Mail::SpamAssassin::AsUseroContributed Perl DMail::SpamAssassin::AsyncLoop(3p)



NAME
       Mail::SpamAssassin::AsyncLoop - scanner asynchronous event loop

DESCRIPTION
       An asynchronous event loop used for long-running operations, performed
       "in the background" during the Mail::SpamAssassin::check() scan
       operation, such as DNS blocklist lookups.

METHODS
       $obj = $async->start_lookup($obj)
           Register the start of a long-running asynchronous lookup operation.
           $obj is a hash reference containing the following items:

           key (required)
               A key string, unique to this lookup.  This is what is reported
               in debug messages, used as the key for "get_lookup()", etc.

           id (required)
               An ID string, also unique to this lookup.  Typically, this is
               the DNS packet ID as returned by DnsResolver's "bgsend" method.
               Sadly, the Net::DNS architecture forces us to keep a separate
               ID string for this task instead of reusing "key" -- if you are
               not using DNS lookups through DnsResolver, it should be OK to
               just reuse "key".

           type (required)
               A string, typically one word, used to describe the type of
               lookup in log messages, such as "DNSBL", "MX", "TXT".

           poll_callback (optional)
               A code reference, which will be called periodically during the
               background-processing period.  If you will be performing an
               async lookup on a non-DNS-based service, you will need to
               implement this so that it checks for new responses and calls
               "set_response_packet()" or "report_id_complete()" as
               appropriate.   DNS-based lookups can leave it undefined, since
               DnsResolver::poll_responses() will be called automatically
               anyway.

               The code reference will be called with one argument, the $ent
               object.

           completed_callback (optional)
               A code reference which will be called when an asynchronous task
               (e.g. a DNS lookup) is completed, either normally, or aborted,
               e.g. by a timeout.

               When a task has been reported as completed via
               "set_response_packet()" the response (as provided to
               "set_response_packet()") is stored in $ent->{response_packet}
               (possibly undef, its semantics is defined by the caller). When
               completion is reported via "report_id_complete()" or a task was
               aborted, the $ent->{response_packet} is guaranteed to be undef.
               If it is necessary to distinguish between the last two cases,
               the $ent->{status} may be examined for a string 'ABORTING' or
               'FINISHED'.

               The code reference will be called with one argument, the $ent
               object.

           zone (optional)
               A zone specification (typically a DNS zone name - e.g. host,
               domain, or RBL) 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.

           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.

               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.

               If a value of the timeout_initial parameter is below
               timeout_min, the initial timeout is set to timeout_min.

           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.

           $obj is returned by this method.

       $obj = $async->get_lookup($key)
           Retrieve the pending-lookup object for the given key $key.

           If the lookup is complete, this will return "undef".

           Note that a lookup is still considered "pending" until
           "complete_lookups()" is called, even if it has been reported as
           complete via "set_response_packet()" or "report_id_complete()".

       @objs = $async->get_pending_lookups()
           Retrieve the lookup objects for all pending lookups.

           Note that a lookup is still considered "pending" until
           "complete_lookups()" is called, even if it has been reported as
           complete via "set_response_packet()" or "report_id_complete()".

       $async->log_lookups_timing()
           Log sorted timing for all completed lookups.

       $alldone = $async->complete_lookups()
           Perform a poll of the pending lookups, to see if any are completed;
           if they are, their <completed_callback> is called with the entry
           object for that lookup.

           If there are no lookups remaining, or if too long has elapsed since
           any results were returned, 1 is returned, otherwise 0.

       $async->abort_remaining_lookups()
           Abort any remaining lookups.

       $async->set_response_packet($id, $pkt, $key, $timestamp)
           Register a "response packet" for a given query.  $id is the ID for
           the query, and must match the "id" supplied in "start_lookup()".
           $pkt is the packet object for the response. A parameter $key
           identifies an entry in a hash %{$self->{pending_lookups}} where the
           object which spawned this query can be found, and through which
           futher information about the query is accessible.

           If this was called, $pkt will be available in the
           "completed_callback" function as "$ent-<gt"{response_packet}>.

           One or the other of "set_response_packet()" or
           "report_id_complete()" should be called, but not both.

       $async->report_id_complete($id,$key,$key,$timestamp)
           Register that a query has completed, and is no longer "pending".
           $id is the ID for the query, and must match the "id" supplied in
           "start_lookup()".

           One or the other of "set_response_packet()" or
           "report_id_complete()" should be called, but not both.

       $time = $async->last_poll_responses_time()
           Get the time of the last call to "poll_responses()" (which is
           called from "complete_lookups()".  If "poll_responses()" was never
           called or "abort_remaining_lookups()" has been called
           "last_poll_responses_time()" will return undef.



perl v5.12.2                      2011-06-06 Mail::SpamAssassin::AsyncLoop(3p)
