1Mail::SpamAssassin::AsyUnsceLrooCpo(n3t)ributed Perl DocMuamieln:t:aStpiaomnAssassin::AsyncLoop(3)
2
6 Mail::SpamAssassin::AsyncLoop - scanner asynchronous event loop
7
9 An asynchronous event loop used for long-running operations, performed
10 "in the background" during the Mail::SpamAssassin::check() scan
11 operation, such as DNS blocklist lookups.
12
14 $obj = $async->start_lookup($obj)
15 Register the start of a long-running asynchronous lookup operation.
16 $obj is a hash reference containing the following items:
17 key (required)
19 A key string, unique to this lookup. This is what is reported
20 in debug messages, used as the key for "get_lookup()", etc.
21 id (required)
23 An ID string, also unique to this lookup. Typically, this is
24 the DNS packet ID as returned by DnsResolver's "bgsend" method.
25 Sadly, the Net::DNS architecture forces us to keep a separate
26 ID string for this task instead of reusing "key" -- if you are
27 not using DNS lookups through DnsResolver, it should be OK to
28 just reuse "key".
29 type (required)
31 A string, typically one word, used to describe the type of
32 lookup in log messages, such as "DNSBL", "MX", "TXT".
33 poll_callback (optional)
35 A code reference, which will be called periodically during the
36 background-processing period. If you will be performing an
37 async lookup on a non-DNS-based service, you will need to
38 implement this so that it checks for new responses and calls
39 "set_response_packet()" or "report_id_complete()" as
40 appropriate. DNS-based lookups can leave it undefined, since
41 DnsResolver::poll_responses() will be called automatically
42 anyway.
43 The code reference will be called with one argument, the $ent
45 object.
46 completed_callback (optional)
48 A code reference which will be called when an asynchronous task
49 (e.g. a DNS lookup) is completed, either normally, or aborted,
50 e.g. by a timeout.
51 When a task has been reported as completed via
53 "set_response_packet()" the response (as provided to
54 "set_response_packet()") is stored in $ent->{response_packet}
55 (possibly undef, its semantics is defined by the caller). When
56 completion is reported via "report_id_complete()" or a task was
57 aborted, the $ent->{response_packet} is guaranteed to be undef.
58 If it is necessary to distinguish between the last two cases,
59 the $ent->{status} may be examined for a string 'ABORTING' or
60 'FINISHED'.
61 The code reference will be called with one argument, the $ent
63 object.
64 zone (optional)
66 A zone specification (typically a DNS zone name - e.g. host,
67 domain, or RBL) which may be used as a key to look up per-zone
68 settings. No semantics on this parameter is imposed by this
69 module. Currently used to fetch by-zone timeouts.
70 timeout_initial (optional)
72 An initial value of elapsed time for which we are willing to
73 wait for a response (time in seconds, floating point value is
74 allowed). When elapsed time since a query started exceeds the
75 timeout value and there are no other queries to wait for, the
76 query is aborted. The actual timeout value ranges from
77 timeout_initial and gradually approaches timeout_min (see next
78 parameter) as the number of already completed queries
79 approaches the number of all queries started.
80 If a caller does not explicitly provide this parameter or its
82 value is undefined, a default initial timeout value is settable
83 by a configuration variable rbl_timeout.
84 If a value of the timeout_initial parameter is below
86 timeout_min, the initial timeout is set to timeout_min.
87 timeout_min (optional)
89 A lower bound (in seconds) to which the actual timeout
90 approaches as the number of queries completed approaches the
91 number of all queries started. Defaults to 0.2 *
92 timeout_initial.
93 $obj is returned by this method.
95 $obj = $async->get_lookup($key)
97 Retrieve the pending-lookup object for the given key $key.
98 If the lookup is complete, this will return "undef".
100 Note that a lookup is still considered "pending" until
102 "complete_lookups()" is called, even if it has been reported as
103 complete via "set_response_packet()" or "report_id_complete()".
104 @objs = $async->get_pending_lookups()
106 Retrieve the lookup objects for all pending lookups.
107 Note that a lookup is still considered "pending" until
109 "complete_lookups()" is called, even if it has been reported as
110 complete via "set_response_packet()" or "report_id_complete()".
111 $async->log_lookups_timing()
113 Log sorted timing for all completed lookups.
114 $alldone = $async->complete_lookups()
116 Perform a poll of the pending lookups, to see if any are completed;
117 if they are, their <completed_callback> is called with the entry
118 object for that lookup.
119 If there are no lookups remaining, or if too long has elapsed since
121 any results were returned, 1 is returned, otherwise 0.
122 $async->abort_remaining_lookups()
124 Abort any remaining lookups.
125 $async->set_response_packet($id, $pkt, $key, $timestamp)
127 Register a "response packet" for a given query. $id is the ID for
128 the query, and must match the "id" supplied in "start_lookup()".
129 $pkt is the packet object for the response. A parameter $key
130 identifies an entry in a hash %{$self->{pending_lookups}} where the
131 object which spawned this query can be found, and through which
132 futher information about the query is accessible.
133 If this was called, $pkt will be available in the
135 "completed_callback" function as "$ent-<gt"{response_packet}>.
136 One or the other of "set_response_packet()" or
138 "report_id_complete()" should be called, but not both.
139 $async->report_id_complete($id,$key,$key,$timestamp)
141 Register that a query has completed, and is no longer "pending".
142 $id is the ID for the query, and must match the "id" supplied in
143 "start_lookup()".
144 One or the other of "set_response_packet()" or
146 "report_id_complete()" should be called, but not both.
147 $time = $async->last_poll_responses_time()
149 Get the time of the last call to "poll_responses()" (which is
150 called from "complete_lookups()". If "poll_responses()" was never
151 called or "abort_remaining_lookups()" has been called
152 "last_poll_responses_time()" will return undef.
153perl v5.10.1 2010-03-16 Mail::SpamAssassin::AsyncLoop(3)