Mail::Box::Mbox(3)

NAME
Mail::Box::Mbox - handle folders in Mbox format

INHERITANCE
 Mail::Box::Mbox
   is a Mail::Box::File
   is a Mail::Box
   is a Mail::Reporter

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

DESCRIPTION
This documentation describes how Mbox mailboxes work, and also describes what you can do with the Mbox folder object Mail::Box::Mbox.

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

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

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::File.

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

$class->new(%options)
    Inherited, see "Constructors" in Mail::Box

     -Option             --Defined in     --Default
      access               Mail::Box        'r'
      body_delayed_type    Mail::Box        Mail::Message::Body::Delayed
      body_type            Mail::Box::File  <see description>
      coerce_options       Mail::Box        +[]
      create               Mail::Box        false
      extract              Mail::Box        10240
      field_type           Mail::Box        undef
      fix_headers          Mail::Box        false
      folder               Mail::Box        $ENV{MAIL}
      folderdir            Mail::Box        $ENV{HOME}.'/Mail'
      head_delayed_type    Mail::Box        Mail::Message::Head::Delayed
      head_type            Mail::Box        Mail::Message::Head::Complete
      keep_dups            Mail::Box        false
      lock_extension       Mail::Box::File  '.lock'
      lock_file            Mail::Box        <foldername><lock-extension>
      lock_timeout         Mail::Box        1 hour
      lock_type            Mail::Box        Mail::Box::Locker::DotLock
      lock_wait            Mail::Box        10 seconds
      locker               Mail::Box        undef
      manager              Mail::Box        undef
      message_type         Mail::Box        Mail::Box::Mbox::Message
      multipart_type       Mail::Box        Mail::Message::Body::Multipart
      remove_when_empty    Mail::Box        true
      save_on_exit         Mail::Box        true
      subfolder_extension                   '.d'
      trusted              Mail::Box        <depends on folder location>
      write_policy         Mail::Box::File  undef

    access => $mode
    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_extension => $file|STRING
    lock_file => $file
    lock_timeout => $seconds
    lock_type => $class|$name|\@names
    lock_wait => $seconds
    locker => $locker
    manager => $manager
    message_type => $class
    multipart_type => CLASS
    remove_when_empty => BOOLEAN
    save_on_exit => BOOLEAN
    subfolder_extension => STRING
        Mbox folders do not support sub-folders. However, this module can simulate sub-directories if the user wants it to. When a subfolder of folder "xyz" is created, we create a directory which is called "xyz.d" to contain them. This extension ".d" can be changed using this option.

    trusted => BOOLEAN
    write_policy => 'REPLACE'|'INPLACE'|undef

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

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

$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->subfolderExtension()

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

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

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

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

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

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

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

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

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

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

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

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

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

$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::File.

$obj->current( [$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::File.

$any->listSubFolders(%options)
    Inherited, 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
      subfolder_extension                   <from object>

    check => BOOLEAN
    folder => $name
    folderdir => $dir
    skip_empty => BOOL
    subfolder_extension => STRING
        When the method is called on an open folder, the extension defined by it is used to detect sub-folders by default. Otherwise, '.d' is taken.

$any->nameOfSubFolder( $subname, [$parentname] )
    Inherited, see "Sub-folders" in Mail::Box

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

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

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

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

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

$any->create($foldername, %options)
    Inherited, see "Internals" in Mail::Box

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

    folderdir => $directory
    subfolder_extension => STRING
        If a directory is found on the location of the folder to be created, this STRING is used to extend that directory name with. This will cause the directory to be seen as sub-folder for the created folder. This argument is passed to folderToFilename().

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

$any->folderToFilename( $foldername, $folderdir, [$extension] )
    Translate a folder name into a filename, using the $folderdir value to replace a leading “"="”. If no $extension is specified and this method is called as instance method, new(subfolder_extension) is used. Otherwise, the extension default to “".d"”. Improves base, see "Internals" in Mail::Box::File

$class->foundIn( [$foldername], %options )
    If no $foldername is specified, then the value of the "folder" option is taken. A mbox folder is a file which starts with a separator line: a line with “"From␣"” as first characters. Blank lines which start the file are ignored, which is not for all MUA's acceptable. Improves base, see "Internals" in Mail::Box

     -Option             --Defined in     --Default
      folder                                undef
      folderdir            Mail::Box        undef
      subfolder_extension                   <from object>

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

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

$obj->messageCreateOptions( [$type, $config] )
    Inherited, see "Internals" in Mail::Box::File

$obj->moveAwaySubFolder($directory, $extension)
    Inherited, see "Internals" in Mail::Box::File

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

$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::File

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

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

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

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

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

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

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

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

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

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

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

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

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

  File based folders
Extends "File based folders" in Mail::Box::File.

  How MBOX folders work
MBOX folders store many messages in one file. Each message begins with a line which starts with the string "From ". Lines inside a message which accidentally start with "From" are, in the file, preceded by `>'. This character is stripped when the message is read.

In this respect must be noted that the format of the MBOX files is not strictly defined. The exact content of the separator lines differ between Mail User Agents (MUA's). Besides, some MUAs (like mutt) forget to encode the "From " lines within message bodies, breaking other parsers....

  Simulation of sub-folders
MBOX folders do not have a sub-folder concept as directory based folders do, but this MBOX module tries to simulate them. In this implementation a directory like

  Mail/subject1/

is taken as an empty folder "Mail/subject1", with the folders in that directory as sub-folders for it. You may also use

  Mail/subject1
  Mail/subject1.d/

where "Mail/subject1" is the folder, and the folders in the "Mail/subject1.d" directory are used as sub-folders. If your situation is similar to the first example and you want to put messages in that empty folder, the directory is automatically (and transparently) renamed, so that the second situation is reached.

DIAGNOSTICS

Error: cannot append messages to folder file $file: $!
    Appending messages to a not-opened file-organized folder may fail when the operating system does not allow write access to the file at hand. Cast by appendMessages()

Fault: cannot move away sub-folder $dir: $!
    Cast by moveAwaySubFolder()

Warning: cannot remove folder $name file $filename: $!
    Writing an empty folder will usually cause that folder to be removed, which fails for the indicated reason. new(remove_when_empty) controls whether the empty folder will removed; setting it to "false" (0) may be needed to avoid this message. Cast by write()

Fault: cannot replace $to by $from to update folder $name: $!
    The replace policy wrote a new folder file to update the existing, but was unable to give the final touch: replacing the old version of the folder file for the indicated reason. Cast by write()

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: file $name too short to get write message $msgnr ($size < $expect)
    Mail::Box is lazy: it tries to leave messages in the folders until they are used, which saves time and memory usage. When this message appears, something is terribly wrong: some lazy message are needed for updating the folder, but they cannot be retrieved from the original file anymore. In this case, messages can be lost.

    This message does appear regularly on Windows systems when using the 'replace' write policy. Please help to find the cause, probably something to do with Windows incorrectly handling multiple filehandles open in the same file. Cast by write()

Warning: folder $name not deleted: not writable.
    The folder must be opened with write access via new(access), otherwise removing it will be refused. So, you may have write-access according to the operating system, but that will not automatically mean that this "delete" method permits you to. The reverse remark is valid as well. Cast by delete()

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 '$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: unable to update folder $name.
    When a folder is to be written, both replace and inplace write policies are tried, If both fail, the whole update fails. You may see other, related, error messages to indicate the real problem. Cast by write()

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

Error: you cannot add a message which is already part of a folder to a new one.  Please use moveTo or copyTo.
    Cast by addMessage()

SEE ALSO
This module is part of Mail-Box 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.