UltraDNS - Client API for the NeuStar UltraDNS Transaction Protocol

    use UltraDNS;

    # establish a secure connection
    my $udns = UltraDNS->connect("$host:$port", $sponsor, $username, $password);

    # Queue up one or more actions to be performed
    $udns->CreateARecord($zone);
    $udns->CreateCNAMERecord($zone);

    # Send actions as a single transaction
    $udns->commit(...); # throws exception on error

    # queue up and commit more requests on the same connection

    # Actions can return results. Each return value is a reference
    # to where the result will be stored when commit() is called.
    $result_ref1 = $udns->GetZoneInfo($zone);
    $result_ref2 = $udns->GetMXRecordsOfZone($zone);

    $udns->commit(...);

    # $result_ref values above now refer to the RPC::XML results for
    # each method, use ($$result_ref1)->value to get the value

    # utility method that calls commit and returns the dereferenced result
    $result = $udns->do( ...some method that queues a request... );

    $result = $udns->do( $udns->AutoSerialUpdateState );
    # $result is either 1 or 0 (no need to deref or call value() method)

    # also works for multiple method calls
    @results = $udns->do( ...multiple method calls... );

  $udns = UltraDNS->connect($host_and_port, $sponsor, $username, $password, $attr);

  $udns->commit;

  $udns->rollback;

  $result = $udns->do( $udns->SomeMethodThatReturnsAResult(...) );

  $result_ref = $udns->SomeMethodThatReturnsAResult(...);
  $udns->commit;
  $result = $$result_ref; # de-reference to get return value

  my ($a, $b, $c) = $udns->do(
      $udns->MethodReturningA(...),
      $udns->MethodReturningB(...),
      $udns->MethodReturningC(...)
  );

  $err = $udns->err;

  $errstr = $udns->errstr;

  $udns->trace($level);
  $prev = $udns->trace($level);
  $prev = $udns->trace;

    Boolean (0-false, 1-true)

    Note: Specify Boolean values as either True or False.

package UltraDNS;

use warnings;
use strict;
use Carp;

our $VERSION = '0.06';

use Symbol qw(gensym);
use Data::Dumper;
use IO::Socket::INET;
use Net::SSLeay qw(die_now die_if_ssl_error);

use UltraDNS::Parser;
use UltraDNS::Type;
use UltraDNS::Methods;


# initialise Net::SSLeay
Net::SSLeay::load_error_strings();
Net::SSLeay::SSLeay_add_ssl_algorithms();
Net::SSLeay::randomize();

sub connect {   ## no critic (ProhibitBuiltinHomonyms)
    my ($class, $host_and_port, $sponsor, $username, $password, $attr) = @_;
    $host_and_port ||= "api.ultradns.net:8755";

    my $version = $attr->{version} || '3.0';

    # create an underlying raw socket and connect it to the UltraDNS server
    my $socket = IO::Socket::INET->new(PeerAddr => $host_and_port)
        or croak ("Error connecting to $host_and_port: $!");

    # create a new SSL instance and link it to the socket
    $Net::SSLeay::trace = $attr->{ssl_trace} if $attr->{ssl_trace};
    my $ctx = Net::SSLeay::CTX_new() or die_now("Failed to create SSL_CTX $!");
    my $ssl = Net::SSLeay::new($ctx) or die_now("Failed to create SSL $!");
    Net::SSLeay::set_fd($ssl, fileno($socket));   # Must use fileno

    # connect and negotiate at the SSL level
    my $resp = Net::SSLeay::connect($ssl);
    die_if_ssl_error("SSL connect failed");

    my $self = bless {
        peer_addr => $host_and_port,
        user  => $username,
        fh    => $socket, # just to hold ref to underlying socket
        ssl   => $ssl,
        queue => [],
        err   => 0,
        errstr=> '',
    } => $class;

    $self->trace($attr->{trace} || $ENV{ULTRADNS_TRACE});

    $self->_send_xml( join "",
        "<?xml version=\"1.0\"?>",
        "<session>",
    ); # no reply at this point

    $self->OpenConnection($sponsor, $username, $password, $version);
    $self->NoAutoCommit(); # for transaction safety

    my $commit = $self->commit;
    # sanity check - probably not needed as commit() throws an exception
    # if the server returns a fault response
    $self->_throw_error("Initial setup failed: $$commit")
        unless $$commit eq 'Transaction succeeded';

    return $self;
}

sub DESTROY {
    # nothing extra needed, just let perl look after it
}

sub commit {
    my ($self) = @_;

    my $queue = $self->{queue};
    # reset the object state
    $self->{queue}  = [];
    $self->{err}    = 0;
    $self->{errstr} = '';

