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.