Mail::Box::POP3(3pm)

NAME
Mail::Box::POP3 - handle POP3 folders as client

INHERITANCE
 Mail::Box::POP3
   is a Mail::Box::Net
   is a Mail::Box
   is a Mail::Reporter

 Mail::Box::POP3 is extended by
   Mail::Box::POP3s

SYNOPSIS
  use Mail::Box::POP3;
  my $folder = Mail::Box::POP3->new(folder => $ENV{MAIL}, ...);

DESCRIPTION
Maintain a folder which has its messages stored on a remote server. The communication between the client application and the server is implemented using the POP3 protocol. This class uses Mail::Transport::POP3 to hide the transport of information, and focusses solely on the correct handling of messages within a POP3 folder.

Be aware: This module versions 4.0 and up is not fully compatible with older releases: mainly the exception handling has changed. When you need to upgrade, please read https://github.com/markov2/perl5-Mail-Box/wiki/ Version 3 is still maintained and may see new releases as well.

Extends "DESCRIPTION" in Mail::Box::Net.

OVERLOADED
Extends "OVERLOADED" in Mail::Box::Net.

overload: '""' stringification
    Inherited, see "OVERLOADED" in Mail::Box

overload: '@{}' use as ARRAY
    Inherited, see "OVERLOADED" in Mail::Box

overload: cmp string comparison
    Inherited, see "OVERLOADED" in Mail::Box

METHODS
Extends "METHODS" in Mail::Box::Net.

  Constructors
Extends "Constructors" in Mail::Box::Net.

$class->new(%options)
    For authentications, you have three choices: specify a foldername which resembles an URL, or specify a pop-client object, or separate options for user, password, pop-server and server-port. Improves base, see "Constructors" in Mail::Box

     -Option           --Defined in     --Default
      access             Mail::Box        'r'
      authenticate                        'AUTO'
      body_delayed_type  Mail::Box        Mail::Message::Body::Delayed
      body_type          Mail::Box        Mail::Message::Body::Lines
      coerce_options     Mail::Box        +[]
      create             Mail::Box        <not applicable>
      extract            Mail::Box        10240
      field_type         Mail::Box        undef
      fix_headers        Mail::Box        false
      folder             Mail::Box        <not applicable>
      folderdir          Mail::Box        <network location>
      head_delayed_type  Mail::Box        Mail::Message::Head::Delayed
      head_type          Mail::Box        Mail::Message::Head::Complete
      keep_dups          Mail::Box        false
      lock_file          Mail::Box        undef
      lock_timeout       Mail::Box        1 hour
      lock_type          Mail::Box        'NONE'
      lock_wait          Mail::Box        10 seconds
      locker             Mail::Box        undef
      manager            Mail::Box        undef
      message_type       Mail::Box        Mail::Box::POP3::Message
      multipart_type     Mail::Box        Mail::Message::Body::Multipart
      password           Mail::Box::Net   undef
      pop_client                          undef
      remove_when_empty  Mail::Box        <false>
      save_on_exit       Mail::Box        true
      server_name        Mail::Box::Net   undef
      server_port        Mail::Box::Net   110
      ssl_options                         undef
      trusted            Mail::Box        <false>
      use_ssl                             false
      username           Mail::Box::Net   undef

    access => $mode
    authenticate => 'LOGIN'|'APOP'|'AUTO'|'OUATH2'|'OAUTH2_SEP'
        POP3 can use two methods of authentication: the old LOGIN protocol, which transmits a username and password in plain text, and the newer APOP protocol which uses MD5 encryption. APOP is therefore much better, however not always supported by the server. With AUTO, first APOP is tried and if that fails LOGIN.

