Ubuntu Manpage: Mail::SpamAssassin::Plugin - SpamAssassin plugin base class

Provided by: spamassassin_4.0.0-8ubuntu5_all

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.

$plugin = MyPluginClass->new ($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; instead this should be stored on the PerMsgStatus 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}", or as
"conf" in the $options hash reference above. By storing it on "conf", this allows per-user and
system-wide configuration precedence to be dealt with correctly.

$plugin->finish_parsing_start ( { options ... } )
Signals that the system-wide configuration has been completely read, but internal data structures are
not yet created. It is possible to use this hook to dynamically change the configuration already read
in or add new config options.

"options" is a reference to a hash containing these options:

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

Note: there are no guarantees that the internal data structures of SpamAssassin will not change from
release to release. In particular to this plugin hook, if you modify the rules data structures in a
third-party plugin, all bets are off until such time that an API is present for modifying that
configuration data.

$plugin->finish_parsing_end ( { options ... } )
Signals that the system-wide configuration parsing has just finished, and SpamAssassin is nearly
ready to check messages.

"options" is a reference to a hash containing these options:

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

$plugin->user_conf_parsing_start ( { options ... } )
Signals that the per-user configuration has been completely read, but not converted to internal data
structures. It is possible to use this hook to dynamically change the configuration already read in
or add new config options.

If "allow_user_rules" is enabled in the configuration, it is possible that additional rules have been
added since the "finish_parsing_start" plugin hook invocation was called.

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

$plugin->user_conf_parsing_end ( { options ... } )
Signals that the per-user configuration parsing has just finished, and SpamAssassin is nearly ready
to check messages. If "allow_user_rules" is enabled in the configuration, it is possible that
additional rules have been added since the "finish_parsing_end" plugin hook invocation was called.

"options" is a reference to a hash containing these options:

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

$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->services_authorized_for_username ( { options ... } )
Validates that a given username is authorized to use certain services.

In order to authorize a user, the plugin should first check that it can handle any of the services
passed into the method and then set the value for each allowed service to true (or any non-negative
value).

The current supported services are: bayessql

username
A username

services
Reference to a hash containing the services you want to check.

{

'bayessql' => 0

}

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

$plugin->compile_now_start ( { options ... } )
This is called at the beginning of Mail::SpamAssassin::compile_now() so plugins can do any necessary
initialization for multi-process SpamAssassin (such as spamd or mass-check -j).

use_user_prefs
The value of $use_user_prefs option in compile_now().

keep_userstate
The value of $keep_userstate option in compile_now().

$plugin->compile_now_finish ( { options ... } )
This is called at the end of Mail::SpamAssassin::compile_now() so plugins can do any necessary
initialization for multi-process SpamAssassin (such as spamd or mass-check -j).

use_user_prefs
The value of $use_user_prefs option in compile_now().

keep_userstate
The value of $keep_userstate option in compile_now().

$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->check_main ( { options ... } )
Signals that a message should be checked. Note that implementations of this hook should return 1.

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_dnsbl ( { options ... } )
Called when DNSBL or other network lookups are being launched, implying current running priority of
-100. This is the place to start your own asynchronously-started network lookups.

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_cleanup ( { options ... } )
Called just before message check is finishing and before possible auto-learning. This is guaranteed
to be always called, unlike check_tick and check_post_dnsbl. Used for cleaning up left callbacks or
forked children etc, last chance to make rules hit.

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->finish_tests ( { options ... } )
Called via "Mail::SpamAssassin::finish". This should clear up any tests that a plugin has added to
the namespace.

In certain circumstances, plugins may find it useful to compile perl functions from the ruleset, on
the fly. It is important to remove these once the "Mail::SpamAssassin" object is deleted, however,
and this API allows this.

Each plugin is responsible for its own generated perl functions.

conf
The "Mail::SpamAssassin::Conf" object on which the configuration data should be stored.

See also the "register_generated_rule_method" helper API, below.

$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.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

$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->start_rules ( { options ... } )
Called before testing a set of rules of a given type and priority.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

ruletype
The type of the rules about to be performed.

priority
The priority level of the rules about to be performed.

$plugin->hit_rule ( { options ... } )
Called when a rule fires.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

ruletype
The type of the rule that fired.

rulename
The name of the rule that fired.

score
The rule's score in the active scoreset.

