<?xml version="1.0"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd">

<?rfc compact="no"?>
<?rfc toc="yes"?>
<?rfc private="The README file"?>
<?rfc header="README"?>

<rfc>
<front>
<title>Tcl MIME</title>

<author initials="M.T." surname="Rose" fullname="Marshall T. Rose">
<organization>Dover Beach Consulting, Inc.</organization>
<address>
<postal>
<street>POB 255268</street>
<city>Sacramento</city> <region>CA</region> <code>95865-5268</code>
<country>US</country>
</postal>
<phone>+1 916 483 8878</phone>
<facsimile>+1 916 483 8848</facsimile>
<email>mrose@dbc.mtview.ca.us</email>
</address>
</author>

<date month="February" year="2000" />

<abstract><t>Tcl MIME generates and parses MIME body parts.</t></abstract>
</front>

<middle>

<section title="SYNOPSIS">
<figure><artwork><![CDATA[
    package provide mime 1.2
    package provide smtp 1.2
]]></artwork></figure>

<t>Tcl MIME is an implementation of a Tcl package that generates and
parses <xref target="RFC2045">MIME</xref> body parts.</t>

<t>Each MIME part consists of a header
(zero or more key/value pairs),
an empty line,
and a structured body.
A MIME part is either a "leaf" or has (zero or more) subordinates.</t>

<t>MIME defines four keys that may appear in the headers:
<list style="hanging">
<t hangText="   Content-Type:">describes the data contained in the body
("the content");</t>

<t hangText="   Content-Transfer-Encoding:">describes how the content is
encoded for transmission in an ASCII stream;</t>

<t hangText="   Content-Description:">a textual description of the
content; and,</t>

<t hangText="   Content-ID:">a globally-unique identifier for the
content.</t>
</list></t>

<t>Consult <xref target="RFC2046" /> for a list of standard content types.
Further,
consult <xref target="RFC822" /> for a list of several other header keys
(e.g., "To", "cc", etc.)</t>

<figure>
<preamble>A simple example might be:</preamble>
<artwork><![CDATA[
    Date: Sun, 04 July 1999 10:38:25 -0600
    From: Marshall Rose <mrose@dbc.mtview.ca.us>
    To: Andreas Kupries <a.kupries@westend.com>
    cc: dnew@messagemedia.com (Darren New)
    MIME-Version: 1.0
    Content-Type: text/plain; charset="us-ascii"
    Content-Description: a simple example
    Content-ID: <4294407315.931384918.1@dbc.mtview.ca.us>

    Here is the body. In this case, simply plain text.
]]></artwork>
</figure>

<t>In addition to an implementation of the mime package,
Tcl MIME includes an implementation of the smtp package.</t>

<vspace blankLines="1000" />

<section title="Requirements">
<t>This package requires:
<list style="symbols">
<t><eref target="http://www.scriptics.com/software/8.1.html">Tcl/Tk version 8.0.3</eref>
</list>
or later</t>
<t>In addition, this package requires one of the following:</t>
<list style="symbols">
<t><eref target="http://www.oche.de/~akupries/soft/trf/">Trf version 2.0p5</eref>
or later</t>
<t><eref target="http://dev.ajubasolutions.com/software/tcllib/">base 64 version 2.0</eref> or later (included with tcllib)</t>
</list></t>
<t>If it is available, Trf will be used to provide better performance;
if not, Tcl-only equivalent functions, based on the base64 package,
are used.</t>
</section>

<section title="Copyrights">
<t>(c) 1999-2000 Marshall T. Rose</t>

<t>Hold harmless the author, and any lawful use is allowed.</t>
</section>
</section>

<section title="SYNTAX">
<figure>
<preamble><xref target="mime_initialize">mime::initialize</xref>
returns a token.
Parameters:</preamble>
<artwork><![CDATA[    ?-canonical type/subtype
        ?-param    {key value}?...
        ?-encoding value?
        ?-header   {key value}?... ?
    (-file name | -string value | -parts {token1 ... tokenN})
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_finalize">mime::finalize</xref> returns
an empty string.
Parameters:</preamble>
<artwork><![CDATA[    token ?-subordinates "all" | "dynamic" | "none"?
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_getproperty">mime::getproperty</xref>
returns a string or a list of strings.
Parameters:</preamble>
<artwork><![CDATA[    token ?property | -names?
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_getheader">mime::getheader</xref> returns
a list of strings.
Parameters:</preamble>
<artwork><![CDATA[    token ?key | -names?
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_setheader">mime::setheader</xref> returns
a list of strings.
Parameters:</preamble>
<artwork><![CDATA[    token key value ?-mode "write" | "append" | "delete"?
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_getbody">mime::getbody</xref> returns a string.
Parameters:</preamble>
<artwork><![CDATA[    ?-command callback ?-blocksize octets? ?
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_copymessage">mime::copymessage</xref>
returns an empty string.
Parameters:</preamble>
<artwork><![CDATA[    token channel
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_buildmessage">mime::buildmessage</xref>
returns an empty string.
Parameters:</preamble>
<artwork><![CDATA[    token
]]></artwork>
</figure>

