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MHSTORE

MHSTORE

Section: [nmh-1.3] (1) Updated: 1 June 2008
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NAME

mhstore - store contents of MIME messages into files  

SYNOPSIS

mhstore [+folder] [msgs] [-file file] [-part number] ... [-type content] ... [-auto | -noauto] [-verbose | -noverbose] [-rcache policy] [-wcache policy] [-check | -nocheck] [-version] [-help]
 

DESCRIPTION

The mhstore command allows you to store the contents of a collection of MIME (multi-media) messages into files or other messages.

mhstore manipulates multi-media messages as specified in RFC-2045 thru RFC-2049.

By default, mhstore will store all the parts of each message. Each part will be store in a separate file. The header fields of the message are not stored. By using the -part and -type switches, you may limit the scope of mhstore to particular subparts (of a multipart content) and/or particular content types.

The option -file file directs mhstore to use the specified file as the source message, rather than a message from a folder. If you specify this file as ``-'', then mhstore will accept the source message on the standard input. Note that the file, or input from standard input should be a validly formatted message, just like any other nmh message. It should NOT be in mail drop format (to convert a file in mail drop format to a folder of nmh messages, see inc(1)).

A part specification consists of a series of numbers separated by dots. For example, in a multipart content containing three parts, these would be named as 1, 2, and 3, respectively. If part 2 was also a multipart content containing two parts, these would be named as 2.1 and 2.2, respectively. Note that the -part switch is effective for only messages containing a multipart content. If a message has some other kind of content, or if the part is itself another multipart content, the -part switch will not prevent the content from being acted upon.

A content specification consists of a content type and a subtype. The initial list of ``standard'' content types and subtypes can be found in RFC-2046.

A list of commonly used contents is briefly reproduced here:


Type         Subtypes
----         --------
text         plain, enriched
multipart    mixed, alternative, digest, parallel
message      rfc822, partial, external-body
application  octet-stream, postscript
image        jpeg, gif, png
audio        basic
video        mpeg

A legal MIME message must contain a subtype specification.

To specify a content, regardless of its subtype, just use the name of the content, e.g., ``audio''. To specify a specific subtype, separate the two with a slash, e.g., ``audio/basic''. Note that regardless of the values given to the -type switch, a multipart content (of any subtype listed above) is always acted upon. Further note that if the -type switch is used, and it is desirable to act on a message/external-body content, then the -type switch must be used twice: once for message/external-body and once for the content externally referenced.  

Checking the Contents

The -check switch tells mhstore to check each content for an integrity checksum. If a content has such a checksum (specified as a Content-MD5 header field), then mhstore will attempt to verify the integrity of the content.  

Storing the Contents

The mhstore will store the contents of the named messages in ``native'' (decoded) format. Two things must be determined: the directory to store the content, and the filenames. Files are written in the directory given by the ``nmh-storage'' profile entry, e.g.,

nmh-storage: /tmp

If this entry isn't present, the current working directory is used.

If the -auto switch is given, then mhstore will check if the message contains information indicating the filename that should be used to store the content. This information should be specified as the attribute ``name=filename'' in the ``Content-Type'' header for the content you are storing. For security reasons, this filename will be ignored if it begins with the character '/', '.', '|', or this switch is not the default, and it is recommended that you do NOT put the -auto switch in your .mh_profile file.

If the -auto switch is not given (or is being ignored for security reasons) then mhstore will look in the user's profile for a ``formatting string'' to determine how the different contents should be stored. First, mhstore will look for an entry of the form:

mhstore-store-<type>/<subtype>

to determine the formatting string. If this isn't found, mhstore will look for an entry of the form:

mhstore-store-<type>

to determine the formatting string.

If the formatting string starts with a ``+'' character, then content is stored in the named folder. A formatting string consisting solely of a ``+'' character is interpreted to be the current folder.

If the formatting string consists solely of a ``-'' character, then the content is sent to the standard output.

If the formatting string starts with a '|', then the display string will represent a command for mhstore to execute which should ultimately store the content. The content will be passed to the standard input of the command. Before the command is executed, mhstore will change to the appropriate directory, and any escapes (given below) in the display string will be expanded.

Otherwise the formatting string will represent a pathname in which to store the content. If the formatting string starts with a '/', then the content will be stored in the full path given, else the file name will be relative to the value of ``nmh-storage'' or the current working directory. Any escapes (given below) will be expanded, except for the a-escape.

A command or pathname formatting string may contain the following escapes. If the content isn't part of a multipart (of any subtype listed above) content, the p-escapes are ignored.


%a  Parameters from Content-type  (only valid with command)
%m  Insert message number
%P  Insert part number with leading dot
%p  Insert part number without leading dot
%t  Insert content type
%s  Insert content subtype
%%  Insert character %

If no formatting string is found, mhstore will check to see if the content is application/octet-stream with parameter ``type=tar''. If so, mhstore will choose an appropriate filename. If the content is not application/octet-stream, then mhstore will check to see if the content is a message. If so, mhstore will use the value ``+''. As a last resort, mhstore will use the value ``%m%P.%s''.