    $self->_trace(sprintf "committing %d requests (+1 transaction)\n", scalar @$queue);

    my $xml = join "\n", map { $_->{xml} } @$queue;
    $self->_send_xml( "<transaction>\n$xml</transaction>\n" );

    $self->{stats}{transactions}++;

    my ($responses, $response_xml) = $self->_get_responses;

    # Shift the @$responses into the result slots in @$queue.
    # We expect one more item in @$responses than @$queue because @$responses
    # should have an extra 'Transaction succeeded' at the end.
    while (@$queue) {
        croak "Didn't get responses for all methods in transaction"
            if @$responses == 0;
        my $slot     = shift @$queue;
        my $response = shift @$responses;
        my $xml      = shift @$response_xml;
        $self->_throw_error("Unexpected response: $response ($xml)")
            if not UNIVERSAL::can($response, 'is_fault');
        $self->_throw_fault($response->value, $slot->{shortmess})
            if $response->is_fault;
        $slot->{result} = $response->value;
    }
    my $response = shift @$responses;
    $self->_throw_fault($response->value, "commit")
        if $response->is_fault;
    $self->_throw_error("Unexpected extra responses after commit")
        if @$responses;

    return $response->value;
}


sub _throw_fault {
    my ($self, $fault, $what) = @_;
    # record the error details in the object
    my $err    = $self->{err}    = $fault->code;
    my $errstr = $self->{errstr} = $fault->string;
    my $msg = "$what failed with server-side error $err: $errstr";
    return $self->_throw_error($msg); # doesn't return
}

sub rollback {
    shift->{queue} = [];
    return;
}

sub do {
    my ($self, @result_refs) = @_;
    croak "Can't call do() without an UltraDNS object reference"
        unless ref $self and UNIVERSAL::isa($self, __PACKAGE__);

    my $queue = $self->{queue};

    $self->_throw_error(sprintf "do() called with %d arguments but %d actions are queued (%s)",
            scalar @result_refs, scalar @$queue,
            join(", ", map { "$_->{method} at $_->{shortmess}" } @$queue) )
        if scalar @result_refs != scalar @$queue;

    $self->_throw_error("do() called in scalar context but with more than one argument")
        if not wantarray and @result_refs > 1;

    # we're asked to do nothing, so we return nothing
    return unless @result_refs;

    $self->commit;

    my @results = map { ($$_)->value } @result_refs;

    return $results[0] if not wantarray;
    return @results;
}

sub eval {  ## no critic (ProhibitBuiltinHomonyms)
    my @results = eval { shift->do( @_ ) };
    return @results; # empty if do() threw an exception
}

sub err    { return shift->{err}    }
sub errstr { return shift->{errstr} }

sub trace { ## no critic (RequireArgUnpacking)
    my $self = shift;
    my $prev = $self->{trace} || 0;
    $self->{trace} = shift || 0 if @_;
    $self->_trace("trace level set to $self->{trace}") if $self->{trace} or $prev;
    return $prev;
}


# ---


sub _description {
    my $self = shift;
    return sprintf "UltraDNS %s@%s", $self->{user}, $self->{peer_addr};
}


# _throw_error message shouldn't have newline at end
sub _throw_error {
    my $self = shift;
    $self->_trace("error: @_\n");
    croak $self->_description . " error: @_";
}
sub _warn  { carp  shift->_description . ": @_\n";     return }
# _trace message argument should have newline at end
sub _trace { warn  "UltraDNS: @_" if shift->{trace};   return }


sub _send_xml {
    my ($self, $xml) = @_;
    $self->_trace("_send_xml $xml") if $self->{trace} >= 2;

    Net::SSLeay::write($self->{ssl}, "$xml\r\n")
        or $self->_throw_error("sending request: $!");

    return;
}


sub _get_xml {
    my $self = shift;

    $self->_trace("_get_xml awaiting response") if $self->{trace} >= 2;

