The README file M.T. Rose
Dover Beach Consulting, Inc.
February 22, 2000
Tcl MIME
Abstract
Tcl MIME generates and parses MIME body parts.
Table of Contents
1. SYNOPSIS . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Copyrights . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. SYNTAX . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. SEMANTICS . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 mime::initialize . . . . . . . . . . . . . . . . . . . . . . 5
3.2 mime::finalize . . . . . . . . . . . . . . . . . . . . . . . 5
3.3 mime::getproperty . . . . . . . . . . . . . . . . . . . . . 5
3.4 mime::getheader . . . . . . . . . . . . . . . . . . . . . . 6
3.5 mime::setheader . . . . . . . . . . . . . . . . . . . . . . 6
3.6 mime::getbody . . . . . . . . . . . . . . . . . . . . . . . 6
3.7 mime::copymessage . . . . . . . . . . . . . . . . . . . . . 7
3.8 mime::buildmessage . . . . . . . . . . . . . . . . . . . . . 7
3.9 smtp::sendmessage . . . . . . . . . . . . . . . . . . . . . 7
3.10 mime::parseaddress . . . . . . . . . . . . . . . . . . . . . 8
3.11 mime::parsedatetime . . . . . . . . . . . . . . . . . . . . 9
3.12 mime::mapencoding . . . . . . . . . . . . . . . . . . . . . 9
3.13 mime::reversemapencoding . . . . . . . . . . . . . . . . . . 9
4. EXAMPLES . . . . . . . . . . . . . . . . . . . . . . . . . . 10
References . . . . . . . . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . 12
A. TODO List . . . . . . . . . . . . . . . . . . . . . . . . . 13
B. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
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README Tcl MIME February 2000
1. SYNOPSIS
package provide mime 1.2
package provide smtp 1.2
Tcl MIME is an implementation of a Tcl package that generates and
parses MIME[1] body parts.
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.
MIME defines four keys that may appear in the headers:
Content-Type: describes the data contained in the body ("the
content");
Content-Transfer-Encoding: describes how the content is encoded
for transmission in an ASCII stream;
Content-Description: a textual description of the content; and,
Content-ID: a globally-unique identifier for the content.
Consult [2] for a list of standard content types. Further, consult
[3] for a list of several other header keys (e.g., "To", "cc", etc.)
A simple example might be:
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.
In addition to an implementation of the mime package, Tcl MIME
includes an implementation of the smtp package.
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1.1 Requirements
This package requires:
o Tcl/Tk version 8.0.3[4] or later
In addition, this package requires one of the following:
o Trf version 2.0p5[5] or later
o base64 version 2.0 or later (included with tcllib)
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.
1.2 Copyrights
(c) 1999-2000 Marshall T. Rose
Hold harmless the author, and any lawful use is allowed.
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2. SYNTAX
mime::initialize (Section 3.1) returns a token. Parameters:
?-canonical type/subtype
?-param {key value}?...
?-encoding value?
?-header {key value}?... ?
(-file name | -string value | -parts {token1 ... tokenN})
mime::finalize (Section 3.2) returns an empty string. Parameters:
token ?-subordinates "all" | "dynamic" | "none"?
mime::getproperty (Section 3.3) returns a string or a list of
strings. Parameters:
token ?property | -names?
mime::getheader (Section 3.4) returns a list of strings. Parameters:
token ?key | -names?
mime::setheader (Section 3.5) returns a list of strings. Parameters:
token key value ?-mode "write" | "append" | "delete"?
mime::getbody (Section 3.6) returns a string. Parameters:
?-command callback ?-blocksize octets? ?
mime::copymessage (Section 3.7) returns an empty string. Parameters:
token channel
mime::buildmessage (Section 3.7) returns a string. Parameters:
token
smtp::sendmessage (Section 3.8) returns a list. Parameters:
token ?-servers list? ?-ports list?
?-queue boolean? ?-atleastone boolean?
?-originator string? ?-recipients string?
?-header {key value}?...
mime::parseaddress (Section 3.9) returns a list of serialized
arrays. Parameters:
string
mime::parsedatetime (Section 3.10) returns a string. Parameters:
[string | -now] property
mime::mapencoding (Section 3.10) returns a string. Parameters:
encoding_name
mime::reversemapencoding (Section 3.10) returns a string. Parameters:
charset_type
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3. SEMANTICS
3.1 mime::initialize
mime::initialize creates a MIME part:
o 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.
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.
