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Eine Error Exception.
Die Schwere einer Exception
Beispiel #1 Verwenden von set_error_handler() zum Verändern von Fehlermeldungen innerhalb ErrorException.
<?php
function exception_error_handler($errno, $errstr, $errfile, $errline ) {
throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}
set_error_handler("exception_error_handler");
/* Exception ausloesen */
strpos();
?>
Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:
Fatal error: Uncaught exception 'ErrorException' with message 'Wrong parameter count for strpos()' in /home/bjori/tmp/ex.php:8
Stack trace:
#0 [internal function]: exception_error_handler(2, 'Wrong parameter...', '/home/bjori/php...', 8, Array)
#1 /home/bjori/php/cleandocs/test.php(8): strpos()
#2 {main}
thrown in /home/bjori/tmp/ex.php on line 8
As noted below, it's important to realize that unless caught, any Exception thrown will halt the script. So converting EVERY notice, warning, or error to an ErrorException will halt your script when something harmlesss like E_USER_NOTICE is triggered.
It seems to me the best use of the ErrorException class is something like this:
<?php
function custom_error_handler($number, $string, $file, $line, $context)
{
// Determine if this error is one of the enabled ones in php config (php.ini, .htaccess, etc)
$error_is_enabled = (bool)($number & ini_get('error_reporting') );
// -- FATAL ERROR
// throw an Error Exception, to be handled by whatever Exception handling logic is available in this context
if( in_array($number, array(E_USER_ERROR, E_RECOVERABLE_ERROR)) && $error_is_enabled ) {
throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}
// -- NON-FATAL ERROR/WARNING/NOTICE
// Log the error if it's enabled, otherwise just ignore it
else if( $error_is_enabled ) {
error_log( $string, 0 );
return false; // Make sure this ends up in $php_errormsg, if appropriate
}
}
?>
Setting this function as the error handler will result in ErrorExceptions only being thrown for E_USER_ERROR and E_RECOVERABLE_ERROR, while other enabled error types will simply get error_log()'ed.
It's worth noting again that no matter what you do, "E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING, and most of E_STRICT" will never reach your custom error handler, and therefore will not be converted into ErrorExceptions. Plan accordingly.
E_USER_WARNING, E_USER_NOTICE, and any other non-terminating error codes, are useless and act like E_USER_ERROR (which terminate) when you combine a custom ERROR_HANDLER with ErrorException and do not CATCH the error. There is NO way to return execution to the parent scope in the EXCEPTION_HANDLER.
<?php
error_reporting(E_ALL);
define('DEBUG', true);
define('LINEBREAK', "\r\n");
error::initiate('./error_backtrace.log');
try
trigger_error("First error", E_USER_NOTICE);
catch ( ErrorException $e )
print("Caught the error: ".$e->getMessage."<br />\r\n" );
trigger_error("This event WILL fire", E_USER_NOTICE);
trigger_error("This event will NOT fire", E_USER_NOTICE);
abstract class error {
public static $LIST = array();
private function __construct() {}
public static function initiate( $log = false ) {
set_error_handler( 'error::err_handler' );
set_exception_handler( 'error::exc_handler' );
if ( $log !== false ) {
if ( ! ini_get('log_errors') )
ini_set('log_errors', true);
if ( ! ini_get('error_log') )
ini_set('error_log', $log);
}
}
public static function err_handler($errno, $errstr, $errfile, $errline, $errcontext) {
$l = error_reporting();
if ( $l & $errno ) {
$exit = false;
switch ( $errno ) {
case E_USER_ERROR:
$type = 'Fatal Error';
$exit = true;
break;
case E_USER_WARNING:
case E_WARNING:
$type = 'Warning';
break;
case E_USER_NOTICE:
case E_NOTICE:
case @E_STRICT:
$type = 'Notice';
break;
case @E_RECOVERABLE_ERROR:
$type = 'Catchable';
break;
default:
$type = 'Unknown Error';
$exit = true;
break;
}
$exception = new \ErrorException($type.': '.$errstr, 0, $errno, $errfile, $errline);
if ( $exit ) {
exc_handler($exception);
exit();
}
else
throw $exception;
}
return false;
}
function exc_handler($exception) {
$log = $exception->getMessage() . "\n" . $exception->getTraceAsString() . LINEBREAK;
if ( ini_get('log_errors') )
error_log($log, 0);
print("Unhandled Exception" . (DEBUG ? " - $log" : ''));
}
}
?>
If you want to control when the exception will be display or when not, you can change the value and enter if condition statement:
<?php
function lockdown($exception)
{
echo " <strong>lockdown:</strong> " , $exception->getMessage();
}
$lockdown = true; //you can change to false if you want to disable the lockdown.
if ($lockdown){
set_exception_handler('lockdown');
throw new Exception('the website is under construction, we will be back soon');
}
?>
the output will be:
lockdown: the website is under construcytion, we will be back soon
and nothing else will be shown in the entire website, just the lockdown comment.
