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 the lookup has been reported as complete via set_response_packet() or report_id_complete().

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

$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().

$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)
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.

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)
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->get_last_start_lookup_time()
Get the time of the last call to start_lookup(). If start_lookup() was never called or abort_remaining_lookups() has been called get_last_start_lookup_time() will return undef.