NAME
cm_perl -- A Perl Plugin for Claws Mail
DESCRIPTION
This plugin provides an extended filtering engine for the email client
Claws Mail. It allows for the use of full Perl power in email filters.
QUICK START
To get started, you can use the matcherrc2perlfilter.pl script in the
tools-directory to translate your old filtering rules to Perl. Simply
execute the script and follow the instructions. (note that with recent
versions of Claws Mail, this script might not work due to upstream
syntax changes. This will get updated in the future. Send me an email
if you have problems getting started).
However, you might want to consider reading the rest of this manual and
rewriting your rules if you choose to use the plugin, since the Perl
code produced by this script is not exactly pretty.
Don’t speak Perl? No problem, "perldoc perlintro" should give you
enough information to do fancy stuff.
USAGE
The Perl plugin expects a Perl script file called perl_filter in Claws
Mail’ config directory (usually $HOME/.claws-mail -- try ‘claws-mail
--config-dir’ if you’re unsure). If that file doesn’t exist on plugin
start, an empty one is created. This file, which doesn’t need to start
with a sha-bang (!#/bin/perl), holds the Perl instructions for your
email filters. To encourage some good manners, the code is executed in
a "use strict;" environment.
Both Claws Mail’ filtering conditions and actions are mapped to Perl
functions with corresponding names, wherever this is possible.
FUNCTION LISTING
For a detailed function description, see section "FUNCTION
DESCRIPTIONS", below.
Standard Filtering Conditions
all, marked, unread, deleted, new, replied,
forwarded, locked, ignore_thread, colorlabel,
match, matchcase, regexp, S<regexpcase, test,
size_greater, size_smaller, size_equal,
score_greater, score_lower, score_equal, age_greater,
age_lower, partial
Standard Filtering Actions
mark, unmark, dele, mark_as_unread, mark_as_read,
lock, unlock, move, copy, color, execute,
hide, set_score, change_score, stop, forward,
forward_as_attachment, redirect
Fun stuff
header, body, filepath, extract_addresses,
move_to_trash, abort, addr_in_addressbook,
from_in_addressbook, get_attribute_value, SA_is_spam,
exit, manual, make_sure_folder_exists,
filter_log, filter_log_verbosity
FUNCTION DESCRIPTIONS
In general, after the filtering invoked by the Perl script, the mail is
passed on to Claws’ internal filtering engine, unless a final rule was
hit. Final rules stop not only the Perl filtering script at the point
of their occurence, but also prevent processing that email by Claws’
internal filtering engine (this might sound confusing, but you are
already familiar with that concept from standard filters: After an
email was e.g. moved, the following rules don’t apply anymore).
Also, be careful with the way you quote. In particular, remember that
the @-sign has a special meaning in Perl, and gets interpolated inside
double quotes. See "Quote and Quote-like Operators" in perlop to learn
more about quoting and interpolation.
Standard Filtering Conditions
all Returns a true value. Available for completness only.
marked Returns a true value if the marked flag is set, false
otherwise.
unread Returns a true value if the unread flag is set, false
otherwise.
deleted Returns a true value if the deleted flag is set, false
otherwise.
new Returns a true value if the new flag is set, false otherwise.
replied Returns a true value if the replied flag is set, false
otherwise.
forwarded
Returns a true value if the forwarded flag is set, false
otherwise.
locked Returns a true value if the locked flag is set, false
otherwise.
ignore_thread
Returns a true value if the "Ignore Thread" flag is set, false
otherwise.
colorlabel COLOR
colorlabel
Returns a true value if message has the color COLOR. COLOR can
be either a numeric value between 0 and 7 (with colors
corresponding to the internal filtering engine), or the english
color name as it is introduced in the filtering dialog (that
is, one of: none, orange, red, pink, sky blue, blue, green or
brown, while upper and lower case letters make no difference).
