phpman > perldoc > Mail::Box::MH

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NAME
    Mail::Box::MH - handle MH folders

INHERITANCE
     Mail::Box::MH
       is a Mail::Box::Dir
       is a Mail::Box
       is a Mail::Reporter

SYNOPSIS
     use Mail::Box::MH;
     my $folder = new Mail::Box::MH folder => $ENV{MAIL}, ...;

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

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

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

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

    overload: @{}
        Inherited, see "OVERLOADED" in Mail::Box

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

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

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

    Mail::Box::MH->new(%options)
         -Option           --Defined in     --Default
          access             Mail::Box        'r'
          body_delayed_type  Mail::Box        Mail::Message::Body::Delayed
          body_type          Mail::Box        Mail::Message::Body::Lines
          coerce_options     Mail::Box        []
          create             Mail::Box        <false>
          directory          Mail::Box::Dir   <derived from folder name>
          extract            Mail::Box        10240
          field_type         Mail::Box        undef
          fix_headers        Mail::Box        <false>
          folder             Mail::Box        $ENV{MAIL}
          folderdir          Mail::Box        $ENV{HOME}/.mh
          head_delayed_type  Mail::Box        Mail::Message::Head::Delayed
          head_type          Mail::Box        Mail::Message::Head::Complete
          index                               undef
          index_filename                      <foldername>/.index
          index_type                          Mail::Box::MH::Index
          keep_dups          Mail::Box        <false>
          keep_index                          0
          labels                              undef
          labels_filename                     <foldername>/.mh_sequence
          labels_type                         Mail::Box::MH::Labels
          lock_file          Mail::Box        <index_file>
          lock_timeout       Mail::Box        1 hour
          lock_type          Mail::Box        Mail::Box::Locker::DotLock
          lock_wait          Mail::Box        10 seconds
          locker             Mail::Box        undef
          log                Mail::Reporter   'WARNINGS'
          manager            Mail::Box        undef
          message_type       Mail::Box        <folder-class>::Message
          multipart_type     Mail::Box        Mail::Message::Body::Multipart
          remove_when_empty  Mail::Box        <true>
          save_on_exit       Mail::Box        <true>
          trace              Mail::Reporter   'WARNINGS'
          trusted            Mail::Box        <depends on folder location>

        access => MODE
        body_delayed_type => CLASS
        body_type => CLASS|CODE
        coerce_options => ARRAY
        create => BOOLEAN
        directory => DIRECTORY
        extract => INTEGER | CODE | METHOD | 'LAZY'|'ALWAYS'
        field_type => CLASS
        fix_headers => BOOLEAN
        folder => FOLDERNAME
        folderdir => DIRECTORY
        head_delayed_type => CLASS
        head_type => CLASS
        index => OBJECT
          You may specify an OBJECT of a type which extends Mail::Box::MH::Index (at least
          implements a "get()" method), as alternative for an index file reader as created by
          "Mail::Box::MH".

        index_filename => FILENAME
          The FILENAME which is used in each directory to store the headers of all mails. The
          filename shall not contain a directory path. (e.g. Do not use "/usr/people/jan/.index",
          nor "subdir/.index", but say ".index".)

        index_type => CLASS
        keep_dups => BOOLEAN
        keep_index => BOOLEAN
          Keep an index file of the specified mailbox, one file per directory. Using an index file
          will speed up things considerably, because it avoids reading all the message files the
          moment that you open the folder. When you open a folder, you can use the index file to
          retrieve information such as the subject of each message, instead of having to read
          possibly thousands of messages.

        labels => OBJECT
          You may specify an OBJECT of a type which extends Mail::Box::MH::Labels (at least
          implements the "get()" method), as alternative for labels file reader as created by
          "Mail::Box::MH".

        labels_filename => FILENAME
          In MH-folders, messages can be labeled, for instance based on the sender or whether it is
          read or not. This status is kept in a file which is usually called ".mh_sequences", but
          that name can be overruled with this flag.

        labels_type => CLASS
        lock_file => FILENAME
        lock_timeout => SECONDS
        lock_type => CLASS|STRING|ARRAY
        lock_wait => SECONDS
        locker => OBJECT
        log => LEVEL
        manager => MANAGER
        message_type => CLASS
        multipart_type => CLASS
        remove_when_empty => BOOLEAN
        save_on_exit => BOOLEAN
        trace => LEVEL
        trusted => BOOLEAN

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

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

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

    Mail::Box::MH->appendMessages(%options)
        Append a message to a folder which is not open.

         -Option  --Defined in     --Default
          folder    Mail::Box        <required>
          message   Mail::Box        undef
          messages  Mail::Box        undef
          share     Mail::Box        <false>

        folder => FOLDERNAME
        message => MESSAGE
        messages => ARRAY-OF-MESSAGES
        share => BOOLEAN

    $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->directory()
        Inherited, see "The folder" in Mail::Box::Dir

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

    $obj->name()
        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->type()
        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::Dir.

    $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::Dir.