$plugin->ran_rule ( { options ... } )
Called after a rule has been tested, whether or not it fired. When the rule fires, the hit_rule
callback is always called before this.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

ruletype
The type of the rule that was tested.

rulename
The name of the rule that was tested.

$plugin->autolearn_discriminator ( { options ... } )
Control whether a just-scanned message should be learned as either spam or ham. This method should
return one of 1 to learn the message as spam, 0 to learn as ham, or "undef" to not learn from the
message at all.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

$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.

Normally, any member variables on the "PerMsgStatus" object will be cleaned up automatically -- but
if your plugin has made a circular reference on that object, this is the place to break them so that
garbage collection can operate correctly.

permsgstatus
The "Mail::SpamAssassin::PerMsgStatus" context object for this scan.

$plugin->have_shortcircuited ( { options ... } )
Has the current scan operation 'short-circuited'? In other words, can further scanning be skipped,
since the message is already definitively classified as either spam or ham?

Plugins should return 0 to indicate that scanning should continue, or 1 to indicate that short-
circuiting has taken effect.

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 backward compatibility 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.

$plugin->plugin_report ( { options ... } )
Called if the message is to be reported as spam. If the reporting system is available, the variable
"$options->{report}->report_available}" should be set to 1; if the reporting system successfully
reported the message, the variable "$options->{report}->report_return}" should be set to 1.

report
Reference to the Reporter object ("$options->{report}" in the paragraph above.)

text
Reference to a markup removed copy of the message in scalar string format.

msg Reference to the original message object.

$plugin->plugin_revoke ( { options ... } )
Called if the message is to be reported as ham (revokes a spam report). If the reporting system is
available, the variable "$options->{revoke}->revoke_available}" should be set to 1; if the reporting
system successfully revoked the message, the variable "$options->{revoke}->revoke_return}" should be
set to 1.

revoke
Reference to the Reporter object ("$options->{revoke}" in the paragraph above.)

text
Reference to a markup removed copy of the message in scalar string format.

msg Reference to the original message object.

$plugin->welcomelist_address( { options ... } )
Previously whitelist_address which will work interchangeably until 4.1.

Called when a request is made to add an address to a persistent address list.

address
Address you wish to add.

cli_p
Indicate if the call is being made from a command line interface.

$plugin->blocklist_address( { options ... } )
Previously blacklist_address which will work interchangeably until 4.1.

Called when a request is made to add an address to a persistent address list.

address
Address you wish to add.

cli_p
Indicate if the call is being made from a command line interface.

$plugin->remove_address( { options ... } )
Called when a request is made to remove an address to a persistent address list.

address
Address you wish to remove.

cli_p
Indicate if the call is being made from a command line interface.

$plugin->spamd_child_init ()
Called in each new child process when it starts up under spamd.

$plugin->log_scan_result ( { options ... } )
Called when spamd has completed scanning a message. Currently, only spamd calls this API.

result
The 'result: ...' line for this scan. Format is as described at
https://wiki.apache.org/spamassassin/SpamdSyslogFormat.

$plugin->spamd_child_post_connection_close ()
Called when child returns from handling a connection.

If there was an accept failure, the child will die and this code will not be called.

$plugin->finish ()
Called when the "Mail::SpamAssassin" object is destroyed.

$plugin->learner_new ()
Used to support human-trained probabilistic classifiers like the BAYES_* ruleset. Called when a new
"Mail::SpamAssassin::Bayes" object has been created; typically when a new user's scan is about to
start.

$plugin->learn_message ()
Train the classifier with a training message.

isspam
1 if the message is spam, 0 if it's non-spam.

msg The message's "Mail::SpamAssassin::Message" object.

id An optional message-identification string, used internally to tag the message. If it is "undef",
one will be generated. It should be unique to that message.

$plugin->forget_message ()
Tell the classifier to 'forget' its training about a specific message.

msg The message's "Mail::SpamAssassin::Message" object.

id An optional message-identification string, used internally to tag the message. If it is "undef",
one will be generated. It should be unique to that message.

$plugin->learner_sync ()
Tell the classifier to 'sync' any pending changes against the current user's training database. This
is called by "sa-learn --sync".

If you do not need to implement these for your classifier, create an implementation that just
contains "return 1".

$plugin->learner_expire_old_training ()
Tell the classifier to perform infrequent, time-consuming cleanup of the current user's training
database. This is called by "sa-learn --force-expire".