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

    body_delayed_type => CLASS
    body_type => CLASS|CODE
    coerce_options => ARRAY
    create => BOOLEAN
    extract => INTEGER|CODE|METHOD|'LAZY'|'ALWAYS'
    field_type => $class
    fix_headers => BOOLEAN
    folder => $name
    folderdir => $directory
    head_delayed_type => $class
    head_type => $class
    keep_dups => BOOLEAN
    lock_file => $file
    lock_timeout => $seconds
    lock_type => $class|$name|\@names
    lock_wait => $seconds
    locker => $locker
    manager => $manager
    message_type => $class
    multipart_type => CLASS
    password => $password
    pop_client => OBJECT
        You may want to specify your own pop-client object. The object which is passed must extend Mail::Transport::POP3.

    remove_when_empty => BOOLEAN
    save_on_exit => BOOLEAN
    server_name => $host
    server_port => $number
    ssl_options => HASH
    trusted => BOOLEAN
    use_ssl => BOOLEAN
    username => $username

    » example:

      my $url = 'pop3://user:password@pop.xs4all.nl'
      my $pop = Mail::Box::POP3->new($url);

      my $pop = $mgr->open(type => 'pop3',
         username => 'myname', password => 'mypassword',
         server_name => 'pop.xs4all.nl'
      );

  Attributes
Extends "Attributes" in Mail::Box::Net.

$obj->fixHeaders()
    Inherited, see "Attributes" in Mail::Box

$obj->folderdir( [$directory] )
    Inherited, see "Attributes" in Mail::Box

$obj->isTrusted()
    Inherited, see "Attributes" in Mail::Box

$obj->name()
    Inherited, see "Attributes" in Mail::Box

$obj->removeEmpty()
    Inherited, see "Attributes" in Mail::Box

$obj->type()
    Inherited, see "Attributes" in Mail::Box

  The folder
Extends "The folder" in Mail::Box::Net.

$obj->addMessage($message)
    It is impossible to write messages to the average POP3 server. There are extensions to the protocol which do permit it, however these are not implemented (yet, patches welcome).

    "undef" is returned, and an error displayed. However, no complaint is given when the $message is "undef" itself. Improves base, see "The folder" in Mail::Box

     -Option--Defined in--Default
      share   Mail::Box   <not used>

    share => BOOLEAN
$obj->addMessages($messages)
    As useless as addMessage(). The only acceptable call to this method is without any message. Improves base, see "The folder" in Mail::Box

$class->appendMessages(%options)
    Inherited, see "The folder" in Mail::Box

$obj->close(%options)
    Inherited, see "The folder" in Mail::Box

$obj->copyTo($folder, %options)
    Inherited, see "The folder" in Mail::Box

$obj->delete(%options)
    It is not possible to delete a POP3 folder remotely: the best we can do is remove all the messages in it... which is the action implemented here. A notice is logged about this. Improves base, see "The folder" in Mail::Box

     -Option   --Defined in--Default
      recursive  Mail::Box   <not used>

    recursive => BOOLEAN
$obj->organization()
    Inherited, see "The folder" in Mail::Box

$obj->size()
    Inherited, see "The folder" in Mail::Box

$obj->update()
    NOT IMPLEMENTED YET Improves base, see "The folder" in Mail::Box

$obj->url()
    Inherited, see "The folder" in Mail::Box

  Folder flags
Extends "Folder flags" in Mail::Box::Net.

$obj->access()
    Inherited, see "Folder flags" in Mail::Box

$obj->isModified()
    Inherited, see "Folder flags" in Mail::Box

$obj->modified( [BOOLEAN] )
    Inherited, see "Folder flags" in Mail::Box

$obj->writable()
    Inherited, see "Folder flags" in Mail::Box

  The messages
Extends "The messages" in Mail::Box::Net.

$obj->current( [$number|$message|$message_id] )
    Inherited, see "The messages" in Mail::Box

$obj->find($message_id)
    Inherited, see "The messages" in Mail::Box

$obj->findFirstLabeled( $label, [BOOLEAN, [\@msgs]] )
    Inherited, see "The messages" in Mail::Box

$obj->message( $index, [$message] )
    Inherited, see "The messages" in Mail::Box

$obj->messageId( $message_id, [$message] )
    Inherited, see "The messages" in Mail::Box

$obj->messageIds()
    Inherited, see "The messages" in Mail::Box

$obj->messages( <'ALL'|$range|'ACTIVE'|'DELETED'|$label| !$label|$filter> )
    Inherited, see "The messages" in Mail::Box

$obj->nrMessages(%options)
    Inherited, see "The messages" in Mail::Box

$obj->scanForMessages($message, $message_ids, $timespan, $window)
    Inherited, see "The messages" in Mail::Box

  Sub-folders
Extends "Sub-folders" in Mail::Box::Net.

