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.\" ========================================================================
.\"
.IX Title "Mail::SpamAssassin::AsyncLoop 3"
.TH Mail::SpamAssassin::AsyncLoop 3 "2015-04-29" "perl v5.16.3" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
Mail::SpamAssassin::AsyncLoop \- scanner asynchronous event loop
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
An asynchronous event loop used for long-running operations, performed \*(L"in the
background\*(R" during the \fIMail::SpamAssassin::check()\fR scan operation, such as \s-1DNS\s0
blocklist lookups.
.SH "METHODS"
.IX Header "METHODS"
.ie n .IP "$ent = $async\->start_lookup($ent, $master_deadline)" 4
.el .IP "\f(CW$ent\fR = \f(CW$async\fR\->start_lookup($ent, \f(CW$master_deadline\fR)" 4
.IX Item "$ent = $async->start_lookup($ent, $master_deadline)"
Register the start of a long-running asynchronous lookup operation.
\&\f(CW$ent\fR is a hash reference containing the following items:
.RS 4
.IP "key (required)" 4
.IX Item "key (required)"
A key string, unique to this lookup.  This is what is reported in
debug messages, used as the key for \f(CW\*(C`get_lookup()\*(C'\fR, etc.
.IP "id (required)" 4
.IX Item "id (required)"
An \s-1ID\s0 string, also unique to this lookup.  Typically, this is the \s-1DNS\s0 packet \s-1ID\s0
as returned by DnsResolver's \f(CW\*(C`bgsend\*(C'\fR method.  Sadly, the Net::DNS
architecture forces us to keep a separate \s-1ID\s0 string for this task instead of
reusing \f(CW\*(C`key\*(C'\fR \*(-- if you are not using \s-1DNS\s0 lookups through DnsResolver, it
should be \s-1OK\s0 to just reuse \f(CW\*(C`key\*(C'\fR.
.IP "type (required)" 4
.IX Item "type (required)"
A string, typically one word, used to describe the type of lookup in log
messages, such as \f(CW\*(C`DNSBL\*(C'\fR, \f(CW\*(C`MX\*(C'\fR, \f(CW\*(C`TXT\*(C'\fR.
.IP "zone (optional)" 4
.IX Item "zone (optional)"
A zone specification (typically a \s-1DNS\s0 zone name \- e.g. host, domain, or \s-1RBL\s0)
which may be used as a key to look up per-zone settings. No semantics on this
parameter is imposed by this module. Currently used to fetch by-zone timeouts.
.IP "timeout_initial (optional)" 4
.IX Item "timeout_initial (optional)"
An initial value of elapsed time for which we are willing to wait for a
response (time in seconds, floating point value is allowed). When elapsed
time since a query started exceeds the timeout value and there are no other
queries to wait for, the query is aborted. The actual timeout value ranges
from timeout_initial and gradually approaches timeout_min (see next parameter)
as the number of already completed queries approaches the number of all
queries started.
.Sp
If a caller does not explicitly provide this parameter or its value is
undefined, a default initial timeout value is settable by a configuration
variable rbl_timeout.
.Sp
If a value of the timeout_initial parameter is below timeout_min, the initial
timeout is set to timeout_min.
.IP "timeout_min (optional)" 4
.IX Item "timeout_min (optional)"
A lower bound (in seconds) to which the actual timeout approaches as the
number of queries completed approaches the number of all queries started.
Defaults to 0.2 * timeout_initial.
.RE
.RS 4
.Sp
\&\f(CW$ent\fR is returned by this method, with its contents augmented by additional
information.
.RE
.ie n .IP "$ent = $async\->bgsend_and_start_lookup($domain, $type, $class, $ent, $cb, %options)" 4
.el .IP "\f(CW$ent\fR = \f(CW$async\fR\->bgsend_and_start_lookup($domain, \f(CW$type\fR, \f(CW$class\fR, \f(CW$ent\fR, \f(CW$cb\fR, \f(CW%options\fR)" 4
.IX Item "$ent = $async->bgsend_and_start_lookup($domain, $type, $class, $ent, $cb, %options)"
A common idiom: calls \f(CW\*(C`bgsend\*(C'\fR, followed by a call to \f(CW\*(C`start_lookup\*(C'\fR,
returning the argument \f(CW$ent\fR object as modified by \f(CW\*(C`start_lookup\*(C'\fR and
filled-in with a query \s-1ID.\s0
.ie n .IP "$ent = $async\->get_lookup($key)" 4
.el .IP "\f(CW$ent\fR = \f(CW$async\fR\->get_lookup($key)" 4
.IX Item "$ent = $async->get_lookup($key)"
Retrieve the pending-lookup object for the given key \f(CW$key\fR.
