class ExceptionHandler

1. 8.x drupal/core/vendor/symfony/debug/Symfony/Component/Debug/ExceptionHandler.php \Symfony\Component\Debug\ExceptionHandler
2. 8.x drupal/core/vendor/symfony/http-kernel/Symfony/Component/HttpKernel/Debug/ExceptionHandler.php \Symfony\Component\HttpKernel\Debug\ExceptionHandler

ExceptionHandler.php in drupal/core/vendor/symfony/http-kernel/Symfony/Component/HttpKernel/Debug/ExceptionHandler.php

ExceptionHandlerTest.php in drupal/core/vendor/symfony/debug/Symfony/Component/Debug/Tests/ExceptionHandlerTest.php

class ExceptionHandler {
  private $debug;
  private $charset;
  public function __construct($debug = true, $charset = 'UTF-8') {
    $this->debug = $debug;
    $this->charset = $charset;
  }

  /**
   * Registers the exception handler.
   *
   * @param Boolean $debug
   *
   * @return ExceptionHandler The registered exception handler
   */
  public static function register($debug = true) {
    $handler = new static($debug);
    set_exception_handler(array(
      $handler,
      'handle',
    ));
    return $handler;
  }

  /**
   * Sends a response for the given Exception.
   *
   * If you have the Symfony HttpFoundation component installed,
   * this method will use it to create and send the response. If not,
   * it will fallback to plain PHP functions.
   *
   * @param \Exception $exception An \Exception instance
   *
   * @see sendPhpResponse
   * @see createResponse
   */
  public function handle(\Exception $exception) {
    if (class_exists('Symfony\\Component\\HttpFoundation\\Response')) {
      $this
        ->createResponse($exception)
        ->send();
    }
    else {
      $this
        ->sendPhpResponse($exception);
    }
  }

  /**
   * Sends the error associated with the given Exception as a plain PHP response.
   *
   * This method uses plain PHP functions like header() and echo to output
   * the response.
   *
   * @param \Exception|FlattenException $exception An \Exception instance
   */
  public function sendPhpResponse($exception) {
    if (!$exception instanceof FlattenException) {
      $exception = FlattenException::create($exception);
    }
    header(sprintf('HTTP/1.0 %s', $exception
      ->getStatusCode()));
    foreach ($exception
      ->getHeaders() as $name => $value) {
      header($name . ': ' . $value, false);
    }
    echo $this
      ->decorate($this
      ->getContent($exception), $this
      ->getStylesheet($exception));
  }

  /**
   * Creates the error Response associated with the given Exception.
   *
   * @param \Exception|FlattenException $exception An \Exception instance
   *
   * @return Response A Response instance
   */
  public function createResponse($exception) {
    if (!$exception instanceof FlattenException) {
      $exception = FlattenException::create($exception);
    }
    return new Response($this
      ->decorate($this
      ->getContent($exception), $this
      ->getStylesheet($exception)), $exception
      ->getStatusCode(), $exception
      ->getHeaders());
  }

  /**
   * Gets the HTML content associated with the given exception.
   *
   * @param FlattenException $exception A FlattenException instance
   *
   * @return string The content as a string
   */
  public function getContent(FlattenException $exception) {
    switch ($exception
      ->getStatusCode()) {
      case 404:
        $title = 'Sorry, the page you are looking for could not be found.';
        break;
      default:
        $title = 'Whoops, looks like something went wrong.';
    }
    $content = '';
    if ($this->debug) {
      try {
        $count = count($exception
          ->getAllPrevious());
        $total = $count + 1;
        foreach ($exception
          ->toArray() as $position => $e) {
          $ind = $count - $position + 1;
          $class = $this
            ->abbrClass($e['class']);
          $message = nl2br($e['message']);
          $content .= sprintf(<<<EOF
                        <div class="block_exception clear_fix">
                            <h2><span>%d/%d</span> %s: %s</h2>
                        </div>
                        <div class="block">
                            <ol class="traces list_exception">

EOF
, $ind, $total, $class, $message);
          foreach ($e['trace'] as $trace) {
            $content .= '       <li>';
            if ($trace['function']) {
              $content .= sprintf('at %s%s%s(%s)', $this
                ->abbrClass($trace['class']), $trace['type'], $trace['function'], $this
                ->formatArgs($trace['args']));
            }
            if (isset($trace['file']) && isset($trace['line'])) {
              if ($linkFormat = ini_get('xdebug.file_link_format')) {
                $link = str_replace(array(
                  '%f',
                  '%l',
                ), array(
                  $trace['file'],
                  $trace['line'],
                ), $linkFormat);
                $content .= sprintf(' in <a href="%s" title="Go to source">%s line %s</a>', $link, $trace['file'], $trace['line']);
              }
              else {
                $content .= sprintf(' in %s line %s', $trace['file'], $trace['line']);
              }
            }
            $content .= "</li>\n";
          }
          $content .= "    </ol>\n</div>\n";
        }
      } catch (\Exception $e) {

        // something nasty happened and we cannot throw an exception anymore
        if ($this->debug) {
          $title = sprintf('Exception thrown when handling an exception (%s: %s)', get_class($exception), $exception
            ->getMessage());
        }
        else {
          $title = 'Whoops, looks like something went wrong.';
        }
      }
    }
    return <<<EOF
            <div id="sf-resetcontent" class="sf-reset">
                <h1>{<span class="php-variable">$title</span>}</h1>
                {<span class="php-variable">$content</span>}
            </div>
EOF;
  }