$any->listSubFolders(%options)
    The standard POP3 protocol does not support sub-folders, so an empty list will be returned in any case. Improves base, see "Sub-folders" in Mail::Box

     -Option    --Defined in     --Default
      check       Mail::Box        false
      folder      Mail::Box        <from calling object>
      folderdir   Mail::Box        <from folder>
      skip_empty  Mail::Box        false

    check => BOOLEAN
    folder => $name
    folderdir => $dir
    skip_empty => BOOL
$any->nameOfSubFolder( $subname, [$parentname] )
    Inherited, see "Sub-folders" in Mail::Box

$obj->openRelatedFolder(%options)
    Inherited, see "Sub-folders" in Mail::Box

$obj->openSubFolder(%options)
    It is not possible to open a sub-folder for a POP3 folder, because that is not supported by the official POP3 protocol. In any case, "undef" is returned to indicate a failure. Improves base, see "Sub-folders" in Mail::Box

$any->topFolderWithMessages()
    Inherited, see "Sub-folders" in Mail::Box

  Internals
Extends "Internals" in Mail::Box::Net.

$obj->coerce($message, %options)
    Inherited, see "Internals" in Mail::Box

$any->create($folder, %options)
    It is not possible to create a new folder on a POP3 server. This method will always return "false". Improves base, see "METHODS" in Mail::Box::Net

     -Option   --Defined in--Default
      folderdir  Mail::Box   undef

    folderdir => $directory
$obj->determineBodyType($message, $head)
    Inherited, see "Internals" in Mail::Box

$class->foundIn( [$foldername], %options )
    Inherited, see "Internals" in Mail::Box

$obj->getHead($message)
    Read the header for the specified message from the remote server.

$obj->getHeadAndBody($message)
    Read all data for the specified message from the remote server.

$obj->lineSeparator( [<STRING|'CR'|'LF'|'CRLF'>] )
    Inherited, see "Internals" in Mail::Box

$obj->locker()
    Inherited, see "Internals" in Mail::Box

$obj->popClient(%options)
    Returns the pop client object. This does not establish the connection.

     -Option     --Default
      ssl_options  <from new(ssl_options)>
      use_ssl      <from new(use_ssl)>

    ssl_options => HASH
    use_ssl => BOOLEAN
$obj->read(%options)
    Inherited, see "Internals" in Mail::Box

$obj->readMessages(%options)
    Inherited, see "Internals" in Mail::Box

$obj->storeMessage($message)
    Inherited, see "Internals" in Mail::Box

$obj->toBeThreaded($messages)
    Inherited, see "Internals" in Mail::Box

$obj->toBeUnthreaded($messages)
    Inherited, see "Internals" in Mail::Box

$obj->updateMessages(%options)
    Inherited, see "Internals" in Mail::Box

$obj->write(%options)
    Inherited, see "Internals" in Mail::Box

$obj->writeMessages(%options)
    Inherited, see "Internals" in Mail::Box

     -Option  --Defined in--Default
      messages  Mail::Box   <required>

    messages => ARRAY

  Other methods
Extends "Other methods" in Mail::Box::Net.

$any->timespan2seconds($time)
    Inherited, see "Other methods" in Mail::Box

  Error handling
Extends "Error handling" in Mail::Box::Net.

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

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

  Cleanup
Extends "Cleanup" in Mail::Box::Net.

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

DETAILS
Extends "DETAILS" in Mail::Box::Net.

  Different kinds of folders
Extends "Different kinds of folders" in Mail::Box::Net.