.Sp
If the lookup is complete, this will return \f(CW\*(C`undef\*(C'\fR.
.Sp
Note that a lookup is still considered \*(L"pending\*(R" until \f(CW\*(C`complete_lookups()\*(C'\fR is
called, even if it has been reported as complete via \f(CW\*(C`set_response_packet()\*(C'\fR.
.ie n .IP "$async\->\fIlog_lookups_timing()\fR" 4
.el .IP "\f(CW$async\fR\->\fIlog_lookups_timing()\fR" 4
.IX Item "$async->log_lookups_timing()"
Log sorted timing for all completed lookups.
.ie n .IP "$alldone = $async\->\fIcomplete_lookups()\fR" 4
.el .IP "\f(CW$alldone\fR = \f(CW$async\fR\->\fIcomplete_lookups()\fR" 4
.IX Item "$alldone = $async->complete_lookups()"
Perform a poll of the pending lookups, to see if any are completed.
Callbacks on completed queries will be called from \fIpoll_responses()\fR.
.Sp
If there are no lookups remaining, or if too much time has elapsed since
any results were returned, \f(CW1\fR is returned, otherwise \f(CW0\fR.
.ie n .IP "$async\->\fIabort_remaining_lookups()\fR" 4
.el .IP "\f(CW$async\fR\->\fIabort_remaining_lookups()\fR" 4
.IX Item "$async->abort_remaining_lookups()"
Abort any remaining lookups.
.ie n .IP "$async\->set_response_packet($id, $pkt, $key, $timestamp)" 4
.el .IP "\f(CW$async\fR\->set_response_packet($id, \f(CW$pkt\fR, \f(CW$key\fR, \f(CW$timestamp\fR)" 4
.IX Item "$async->set_response_packet($id, $pkt, $key, $timestamp)"
Register a \*(L"response packet\*(R" for a given query.  \f(CW$id\fR is the \s-1ID\s0 for the
query, and must match the \f(CW\*(C`id\*(C'\fR supplied in \f(CW\*(C`start_lookup()\*(C'\fR. \f(CW$pkt\fR is the
packet object for the response. A parameter \f(CW$key\fR identifies an entry in a
hash %{$self\->{pending_lookups}} where the object which spawned this query can
be found, and through which futher information about the query is accessible.
.Sp
\&\f(CW$pkt\fR may be undef, indicating that no response packet is available, but a
query has completed (e.g. was aborted or dismissed) and is no longer \*(L"pending\*(R".
.Sp
The \s-1DNS\s0 resolver's response packet \f(CW$pkt\fR will be made available to a callback
subroutine through its argument as well as in \f(CW\*(C`$ent\-<gt\*(C'\fR{response_packet}>.
.ie n .IP "$async\->report_id_complete($id,$key,$key,$timestamp)" 4
.el .IP "\f(CW$async\fR\->report_id_complete($id,$key,$key,$timestamp)" 4
.IX Item "$async->report_id_complete($id,$key,$key,$timestamp)"
Legacy. Equivalent to \f(CW$self\fR\->set_response_packet($id,undef,$key,$timestamp),
i.e. providing undef as a response packet. Register that a query has
completed and is no longer \*(L"pending\*(R". \f(CW$id\fR is the \s-1ID\s0 for the query,
and must match the \f(CW\*(C`id\*(C'\fR supplied in \f(CW\*(C`start_lookup()\*(C'\fR.
.Sp
One or the other of \f(CW\*(C`set_response_packet()\*(C'\fR or \f(CW\*(C`report_id_complete()\*(C'\fR
should be called, but not both.
.ie n .IP "$time = $async\->\fIlast_poll_responses_time()\fR" 4
.el .IP "\f(CW$time\fR = \f(CW$async\fR\->\fIlast_poll_responses_time()\fR" 4
.IX Item "$time = $async->last_poll_responses_time()"
Get the time of the last call to \f(CW\*(C`poll_responses()\*(C'\fR (which is called
from \f(CW\*(C`complete_lookups()\*(C'\fR.  If \f(CW\*(C`poll_responses()\*(C'\fR was never called or
\&\f(CW\*(C`abort_remaining_lookups()\*(C'\fR has been called \f(CW\*(C`last_poll_responses_time()\*(C'\fR
will return undef.