http://tcllib.sourceforge.net/doc/mime.html
package require mime ;# http://purl.org/tcl/home/software/tcllib/
Based upon the Tcl MIME package from Marshall Rose. See http://www.purl.org/NET/akupries/soft/mail/ for the original.
The original has a hard dependency upon Trf. The variant in Tcllib converts that into a soft dependency. In other words, it tries to use Trf to gain performance but will fall back to pure tcl if that package is not present.
LV Anyone have some examples of using this package to parse a mail message in a file? Answer: that's the mission of "Reading messages that might be MIME-encoded".
Andreas Kupries: One issue with performance (splitting a large string at each character created thousands of Tcl_Obj's containing all the same character, gobbling up memory like mad) was solved for Tcl 8.4a3, by Donal Fellows.
Note that this performance improvement was also one of the Changes in Tcl/Tk 8.3.3.
Things to explain: performance issues (large messages: headers, split, buffering); package (including fix-up); examples; exception-(mis)handling; magic arrays; ...
CL has found two principal difficulties in trying to use mime with 8.0 or early 8.1: the "format %c ..." change (explain) and the incompatibility in interpretation of "\n" vs. {\n} to regsub (explain).
One of the difficulties in explaining mime is its flexibility. It can do many, many things, and it's hard to know where to begin explaining it. In a case like this, I like a few examples--feel free to think of them as a cookbook of recipes for starting points. How, for instance, can you use Tcl to automate emission of a message which includes an attachment? This [L1 ] shows how.
One definite fault of 0.8 is that it only reports some of the filenames of attachments it detects (explain Content-Disposition alternative). CL has code that repairs this, but has yet to check it in.
The distribution documentation deserves many more examples. Until CL makes the time to update it, we'll keep several of them here. Notice that individual mail items might well have originated as return values from the pop3 package.
package require mime
set item {From [email protected] Tue May 29 11:49:26 EDT 2001
Date: Tue, 29 May 2001 11:03:02 -0500
From: Cameron Laird <[email protected]>
To: [email protected],[email protected]
Subject: some subject
Message-ID: <[email protected]>
This is only a test.}
# A production version deserves exception-handling.
set token [mime::initialize -string $item]
puts "The subject is '[mime::getheader $token Subject]'."Address parsing is an area where many, MANY square wheels have been reinvented, in part because RFC 822 (and updates ... ) are so poorly understood. Here's an example of a correct usage:
# Take $item from above.
set token [mime::initialize -string $item]
set to [mime::getheader $token To]
puts "The (unparsed) recipients are '$to'."
set parsed [mime::parseaddress $to]
foreach element $parsed {
array set array $element
puts "One deliverable address is $array(address)."
} This prints
The (unparsed) recipients are '[email protected],[email protected]'. One deliverable address is [email protected]. One deliverable address is [email protected].
Here is an example and functional script for use by anybody [L2 ]. It is an SMTP email authenticator. It turns out that to authenticate a user in SMTP requires MIME format. The script will display a gui asking for the username, password, and server (port will always be 25, unless the programmer changes that or modifies the script for their own use). After receiving this information (and pressing the "Ok" button or <Return>) the script attempts to authenticate the user. Jeff Gosnell
Background information on MIME is available [L3 ].
RFC822 items can be big, and correspondingly expensive to manipulate. tcllib's mime package parses any presented item completely. What if one only wants, say, the "Subject:" of the item, while needing performance? In principle, there ought to be a "lazy" evaluation that intelligently scans the few header lines necessary to determine this value.
A comp.lang.tcl thread ?? discusses this. One highlight is that Don Libes's "mail notification tools (i.e., biff)" page on tkbiff points to code which directly models such a requirement.
Category Package, subset tcllib