IO::Lambda::DNS - DNS queries lambda style
The module provides access to asynchronous DNS queries through Net::DNS.
Two function doing the same operation are featured: constructor new and predicate dns.
use strict;
use IO::Lambda::DNS qw(:all);
use IO::Lambda qw(:all);
# simple async query
my $reply = IO::Lambda::DNS-> new( "www.site.com" )-> wait;
print (($reply =~ /^\d/) ? "Resolved to $reply\n" : "Error: $reply\n");
# parallel async queries
lambda {
for my $site ( map { "www.$_.com" } qw(google yahoo perl)) {
context $site, 'MX', timeout => 0.25;
dns { print shift-> string if ref($_[0]) }
}
}-> wait;
Accepted options specific to the module are timeout or deadline (in seconds) and retry (in times). All other options, such as nameservers, dnssec etc etc are passed as is to the Net::DNS::Resolver constructor. See its man page for details.
Constructor new accepts Net::DNS-specific options (see OPTIONS above) and query, and returns a lambda. The lambda accepts no parameters, return either IP address or response object, depending on the call, or an error string.
new ($CLASS, %OPTIONS, $HOSTNAME) :: () -> $IP_ADDRESS|$ERROR
In simple case, accepts $HOSTNAME string, and returns a string, either IP address or an error. To distinguish between these use /^\d/ regexp, because it is guaranteed that no error message will begin with digit, and no IP address will begin with anything other than digit.
dns (%OPTIONS, ($PACKET | $HOSTNAME $TYPE)) :: () -> $RESPONSE|$ERROR
In complex case, accepts either $HOSTNAME string and $TYPE string, where the latter is A, MX, etc DNS query type. See "new" in Net::DNS::Resolver. Returns either Net::DNS::RR object or error string.
Predicate wrapper over new.
dns (%OPTIONS, $HOSTNAME) -> $IP_ADDRESS|$ERROR dns (%OPTIONS, ($PACKET | $HOSTNAME $TYPE)) -> $RESPONSE|$ERROR
IO::Lambda, Net::DNS::Resolver.
Dmitry Karasik, <dmitry@karasik.eu.org>.
