[mmh] / man / mhbuild.man1

.\"
.\" %nmhwarning%
.\"
.TH MHBUILD %manext1% "%nmhdate%" MH.6.8 [%nmhversion%]
.SH NAME
mhbuild \- translate MIME composition draft
.SH SYNOPSIS
.na
.HP 5
.B mhbuild
.I file
.RB [ \-list " | " \-nolist ]
.RB [ \-realsize " | " \-norealsize ]
.RB [ \-headers " | " \-noheaders ]
.RB [ \-ebcdicsafe " | " \-noebcdicsafe ]
.RB [ \-rfc934mode " | " \-norfc934mode ]
.RB [ \-contentid " | " \-nocontentid ]
.RB [ \-verbose " | " \-noverbose ]
.RB [ \-version ]
.RB [ \-help ]
.ad
.SH DESCRIPTION
The
.B mhbuild
command will translate a MIME composition draft into
a valid MIME message.
.PP
.B mhbuild
creates multi-media messages as specified in RFC\-2045
thru RFC\-2049.  Currently
.B mhbuild
only supports encodings in
message bodies, and does not support the encoding of message headers as
specified in RFC\-2047.
.PP
If you specify the name of the composition file as \*(lq-\*(rq,
then
.B mhbuild
will accept the composition draft on the standard
input.  If the translation of this input is successful,
.B mhbuild
will output the new MIME message to the standard output.  This argument
must be the last argument on the command line.
.PP
Otherwise if the file argument to
.B mhbuild
is the name of a valid
composition file, and the translation is successful,
.B mhbuild
will replace the original file with the new MIME message.  It will rename
the original file to start with the \*(lq,\*(rq character and end with the
string \*(lq.orig\*(rq, e.g., if you are editing the file \*(lqdraft\*(rq,
it will be renamed to \*(lq,draft.orig\*(rq.  This allows you to easily
recover the
.B mhbuild
input file.
.SS "Listing the Contents"
The
.B \-list
switch tells
.B mhbuild
to list the table of contents associated with the MIME message that is created.
.PP
The
.B \-headers
switch indicates
that a one-line banner should be displayed above the listing.  The
.B \-realsize
switch tells
.B mhbuild
to evaluate the \*(lqnative\*(rq
(decoded) format of each content prior to listing.  This provides an
accurate count at the expense of a small delay.  If the
.B \-verbose
switch
is present, then the listing will show any \*(lqextra\*(rq information
that is present in the message, such as comments in the
\*(lqContent-Type\*(rq header.
.SS "Translating the Composition File"
.B mhbuild
is essentially a filter to aid in the composition of MIME
messages.
.B mhbuild
will convert an
.B mhbuild
\*(lqcomposition file\*(rq
into a valid MIME message.  A
.B mhbuild
\*(lqcomposition file\*(rq
is just a file containing plain text that is interspersed
with various
.B mhbuild
directives.  When this file is processed
by
.BR mhbuild ,
the various directives will be expanded to the
appropriate content, and will be encoded according to the MIME standards.
The resulting MIME message can then be sent by electronic mail.
.PP
The formal syntax for a
.B mhbuild
composition file is defined at the
end of this document, but the ideas behind this format are not complex.
Basically, the body contains one or more contents.  A content consists of
either a directive, indicated with a \*(lq#\*(rq as the first character
of a line; or, plaintext (one or more lines of text).  The continuation
character, \*(lq\\\*(lq, may be used to enter a single directive on more
than one line, e.g.,
.PP
.RS 5
.nf
#image/png \\
    /home/foobar/junk/picture.png
.fi
.RE
.PP
There are four kinds of directives:
\*(lqtype\*(rq,
\*(lqexternal-type\*(rq,
\*(lqmessage\*(rq (#forw),
and \*(lqbegin\*(rq (#begin).
.PP
.B "(1) The \*(lqtype\*(rq directive
is used to directly specify the type and
subtype of a content.  You may only specify discrete types in this manner
(can't specify the types multipart or message with this directive).
You may optionally specify the name of a file containing the contents
in \*(lqnative\*(rq (decoded) format.  If this filename starts with the
\*(lq|\*(rq character, then it represents a command to execute whose
output is captured accordingly.
For example,
.PP
.RS 5
.nf
#audio/basic |raw2audio -F < /usr/lib/sound/giggle.au
.fi
.RE
.PP
If a filename is not given,
.B mhbuild
will look for information in the
user's profile to determine how the different contents should be composed.
This is accomplished by consulting a composition string, and executing
it under
.BR /bin/sh ,
with the standard output set to the content.
If the