  /**
   * Gets the stylesheet associated with the given exception.
   *
   * @param FlattenException $exception A FlattenException instance
   *
   * @return string The stylesheet as a string
   */
  public function getStylesheet(FlattenException $exception) {
    return <<<EOF
            .sf-reset { font: 11px Verdana, Arial, sans-serif; color: #333 }
            .sf-reset .clear { clear:both; height:0; font-size:0; line-height:0; }
            .sf-reset .clear_fix:after { display:block; height:0; clear:both; visibility:hidden; }
            .sf-reset .clear_fix { display:inline-block; }
            .sf-reset * html .clear_fix { height:1%; }
            .sf-reset .clear_fix { display:block; }
            .sf-reset, .sf-reset .block { margin: auto }
            .sf-reset abbr { border-bottom: 1px dotted #000; cursor: help; }
            .sf-reset p { font-size:14px; line-height:20px; color:#868686; padding-bottom:20px }
            .sf-reset strong { font-weight:bold; }
            .sf-reset a { color:#6c6159; }
            .sf-reset a img { border:none; }
            .sf-reset a:hover { text-decoration:underline; }
            .sf-reset em { font-style:italic; }
            .sf-reset h1, .sf-reset h2 { font: 20px Georgia, "Times New Roman", Times, serif }
            .sf-reset h2 span { background-color: #fff; color: #333; padding: 6px; float: left; margin-right: 10px; }
            .sf-reset .traces li { font-size:12px; padding: 2px 4px; list-style-type:decimal; margin-left:20px; }
            .sf-reset .block { background-color:#FFFFFF; padding:10px 28px; margin-bottom:20px;
                -webkit-border-bottom-right-radius: 16px;
                -webkit-border-bottom-left-radius: 16px;
                -moz-border-radius-bottomright: 16px;
                -moz-border-radius-bottomleft: 16px;
                border-bottom-right-radius: 16px;
                border-bottom-left-radius: 16px;
                border-bottom:1px solid #ccc;
                border-right:1px solid #ccc;
                border-left:1px solid #ccc;
            }
            .sf-reset .block_exception { background-color:#ddd; color: #333; padding:20px;
                -webkit-border-top-left-radius: 16px;
                -webkit-border-top-right-radius: 16px;
                -moz-border-radius-topleft: 16px;
                -moz-border-radius-topright: 16px;
                border-top-left-radius: 16px;
                border-top-right-radius: 16px;
                border-top:1px solid #ccc;
                border-right:1px solid #ccc;
                border-left:1px solid #ccc;
                overflow: hidden;
                word-wrap: break-word;
            }
            .sf-reset li a { background:none; color:#868686; text-decoration:none; }
            .sf-reset li a:hover { background:none; color:#313131; text-decoration:underline; }
            .sf-reset ol { padding: 10px 0; }
            .sf-reset h1 { background-color:#FFFFFF; padding: 15px 28px; margin-bottom: 20px;
                -webkit-border-radius: 10px;
                -moz-border-radius: 10px;
                border-radius: 10px;
                border: 1px solid #ccc;
            }
EOF;
  }
  private function decorate($content, $css) {
    return <<<EOF
<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <meta name="robots" content="noindex,nofollow" />
        <style>
            /* Copyright (c) 2010, Yahoo! Inc. All rights reserved. Code licensed under the BSD License: http://developer.yahoo.com/yui/license.html */
            html{color:#000;background:#FFF;}body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,textarea,p,blockquote,th,td{margin:0;padding:0;}table{border-collapse:collapse;border-spacing:0;}fieldset,img{border:0;}address,caption,cite,code,dfn,em,strong,th,var{font-style:normal;font-weight:normal;}li{list-style:none;}caption,th{text-align:left;}h1,h2,h3,h4,h5,h6{font-size:100%;font-weight:normal;}q:before,q:after{content:'';}abbr,acronym{border:0;font-variant:normal;}sup{vertical-align:text-top;}sub{vertical-align:text-bottom;}input,textarea,select{font-family:inherit;font-size:inherit;font-weight:inherit;}input,textarea,select{*font-size:100%;}legend{color:#000;}

            html { background: #eee; padding: 10px }
            img { border: 0; }
            #sf-resetcontent { width:970px; margin:0 auto; }
            {<span class="php-variable">$css</span>}
        </style>
    </head>
    <body>
        {<span class="php-variable">$content</span>}
    </body>
</html>
EOF;
  }
  private function abbrClass($class) {
    $parts = explode('\\', $class);
    return sprintf("<abbr title=\"%s\">%s</abbr>", $class, array_pop($parts));
  }

  /**
   * Formats an array as a string.
   *
   * @param array $args The argument array
   *
   * @return string
   */
  private function formatArgs(array $args) {
    $result = array();
    foreach ($args as $key => $item) {
      if ('object' === $item[0]) {
        $formattedValue = sprintf("<em>object</em>(%s)", $this
          ->abbrClass($item[1]));
      }
      elseif ('array' === $item[0]) {
        $formattedValue = sprintf("<em>array</em>(%s)", is_array($item[1]) ? $this
          ->formatArgs($item[1]) : $item[1]);
      }
      elseif ('string' === $item[0]) {
        $formattedValue = sprintf("'%s'", htmlspecialchars($item[1], ENT_QUOTES | ENT_SUBSTITUTE, $this->charset));
      }
      elseif ('null' === $item[0]) {
        $formattedValue = '<em>null</em>';
      }
      elseif ('boolean' === $item[0]) {
        $formattedValue = '<em>' . strtolower(var_export($item[1], true)) . '</em>';
      }
      elseif ('resource' === $item[0]) {
        $formattedValue = '<em>resource</em>';
      }
      else {
        $formattedValue = str_replace("\n", '', var_export(htmlspecialchars((string) $item[1], ENT_QUOTES | ENT_SUBSTITUTE, $this->charset), true));
      }
      $result[] = is_int($key) ? $formattedValue : sprintf("'%s' => %s", $key, $formattedValue);
    }
    return implode(', ', $result);
  }

}