Also, -encoding, if present, specifies the
"Content-Transfer-Encoding" when copying the body.
o 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.
3.2 mime::finalize
mime::finalize destroys a MIME part.
If the -subordinates option is present, it specifies which
subordinates should also be destroyed. The default value is
"dynamic".
3.3 mime::getproperty
mime::getproperty returns the properties of a MIME part.
The properties are:
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)
The "parts" property is present only if the MIME part has
subordinates.
If mime::getproperty is invoked with the name of a specific
property, then the corresponding value is returned; instead, if
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-names is specified, a list of all properties is returned;
otherwise, a serialized array of properties and values is returned.
3.4 mime::getheader
mime::getheader returns the header of a MIME part.
A header consists of zero or more key/value pairs. Each value is a
list containing one or more strings.
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.
3.5 mime::setheader
mime::setheader writes, appends to, or deletes the value associated
with a key in the header.
The value for -mode is one of:
write: the key/value is either created or overwritten (the
default);
append: a new value is appended for the key (creating it as
necessary); or,
delete: all values associated with the key are removed (the
"value" parameter is ignored).
Regardless, mime::setheader returns the previous value associated
with the key.
3.6 mime::getbody
mime::getbody returns the body of a leaf MIME part in canonical form.
If the -command option is present, then it is repeatedly invoked
with a fragment of the body as this:
uplevel #0 $callback [list "data" $fragment]
(The -blocksize option, if present, specifies the maximum size of
each fragment passed to the callback.)
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When the end of the body is reached, the callback is invoked as:
uplevel #0 $callback "end"
Alternatively, if an error occurs, the callback is invoked as:
uplevel #0 $callback [list "error" reason]
Regardless, the return value of the final invocation of the callback
is propagated upwards by mime::getbody.
If the -command option is absent, then the return value of
mime::getbody is a string containing the MIME part's entire body.
3.7 mime::copymessage
mime::copymessage copies the MIME part to the specified channel.
mime::copymessage operates synchronously, and uses fileevent to
allow asynchronous operations to proceed independently.
3.7 mime::buildmessage
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.
3.8 smtp::sendmessage
smtp::sendmessage sends a MIME part to an SMTP server. (Note that
this procedure is in the "smtp" package, not the "mime" package.)
The options are:
-servers: a list of SMTP servers (the default is "localhost");
-ports: a list of SMTP ports (the default is 25)
-queue: indicates that the SMTP server should be asked to queue
the message for later processing;
-atleastone: indicates that the SMTP server must find at least
one recipient acceptable for the message to be sent;
-originator: a string containing an 822-style address
specification (if present the header isn't examined for an
originator address);
-recipients: a string containing one or more 822-style address
specifications (if present the header isn't examined for
recipient addresses); and,
-header: a keyword/value pairing (may occur zero or more times).
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",
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"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.
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.
3.9 mime::parseaddress
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.
Each serialized array contains these properties:
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)
Note that one or more of these properties may be empty.
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3.10 mime::parsedatetime
mime::parsedatetime takes a string containing an 822-style date-time
specification and returns the specified property.
The list of properties and their ranges are:
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)
3.10 mime::mapencoding
mime::mapencodings 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.
3.10 mime::reversemapencoding
mime::reversemapencoding maps MIME charset types onto tcl encoding names.
Those that are unknown return "".
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4. EXAMPLES
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]]
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# 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
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References
[1] Freed, N. and N.S. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message Bodies",
RFC 2045, November 1996.
[2] Freed, N. and N.S. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, November
1995.
[3] Crocker, D., "Standard for the format of ARPA Internet Text
Messages", RFC 822, STD 11, August 1982.
[4] http://www.scriptics.com/software/8.1.html
[5] http://www.oche.de/~akupries/soft/trf/
[6] mailto:dnew@messagemedia.com
[7] mailto:a.kupries@westend.com
Author's Address
Marshall T. Rose
Dover Beach Consulting, Inc.
POB 255268
Sacramento, CA 95865-5268
US
Phone: +1 916 483 8878
Fax: +1 916 483 8848
EMail: mrose@dbc.mtview.ca.us
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Appendix A. TODO List
mime::initialize
* well-defined errorCode values
* catch nested errors when processing a multipart
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Appendix B. Acknowledgements
This package is influenced by the safe-tcl package (Borenstein and
Rose, circa 1993), and also by Darren New[6]'s unpublished package
of 1999.
This package makes use of Andreas Kupries[7]'s excellent Trf package.
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