PHP - 生产环境的合理/优雅/优雅错误处理

Question

I'm writing a PHP web application which will be running under a production environment in the not too distant future, and rather than use the non-user-friendly die(), I thought I'd come up with a Class that handles ErrorMessages.

Basically, my thought process is this:

1. If the web application is in debug/development mode, die() is OK.

2. If the web application is in production/live mode, don't disturb the user with the error message - instead continue as best as possible but send an e-mail to the admin, dumping the error message and anything else we can (e.g: logged in user, session details, IP address, time, etc.)

My (rough) code is as follows:

<?php
require_once('config.php');

class ErrorMessage
{
      private $myErrorDescription;

      public function __construct($myErrorDescription)
      {
           $this->myErrorDescription = (string) $myErrorDescription;

           if (DEBUG_MODE === true)
                die($myErrorDescription);
           else
                $this->sendEmailToAdministrator();
      }

      private function sendEmailToAdministrator()
      {
        // Send an e-mail to ERROR_LOGGING_EMAIL_ADDRESS with the description of the problem.
      }
} 

?>

This Class would be used as:

if (EXPECTED_OUTCOME) {
 // ...
}
else {
    new ErrorMessage('Application failed to do XYZ');
}

Is this a sensible approach or am I reinventing the wheel here? I know that frameworks often have solutions for Error Handling, but I'm not using one (and don't really want to).

That said, should I be using Exceptions and Throw for this instead? What are the pros/cons of this approach?

Answer 1

I would suggest using Exceptions.

You can switch php over to sending Exceptions instead of errors by doing this: (from PHP ErrorException Page)

<?php
function exception_error_handler($errno, $errstr, $errfile, $errline ) {
    throw new ErrorException($errstr, $errno, 0, $errfile, $errline);
}
set_error_handler("exception_error_handler");

/* Trigger exception */
strpos();
?>

Then in your code when you encounter an error condition throw an Exception

throw(new Exception("Meaningful Description", "optional error number"));

Exceptions can be typed so you can derive an instance so that you can target it in a catch

class MyRecoverableException extends Exception {}

Then in your code you can enclose code that may throw a potentially recoverable error in a try/catch block.

 try {
     $res = doSomething();
     if (!$res) throw new MyRecoverableException("Do Somthing Failed");
 } catch(MyRecoverableException $e){
     logError($e);
     showErrorMessage($e->getMessage());
 }

This is especially useful in Database Transactions

 try {
      $db->beginTransaction();
      // do a lot of selectes and inserts and stuff
      $db->commit();
 } catch (DBException $e){
      $db->rollback();
      logError($e);
      showErrorMessage("I was unable to do the stuff you asked me too");
 }

with error reporting turned on, an uncaught exception will give you a detailed stack trace that tells you where the exception was thrown.

with error reporting turned off you will get a 500 Error.