.B \-verbose
switch is given,
.B mhbuild
will echo any commands that are used to create contents in this way.
.PP
The composition string may contain the following escapes:
.PP
.RS 5
.nf
.ta \w'%P  'u
%a      Insert parameters from directive
%f      Insert filename containing content
%F      %f, and stdout is not re-directed
%s      Insert content subtype
%%      Insert character %
.fi
.RE
.PP
First,
.B mhbuild
will look for an entry of the form:
.PP
.RS 5
mhbuild-compose-<type>/<subtype>
.RE
.PP
to determine the command to use to compose the content.  If this isn't
found,
.B mhbuild
will look for an entry of the form:
.PP
.RS 5
mhbuild-compose-<type>
.RE
.PP
to determine the composition command. If this isn't found,
.B mhbuild
will complain.
.PP
An example entry might be:
.PP
.RS 5
mhbuild-compose-audio/basic: record | raw2audio -F
.RE
.PP
Because commands like these will vary, depending on the display
environment used for login, composition strings for different
contents should probably be put in the file specified by the
.B $MHBUILD
environment variable, instead of directly in your
user profile.
.PP
.B "(2) The \*(lqexternal-type\*(rq directives
are used to provide a MIME
reference to a content, rather than enclosing the contents itself
(for instance, by specifying an ftp site).  Hence, instead of
providing a filename as with the type directives, external-parameters
are supplied.  These look like regular parameters, so they must be
separated accordingly.  For example,
.PP
.RS 5
.nf
#@application/octet-stream; \\
    type=tar; \\
    conversions=compress \\
    [this is the nmh distribution] \\
    {application; filename="nmh.tar.gz"} \\
    name="nmh.tar.gz"; \\
    directory="/pub/nmh"; \\
    site="ftp.math.gatech.edu"; \\
    access-type=anon-ftp; \\
    mode="image"
.fi
.RE
.PP
You must give a description string to separate the content parameters
from the external-parameters (although this string may be empty).
This description string is specified by enclosing it within
\*(lq[]\*(rq.  A disposition string, to appear in a
\*(lqContent-Disposition\*(rq header, may appear in the optional
\*(lq{}\*(rq.
.PP
These parameters are of the form:
.PP
.RS 5
.nf
.ta \w'access-type=  'u
access-type=    usually \fIanon-ftp\fR or \fImail-server\fR
name=   filename
permission=     read-only or read-write
site=   hostname
directory=      directoryname (optional)
mode=   usually \fIascii\fR or \fIimage\fR (optional)
size=   number of octets
server= mailbox
subject=        subject to send
body=   command to send for retrieval
.fi
.RE
.PP
.B "(3) The \*(lqmessage\*(rq directive (#forw)
is used to specify a message or
group of messages to include.  You may optionally specify the name of
the folder and which messages are to be forwarded.  If a folder is not
given, it defaults to the current folder.  Similarly, if a message is not
given, it defaults to the current message.  Hence, the message directive
is similar to the
.B forw
command, except that the former uses
the MIME rules for encapsulation rather than those specified in RFC\-934.
For example,
.PP
.RS 5
.nf
#forw +inbox 42 43 99
.fi
.RE
.PP
If you include a single message, it will be included directly as a content
of type \*(lqmessage/rfc822\*(rq.  If you include more than one message,
then
.B mhbuild
will add a content of type \*(lqmultipart/digest\*(rq
and include each message as a subpart of this content.
.PP
If you are using this directive to include more than one message, you
may use the
.B \-rfc934mode
switch.  This switch will indicate that
.B mhbuild
should attempt to utilize the MIME encapsulation rules
in such a way that the \*(lqmultipart/digest\*(rq that is created
is (mostly) compatible with the encapsulation specified in RFC\-934.
If given, then RFC\-934 compliant user-agents should be able to burst the
message on reception\0--\0providing that the messages being encapsulated
do not contain encapsulated messages themselves.  The drawback of this
approach is that the encapsulations are generated by placing an extra
newline at the end of the body of each message.
.PP
.B "(4) The \*(lqbegin\*(rq directive
is used to create a multipart content.
When using the \*(lqbegin\*(rq directive, you must specify at least one
content between the begin and end pairs.
.PP
.RS 5
.nf
#begin
This will be a multipart with only one part.
