteria(search_keys)
  end
  normalize_searching_criteria(search_keys)
  send_command(cmd, algorithm, charset, *search_keys)
  return @responses.delete("THREAD")[-1]
end
validate_data(data) click to toggle source
# File lib/net/imap.rb, line 1277
def validate_data(data)
  case data
  when nil
  when String
  when Integer
    NumValidator.ensure_number(data)
  when Array
    data.each do |i|
      validate_data(i)
    end
  when Time
  when Symbol
  else
    data.validate
  end
end