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Mail::SpamAssassin::PlUusgeirn(C3o)ntributed
NAME
Mail::SpamAssassin::Plugin - SpamAssassin plugin base class
SYNOPSIS
SpamAssassin configuration:
loadplugin MyPlugin /path/to/myplugin.pm
Perl code:
package MyPlugin;
use Mail::SpamAssassin::Plugin;
our @ISA = qw(Mail::SpamAssassin::Plugin);
sub new {
my ($class, $mailsa) = @_;
# the usual perlobj boilerplate to create a subclass object
$class = ref($class) || $class;
my $self = $class->SUPER::new($mailsa);
bless ($self, $class);
# then register an eval rule, if desired...
$self->register_eval_rule ("check_for_foo");
# and return the new plugin object
return $self;
}
...methods...
1;
DESCRIPTION
This is the base class for SpamAssassin plugins; all plugins must be
objects that implement this class.
This class provides no-op stub methods for all the callbacks that a plugin
can receive. It is expected that your plugin will override one or more of
these stubs to perform its actions.
SpamAssassin implements a plugin chain; each callback event is passed to
each of the registered plugin objects in turn. Any plugin can call
"$self->inhibit_further_callbacks()" to block delivery of that event to
later plugins in the chain. This is useful if the plugin has handled the
event, and there will be no need for later plugins to handle it as well.
If you're looking to write a simple eval rule, skip straight to
"register_eval_rule()", below.
INTERFACE
In all the plugin APIs below, "options" refers to a reference to a hash
containing name-value pairs. This is used to ensure future-compatibility,
in that we can add new options in future without affecting objects built to
an earlier version of the API.
For example, here would be how to print out the "line" item in a
"parse_config()" method:
sub parse_config {
my ($self, $opts) = @_;
print "MyPlugin: parse_config got ".$opts->{line}."\n";
}
METHODS
The following methods can be overridden by subclasses to handle events that
SpamAssassin will call back to:
$plugin = MyPluginClass->new ($mailsaobject)
Constructor. Plugins that need to register themselves will need to
define their own; the default super-class constructor will work fine
for plugins that just override a method.
Note that subclasses must provide the $mailsaobject to the superclass
constructor, like so:
my $self = $class->SUPER::new($mailsaobject);
Lifecycle note: plugins that will need to store per-scan state should
not store that on the Plugin object; see "check_start()" below. It is
also likewise recommended that configuration settings be stored on the
Conf object; see "parse_config()".
$plugin->parse_config ( { options ... } )
Parse a configuration line that hasn't already been handled. "options"
is a reference to a hash containing these options:
line
The line of configuration text to parse. This has leading and
trailing whitespace, and comments, removed.
key The configuration key; ie. the first "word" on the line.
value
The configuration value; everything after the first "word" and any
whitespace after that.
conf
The "Mail::SpamAssassin::Conf" object on which the configuration
data should be stored.
user_config
A boolean: 1 if reading a user's configuration, 0 if reading the
system-wide configuration files.
If the configuration line was a setting that is handled by this plugin,
the method implementation should call
"$self->inhibit_further_callbacks()".
If the setting is not handled by this plugin, the method should return
0 so that a later plugin may handle it, or so that SpamAssassin can
output a warning message to the user if no plugin understands it.
Lifecycle note: it is suggested that configuration be stored on the
"Mail::SpamAssassin::Conf" object in use, instead of the plugin object
itself. That can be found as "$plugin->{main}->{conf}". This allows
per-user and system-wide configuration to be dealt with correctly, with
per-user overriding system-wide.
$plugin->signal_user_changed ( { options ... } )
Signals that the current user has changed for a new one.
username
The new user's username.
user_dir
The new user's home directory. (equivalent to "~".)
userstate_dir
The new user's storage directory. (equivalent to
"~/.spamassassin".)
$plugin->check_start ( { options ... } )
Signals that a message check operation is starting.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
Lifecycle note: it is recommended that rules that need to track
test state on a per-scan basis should store that state on this
object, not on the plugin object itself, since the plugin object
will be shared between all active scanners.
The message being scanned is accessible through the
"$permsgstatus->get_message()" API; there are a number of other
public APIs on that object, too. See
"Mail::SpamAssassin::PerMsgStatus" perldoc.
$plugin->extract_metadata ( { options ... } )
Signals that a message is being mined for metadata. Some plugins may
wish to add their own metadata as well.
msg The "Mail::SpamAssassin::Message" object for this message.
$plugin->parsed_metadata ( { options ... } )
Signals that a message's metadata has been parsed, and can now be
accessed by the plugin.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
$plugin->check_tick ( { options ... } )
Called periodically during a message check operation. A callback set
for this method is a good place to run through an event loop dealing
with network events triggered in a "parse_metadata" method, for
example.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
$plugin->check_post_dnsbl ( { options ... } )
Called after the DNSBL results have been harvested. This is a good
place to harvest your own asynchronously-started network lookups.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
$plugin->check_post_learn ( { options ... } )
Called after auto-learning may (or may not) have taken place. If you
wish to perform additional learning, whether or not auto-learning
happens, this is the place to do it.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
$plugin->check_end ( { options ... } )
Signals that a message check operation has just finished, and the
results are about to be returned to the caller.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan. The current score, names of rules that hit, etc. can be
retrieved using the public APIs on this object.
