Mail::Transport::POP3(3pm)

NAME
Mail::Transport::POP3 - receive messages via POP3

INHERITANCE
 Mail::Transport::POP3
   is a Mail::Transport::Receive
   is a Mail::Transport
   is a Mail::Reporter

SYNOPSIS
  my $receiver = Mail::Transport::POP3->new(...);
  my $message = $receiver->receive($id);

DESCRIPTION
Receive messages via the POP3 protocol from one remote server, as specified in rfc1939. This object hides much of the complications in the protocol and recovers broken connections automatically. Although it is part of the MailBox distribution, this object can be used separately.

You probably should not use this module, but Mail::Box::POP3. This module is the interface to POP3, whereas Mail::Box::POP3 hides the protocol weirdness and works as any other mail folder.

Extends "DESCRIPTION" in Mail::Transport::Receive.

METHODS
Extends "METHODS" in Mail::Transport::Receive.

  Constructors
Extends "Constructors" in Mail::Transport::Receive.

$class->new(%options)
    Create a new pop3 server connection. One object can only handle one connection: for a single user to one single server. If the server could not be reached, or when the login fails, this instantiating "new" will return "undef". Improves base, see "Constructors" in Mail::Reporter

     -Option      --Defined in     --Default
      authenticate                   'AUTO'
      executable    Mail::Transport  undef
      hostname      Mail::Transport  'localhost'
      interval      Mail::Transport  30
      password      Mail::Transport  undef
      port          Mail::Transport  110
      proxy         Mail::Transport  undef
      retry         Mail::Transport  <unlimited>
      ssl_options                    undef
      timeout       Mail::Transport  120
      use_ssl                        false
      username      Mail::Transport  undef
      via           Mail::Transport  'sendmail'

    authenticate => 'LOGIN'|'APOP'|'AUTO'|'OAUTH2'|'OAUTH2_SEP'
        Authenthication method. The standard defines two methods, named LOGIN and APOP. The first sends the username and password in plain text to the server to get permission, the latter encrypts this data using MD5. When AUTO is used, first APOP is tried, and then LOGIN.

        [3.006] OAUTH* requires the authorization token to be passed as Password. Microsoft Office365 needs "OAUTH2_SEP", where other oauth2 implementations use "OAUTH2".

    executable => $file
    hostname => $host|\@hosts
    interval => $span
    password => $password
    port => $port
    proxy => $path
    retry => $count|undef
    ssl_options => HASH
        Unless overruled, "verify_hostname" will be set to "false" and "SSL_verify_mode" to "SSL_VERIFY_NONE}"

        You can also set the SSL parameters via IO::Socket::SSL subroutine set_defaults. Connections will get restarted when they are lost: you have to keep the defaults in place during POP actions.

    timeout => $span
    use_ssl => BOOLEAN
    username => $username
    via => CLASS|$name

  Attributes
Extends "Attributes" in Mail::Transport::Receive.

$obj->SSLOptions()

$obj->useSSL()
    Returns "true" when SSL must be used.

  Receiving mail
Extends "Receiving mail" in Mail::Transport::Receive.

$obj->receive( [$unique_message_id] )
    Inherited, see "Receiving mail" in Mail::Transport::Receive

  Exchanging information

$obj->deleteFetched()
    Mark all messages that have been fetched with message() for deletion. See fetched().

$obj->deleted(BOOLEAN, @ids)
    Either mark the specified message(s) to be deleted on the remote server or unmark them for deletion (if the first parameter is "false"). Deletion of messages will take place only when the connection is specifically disconnected or the last reference to the object goes out of scope.

$obj->disconnect()
    Break contact with the server, if that (still) exists. Returns "true" if successful. Please note that even if the disconnect was not successful, all knowledge of messages etc. will be removed from the object: the object basically has reverted to the state in which it was before anything was done with the mail box.

$obj->fetched()
    Returns a reference to a list of ID's that have been fetched using message(). This can be used to update a database of messages that were fetched (but maybe not yet deleted) from the mailbox.

    Please note that if the POP3 server did not support the UIDL command, this method will always return "undef" because it is not possibly to reliably identify messages between sessions (other than looking at the contents of the messages themselves).

    See also deleteFetched().

$obj->folderSize()
    Returns the total number of octets used by the mailbox on the remote server.

$obj->header( $id, [$bodylines] )
    Returns an ARRAY which contains the header of the message with the specified $id. A "undef" is returned if something has gone wrong.

    The optional integer $bodylines specifies the number of lines from the body which should be added, by default none.

    » example:

      my $ref_lines = $pop3->header($uidl);
      print @$ref_lines;

$obj->id2n($id)
    Translates the unique $id of a message into a sequence number which represents the message as long a this connection to the POP3 server exists. When the message has been deleted for some reason, "undef" is returned.

