Abstract

Tcl MIME generates and parses MIME body parts.

Table of Contents

1.  SYNOPSIS
1.1  Requirements
1.2  Copyrights
2.  SYNTAX
3.  SEMANTICS
3.1  mime::initialize
3.2  mime::finalize
3.3  mime::getproperty
3.4  mime::getheader
3.5  mime::setheader
3.6  mime::getbody
3.7  mime::copymessage
3.7  mime::buildmessage
3.8  smtp::sendmessage
3.9  mime::parseaddress
3.10  mime::parsedatetime
3.10  mime::mapencoding
3.10  mime::reversemapencoding
4.  EXAMPLES
§  References
§  Author's Address
A.  TODO List
B.  Acknowledgements

1. SYNOPSIS

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:

In addition to an implementation of the mime package, Tcl MIME includes an implementation of the smtp package.

1.1 Requirements

This package requires:

• Tcl/Tk version 8.0.3 or later

In addition, this package requires one of the following:

• Trf version 2.0p5 or later
• base 64 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.

2. SYNTAX

mime::initialize returns a token. Parameters:

mime::finalize returns an empty string. Parameters:

mime::getproperty returns a string or a list of strings. Parameters:

mime::getheader returns a list of strings. Parameters:

mime::setheader returns a list of strings. Parameters:

mime::getbody returns a string. Parameters:

mime::copymessage returns an empty string. Parameters:

mime::buildmessage returns a string. Parameters:

smtp::sendmessage returns a list. Parameters:

mime::parseaddress returns a list of serialized arrays. Parameters:

mime::parsedatetime returns a string. Parameters:

mime::mapencoding returns a string. Parameters:

mime::reversemapencoding returns a string. Parameters:

3. SEMANTICS

3.1 mime::initialize

mime::initialize creates a MIME part:

• 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.
• 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:

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 -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:

(The -blocksize option, if present, specifies the maximum size of each fragment passed to the callback.)

When the end of the body is reached, the callback is invoked as:

Alternatively, if an error occurs, the callback is invoked as:

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", "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:

Note that one or more of these properties may be empty.

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:

3.10 mime::mapencoding

mime::mapencoding takes a string containing the name of a tcl encoding (see [encoding names]) and returns the MIME charset name for that encoding (or "" if the charset name is unknown).

3.10 mime::reversemapencoding

mime::reversemapencoding takes a string containing the name of a MIME charset tcl encoding (see [encoding names]) and returns the MIME charset name for that encoding (or "" if no known tcl encoding maps to the mime charset type).

4. EXAMPLES

References

Author's Address

Appendix A. TODO List

mime::initialize

• well-defined errorCode values
• catch nested errors when processing a multipart

Appendix B. Acknowledgements

This package is influenced by the safe-tcl package (Borenstein and Rose, circa 1993), and also by Darren New's unpublished package of 1999.

This package makes use of Andreas Kupries's excellent Trf package.