<figure>
<preamble><xref target="smtp_sendmessage">smtp::sendmessage</xref>
returns a list.
Parameters:</preamble>
<artwork><![CDATA[    token ?-servers list? ?-ports list?
          ?-queue boolean?     ?-atleastone boolean?
          ?-originator string? ?-recipients string?
          ?-header {key value}?...
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_parseaddress">mime::parseaddress</xref>
returns a list of serialized arrays.
Parameters:</preamble>
<artwork><![CDATA[    string
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_parsedatetime">mime::parsedatetime</xref>
returns a string.
Parameters:</preamble>
<artwork><![CDATA[    [string | -now] property
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_mapencoding">mime::mapencoding</xref>
returns a string.
Parameters:</preamble>
<artwork><![CDATA[    encoding_name
]]></artwork>
</figure>

<figure>
<preamble><xref target="mime_reversemapencoding">mime::reversemapencoding</xref>
returns a string.
Parameters:</preamble>
<artwork><![CDATA[    content_type
]]></artwork>
</figure>

</section>

<section title="SEMANTICS">

<section anchor="mime_initialize" title="mime::initialize">
<t>mime::initialize creates a MIME part:
<list style="symbols">
<t>If the -canonical option is present,
then the body is in canonical (raw) form and is found by consulting
either the -file, -string, or -part option.
<vspace blankLines="1" />
In addition,
both the -param and -header options may occur zero or more times to
specify "Content-Type" parameters (e.g., "charset")
and header keyword/values (e.g., "Content-Disposition"),
respectively.
<vspace blankLines="1" />
Also, -encoding, if present,
specifies the "Content-Transfer-Encoding" when copying the body.</t>

<t>If the -canonical option is not present,
then the MIME part contained in either the -file or the -string option
is parsed,
dynamically generating subordinates as appropriate.</t>
</list></t>
</section>

<section anchor="mime_finalize" title="mime::finalize">
<t>mime::finalize destroys a MIME part.</t>

<t>If the -subordinates option is present,
it specifies which subordinates should also be destroyed.
The default value is "dynamic".</t>
</section>

<section anchor="mime_getproperty" title="mime::getproperty">
<t>mime::getproperty returns the properties of a MIME part.</t>

<figure>
<preamble>The properties are:</preamble>
<artwork><![CDATA[
    property    value
    ========    =====
    content     the type/subtype describing the content
    encoding    the "Content-Transfer-Encoding"
    params      a list of "Content-Type" parameters
    parts       a list of tokens for the part's subordinates
    size        the approximate size of the content (unencoded)
]]></artwork>
<postamble>The "parts" property is present only if the MIME part has
subordinates.</postamble>
</figure>

<t>If mime::getproperty is invoked with the name of a specific property,
then the corresponding value is returned;
instead,
if -names is specified,
a list of all properties is returned;
otherwise,
a serialized array of properties and values is returned.</t>
</section>

<section anchor="mime_getheader" title="mime::getheader">
<t>mime::getheader returns the header of a MIME part.</t>

<t>A header consists of zero or more key/value pairs.
Each value is a list containing one or more strings.</t>

<t>If mime::getheader is invoked with the name of a specific key,
then a list containing the corresponding value(s) is returned;
instead,
if -names is specified,
a list of all keys is returned;
otherwise,
a serialized array of keys and values is returned.
Note that when a key is specified (e.g., "Subject"),
the list returned usually contains exactly one string;
however,
some keys (e.g., "Received") often occur more than once in the header,
accordingly the list returned usually contains more than one string.</t>
</section>

<section anchor="mime_setheader" title="mime::setheader">
<t>mime::setheader writes, appends to, or deletes the value associated
with a key in the header.</t>

<t>The value for -mode is one of:
<list style="hanging">
<t hangText="   write:"> the key/value is either created or
overwritten (the default);</t>

<t hangText="   append:"> a new value is appended for the key
(creating it as necessary); or,</t>

<t hangText="   delete:"> all values associated with the key are removed
(the "value" parameter is ignored).</t>
</list></t>

<t>Regardless,
mime::setheader returns the previous value associated with the key.</t>
</section>

<section anchor="mime_getbody" title="mime::getbody">
<t>mime::getbody returns the body of a leaf MIME part in canonical form.</t>