  Available folder types
Extends "Available folder types" in Mail::Box::Net.

  Folder class implementation
Extends "Folder class implementation" in Mail::Box::Net.

  How POP3 folders work
Rfc1939 defines how POP3 works. POP3 is a really simple protocol to receive messages from a server to a user's client. POP3 is also really limited: it can only be used to fetch messages, but has not many ways to limit the amount of network traffic, like the IMAP4 protocol has.

One POP3 account represents only one folder: there is no way of sub-folders in POP3. POP3 doesn't support writing (except for some message status flags).

  This implementation
The protocol specifics are implemented in Mail::Transport::POP3, written by Liz Mattijsen. That module does not use any of the other POP3 modules available on CPAN for the reason that MailBox tries to be smarter: it is capable of re-establishing broken POP3 connection when the server supports UIDs.

The implementation has shown to work with many different POP servers. In the test directory of the distribution, you will find a small server implementation, which is used to test the client.

DIAGNOSTICS

Error: Cannot find head back for $id on POP3 server $name.
    The server told to have this message, but when asked for its headers, no single line was returned. Did the message get destroyed? Cast by getHeadAndBody()

Error: Cannot read body for $id on POP3 server $name.
    The message's headers are retrieved from the server, but the body seems to be lost. Did the message get destroyed between reading the header and reading the body? Cast by getHeadAndBody()

Error: Folder $name is opened read-only
    You can not write to this folder unless you have opened the folder to write or append with new(access), or the "force" option is set "true". Cast by write()

Warning: Message $id on POP3 server $name disappeared.
    The server indicated the existence of this message before, however it has no information about the message anymore. Cast by getHeadAndBody()

Warning: POP3 folders cannot be deleted.
    Each user has only one POP3 folder on a server. This folder is created and deleted by the server's administrator only. Cast by delete()

Error: cannot create POP3 client for $name.
    The connection to the POP3 server cannot be established. You may see more, related, error messages about the failure. Cast by popClient()

Warning: changes not written to read-only folder $name.
    You have opened the folder read-only --which is the default set by new(access)--, made modifications, and now want to close it. Set close(force) if you want to overrule the access mode, or close the folder with close(write) set to "NEVER". Cast by close()

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: copying failed for one message.
    For some reason, for instance disk full, removed by external process, or read-protection, it is impossible to copy one of the messages. Copying will proceed for the other messages. Cast by copyTo()

Error: destination folder $name is not writable.
    The folder where the messages are copied to is not opened with write access (see new(access)). This has no relation with write permission to the folder which is controlled by your operating system. Cast by copyTo()

Warning: different messages with id $msgid.
    The message id is discovered more than once within the same folder, but the content of the message seems to be different. This should not be possible: each message must be unique. Cast by messageId()

Error: invalid timespan '$span'.
    The string does not follow the strict rules of the time span syntax which is permitted as parameter. Cast by timespan2seconds()

Warning: message $id disappeared from POP3 server $name.
    Cast by getHead()

Warning: message-id '$msgid' does not contain a domain.
    According to the RFCs, message-ids need to contain a unique random part, then an "@", and then a domain name. This is made to avoid the creation of two messages with the same id. The warning emerges when the "@" is missing from the string. Cast by messageId()

Error: unknown value to folder->close(write => $when).
    Cast by close()

Warning: update of $count messages ignored for POP3 folder $name.
    The standard POP3 implementation does not support writing from client back to the server. Therefore, modifications may be lost. Cast by writeMessages()

Error: you cannot write a message to a pop server (yet)
    Some extensions to the POP3 protocol do permit writing messages to the server, but the standard protocol only implements retreival. Feel invited to extend our implementation with writing. Cast by addMessage()

Error: you cannot write messages to a pop server (yet)
    Cast by addMessages()

SEE ALSO
This module is part of Mail-Box-POP3 version 4.02, built on April 10, 2026. Website: http://perl.overmeer.net/CPAN/

LICENSE
For contributors see file ChangeLog.

This software is copyright (c) 2001-2026 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.