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  • 位置: php7教程 -> php7语言

    php7预定义异常类ErrorException

    错误异常。

    ErrorException extends Exception
    {
    	/* 属性 */
    	protected int $severity ;
    	/* 方法 */
    	public __construct ([ string $message = "" [, int $code = 0 [, int $severity = E_ERROR [, string $filename = __FILE__ [, int $lineno = __LINE__ [, Exception $previous = NULL ]]]]]] )
    	final public getSeverity ( void ) : int
    	/* 继承的方法 */
    	final public Exception::getMessage ( void ) : string
    	final public Exception::getPrevious ( void ) : Throwable
    	final public Exception::getCode ( void ) : int
    	final public Exception::getFile ( void ) : string
    	final public Exception::getLine ( void ) : int
    	final public Exception::getTrace ( void ) : array
    	final public Exception::getTraceAsString ( void ) : string
    	public Exception::__toString ( void ) : string
    	final private Exception::__clone ( void ) : void
    }
    

    属性

    severity

    异常级别

    范例

    Example #1 使用set_error_handler()函数将错误信息托管至ErrorException

    <?php
    function exception_error_handler($errno, $errstr, $errfile, $errline ) {
        throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
    }
    set_error_handler("exception_error_handler");
    /* Trigger exception */
    strpos();
    ?>
    

    以上例程的输出类似于:

    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" : ''));
        }
        
      }
    ?>
    
    I have been Googling all over the place for how to convert an E_NOTICE error into an exception, and I think I finally found a clean way to do it:
    @include "errorcausingcode.php";
    $lastError = error_get_last();
    if ( !empty( $lastError ) ) {
      throw new TemplateRenderingException($lastError['message'], $lastError['type']);
    }
    Basically, if it's something not system haulting it will likely hit this. Then you can throw whatever exception you want. Now, this is of course if you have a need. I did, because I wanted to clean up my output buffer if there was an error that skipped over it.
    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.
    <?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();
    ?>
    Please note that property $severity of class ErrorException is set to a constant zero for all kinds of errors in the above example.
    I think it was a bug and tried to file a bug report, but it was closed as not a bug, so I could not say the above is wrong.
    Let me show an example that uses $severity not as a constant:
    <?php
     set_error_handler(function ($errno, $errstr, $errfile, $errline) {
      throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
     });
     class MyClass {
      public function methodA() {
       echo("methodA:\n");
       strpos();
      }
      public function methodB() {
       echo("methodB:\n");
       trigger_error("warning message form methodB", E_WARNING);
      }
      public function methodC() {
       echo("methodC:\n");
       throw new ErrorException();
      }
      public function methodD() {
       echo("methodD:\n");
       throw new ErrorException('warning message from methodD', 0, 
    E_WARNING);
      }
      public function run($i) {
        if ($i === 0) {
         $this->methodA();
        } else if ($i === 1) {
         $this->methodB();
        } else if ($i === 2) {
         $this->methodC();
        } else {
         $this->methodD();
        }
      }
      public function test() {
       for ($i = 0; $i < 4; ++$i) {
        try {
          $this->run($i);
        } catch (ErrorException $e) {
         if ($e->getSeverity() === E_ERROR) {
          echo("E_ERROR triggered.\n");
         } else if ($e->getSeverity() === E_WARNING) {
          echo("E_WARNING triggered.\n");
         }
        }
       }
      }
     }
     $myClass = new MyClass();
     $myClass->test();
    ?>
    Please note that methodC() uses (constructor of) class ErrorException with default parameters.
    I believe it is the original intention to make $severity having default value of 1, which is exactly equal to E_ERROR.
    Using property $code or Exception::getCode() to compare with E_* values could not do the same thing (as in methodC()), as $code has a default value of 0, and class Exception has it too, users may use $code for some other purposes.