mysqli try-catch oddities?

[Serenarules]

When I put a try-catch around mysqli_connect, specifically passing in bad values, the error never seems to catch. Any clue why this is?

define('_CONN_HOST_', 'foo');
 
define('_CONN_USER_', 'bar');
 
define('_CONN_PASS_', 'this');
 
define('_CONN_DATA_', 'that');
 
final class Connection {
 
function __construct($host = _CONN_HOST_, $user = _CONN_USER_, $pass = _CONN_PASS_, $data = _CONN_DATA_) {
 
try {
 
mysqli_connect($host, $user, $pass, $data);
 
} catch (Exception $e) {
 
echo 'Error';
 
}
 
}
 
}
 
$conn = new Connection();
 
unset($conn); 

[wills0n]

c/p, php.net/mysqli_connect :
The mysqli_connect() function attempts to open a connection to the MySQL Server running on host which can be either a host name or an IP address. Passing the NULL value or the string "localhost" to this parameter, the local host is assumed. When possible, pipes will be used instead of the TCP/IP protocol. If successful, the mysqli_connect() will return an object representing the connection to the database, or FALSE on failure.

[Dr Livingston]

I use

...
if (! $connection = mysql_connect( '...', '...', '...' ) ) {
throw new SqlException( mysql_error( $connection ) );
return false;
}
mysql_select_db( '...', $connection );
return true;
... 

// somewhere in your script you have this
...
try {
$db = new MySqlConnection;
} catch( SqlException $e ) {
die( $e -> getMessage() );
}
... 

In my view, it is far better to throw an exception and catch it later at a higher layer. In doing so, if at that layer you don't want or need to handle the exception, you throw it again to a (yet) higher layer.

Okay, it's not for the latest mysql extension but it should still be the same principle no?

[Serenarules]

Livingston, thanks. I also do my real error handling all at the top script level. I just moved to PHP5/mysqli and was testing things, hence the odd code. I'll try yours out later but if I'm not mistaken, and I may be, even if the "$connection = mysql_connect(...)" test fails, the mysqli engine will produce it's own exception. Unless you turn off errors with @. If you do that, you can't catch errors unless you DO test the return. This is totally unlike the way any other function is handled. My question was basically this: is this by design, or a fluke?

[Dr Livingston]

In that event I don't have an answer for you since I've not used the new features available to mysql with this extension

However I'll try to simulate the effect you have (with @) with the bog standard extension, to see if @ effects the return value

[Serenarules]

Thanks regardless. I think the mysql/mysqli connect functions, and maybe a few others, handle errors internally and simply die with a custoim message instead of throwing exceptions. I tested a few other scenarios and it seems impossible to trap errors from them without resorting specifically to testing return values together with the mysql_error/mysqli_connect_error functions. Oh well...