Help with exceptions

[fjm]

Hello everyone,

Can someone please give me a hand with an exception? I cannot seem to get this to work correctly or I just don't fully understand exceptions.

It's my assumption that I should be able to trap an exception, log that exception and have the code continue, not halt. What happens is that my code just stops dead instead of continuing.

I don't have a subclass to the exception class and maybe that is the problem. Can someone please shine a light on this for me?

Thanks.

Here is what I have so far.

    $ex = new Exception('My message');
    try
    {
      foreach ($clients as $_client)
      {
        try
        {
          // execute some code here
        }
        catch (Exception $ex)
        {
          throw $ex;
        }
      }
    // execute something here
    }
    catch (Exception $ex)
    {
      throw $ex;
    }

[Dormilich]

@fjm
that's because you throw the Exception inside the catch block (the catch block catches an Exception thown in the according try block), where it isn't caught. this should result in a "uncaught exception" error.

usually you throw the (primary) exception in the try block. the catch block is there to correct things, that may be corrupted by the failing code (i.e. tell the user that today the DB doesn't work…)

try {
    // …
    if (requirement not met)
    {
        throw new Exception($msg, $code);
    }
}
catch (Exception $e)
{
    logException($e);
    // do something to put things right
}

you may re-throw an Exception in the catch block, although you should only do that, if necessary (otherwise consider catching the Exception later)

try {
    // in a subfunction the Exception may be thrown
    myfunction();
}
catch (Exception $e)
{
    // put things right
}

PS: consider using the ErrorException class, there you can specify the severity level.

[fjm]

Hi Dormilich, thanks for the hand and the great examples. I've not used exceptions until now because I have a block of code that is really important to know if something goes wrong with.

The exception you see in the catch block was not originally in there, I put it there while trying to follow a tutorial on try/catch. Even with the exception removed, the code still stops dead and I need it to keep going. I also need to be made aware of the error whether that is through an error log or some other method.

What am I doing wrong that is making the code halt?

[Dormilich]

I guess there is an Exception thrown in your code (but it's hard to tell without seeing it)

try*

try {
// your code as is
}
catch (Exception $e)
{
// echo message
    echo $e->getMessage(), "\n\n", $e->getTraceAsString();
// abort script for now
    exit;
}

you may also want to set a default exception handler (set_exception_h andler())


* what a pun…

[fjm]

Thanks again for the hand.

Here is what I now have. It is not halting anymore but I am not getting any errors either in my log.

Just to test to see if I could get this thing to work, I copied the block of code to three different places. It's working, but I need to get this right.

Thanks again for the help. Can you please tell me what I need to do to get this correct? I understand the principle behind exceptions but I'm having a hard time putting it into practice. One thing is certain... The last three lines in the code are incorrect because they need to be in the foreach loop so that narrows it down a little. :)

    $ex = new Exception('An error message');
    try
    {
      foreach ($xdop as $_xdop)
      {
        $page = GenerateRpt($_xdop, $rptop);
        $message = new Message("$title", "$page");
 
        try
        {
          $message->add($_xdop['email']);
        }
        catch (complianceException $ex)
        {
          $message->from("$email");
          $mailer = new Mailer(Transport::newInstance("$host"));
          $mailer->send($message);
        }
 
        $message->from("$email");
        $mailer = new Mailer(Transport::newInstance("$host"));
        $mailer->send($message);
      }
      $message->From("$email");
      $mailer = new Mailer(Transport::newInstance("$host"));
      $mailer->send($message);

[fjm]

Dormilich,

I'm curious.. Is set_exception_h andler() to be used in place of a myException class that would extend php's Exception class or would I use both of them?

Thanks again!

[Dormilich]

@fjm
set_exception_h andler() is used to catch uncaught exceptions

PS: I'll look into your code later, but there is a catch block missing (in the posted code)

[fjm]

Thanks Dormilich. I'll check back in the morning, well... the afternoon. It wound up to be another late night. :)