Marc A. Lehmann

NAME

EV::ADNS - lightweight asynchronous dns queries using EV and libadns

SYNOPSIS

 use EV;
 use EV::ADNS;

 EV::ADNS::submit "example.com", EV::ADNS::r_addr, EV::ADNS::qf_cname_loose, sub {
    my ($status, $expires, @a) = @_;
    warn $a[0]; # "127.13.166.3" etc.
 };

 EV::run;

DESCRIPTION

This is a simple interface to libadns (asynchronous dns) that integrates well and automatically into the EV event loop. The documentation for libadns is vital to understand this module, see http://www.chiark.greenend.org.uk/~ian/adns/.

You can use it only with EV (directly or indirectly, e.g. via Glib::EV). Apart from loading and using the submit function you need not do anything (except run an EV event loop).

OVERVIEW

All the constants/enums from adns.h are available in the EV::ADNS namespace, without the adns_ prefix, i.e. adns_r_a becomes EV::ADNS::r_a and so on.

FUNCTIONS

$query = EV::ADNS::submit "domain", $rrtype, $flags, $cb

Submits a new request to be handled. See the adns_submit C function description for more details. The function optionally returns a query object which can be used to cancel an in-progress request. You do not need to store the query object, even if you ignore it, the query will proceed.

The callback will be invoked with a result status, the time the resource record validity expires and zero or more resource records, one scalar per result record. Example:

   sub adns_cb {
      my ($status, $expires, @rr) = @_;
      if ($status == EV::ADNS::s_ok) {
         use JSON::XS;
         warn encode_json \@rr;
      }
   }

The format of result records varies considerably, here is some cursory documentation of how each record will look like, depending on the query type:

EV::ADNS::r_a, EV::ADNS::r_addr

An IPv4 address in dotted quad (string) form.

EV::ADNS::r_ns_raw, EV::ADNS::r_cname, EV::ADNS::r_ptr, EV::ADNS::r_ptr_raw

The resource record as a simple string.

EV::ADNS::r_txt

An arrayref of strings.

EV::ADNS::r_ns

A "host address", a hostname with any number of addresses (hint records).

The record will be an arrayref with domainname, adns status and any number of associated addresses: ["domain", adns_status, addr...].

EV::ADNS::r_hinfo

An arrayref consisting of the two strings.

EV::ADNS::r_rp, EV::ADNS::r_rp_raw

An arrayref with two strings.

EV::ADNS::r_mx

An arrayref consisting of the priority and a "host address" (see EV::ADNS::r_ns). Example:

   [10, [["alt3.aspmx.l.google.com", 0, "64.233.189.27", "2404:6800:4008:c07::1a"]]]
EV::ADNS::r_mx_raw

An arrayref consisting of the priority and the hostname, e.g. [10, "mail.example.com"].

EV::ADNS::r_soa, EV::ADNS::r_soa_raw

An arrayref consisting of the primary nameserver, admin name, serial, refresh, retry expire and minimum times, e.g.:

  ["ns.example.net", "hostmaster@example.net", 2000001102, 86400, 21600, 2592000, 172800]

The "raw" form doesn't mangle the e-mail address.

EV::ADNS::r_srv_raw

An arrayref consisting of the priority, weight, port and hostname, e.g.:

   [10, 10, 5060, "sip1.example.net"]
EV::ADNS::r_srv

The same as EV::ADNS::r_srv_raw, but the hostname is replaced by a "host address" (see EV::ADNS::r_ns).

EV::ADNS::r_unknown

A single octet string with the raw contents.

anything else

Currently undef.

$query->cancel

Cancels a request that is in progress.

EV::ADNS::reinit undef, $resolvdata_or_undef

Cancels all outstanding queries, frees all adns state and reinitialises it. It is highly recommended to only call this when there are no outstanding requests.

The first argument must currently be specified as undef.

The second argument can be missing or undef; in which case the normal initialisation is done (such as reading the resolv.conf), or it might be a stirng, in which case no config files or environment variables will be read and the given string will be interpreted as the resolv.conf contents.

SEE ALSO

EV, Net::ADNS another interface to adns, maybe better, but without real support to integrate it into other event loops.

AUTHOR

 Marc Lehmann <schmorp@schmorp.de>
 http://home.schmorp.de/