If you do not need to implement these for your classifier, create an implementation that just
contains "return 1".

$plugin->learner_is_scan_available ()
Should return 1 if it is possible to use the current user's training data for a message-scan
operation, or 0 otherwise.

$plugin->learner_dump_database ()
Dump information about the current user's training data to "stdout". This is called by "sa-learn
--dump".

magic
Set to 1 if "magic" name-value metadata should be dumped.

toks
Set to 1 if the database of tokens should be dumped.

regex
Either "undef" to dump all tokens, or a value which specifies a regular expression subset of the
tokens to dump.

$plugin->learner_close ()
Close any open databases.

quiet
Set to 1 if warning messages should be suppressed.

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, $ruletype)
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.

Since 4.0, optional $ruletype can be specified to enforce that eval function cannot be called with
wrong ruletype from configuration, for example user using "header FOO eval:foobar()" instead of "body
FOO eval:foobar()". Mismatch will result in lint failure. $ruletype can be one of:

$Mail::SpamAssassin::Conf::TYPE_HEAD_EVALS
$Mail::SpamAssassin::Conf::TYPE_BODY_EVALS (allows both body and rawbody)
$Mail::SpamAssassin::Conf::TYPE_RAWBODY_EVALS
$Mail::SpamAssassin::Conf::TYPE_FULL_EVALS

$plugin->register_generated_rule_method ($nameofsub)
In certain circumstances, plugins may find it useful to compile perl functions from the ruleset, on
the fly. It is important to remove these once the "Mail::SpamAssassin" object is deleted, however,
and this API allows this.

Once the method $nameofsub has been generated, call this API with the name of the method (including
full package scope). This indicates that it's a temporary piece of generated code, built from the
SpamAssassin ruleset, and when Mail::SpamAssassin::finish() is called, the method will be destroyed.

This API was added in SpamAssassin 3.2.0.

$plugin->register_method_priority($methodname, $priority)
Indicate that the method named $methodname on the current object has a callback priority of
$priority.

This is used by the plugin handler to determine the relative order of callbacks; plugins with lower-
numbered priorities are called before plugins with higher-numbered priorities. Each method can have
a different priority value. The default value is 0. The ordering of callbacks to methods with equal
priority is undefined.

Typically, you only need to worry about this if you need to ensure your plugin's method is called
before another plugin's implementation of that method. It should be called from your plugin's
constructor.

This API was added in SpamAssassin 3.2.0.

$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().

LOGGING

       Mail::SpamAssassin::Plugin::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).

       Mail::SpamAssassin::Plugin::info($message)
           Output an informational message $message, if the SpamAssassin object is  running  with  informational
           messages turned on.

           NOTE:  This function is not available in the package namespace of general plugins and can't be called
           via  $self->info().   If  a  plugin  wishes   to   output   debug   information,   it   should   call
           Mail::SpamAssassin::Plugin::info($msg).

           In  general,  it is better for plugins to use the "Mail::SpamAssassin::Logger" module to import "dbg"
           and "info" directly, like so:

             use Mail::SpamAssassin::Logger;
             dbg("some message");
             info("some other message");

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', $Mail::SpamAssassin::Conf::TYPE_HEAD_EVALS)

       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 (miss), 1 (hit), or undef (async function)
         }

       The  eval  rule  should  return 1 for a hit, or 0 if the rule is not hit.  Special case of "return undef"
       must be used when result is not yet ready and it will  be  later  declared  with  PerMsgStatus  functions
       got_hit()  or  rule_ready()  -  see  their documentation for more info.  Make sure not to return undef by
       mistake.

       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}".

       State for a single message being scanned should be stored on the $permsgstatus 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.

BACKWARD COMPATIBILITY

       Note  that  if  you  write  a  plugin and need to determine if a particular helper method is supported on
       "Mail::SpamAssassin::Plugin", you can do this:

           if ($self->can("name_of_method")) {
             eval {
               $self->name_of_method();        # etc.
             }
           } else {
             # take fallback action
           }

       The   same   applies   for   the   public    APIs    on    objects    of    other    types,    such    as
       "Mail::SpamAssassin::PerMsgStatus".

NAME

SYNOPSIS

DESCRIPTION

INTERFACE

METHODS

HELPER APIS

LOGGING

REGISTERING EVAL RULES

STANDARD ARGUMENTS FOR RULE TYPES

BACKWARD COMPATIBILITY

SEE ALSO