If you're looking for a quick one-line way to change all errors in to Exceptions, you can do it this way:
set_error_handler(create_function('$a, $b, $c, $d', 'throw new ErrorException($b, 0, $a, $c, $d);'), E_ALL);
using create_function() saves you a few lines of code by embedding it all in to a single line, plus saves your namespace from a function name that should only ever be called in the event of an error (this saves from direct invocation).
To add to the comments made by chris AT cmbuckley DOT co DOT uk about the ErrorException problem with args:
I noticed that the problem is in the ErrorException class itself, not the Exception class. When using just the exception class, it's no longer an issue. Besides the args problem, the only difference between Exception and ErrorException in the stack trace is that the args are left out of the error handler exception function. I'm not sure if this was on purpose or not, but it shouldn't hurt to show this information anyway.
So instead of using this broken extended class, you can ignore it and make your own extended class and avoid the problem all together:
<?php
header('Content-Type: text/plain');
class ErrorHandler extends Exception {
protected $severity;
public function __construct($message, $code, $severity, $filename, $lineno) {
$this->message = $message;
$this->code = $code;
$this->severity = $severity;
$this->file = $filename;
$this->line = $lineno;
}
public function getSeverity() {
return $this->severity;
}
}
function exception_error_handler($errno, $errstr, $errfile, $errline ) {
throw new ErrorHandler($errstr, 0, $errno, $errfile, $errline);
}
set_error_handler("exception_error_handler", E_ALL);
function A() {
$foo->bar; // Purposely cause error
}
function B($c) {
A();
}
try {
B('foobar');
} catch (Exception $e) {
var_dump($e->getTrace());
}
?>
The only thing I wish I could do was remove the entry for the error handler function because it's quite irrelevant. Maybe that's what they were trying to do with the ErrorException class? Either way, you can't change it because the trace functions are final, and the variable is private.
The backtrace of ErrorException is broken in PHP 5.2 (listed at http://bugs.php.net/bug.php?id=46449 and explained at http://bugs.php.net/bug.php?id=45895#c140511).
A simple fix for your exception handler:
<?php
$backtrace = $exception->getTrace();
if ($exception instanceof ErrorException) {
for ($i = count($backtrace) - 1; $i > 0; --$i) {
$backtrace[$i]['args'] = $backtrace[$i - 1]['args'];
}
}
?>
Building upon the notes present, here is a set of functions that transforms the error into an exception and reports the error to screen / log depending upon the PHP ini settings.
//Begin helper function definition
function ReportError ($msg)
{
// be sure that the supplied parameter is a string and not empty
if (empty ($msg) || !is_string ($msg))
{
throw new ErrorException ('Invalid parameter supplied to ReportError', 0, E_ERROR);
}
// retrieve error settings
$display = strtolower (ini_get ('display_errors'));
$log = strtolower (ini_get ('log_errors'));
// check if we're displaying errors
if ($display === 'on' || $display === '1' || $display === 1 || $display === 'true' || $display === true)
{
echo $msg;
}
// check if we're logging errors
if ($log === 'on' || $log === '1' || $log === 1 || $log === 'true' || $log === true)
{
$result = error_log ($msg);
// check for error while logging
if (!$result)
{
throw new ErrorException ('Attempt to write message to error log failed in ReportError', 0, E_ERROR);
}
}
}
//Begin main function definition
function ErrorsAsExceptions ($level, $msg, $fileName, $lineNumber)
{
// do nothing if error reporting is turned off
if (error_reporting () === 0)
{
return;
}
// be sure received error is supposed to be reported
if (error_reporting () & $level)
{
try
{
// report error to appropriate channels
ReportError ($reportMsg);
}
catch (ErrorException $e)
{
// ignore errors while reporting
}
// go ahead and throw the exception
throw new ErrorException ($msg, 0, $level, $fileName, $lineNumber);
}
}
The following snippet installs an error-handler that turns errors into exceptions. It respects error-reporting level, so that you can still use error-suppression:
<?php
function exceptions_error_handler($severity, $message, $filename, $lineno) {
if (error_reporting() == 0) {
return;
}
if (error_reporting() & $severity) {
throw new ErrorException($message, 0, $severity, $filename, $lineno);
}
}
set_error_handler('exceptions_error_handler');
?>
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