If COLOR is omitted, 0 (none) is assumed.
size_greater SIZE
Returns a true value if message size is greater than SIZE,
false otherwise.
size_smaller SIZE
Returns a true value if message size is smaller than SIZE,
false otherwise.
size_equal SIZE
Returns a true value if message size is equal to SIZE, false
otherwise.
score_greater SCORE
Returns a true value if message score is greater than SCORE,
false otherwise.
score_lower SCORE
Returns a true value if message score is lower than SCORE,
false otherwise.
score_equal SCORE
Returns a true value if message score is equal to SCORE, false
otherwise.
age_greater AGE
Returns a true value if message age is greater than AGE, false
otherwise.
age_lower AGE
Returns a true value if message age is lower than AGE, false
otherwise.
partial Returns a true value if message has only partially been
downloaded, false otherwise.
test Corresponds the ’test’ internal filtering rule. In particular,
it accepts the same symbols, namely:
%% %
%s Subject
%f From
%t To
%c Cc
%d Date
%i Message-ID
%n Newsgroups
%r References
%F Filename -- should not be modified
match WHERE WHAT
matchcase WHERE WHAT
regexp WHERE WHAT
regexpcase WHERE WHAT
The matching functions have a special syntax. The first
argument is either any of to_or_cc, body_part, headers_part,
message, to, from, subject, cc, newsgroups, inreplyto or
references (those strings may or may not be quoted), the patter
matching works on that area. If it is any other string (which
must then be quoted), this string is taken to be the name of a
header field.
The second argument is the string to look for. For match,
matchcase, regexp and regexpcase we have case sensitive normal
matching, case insensitive normal matching, case sensitive
regular expression matching and case insensitive regular
expression pattern matching, respectively.
The functions return true if the pattern was found, false
otherwise.
Just as with the built-in filtering engine, the message body is
searched and provided as is - no character-set analysis is
done. Likewise, no HTML-tags are stripped. It should be
possible to use external modules or programs for these tasks
though. If you’re doing that, drop me a message with your
experiences.
With Perl having its strenghts in pattern matching, using
Perl’s builtin operators are usually a better option than using
these functions.
Standard Filtering Actions
The actions return a true value upon success, and ’undef’ when an error
occured. Final message rules are indicated. (See above for a sketch
what a final rule is)
mark Mark the message.
unmark Unmark the message.
dele Delete the message. Note the name change of Claws Mail’
"delete" to "dele". This is because "delete" is one of Perl’s
builtin commands which cannot be redefined (if it can, tell me
how).
This is a final rule.
mark_as_read
Mark the message as read
mark_as_unread
Mark the message as unread
lock Lock the message
unlock Remove the message lock
move DESTINATION
Move the message to folder DESTINATION. The folder notation is
the same that Claws Mail uses. You can copy & paste from the
move dialog of the normal filtering, until you get a feeling
for the notation.
This is a final rule.
copy DESTINATION
Copy the message to folder DESTINATION. The folder notation is
the same that Claws Mail uses. You can copy & paste from the
move dialog of the normal filtering, until you get a feeling
for the notation.
execute COMMAND
This is the same as the test - rule from section "Standard
Filtering Conditions" execpt that it always returns a true
value.
hide Hide the message
set_score SCORE
Set message score to SCORE
change_score SCORE
Change message score by SCORE
stop Stop Perl script at this point. Note that this is not a final
rule, meaning that the email gets passed on to the internal
filtering engine. See "abort" below if you don’t want that.
forward ACCOUNT, EMAIL
Forward the message to email address EMAIL, using the account
ID ACCOUNT as sender account. So far, you have to create a rule
in the normal filtering engine to find out that number.
forward_as_attachment, ACCOUNT EMAIL
Forward the message to email address EMAIL in an attachment,
using the account ID ACCOUNT as sender account. So far, you
have to create a rule in the normal filtering engine to find
out that number.
redirect ACCOUNT, EMAIL
Redirect the message to EMAIL, using the account ID ACCOUNT as
sender account. So far, you have to create a rule in the normal
filtering engine to find out that number.