<figure>
<preamble>If the -command option is present,
then it is repeatedly invoked with a fragment of the body as this:</preamble>
<artwork><![CDATA[
    uplevel #0 $callback [list "data" $fragment]
]]></artwork>
<postamble>(The -blocksize option,
if present,
specifies the maximum size of each fragment passed to the
callback.)</postamble>
</figure>

<figure>
<preamble>When the end of the body is reached,
the callback is invoked as:</preamble>
<artwork><![CDATA[
    uplevel #0 $callback "end"
]]></artwork>
</figure>

<figure>
<preamble>Alternatively,
if an error occurs,
the callback is invoked as:</preamble>
<artwork><![CDATA[
    uplevel #0 $callback [list "error" reason]
]]></artwork>
</figure>

<t>Regardless,
the return value of the final invocation of the callback is propagated
upwards by mime::getbody.</t>

<t>If the -command option is absent,
then the return value of mime::getbody is a string containing the MIME
part's entire body.</t>
</section>

<section anchor="mime_copymessage" title="mime::copymessage">
<t>mime::copymessage copies the MIME part to the specified channel.</t>

<t>mime::copymessage operates synchronously,
and uses fileevent to allow asynchronous operations to proceed
independently.</t>
</section>

<section anchor="mime_buildmessage" title="mime::buildmessage">
<t>mime::buildmessage returns the MIME part as a string.  It is similar
to mime::copymessage, only it returns the data as a return string
instead of writing to a channel.</t>
</section>

<section anchor="smtp_sendmessage" title="smtp::sendmessage">
<t>smtp::sendmessage sends a MIME part to an SMTP server.
(Note that this procedure is in the "smtp" package,
not the "mime" package.)</t>

<t>The options are:
<list style="hanging">
<t hangText="   -servers:">a list of SMTP servers
(the default is "localhost");</t>

<t hangText="   -ports:">a list of SMTP ports
(the default is 25);</t>

<t hangText="   -queue:">indicates that the SMTP server should be
asked to queue the message for later processing;</t>

<t hangText="   -atleastone:">indicates that the SMTP server must find
at least one recipient acceptable for the message to be sent;</t>

<t hangText="   -originator:">a string containing an 822-style address
specification
(if present the header isn't examined for an originator address);</t>

<t hangText="   -recipients:">a string containing one or more 822-style
address specifications
(if present the header isn't examined for recipient addresses); and,</t>

<t hangText="   -header:">a keyword/value pairing
(may occur zero or more times).</t>
</list></t>

<t>If the -originator option is not present,
the originator address is taken from "From" (or "Resent-From");
similarly,
if the -recipients option is not present,
recipient addresses are taken from "To", "cc", and "Bcc" (or
"Resent-To", and so on).
Note that the header key/values supplied by the "-header" option
(not those present in the MIME part)
are consulted.
Regardless,
header key/values are added to the outgoing message as necessary to
ensure that a valid 822-style message is sent.</t>

<t>smtp::sendmessage returns a list indicating which recipients were
unacceptable to the SMTP server.
Each element of the list is another list,
containing the address, an SMTP error code, and a textual diagnostic.
Depending on the -atleastone option and the intended recipients,,
a non-empty list may still indicate that the message was accepted by
the server.</t>
</section>

<section anchor="mime_parseaddress" title="mime::parseaddress">
<t>mime::parseaddr takes a string containing one or more 822-style
address specifications and returns a list of serialized arrays,
one element for each address specified in the argument.</t>

<figure>
<preamble>Each serialized array contains these properties:</preamble>
<artwork><![CDATA[
    property    value
    ========    =====
    address     local@domain
    comment     822-style comment
    domain      the domain part (rhs)
    error       non-empty on a parse error
    group       this address begins a group
    friendly    user-friendly rendering
    local       the local part (lhs)
    memberP     this address belongs to a group
    phrase      the phrase part
    proper      822-style address specification
    route       822-style route specification (obsolete)
]]></artwork>
<postamble>Note that one or more of these properties may be empty.</postamble>
</figure>
</section>

<vspace blankLines="10000" />

<section anchor="mime_parsedatetime" title="mime::parsedatetime">
<t>mime::parsedatetime takes a string containing an 822-style
date-time specification and returns the specified property.</t>

<figure>
<preamble>The list of properties and their ranges are:</preamble>
<artwork><![CDATA[
    property     range
    ========     =====
    hour         0 .. 23
    lmonth       January, February, ..., December
    lweekday     Sunday, Monday, ... Saturday
    mday         1 .. 31
    min          0 .. 59
    mon          1 .. 12
    month        Jan, Feb, ..., Dec
    proper       822-style date-time specification
    rclock       elapsed seconds between then and now
    sec          0 .. 59
    wday         0 .. 6 (Sun .. Mon)
    weekday      Sun, Mon, ..., Sat
    yday         1 .. 366
    year         1900 ...
    zone         -720 .. 720 (minutes east of GMT)
]]></artwork>
</figure>
</section>