Example profile entries might be:

mhstore-store-text: %m%P.txt
mhstore-store-text: +inbox
mhstore-store-message/partial: +
mhstore-store-audio/basic: | raw2audio -e ulaw -s 8000 -c 1 > %m%P.au
mhstore-store-image/jpeg: %m%P.jpg
mhstore-store-application/PostScript: %m%P.ps

 

Reassembling Messages of Type message/partial

mhstore is also able to reassemble messages that have been split into multiple messages of type ``message/partial''.

When asked to store a content containing a partial message, mhstore will try to locate all of the portions and combine them accordingly. The default is to store the combined parts as a new message in the current folder, although this can be changed using formatting strings as discussed above. Thus, if someone has sent you a message in several parts (such as the output from sendfiles), you can easily reassemble them all into a single message in the following fashion:

% mhlist 5-8
 msg part  type/subtype             size description
   5       message/partial           47K part 1 of 4
   6       message/partial           47K part 2 of 4
   7       message/partial           47K part 3 of 4
   8       message/partial           18K part 4 of 4
% mhstore 5-8
reassembling partials 5,6,7,8 to folder inbox as message 9
% mhlist -verbose 9
 msg part  type/subtype             size description
   9       application/octet-stream 118K
             (extract with uncompress | tar xvpf -)
             type=tar
             conversions=compress

This will store exactly one message, containing the sum of the parts. It doesn't matter whether the partials are specified in order, since mhstore will sort the partials, so that they are combined in the correct order. But if mhstore can not locate every partial necessary to reassemble the message, it will not store anything.  

External Access

For contents of type message/external-body, mhstore supports these access-types:

afs
anon-ftp
ftp
local-file
mail-server

For the ``anon-ftp'' and ``ftp'' access types, mhstore will look for the ``nmh-access-ftp'' profile entry, e.g.,

nmh-access-ftp: myftp.sh

to determine the pathname of a program to perform the FTP retrieval. This program is invoked with these arguments:

domain name of FTP-site
username
password
remote directory
remote filename
local filename
``ascii'' or ``binary''

The program should terminate with an exit status of zero if the retrieval is successful, and a non-zero exit status otherwise.

If this entry is not provided, then mhstore will use a simple built-in FTP client to perform the retrieval.  

The Content Cache

When mhstore encounters an external content containing a ``Content-ID:'' field, and if the content allows caching, then depending on the caching behavior of mhstore, the content might be read from or written to a cache.

The caching behavior of mhstore is controlled with the -rcache and -wcache switches, which define the policy for reading from, and writing to, the cache, respectively. One of four policies may be specified: ``public'', indicating that mhstore should make use of a publically-accessible content cache; ``private'', indicating that mhstore should make use of the user's private content cache; ``never'', indicating that mhstore should never make use of caching; and, ``ask'', indicating that mhstore should ask the user.

There are two directories where contents may be cached: the profile entry ``nmh-cache'' names a directory containing world-readable contents, and, the profile entry ``nmh-private-cache'' names a directory containing private contents. The former should be an absolute (rooted) directory name.

For example,

nmh-cache: /tmp

might be used if you didn't care that the cache got wiped after each reboot of the system. The latter is interpreted relative to the user's nmh directory, if not rooted, e.g.,

nmh-private-cache: .cache

(which is the default value).  

User Environment

Because the display environment in which mhstore operates may vary for different machines, mhstore will look for the environment variable If present, this specifies the name of an additional user profile which should be read. Hence, when a user logs in on a particular machine, this environment variable should be set to refer to a file containing definitions useful for that machine. Finally, mhstore will attempt to consult one other additional user profile, e.g.,

/etc/nmh/mhn.defaults

which is created automatically during nmh installation.

 

FILES


^$HOME/.mh_profile~^The user profile
^$MHSTORE~^Additional profile entries
^/etc/nmh/mhn.defaults~^System default MIME profile entries

 

PROFILE COMPONENTS



^Path:~^To determine the user's nmh directory
^Current-Folder:~^To find the default current folder
^nmh-access-ftp:~^Program to retrieve contents via FTP
^nmh-cache~^Public directory to store cached external contents
^nmh-private-cache~^Personal directory to store cached external contents
^nmh-storage~^Directory to store contents
^mhstore-store-<type>*~^Template for storing contents

 

SEE ALSO

mhbuild(1), mhlist(1), mhshow(1), sendfiles(1)

 

DEFAULTS

`+folder' defaults to the current folder
`msgs' defaults to cur
`-noauto'
`-nocheck'
`-rcacheask'
`-wcacheask'
`-noverbose'

 

CONTEXT

If a folder is given, it will become the current folder. The last message selected will become the current message.

 

BUGS

Partial messages contained within a multipart content are not reassembled.


 

Index

NAME
SYNOPSIS
DESCRIPTION
Checking the Contents
Storing the Contents
Reassembling Messages of Type message/partial
External Access
The Content Cache
User Environment
FILES
PROFILE COMPONENTS
SEE ALSO
DEFAULTS
CONTEXT
BUGS

This document was created by man2html, using the manual pages.
Time: 21:23:52 GMT, April 16, 2011