Fun stuff
Functions
header ARG
header If ARG is not given, returns a list of all header field names
of the mail.
If ARG is given, returns ’undef’ if the header field ARG does
not exist in the email. Otherwise, it returns
in scalar context
The value of the header field ARG.
in list context
A list of all available header field values. This is useful
if a header field occurs more than once in an email (eg the
Received - header).
The header field "References" forms a special case. In a scalar
context, it returns the first reference. In a list context, it
returns a list of all references.
body Returns the email body in a scalar.
filepath
Returns the file and path of the email that is currently
filtered (corresponds to the %F arguemnt in the ’test’ rule).
extract_addresses
Extracts email addresses from a string and gives back a list of
addresses found. Currently an email address is found using the
regular expression ’[-.+\w]+\@[-.+\w]+’. This will not find all
valid email addresses. Feel free to send me a better regexp.
move_to_trash
Move the email message to default trash folder.
This is a final rule.
abort Stop Perl script at this point.
In contrast to ’stop’, this is a final rule.
addr_in_addressbook EMAIL, ADDRESSBOOK
addr_in_addressbook EMAIL
Returns a true value if the email address EMAIL is in the
addressbook with the name ADDRESSBOOK. If ADDRESSBOOK is not
given, returns true if the email address is in any addressbook.
from_in_addressbook ADDRESSBOOK
from_in_addressbook
Checks if the email address found in the From-header is in
addressbook ADDRESSBOOK (or any, if omitted). It is implemented
as
my ($from) = extract_addresses(header("from"));
return 0 unless $from;
return addr_in_addressbook($from,@_);
so the same restrictions as to extract_addresses apply.
get_attribute_value EMAIL, ATTRIBUTE, ADDRESSBOOK
get_attribute_value EMAIL, ATTRIBUTE
Looks through the addressbook ADDRESSBOOK (or all addressbooks,
if omitted) for a contact with the an email address EMAIL. If
found, the function checks if this contact has a user attribute
with name ATTRIBUTE. It returns the value of this attribute, or
an empty string if it was not found. As usual, ’undef’ is
returned if an error occured.
SA_is_spam
Is an alias to
not test ’spamc -c < %F > /dev/null’
exit Has been redefined to be an alias to ’stop’. You shouldn’t use
Perl’s own ’exit’ command, since it would exit Claws Mail.
manual Returns a true value if the filter script was invoked manually,
that is, via the Tools menu.
make_sure_folder_exists IDENTIFIER
Returns a true value if the folder with id IDENTIFIER (e.g.
#mh/Mail/foo/bar) exists or could be created.
filter_log SECTION, TEXT
filter_log TEXT
Writes TEXT to the filter logfile. SECTION can be any of
· "LOG_MANUAL"
· "LOG_MATCH"
· "LOG_ACTION"
If the SECTION is omitted, "LOG_MANUAL" is assumed.
filter_log_verbosity VERBOSITY
filter_log_verbosity
Changes the filter log verbosity for the current mail.
VERBOSITY must be any of
· 0
· 1
· 2
· 3
For the meaning of those numbers, read section "LOGGING". If
VERBOSITY is omitted, the filter logfile verbosity is not
changed.
This function returns the filter_log_verbosity number before
the change (if any).
Variables
$permanent
This scalar keeps its value between filtered mail messages. On
plugin start, it is initialized to the empty string.
LOGGING
To keep track of what has been done to the mails while filtering, the
plugin supports logging. Three verbosity levels are recognized:
0 logging disabled
1 log only manual messages, that is, messages introduced by the
"filter_log" command in filter scripts
2 log manual messages and filter actions
3 log manual messages, filter actions and filter matches
The messages are logged in Claws Mail’ log window. The default log
level is 2. Log level 3 is not recommended, because the matcher
functions log a message if they succeeded, and thus, if you have
negative checks, you’ll get confusing entries. If you want to keep
track of matching, do it manually, using "filter_log", or do it by
temporary enabling matcher logging using "filter_log_verbosity".