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

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

    $obj->nameOfSubFolder( $subname, [$parentname] )
    Mail::Box::MH->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

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

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

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

    $obj->create($foldername, %options)
    Mail::Box::MH->create($foldername, %options)
         -Option   --Defined in--Default
          folderdir  Mail::Box   undef

        folderdir => DIRECTORY

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

    $obj->folderToDirectory($foldername, $folderdir)
        Inherited, see "Internals" in Mail::Box::Dir

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

    $obj->highestMessageNumber()
        Returns the highest number which is used in the folder to store a file. This method may be
        called when the folder is read (then this number can be derived without file-system access),
        but also when the folder is not read (yet).

    $obj->index()
        Create a index reader/writer object.

    $obj->labels()
        Create a label reader/writer object.

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

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

    $obj->messageInFile($filename)
        Inherited, see "Internals" in Mail::Box::Dir

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

    $obj->readMessageFilenames($directory)
        Inherited, see "Internals" in Mail::Box::Dir

    $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)
         -Option  --Defined in     --Default
          messages  Mail::Box        <required>
          renumber                   <true>

        messages => ARRAY
        renumber => BOOLEAN
          Permit renumbering of message. By default this is true, but for some unknown reason, you
          may be thinking that messages should not be renumbered.

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

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

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

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

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

    $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
    Mail::Box::MH->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
        Inherited, see "Error handling" in Mail::Reporter

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

    $obj->log( [$level, [$strings]] )
    Mail::Box::MH->log( [$level, [$strings]] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->logPriority($level)
    Mail::Box::MH->logPriority($level)
        Inherited, see "Error handling" in Mail::Reporter

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

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

    $obj->report( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->reportAll( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

    $obj->trace( [$level] )
        Inherited, see "Error handling" in Mail::Reporter

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

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

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

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

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

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

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

  How MH folders work
    MH-type folders use a directory to store the messages of one folder. Each message is stored in a
    separate file. This seems useful, because changes in a folder change only a few of these small
    files, in contrast with file-based folders where changes in a folder cause rewrites of huge
    folder files.

    However, MH-based folders perform very bad if you need header information of all messages. For
    instance, if you want to have full knowledge about all message-threads (see
    Mail::Box::Thread::Manager) in the folder, it requires to read all header lines in all message
    files. And usually, reading your messages in threads is desired.

    So, each message is written in a separate file. The filenames are numbers, which count from 1.
    Next to these message files, a directory may contain a file named ".mh_sequences", storing
    labels which relate to the messages. Furthermore, a folder-directory may contain
    sub-directories, which are seen as sub-folders.

  This implementation
    This implementation supports the ".mh-sequences" file and sub-folders. Next to this,
    considerable effort it made to avoid reading each message-file. This should boost performance of
    the MailBox distribution over other Perl-modules which are able to read folders.

    Folder types which store their messages each in one file, together in one directory, are bad for
    performance. Consider that you want to know the subjects of all messages, while browser through
    a folder with your mail-reading client. This would cause all message-files to be read.

    Mail::Box::MH has two ways to try improve performance. You can use an index-file, and use on
    delay-loading. The combination performs even better. Both are explained in the next sections.

  An index-file
    If you specify new(keep_index), then all header-lines of all messages from the folder which have
    been read once, will also be written into one dedicated index-file (one file per folder). The
    default filename is ".index"

    However, index-files are not supported by any other reader which supports MH (as far as I know).
    If you read the folders with such I client, it will not cause unrecoverable conflicts with this
    index-file, but at most be bad for performance.

    If you do not (want to) use an index-file, then delay-loading may save your day.

DIAGNOSTICS
    Error: Cannot append message without lock on $folder.
        It is impossible to append one or more messages to the folder which is not opened, because
        locking it fails. The folder may be in use by an other application, or you may need to
        specify some lock related options (see new()).

    Error: Cannot create MH folder $name: $!
        For some reason, it is impossible to create the folder. Check the permissions and the name
        of the folder. Does the path to the directory to be created exist?

    Error: Cannot write folder $name without lock.
        It is impossible to get a lock on the folder, which means that the changes can not be made.
        You may need to tune the lock related options which are available at folder creation.

    Warning: Changes not written to read-only folder $self.
        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".

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

    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.

    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.

    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.

    Error: 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.

    Error: Invalid timespan '$timespan' specified.
        The string does not follow the strict rules of the time span syntax which is permitted as
        parameter.

    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.

    Error: Package $package does not implement $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.

    Error: Unable to create subfolder $name of $folder.
        The copy includes the subfolders, but for some reason it was not possible to copy one of
        these. Copying will proceed for all other sub-folders.

    Error: Unable to write message for $folder to $filename: $!
        The new message could not be written to its new file, for the specific reason.

    Error: Writing folder $name failed
        For some reason (you probably got more error messages about this problem) it is impossible
        to write the folder, although you should because there were changes made.

SEE ALSO
    This module is part of Mail-Box distribution version 3.009, built on August 18, 2020. Website:
    http://perl.overmeer.net/CPAN/

LICENSE
    Copyrights 2001-2020 by [Mark Overmeer]. For other contributors see ChangeLog.

    This program is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself. See http://dev.perl.org/licenses/

Mail::Box::MH
NAME INHERITANCE SYNOPSIS DESCRIPTION OVERLOADED METHODS
Constructors The folder Folder flags The messages Sub-folders Internals Other methods Error handling Cleanup
DETAILS
Different kinds of folders Available folder types Folder class implementation How MH folders work This implementation An index-file
DIAGNOSTICS SEE ALSO LICENSE

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