#end
.fi
.RE
.PP
If you use multiple directives in a composition draft,
.B mhbuild
will
automatically encapsulate them inside a multipart content.  Therefore the
\*(lqbegin\*(rq directive is only necessary if you wish to use nested
multiparts, or create a multipart message containing only one part.
.PP
For all of these directives, the user may include a brief description
of the content between the \*(lq[\*(rq character and the \*(lq]\*(rq
character.  This description will be copied into the
\*(lqContent-Description\*(rq header when the directive is processed.
.PP
.RS 5
.nf
#forw [important mail from Bob] +bob 1 2 3 4 5
.fi
.RE
.PP
Similarly, a disposition string may optionally be provided between
\*(lq{\*(rq and \*(lq}\*(rq characters; it will be copied into the
\*(lqContent-Disposition\*(rq header when the directive is processed.
If a disposition string is provided that does not contain a filename
parameter, and a filename is provided in the directive, it will be
added to the \*(lqContent-Disposition\*(rq header.  For example, the
following directive:
.PP
.RS 5
.nf
#text/plain; charset=iso-8859-1 <>{attachment} /tmp/summary.txt
.fi
.RE
.PP
creates these message part headers:
.PP
.RS 5
.nf
Content-Type: text/plain; charset="iso-8859-1"
Content-Disposition: attachment; filename="summary.txt"
.fi
.RE
.PP
By default,
.B mhbuild
will generate a unique \*(lqContent-ID:\*(rq for each directive,
corresponding to each message part; however, the user may override
this by defining the ID using the \*(lq<\*(rq and \*(lq>\*(rq
characters.  The
.B \-nocontentid
switch suppresses creation of all \*(lqContent-ID:\*(rq headers,
even in the top level of the message.
.PP
In addition to the various directives, plaintext can be present.
Plaintext is gathered, until a directive is found or the draft is
exhausted, and this is made to form a text content.  If the plaintext
must contain a \*(lq#\*(rq at the beginning of a line, simply double it,
e.g.,
.PP
.RS 5
##when sent, this line will start with only one #
.RE
.PP
If you want to end the plaintext prior to a directive, e.g., to have two
plaintext contents adjacent, simply insert a line containing a single
\*(lq#\*(rq character, e.g.,
.PP
.RS 5
.nf
this is the first content
#
and this is the second
.fi
.RE
.PP
Finally, if the plaintext starts with a line of the form:
.PP
.RS 5
Content-Description: text
.RE
.PP
then this will be used to describe the plaintext content.
You MUST follow this line with a blank line before starting
your text.
.PP
By default, plaintext is captured as a text/plain content.  You can
override this by starting the plaintext with \*(lq#<\*(rq followed by
a content-type specification.  For example, e.g.,
.PP
.RS 5
.nf
#<text/enriched
this content will be tagged as text/enriched
#
and this content will be tagged as text/plain
#
#<application/x-patch [this is a patch]
and this content will be tagged as application/x-patch
.fi
.RE
.PP
Note that if you use the \*(lq#<\*(rq plaintext-form, then the
content-description must be on the same line which identifies the content
type of the plaintext.
.PP
When composing a text content, you may indicate the relevant character
set by adding the \*(lqcharset\*(rq parameter to the directive.
.PP
.RS 5
#<text/plain; charset=iso-8859-5
.RE
.PP
If a text content contains any 8\-bit characters (characters with the
high bit set) and the character set is not specified as above, then
.B mhbuild
will assume the character set is of the type given by the
environment variable MM_CHARSET.  If this environment variable is not
set, then the character set will be labeled as \*(lqx-unknown\*(rq.
.PP
If a text content contains only 7\-bit characters and the character set
is not specified as above, then the character set will be labeled as
\*(lqus-ascii\*(rq.
.PP
Putting this all together,
here is an example of a more complicated message draft.  The
following draft will expand into a multipart/mixed message
containing five parts:
.PP
.RS 5
.nf
To: nobody@nowhere.org
Cc:
Subject: Look and listen to me!
--------
The first part will be text/plain
#<text/enriched
The second part will be text/enriched
#
This third part will be text/plain
#audio/basic [silly giggle]  \\
    |raw2audio -F < /usr/lib/sounds/giggle.au
#image/gif   [photo of foobar] \\
                    /home/foobar/lib/picture.gif
.fi
.RE

