Did you copy and paste that code? Do you know that when calling can() you are
using $ojb instead of $obj?
--------
Paul Anderson -- VE3HOP
On 2012-09-12, at 9:17 AM, pangj <pa...@riseup.net> wrote:
> Hi,
>
> Today I wrote a script for validate a dns record from the specified DNS
> server, the subroutine is:
>
> sub validate_dns {
> my $host = shift; # a host, for example, www.google.com
> my $value = shift; # the host's DNS value, may be a CNAME or an iP
> address
> my $dns = shift; # DNS server, for example, 8.8.8.8
>
> my $method = $value =~ /^\d+\.\d+\.\d+\.\d+$/ ? "address" : "cname";
> my $res = Net::DNS::Resolver->new(nameservers => [$dns]);
> my $answer = $res->query($host);
>
> if (defined $answer) {
> return 1 if ($answer->answer)[0]->$method eq $value;
> }
>
> return 0;
> }
>
> Sometime the $host's value is an A record, thus it has a address() method.
> Sometime the $host's value is a CNAME record, it has a cname() method.
> When calling the subroutine abve with the wrong arguments, it will cause
> warnings.
> For example,
> validate_dns("www.nsbeta.info","1.2.3.4","8.8.8.8");
> This will throw up warnings, because www.nsbeta.info is a CNAME but the
> subroutine calls address() method which belongs to the A record.
>
> So I modified the subroutine as:
>
> sub validate_dns {
> my $host = shift;
> my $value = shift;
> my $dns = shift;
>
> my $res = Net::DNS::Resolver->new(nameservers => [$dns]);
> my $answer = $res->query($host);
>
> if (defined $answer) {
> my $obj = ($answer->answer)[0];
> if ($ojb->can("address") ) {
> return 1 if $obj->address eq $value;
> } elsif ($ojb->can("cname") ) {
> return 1 if $obj->cname eq $value;
> }
> }
>
> return 0;
> }
>
> This totally can't work, it seems $obj->can() method has no effect.
> What's wrong with my code? thanks.
>
>
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