$plugin->autolearn ( { options ... } )
Signals that a message is about to be auto-learned as either ham or
spam.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
isspam
1 if the message is spam, 0 if ham.
$plugin->per_msg_finish ( { options ... } )
Signals that a "Mail::SpamAssassin::PerMsgStatus" object is being
destroyed, and any per-scan context held on that object by this plugin
should be destroyed as well.
permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this
scan.
$plugin->bayes_learn ( { options ... } )
Called at the end of a bayes learn operation.
This phase is the best place to map the raw (original) token value to
the SHA1 hashed value.
toksref
Reference to hash returned by call to tokenize. The hash takes the
format of:
{
'SHA1 Hash Value' => 'raw (original) value'
}
NOTE: This data structure has changed since it was originally
introduced in version 3.0.0. The values are no longer perl
anonymous hashes, they are a single string containing the raw token
value. You can test for backwards compatability by checking to see
if the value for a key is a reference to a perl HASH, for instance:
if (ref($toksref->{$sometokenkey}) eq 'HASH') {...
If it is, then you are using the old interface, otherwise you are
using the current interface.
isspam
Boolean value stating what flavor of message the tokens represent,
if true then message was specified as spam, false is nonspam.
Note, when function is scan then isspam value is not valid.
msgid
Generated message id of the message just learned.
msgatime
Received date of the current message or current time if received
date could not be determined. In addition, if the receive date is
more than 24 hrs into the future it will be reset to current
datetime.
$plugin->bayes_forget ( { options ... } )
Called at the end of a bayes forget operation.
toksref
Reference to hash returned by call to tokenize. See bayes_learn
documentation for additional information on the format.
isspam
Boolean value stating what flavor of message the tokens represent,
if true then message was specified as spam, false is nonspam.
Note, when function is scan then isspam value is not valid.
msgid
Generated message id of the message just forgotten.
$plugin->bayes_scan ( { options ... } )
Called at the end of a bayes scan operation. NOTE: Will not be called
in case of error or if the message is otherwise skipped.
toksref
Reference to hash returned by call to tokenize. See bayes_learn
documentation for additional information on the format.
probsref
Reference to hash of calculated probabilities for tokens found in
the database.
{
'SHA1 Hash Value' => {
'prob' => 'calculated probability',
'spam_count' => 'Total number of spam msgs w/ token',
'ham_count' => 'Total number of ham msgs w/ token',
'atime' => 'Atime value for token in database'
}
}
score
Score calculated for this particular message.
msgatime
Calculated atime of the message just learned, note it may have been
adjusted if it was determined to be too far into the future.
significant_tokens
Array ref of the tokens found to be significant in determining the
score for this message.
$plugin->finish ()
Called when the "Mail::SpamAssassin" object is destroyed.
HELPER APIS
These methods provide an API for plugins to register themselves to receive
specific events, or control the callback chain behaviour.
$plugin->register_eval_rule ($nameofevalsub)
Plugins that implement an eval test will need to call this, so that
SpamAssassin calls into the object when that eval test is encountered.
See the REGISTERING EVAL RULES section for full details.
$plugin->inhibit_further_callbacks()
Tells the plugin handler to inhibit calling into other plugins in the
plugin chain for the current callback. Frequently used when parsing
configuration settings using "parse_config()".
dbg ($message)
Output a debugging message $message, if the SpamAssassin object is
running with debugging turned on.
NOTE: This function is not available in the package namespace of
general plugins and can't be called via $self->dbg(). If a plugin
wishes to output debug information, it should call
"Mail::SpamAssassin::Plugin::dbg($msg)".
REGISTERING EVAL RULES
Plugins that implement an eval test must register the methods that can be
called from rules in the configuration files, in the plugin class'
constructor.
For example,
$plugin->register_eval_rule ('check_for_foo')
will cause "$plugin->check_for_foo()" to be called for this SpamAssassin
rule:
header FOO_RULE eval:check_for_foo()
Note that eval rules are passed the following arguments:
The plugin object itself
The "Mail::SpamAssassin::PerMsgStatus" object calling the rule
standard arguments for the rule type in use
any and all arguments as specified in the configuration file
In other words, the eval test method should look something like this:
sub check_for_foo {
my ($self, $permsgstatus, ...arguments...) = @_;
...code returning 0 or 1
}
Note that the headers can be accessed using the "get()" method on the
"Mail::SpamAssassin::PerMsgStatus" object, and the body by
"get_decoded_stripped_body_text_array()" and other similar methods.
Similarly, the "Mail::SpamAssassin::Conf" object holding the current
configuration may be accessed through "$permsgstatus->{main}->{conf}".
The eval rule should return 1 for a hit, or 0 if the rule is not hit.
State for a single message being scanned should be stored on the $checker
object, not on the $self object, since $self persists between scan
operations. See the 'lifecycle note' on the "check_start()" method above.
STANDARD ARGUMENTS FOR RULE TYPES
Plugins will be called with the same arguments as a standard EvalTest.
Different rule types receive different information by default:
header tests, no extra arguments
body tests, fully rendered message as array reference
rawbody tests, fully decoded message as array reference
full tests, pristine message as scalar reference
The configuration file arguments will be passed in after the standard
arguments.
SEE ALSO
"Mail::SpamAssassin"
"Mail::SpamAssassin::PerMsgStatus"
http://wiki.apache.org/spamassassin/PluginWritingTips
http://bugzilla.spamassassin.org/show_bug.cgi?id=2163
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