NAME¶
Net::DNS::Async - Asynchronous DNS helper for high volume applications
SYNOPSIS¶
use Net::DNS::Async;
my $c = new Net::DNS::Async(QueueSize => 20, Retries => 3);
for (...) {
$c->add(\&callback, @query);
}
$c->await();
sub callback {
my $response = shift;
...
}
DESCRIPTION¶
Net::DNS::Async is a fire-and-forget asynchronous DNS helper. That is, the user
application adds DNS questions to the helper, and the callback will be called
at some point in the future without further intervention from the user
application. The application need not handle selects, timeouts, waiting for a
response or any other such issues.
If the same query is added to the queue more than once, the module may combine
the queries; that is, it will perform the query only once, and will call each
callback registered for that query in turn, passing the same
Net::DNS::Response object to each query. For this reason, you should not
modify the Net::DNS::Response object in any way lest you break things horribly
for a subsequent callback.
This module is similar in principle to POE::Component::Client::DNS, but does not
require POE.
CONSTRUCTOR¶
The class method new(...) constructs a new helper object. All arguments are
optional. The following parameters are recognised as arguments to
new():
- QueueSize
- The size of the query queue. If this is exceeded, further calls to
add() will block until some responses are received or time
out.
- Retries
- The number of times to retry a query before giving up.
- Timeout
- The timeout for an individual query.
METHODS¶
- $c->add($callback, @query)
- Adds a new query for asynchronous handling. The @query arguments are those
to Net::DNS::Resolver-> bgsend(), q.v. This call will block if
the queue is full. When some pending responses are received or timeout
events occur, the call will unblock.
The user callback will be called at some point in the future, with a
Net::DNS::Packet object representing the response. If the query timed out
after the specified number of retries, the callback will be called with
undef.
- $c->await()
- Flushes the queue, that is, waits for and handles all remaining
responses.
BUGS¶
The test suite does not test query timeouts.
SEE ALSO¶
Net::DNS, POE::Component::Client::DNS
COPYRIGHT¶
Copyright (c) 2005-2006 Shevek. All rights reserved.
This program is free software; you can redistribute it and/or modify it under
the same terms as Perl itself.