Metaname (NZ Domain Registrar) API Script to allow something approaching ALIAS (aka ANAME) records to sort of set the Apex of a zone to be a CNAME.

update_apex_alias.php

<?php

/** 
 * Go through all DNS Zones in your Metaname account and for any zone that have 
 *  a CNAME record called "_apex_", resolve the cname to an IP address and 
 *  update thea actual Apex A record (what you get when you resolve the domain 
 *  without a host) with that IP address.
 *
 *  So you can do like for your example.com zone
 *
 *     _apex_ CNAME host1.myhostingservers.com.
 *    www     CNAME _apex_
 *
 *  and (after running this) you can resolve example.com and will get the IP
 *  address of host1.myhostingservers.com (as it was when the script ran).
 
 */
 
include('lib/my_metaname.php');

$domains = $metaname->domain_names();
foreach($domains as $domain)
{
  if(!$domain->uses_dns_hosting)          continue;
  if(strlen(@$domain->redirected_to))     continue;
  
  echo $domain->name . "\n\n";
  
  $ApexAlias = NULL;
  $Apex      = NULL;
  $AliasIP   = NULL;
  
  // Find the apex A record, and the _apex_ CNAME
  //  record if it exists
  foreach($metaname->dns_zone($domain->name) as $rr)
  {
    if($rr->type === 'CNAME' && $rr->name === '_apex_')
    {
      $ApexAlias = $rr;
    }
    
    if($rr->type === 'A' && $rr->name === "{$domain->name}.")
    {
      $Apex = $rr;
    }
  }
  
  // If we have both then update the Apex with the Alias
  if($ApexAlias && $Apex)
  {
    // Allow relative alias, example...
    //    _alias_apex_ 3600 IN CNAME www
    //    www          3600 IN CNAME some.other.host.com.
    // would then set the apex to be the IP address of some.other.host.com.
    //  (if it resolves, unchanged otherwise).
    
    if(!preg_match('/\.$/', $ApexAlias->data))
    {
      $ApexAlias->data = $ApexAlias->data.'.'.$domain->name . '.';
    }
    
    // Resolve alias
    $AliasIP = gethostbyname($ApexAlias->data);
    if(!preg_match('/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/', $AliasIP))
    {
      echo "Unable to resolve Alias {$ApexAlias->data}\n";
      continue;
    }
    else
    {
      echo "  Apex : {$Apex->name} {$Apex->data}\n";
      echo "  Alias: {$ApexAlias->data} ({$AliasIP})\n";
      
      // Update if it needs to be
      if($Apex->data !== $AliasIP)
      {
        $NewApex = array(
          'name' => $Apex->name,
          'type' => $Apex->type,
          'aux'  => null,
          'ttl'  => $Apex->ttl,
          'data' => $AliasIP
        );
        
        try
        {
          $metaname->update_dns_record($domain->name, $Apex->reference, $NewApex);
          echo "  Updated\n";
        }
        catch(JsonRpcFault $E)
        {
          echo "  Error Updating New Apex\n";        
          print_r($NewApex);
          echo "\n";
          switch($E->getCode())
          {
            case -4:  echo "  Invalid Domain\n"; break;
            case -3:  echo "  Domain Not Found\n"; break;
            case -12: echo "  DNS Not Enabled\n"; break;
            case -16: echo "  Invalid Record\n"; break;
            case -17: echo "  Record Not Found\n"; break;
            default:  
              {
                echo "  {$E->getMessage()}\n";
                echo "  Unknown Error {$E->getCode()}\n"; 
                break;
              }
          }
        }
      }
      else
      {
        echo "  No Change\n";
      }
    }
  }
  
  
  echo str_repeat('-', 80) ."\n\n";
}

?>