<section anchor="mime_mapencoding" title="mime::mapencoding">
<t>mime::mapencoding maps tcl encodings onto the proper names for their
MIME charset type.  This is only done for encodings whose charset types
were known.  The remaining encodings return "" for now.</t>
</section>

<section anchor="mime_reversemapencoding" title="mime::reversemapencoding">
<t>mime::reversemapencoding maps MIME charset types onto tcl encoding names.
Those that are unknown return "".</t>
</section>

</section>

<section title="EXAMPLES">
<figure>
<artwork><![CDATA[
package require mime 1.0
package require smtp 1.0


# create an image

set imageT [mime::initialize -canonical image/gif \
                             -file logo.gif]


# parse a message

set messageT [mime::initialize -file example.msg]


# recursively traverse a message looking for primary recipients

proc traverse {token} {
    set result ""

# depth-first search
    if {![catch { mime::getproperty $token parts } parts]} {
        foreach part $parts {
            set result [concat $result [traverse $part]]
        }
    }

# one value for each line occuring in the header
    foreach value [mime::getheader $token To] {
        foreach addr [mime::parseaddress $value] {
            catch { unset aprops }
            array set aprops $addr
            lappend result $aprops(address)
        }
    }

    return $result
}


# create a multipart containing both, and a timestamp

set multiT [mime::initialize -canonical multipart/mixed
                             -parts [list $imageT $messageT]]




# send it to some friends

smtp::sendmessage $multiT \
      -header [list From "Marshall Rose <mrose@dbc.mtview.ca.us>"] \
      -header [list To "Andreas Kupries <a.kupries@westend.com>"] \
      -header [list cc "dnew@messagemedia.com (Darren New)"] \
      -header [list Subject "test message..."]


# clean everything up

mime::finalize $multiT -subordinates all
]]></artwork>
</figure>
</section>

</middle>

<back>
<references>
<reference anchor="RFC2045">
<front>
<title>Multipurpose Internet Mail Extensions (MIME)
Part One: Format of Internet Message Bodies</title>
<author initials="N." surname="Freed" fullname="Ned Freed">
<organization>Innosoft International, Inc.</organization>
<address>
<email>ned@innosoft.com</email>
</address>
</author>
<author initials="N.S." surname="Borenstein"
        fullname="Nathaniel S. Borenstein">
<organization>First Virtual Holdings, Incorporated</organization>
<address>
<email>nsb@messagemedia.com</email>
</address>
</author>
<date month="November" year="1996"/>
</front>
<seriesInfo name="RFC" value="2045" />
</reference>

<reference anchor="RFC2046">
<front>
<title>Multipurpose Internet Mail Extensions (MIME)
Part Two: Media Types</title>
<author initials="N." surname="Freed" fullname="Ned Freed">
<organization>Innosoft International, Inc.</organization>
<address>
<email>ned@innosoft.com</email>
</address>
</author>
<author initials="N.S." surname="Borenstein"
        fullname="Nathaniel S. Borenstein">
<organization>First Virtual Holdings, Incorporated</organization>
<address>
<email>nsb@messagemedia.com</email>
</address>
</author>
<date month="November" year="1995"/>
</front>
<seriesInfo name="RFC" value="2046" />
</reference>

<reference anchor="RFC822">
<front>
<title>Standard for the format of ARPA Internet Text Messages</title>
<author initials="D." surname="Crocker" fullname="Dave Crocker">
<organization abbrev="UDEL">University of Delaware</organization>
<address>
<email>DCrocker@UDel-Relay</email>
</address>
</author>
<date month="August" year="1982"/>
</front>
<seriesInfo name="RFC" value="822" />
<seriesInfo name="STD" value="11" />
</reference>

</references>

<section title="TODO List">
<t><list style="hanging">
<t hangText="mime::initialize">
<list style="symbols">
<t>well-defined errorCode values</t>

<t>catch nested errors when processing a multipart</t>
</list></t>

</list></t>
</section>

<section title="Acknowledgements">
<t>This package is influenced by the safe-tcl package
(Borenstein and Rose, circa 1993),
and also by <eref target="mailto:dnew@messagemedia.com">Darren New</eref>'s
unpublished package of 1999.</t>

<t>This package makes use of
<eref target="mailto:a.kupries@westend.com">Andreas Kupries</eref>'s
excellent Trf package.</t>
</section>

</back>
</rfc>