    # if we always use a transaction then we can use </methodResponses> (note the plural)
    # to identify the end of the server response to our request, saving ourselves
    # a whole bunch of headaches and inefficiencies
    my $response_body = Net::SSLeay::ssl_read_until($self->{ssl}, "</methodResponses>");
    $self->_trace(Dumper($response_body)) if $self->{trace} >= 2;

    return $response_body;
}


sub _get_responses {
    my ($self) = @_;

    my $response_body = $self->_get_xml;

    # RPC::XML can't handle the UltraDNS methodResponses (plural)
    # so we chop out and process each individual methodResponse in turn
    my @response_xml;
    my @responses;
    while ($response_body =~ s{(<methodResponse>.*?</methodResponse>)}{}m) {
        my $xml = $1;
        push @response_xml, $xml;
        my $resp = UltraDNS::Parser->_parse_rpc_xml($xml);
        push @responses, $resp;
        print "XML:  $xml:\nPerl: ".Dumper($resp) if $self->{trace} >= 3;
    }

    $self->_throw_error("No responses found in $response_body")
        unless @responses;
    $self->_trace("_get_responses received ".scalar(@responses)." responses")
        if $self->{trace} >= 2;

    # cleanse and sanity check the remaining rump of $response_body
    $response_body =~ s{<\?xml version=".*?"\?>}{};
    $response_body =~ s{\s*<methodResponses>\s*</methodResponses>\s*}{};
    if ($response_body ne '') {
        $self->_warn("Unprocessed remnants in response body: '$response_body'");
    }
    
    return  \@responses unless wantarray;
    return (\@responses, \@response_xml);
}


sub AUTOLOAD {  ## no critic (RequireArgUnpacking)
    (my $method = our $AUTOLOAD) =~ s/.*::(?:UDNS_)?//;
    my $self = shift;

    # sanity check to avoid obscure errors when users do odd things
    croak sprintf "Can't call %s->%s() because '%s' isn't an UltraDNS object reference",
            $self, $method, $self
        unless ref $self and UNIVERSAL::isa($self, __PACKAGE__);

    return $self->_enqueue_method_call($method, \@_);
}


sub _shortmess { # much faster version of Carp::shortmess
    my ($self, $what) = @_;

    my ($pkg, $file, $line, $level);
    do { ($pkg, $file, $line) = caller(++$level) } while $pkg =~ /^UltraDNS\b/;

    my $shortmess = "$file line $line";
    $shortmess = "$what at $shortmess" if $what;

    return $shortmess;
}


sub _enqueue_method_call {
    my ($self, $method, $args) = @_;

    my $shortmess = $self->_shortmess($method);
    $self->_trace($shortmess)
        if $self->{trace};
    $self->{stats}{methods}{$method}++;

    my $xml = $self->_xml_for_method_call($method, $args);

    return $self->_enqueue_xml($xml, {
        method => $method,
        args => $args,
        shortmess => $shortmess,
    });
}


sub _enqueue_xml {
    my ($self, $xml, $meta) = @_;
    my $queue = $self->{queue};
    push @$queue, { %{ $meta || {} }, xml => $xml, result => undef };
    # return reference to the slot that will hold the result value for this method call
    return \$queue->[-1]{result};
}


sub _xml_for_method_call {
    my ($self, $method, $args) = @_;

    my $method_info = UltraDNS::Methods->_method_spec("UDNS_$method")
        or croak "Can't call unknown method '$method'"; # XXX could allow later

    my $arg_info = $method_info->{arg_info};
    if (@$args < @$arg_info) {
        croak sprintf "%s called with too few parameters (has %d parameters but %d only arguments were given)",
                $method, scalar @$arg_info, scalar @$args;
    }
    if (@$args > @$arg_info) {
        croak sprintf "%s called with too many parameters (has %d parameters but %d arguments were given)",
                $method, scalar @$arg_info, scalar @$args
            unless $method_info->{last_arg_repeats};
        # clone and pad out arg_info with copies of the final arg
        $arg_info = [ @$arg_info ];
        push @$arg_info, $arg_info->[-1] while @$arg_info < @$args;
    }

    my @value_xml;
    for my $arg_info (@$arg_info) {
        my $value = shift @$args;
        my $class = "RPC::XML::$arg_info->{type}";
        my $value_obj = $class->new($value);
        push @value_xml, sprintf "<param><value>%s</value></param>\n",
            $value_obj->as_string;
    }

    return "<methodCall><methodName>UDNS_$method</methodName><params>\n@value_xml</params></methodCall>\n";
}


1;

__END__