Net::DNS::Async(3pm)					User Contributed Perl Documentation				      Net::DNS::Async(3pm)

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.

perl v5.10.0							    2008-10-03						      Net::DNS::Async(3pm)