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Mail::SpamAssassin::AsyncLoop.3pm

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.