$obj->ids()
    Returns a list (in list context) or a reference to a list (in scalar context) of all IDs which are known by the server on this moment.

$obj->message($id)
    Returns a reference to an array which contains the lines of the message with the specified $id. Returns "undef" if something has gone wrong.

    » example:

      my $ref_lines = $pop3->message($uidl);
      print @$ref_lines;

$obj->messageSize($id)
    Returns the size of the message which is indicated by the $id, in octets. If the message has been deleted on the remote server, this will return "undef".

$obj->messages()
    Returns (in scalar context only) the number of messages that are known to exist in the mailbox.

  Protocol internals
The follow methods handle protocol internals, and should not be used by a normal user of this class.

$obj->login()
    Establish a new connection to the POP3 server, using username and password.

$obj->send($socket, $data)
    Send $data to the indicated socket and return the first line read from that socket. Logs an error if either writing to or reading from socket failed.

    This method does not attempt to reconnect or anything: if reading or writing the socket fails, something is very definitely wrong.

$obj->sendList($socket, $command)
    Sends the indicated $command to the specified socket, and retrieves the response. It returns a reference to an array with all the lines that were reveived after the first "+OK" line and before the end-of-message delimiter (a single dot on a line). Returns "undef" whenever something has gone wrong.

$obj->socket()
    Returns a connection to the POP3 server. If there was no connection yet, it will be created transparently. If the connection with the POP3 server was lost, it will be reconnected and the assures that internal state information (STAT and UIDL) is up-to-date in the object.

    If the contact to the server was still present, or could be established, an IO::Socket::INET object is returned. Else, "undef" is returned and no further actions should be tried on the object.

$obj->status($socket)
    Update the current status of folder on the remote POP3 server.

  Server connection
Extends "Server connection" in Mail::Transport::Receive.

$obj->findBinary( $name, [@directories] )
    Inherited, see "Server connection" in Mail::Transport

$obj->remoteHost()
    Inherited, see "Server connection" in Mail::Transport

$obj->retry()
    Inherited, see "Server connection" in Mail::Transport

$obj->url()
    Represent this pop3 connection as URL.

  Error handling
Extends "Error handling" in Mail::Transport::Receive.

$obj->AUTOLOAD()
    Inherited, see "Error handling" in Mail::Reporter

$obj->notImplemented()
    Inherited, see "Error handling" in Mail::Reporter

  Cleanup
Extends "Cleanup" in Mail::Transport::Receive.

$obj->DESTROY()
    Inherited, see "Cleanup" in Mail::Reporter

DIAGNOSTICS

Error: POP3 Could not do a STAT
    For some weird reason, the server does not respond to the STAT call. Cast by status()

Error: POP3 requires a username and password.
    No username and/or no password specified for this POP3 folder, although these are obligatory parts in the protocol. Cast by login()

Fault: cannot connect to $service for POP3: $!
    Unsuccessful in connecting to the remote POP3 server. Cast by login()

Error: cannot get all messages of pop3 at once via messages().
    It is not possible to retrieve all messages on a remote POP3 folder at once: each shall be taken separately. The POP3 folder will hide this for you. Cast by messages()

Error: cannot re-connect reliably to server which doesn't support UIDL.
    The connection to the remote POP3 was lost, and cannot be re-established because the server's protocol implementation lacks the necessary information. Cast by socket()

Fault: cannot read POP3 from socket: $!
    It is not possible to read the success status of the previously given POP3 command. Connection lost? Cast by send()

Error: cannot write POP3 to socket: $@
    It is not possible to send a protocol command to the POP3 server. Connection lost? Cast by send()

Error: class $package does not implement method $method.
    Fatal error: the specific $package (or one of its superclasses) does not implement this method where it should. This message means that some other related classes do implement this method however the class at hand does not. Probably you should investigate this and probably inform the author of the package. Cast by notImplemented()

Error: could not authenticate using '$type' method.
    The authenication method to get access to the POP3 server did not result in a connection. Maybe you need a different authentication protocol, or your username with password are invalid. Cast by login()

Error: could not authenticate using any login method.
    No authentication method was explicitly prescribed, so both AUTH and APOP were tried. However, both failed. There are other authentication methods, which are not defined by the main POP3 RFC rfc1939. These protocols are not implemented yet. Please contribute your implementation. Cast by login()

Error: server at $service does not seem to be talking POP3.
    The remote server did not respond to an initial exchange of messages as is expected by the POP3 protocol. The server has probably a different service on the specified port. Cast by login()

SEE ALSO
This module is part of Mail-Box-POP3 version 4.01, built on December 13, 2025. Website: http://perl.overmeer.net/CPAN/

LICENSE
For contributors see file ChangeLog.

This software is copyright (c) 2001-2025 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.