Question

I’ve been doing some research on php error handling as well as exception handling.

For instance, to handle user errors, it is best to use set_error_handler() for user errors. Example code:

// Destinations
define("ADMIN_EMAIL", "[e-mail]"); 
define("LOG_FILE", "/my/home/errors.log");

// Destination types
define("DEST_EMAIL", "1");
define("DEST_LOGFILE", "3");

/**
* my_error_handler($errno, $errstr, $errfile, $errline)
*
* Author(s): thanosb, ddonahue
* Date: May 11, 2008
* 
* custom error handler
*
* Parameters:
*  $errno:   Error level
*  $errstr:  Error message
*  $errfile: File in which the error was raised
*  $errline: Line at which the error occurred
*/

function my_error_handler($errno, $errstr, $errfile, $errline)
{  
 switch ($errno) {
 case E_USER_ERROR:
  // Send an e-mail to the administrator
  error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_EMAIL, ADMIN_EMAIL);

  // Write the error to our log file
  error_log("Error: $errstr \n Fatal error on line $errline in file $errfile \n", DEST_LOGFILE, LOG_FILE);
  break;

case E_USER_WARNING:
  // Write the error to our log file
  error_log("Warning: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
  break;

case E_USER_NOTICE:
  // Write the error to our log file
  error_log("Notice: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
  break;

default:
  // Write the error to our log file
  error_log("Unknown error [#$errno]: $errstr \n in $errfile on line $errline \n", DEST_LOGFILE, LOG_FILE);
  break;
}

// Don't execute PHP's internal error handler
return TRUE;
}


// Use set_error_handler() to tell PHP to use our method
$old_error_handler = set_error_handler("my_error_handler");

Code found at http://www.stanford.edu/dept/its/communications/webservices/wiki/index.php/How_to_perform_error_handling_in_PHP.

Then for fatal errors:

register_shutdown_function('handleShutdown');

function handleShutdown() {
    $error = error_get_last();
    if($error !== NULL){
        $info = "[SHUTDOWN] file:".$error['file']." | ln:".$error['line']." |    msg:".$error['message'] .PHP_EOL;
        yourPrintOrMailFunction($info);
    }
    else{
        yourPrintOrMailFunction("SHUTDOWN");
    }
}

Code found at How do I catch a PHP Fatal Error.

From what I can tell, it appears that this will cover essentially all errors that can occur within a script (as a very general statement – it’s hard to predict all errors). When developing a class, thought, it seems that it is suggested to use exceptions to handle them internally.

My question is whether or not these examples are generally considered appropriate to handle errors in a production setting, or if anything is blatantly incorrect or lacking.

In any case, are these functions attached to all files or set within a class?

Any help is appreciated.

Edit: I also meant to add, how would I stop a script if a certain error is encountered. Obviously, exit() or die() does the trick, but is there anything more appropriate to do so?

Answer 1

My question is whether or not these examples are generally considered appropriate to handle errors in a production setting, or if anything is blatantly incorrect or lacking.

Yes it is. You just have to be sure that you catch ALL generated exception.
I also want to remember you that if there is a synthax error in your scrip, or if your server is bad configured, php could output errors that are not handled because they are compile time errors.

n any case, are these functions attached to all files or set within a class?

Once you registered them (with set_error_handler) they are applied to every files that are called in your script apart from if one of your file redifine the handler.

and to stop a script, exit is the good way