The first time you unload this plugin (or shut down Claws Mail), a
section called [PerlPlugin] will be created in Claws Mail’
configuration file clawsrc, containing one variable:
* filter_log_verbosity
If you want to change the default behaviour, you can edit this line.
Make sure Claws Mail is not running while you do this.
It will be possible to access these setting via the GUI, as soon as I
find the time to write a corresponding GTK plugin, or somebody else is
interested in contributing that.
EXAMPLE
This section lists a small example of a Perl script file. I’m sure you
get the idea..
#-8<----------------------------------------------------
# -*- perl -*-
# local functions
# Learn ham messages, and move them to specified folder. This is
# useful for making sure a bayes filter sees ham as well.
sub learn_and_move {
execute('put command to learn ham here');
move(@_);
}
# Two-stage spam filter. Every email that scores higher than 15
# on SpamAssassin gets moved into the default trash folder.
# All mails lower than that, but higher than SpamAssassin's
# 'required_hits' go into #mh/mail/Spam.
sub spamcheck {
my $surely_spam = 15;
my $filepath = filepath;
my $spamc = `spamc -c < $filepath`;
my ($value,$threshold) = ($spamc =~ m|([-.,0-9]+)/([-.,0-9]+)|);
if($value >= $surely_spam) {
mark_as_read;
move_to_trash;
}
if($value >= $threshold) {mark_as_read; move '#mh/mail/Spam';}
}
# Perl script execution starts here.
# Some specific sorting
learn_and_move '#mh/mail/MailLists/Claws Mail/user'
if matchcase('sender','claws-mail-users-admin@lists.sourceforge.net');
learn_and_move '#mh/mail/MailLists/Sylpheed'
if matchcase('list-id','sylpheed.good-day.net');
# Implement imcomming folders using addressbook
# attributes. Target folders for specific email addresses are
# stored directly in the addressbook. This way, if an email
# address changes, we only have to update the addressbook, not
# the filter rules! Besides that, we can greatly unclutter the
# filter script.
# get the email address in the from header
my $fromheader = header "from";
my ($from) = extract_addresses $fromheader;
# check if this email address has an associated attribute
# called "incomming_folder". If if has, the value of this
# attribute is supposed to be the target folder.
my $value = get_attribute_value $from, "incomming_folder";
learn_and_move($value) if $value;
# An example of a whitelist: If the from-address is in my
# "office" addressbook, move the mail to folder #mh/mail/office
learn_and_move '#mh/mail/office' if from_in_addressbook("office");
# If the from-address is in any other addressbook, move the
# mail to folder #mh/mail/inbox/known
learn_and_move '#mh/mail/inbox/known' if from_in_addressbook;
# Feed the remaining mails through SpamAssassin.
spamcheck;
# mails that make it to the end of the script are passed on to
# the internal filtering engine. If the internal rules don't say
# otherwise, the mails end up in the default inbox.
#-8<----------------------------------------------------
BUGS
· Do not use this plugin together with other filtering plugins,
especially the Spamassassin and ClamAV plugins. They are registered
on the same hook and the order in which the plugins are executed is
not guaranteed.
· The filter script is not (yet) updated automatically when a folder
gets renamed. The same applies for folder names in addressbook user
attributes.
· This plugin has only be tested with POP3 accounts. If you have
experiences with IMAP or newsgroup accounts, drop me a message.
· Warning during compile time:
*** Warning: Linking the shared library perl_plugin.la against the
*** static library
/usr/lib/perl5/5.8.3/i586-linux-thread-multi/auto/DynaLoader/DynaLoader.a
is not portable!
Ideas to solve this one are welcome :-)
Please report comments, suggestions and bugreports to the address given
in the "AUTHOR" section of this document.
LICENSE and (no) WARRANTY
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see http://www.gnu.org/licenses/.
SEE ALSO
claws-mail(1), perl(1)
AUTHOR
Holger Berndt <berndth@gmx.de>