PHP cannot catch Error from within included file

Question

i try to implement a fallback solution for when my database is not available. Somhow i do not manage to catch the error.

Call to create connection:

if(!$this->connection = mysqli_connect(
        $this->host,
        $this->name,
        $this->pass,
        $this->db
    )) { throw new Exception('Unable to connect to Database'); }

init.php to include dbClass

require_once __DIR__ . '/../classes/Database.php';
$db = new Database();
$connection = $db->getConnection();

actual usage with try catch wrap

try {
        include __DIR__ . '/../out/script/content/config/init_direct.php';
        ... do stuff regulary
}catch (Exception $e) {
        ... do fallback stuff
}

i do not get into the catch block. for test purpose i just set the database offline.

Dont throw Exception, it 'll block you script and prevent your alternate solution to work. — ThinkTank, Oct 15 '15 at 14:25
now receive the error in my log - still not able to catch it ... [15-Oct-2015 16:26:14 Europe/Berlin] PHP Warning: mysqli_connect(): (HY000/2002): No connection could be made because the target machine actively refused it. in C:\xampp\htdocs\finevisuals\out\script\content\classes\Database.php on line 29 [15-Oct-2015 16:26:14 Europe/Berlin] PHP Fatal error: Call to a member function set_charset() on boolean in C:\xampp\htdocs\finevisuals\out\script\content\classes\Database.php on line 31 — Frnak, Oct 15 '15 at 14:27
those aren't execeptions. they're warnings/errors. unless your `Database` class actually throws an exception, there'll be nothing to catch. — Marc B, Oct 15 '15 at 14:34
Well this seems to be true for the first one - however, the second is a Fatal error - shouldn't this get caught? — Frnak, Oct 15 '15 at 14:39

score 1 · Accepted Answer · edited May 23 '17 at 11:44

there are several problems with your approach

First, your problem is insufficient debugging. You just assume that exception has been thrown, but in reality it weren't.
Second, this happened because mysqli_connect returns an object, not boolean you expect.
Third, as you've been told in the comments, errors aren't exceptions and you cannot catch them.

Anyway, with mysqli you don't need to throw exceptions manually - this extension can throw them by itself, so, all you need is to set the proper mode up - an exception will be thrown which will be caught all right.

PHP cannot catch Error from within included file

1 Answers1