php - Suppressing PDO Warnings

Question

I'm trying to display a server status, based upon whether the database can be connected to or not. With the old school mysql_connect() and mysqli_connect() it was easy. I'm trying to stay modern, so I'm using PDO, but I can't figure out how-to suppress the default warning. From what I can tell, you need to use the getMessage() function for it to print the PDO warning, but I'm not using it.

Here's my code:

8  $dbstatus = 1;
9  try {
10  $db = new PDO($dbms . ':host=' . $dbhost . ';port=' . $dbport . ';dbname=' . $dbname, $dbuser, $dbpasswd);
11  $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
12 } catch(PDOException $e) {
13  $dbstatus = 0;
14 }
15 if($dbstatus == 1) {
16  echo '<span style="color: green">DB Up</span>';
17 } else {
18  echo '<span style="color: red">DB Down</span>';
19  exit;
20 }

All the connection variables are supplied and correct, except the $dbhost, which is intentionally broken to test this. Now, it produces the desired results, but is also prints a warning message too:

Warning: PDO::__construct(): php_network_getaddresses: getaddrinfo failed: No such host is known. in C:xampphtdocscdincludesdbconnect.php on line 10

If I correct the $dbhost variable, it works fine, so I know the issue isn't with the PDO statement being usable.

Any ideas on what I'm missing?

Solution

I used a variation of what was supplied by jeroen:

if(filter_var(gethostbyname($dbhost), FILTER_VALIDATE_IP)) {
 $dbstatus = 1;
 try {
  $db = new PDO($dbms . ':host=' . $dbhost . ';port=' . $dbport . ';dbname=' . $dbname, $dbuser, $dbpasswd, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
 } catch(PDOException $e) {
  $dbstatus = 0;
 }
} else {
 $dbstatus = 0;
}
if($dbstatus == 1) {
 echo '<span style="color: green">DB Up</span>';
} else {
 echo '<span style="color: red">DB Down</span>';
 exit;
}

Thank you for the help and I hope this helps someone else! ^^

Answer 1

The only thing I can see here, is that you tell PDO to throw exceptions after you have tried to open the connection. That is most likely too late.

What you could do instead, is send that option to the constructor directly using the 4th parameter:

try {
  $opts = array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION);
  $db = new PDO($dbms . ':host=' . $dbhost . ';port=' . $dbport . ';dbname=' . $dbname,
                $dbuser, $dbpasswd, $opts);
} catch(PDOException $e) {
...

That will probably solve your problem.

Edit: If the host name is provided by the user, you could validate it before sending it to the PDO constructor.

For example using:

if (filter_var(gethostbyname($user_provided_host_name), FILTER_VALIDATE_IP)) {
  // valid hostname / ip address
}

That will work for domain names, localhost and ip addresses.