.SS "Transfer Encodings"
After
.B mhbuild
constructs the new MIME message by parsing directives,
including files, etc., it scans the contents of the message to determine
which transfer encoding to use.  It will check for 8bit data, long lines,
spaces at the end of lines, and clashes with multipart boundaries.  It will
then choose a transfer encoding appropriate for each content type.
.PP
The switch
.B \-ebcdicsafe
will cause
.B mhbuild
to slightly change
the way in which it performs the \*(lqquoted-printable\*(rq transfer
encoding.  Along with encoding 8\-bit characters, it will now also encode
certain common punctuation characters as well.  This slightly reduces the
readability of the message, but allows the message to pass more reliably
through mail gateways which involve the EBCDIC character encoding.

.SS "Invoking mhbuild"
Typically,
.B mhbuild
is invoked by the
.B send
program.
It expects an
.B mhbuild
composition file, which
.B send
will create, from the draft file, if MIME features are requested.
This is the case with attachment headers.
.PP
In contrast to previous versions, the user does not need to care
for any special actions anymore.

.SS "User Environment"
Because the environment in which
.B mhbuild
operates may vary for a
user,
.B mhbuild
will look for the environment variable
.BR $MHBUILD .
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.
.PP
Finally,
.B mhbuild
will attempt to consult a global
.B mhbuild
user profile, e.g.,
.PP
.RS 5
%etcdir%/mhn.defaults
.RE
.PP
if it exists.

.SS "Syntax of Composition Files"
The following is the formal syntax of a
.B mhbuild
\*(lqcomposition file\*(rq.
.PP
.RS 5
.nf
body         ::=     1*(content | EOL)

content      ::=     directive | plaintext

directive    ::=     "#" type "/" subtype
                         0*(";" attribute "=" value)
                         [ "(" comment ")" ]
                         [ "<" id ">" ]
                         [ "[" description "]" ]
                         [ "{" disposition "}" ]
                         [ filename ]
                         EOL

                   | "#@" type "/" subtype
                         0*(";" attribute "=" value)
                         [ "(" comment ")" ]
                         [ "<" id ">" ]
                         [ "[" description "]" ]
                         [ "{" disposition "}" ]
                         external-parameters
                         EOL

                   | "#forw"
                         [ "<" id ">" ]
                         [ "[" description "]" ]
                         [ "{" disposition "}" ]
                         [ "+"folder ] [ 0*msg ]
                         EOL

                   | "#begin"
                           [ "<" id ">" ]
                           [ "[" description "]" ]
                           [ "{" disposition "}" ]
                           [   "alternative"
                             | "parallel"
                             | something-else    ]
                           EOL
                         1*body
                     "#end" EOL

plaintext    ::=     [ "Content-Description:"
                           description EOL EOL ]
                         1*line
                     [ "#" EOL ]

                   | "#<" type "/" subtype
                         0*(";" attribute "=" value)
                         [ "(" comment ")" ]
                         [ "[" description "]" ]
                         [ "{" disposition "}" ]
                         EOL
                         1*line
                     [ "#" EOL ]

line         ::=     "##" text EOL
                     -- interpreted as "#"text EOL
                   | text EOL
.fi
.RE
.PP

.SH FILES
.fc ^ ~
.nf
.ta \w'%etcdir%/ExtraBigFileName  'u
^$HOME/.mmh/profile~^The user profile
^$MHBUILD~^Additional profile entries
^%etcdir%/mhn.defaults~^System default MIME profile entries
.fi

.SH "PROFILE COMPONENTS"
.fc ^ ~
.nf
.ta 2.4i
.ta \w'ExtraBigProfileName  'u
^Path:~^To determine the user's mail storage
^Current\-Folder:~^To find the default current folder
^mhbuild-compose-<type>*~^Template for composing contents
.fi

.SH "SEE ALSO"
mhlist(1), mhshow(1), mhstore(1),
.br
.I "Proposed Standard for Message Encapsulation"
(RFC\-934),
.br
.I "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies"
(RFC\-2045),
.br
.I "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types"
(RFC\-2046),
.br
.I "Multipurpose Internet Mail Extensions (MIME) Part Three: Message Header Extensions for Non-ASCII Text"
(RFC\-2047),
.br
.I "Multipurpose Internet Mail Extensions (MIME) Part Four: Registration Procedures"
(RFC\-2048),
.br
.I "Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples"
(RFC\-2049)

.SH DEFAULTS
.nf
.RB ` \-headers '
.RB ` \-realsize '
.RB ` \-norfc934mode '
.RB ` \-contentid '
.RB ` \-noebcdicsafe '
.RB ` \-noverbose '
.fi

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