From The Holy Mountain : A Jou: A Journey In The Shadow Of Byzantium

        if ($this->useLocking) {
            // ignoring errors here, there's not much we can do about them
            flock($this->stream, LOCK_EX);
        }
 
        $this->streamWrite($this->stream, $record);
 
        if ($this->useLocking) {
            flock($this->stream, LOCK_UN);
        }
    }
 
    /**
     * Write to stream
     * @param resource $stream
     * @param array $record
     */
    protected function streamWrite($stream, array $record)
    {
        fwrite($stream, (string) $record['formatted']);
    }
 
    private function customErrorHandler($code, $msg)
    {
        $this->errorMessage = preg_replace('{^(fopen|mkdir)\(.*?\): }', '', $msg);
    }
 
    /**
     * @param string $stream
     *
     * @return null|string
     */
    private function getDirFromStream($stream)
    {
        $pos = strpos($stream, '://');
        if ($pos === false) {
            return dirname($stream);
        }
 
        if ('file://' === substr($stream, 0, 7)) {

            $this->errorMessage = null;
            set_error_handler(array($this, 'customErrorHandler'));
            $this->stream = fopen($this->url, 'a');
            if ($this->filePermission !== null) {
                @chmod($this->url, $this->filePermission);
            }
            restore_error_handler();
            if (!is_resource($this->stream)) {
                $this->stream = null;
 
                throw new \UnexpectedValueException(sprintf('The stream or file "%s" could not be opened in append mode: '.$this->errorMessage, $this->url));
            }
        }
 
        if ($this->useLocking) {
            // ignoring errors here, there's not much we can do about them
            flock($this->stream, LOCK_EX);
        }
 
        $this->streamWrite($this->stream, $record);
 
        if ($this->useLocking) {
            flock($this->stream, LOCK_UN);
        }
    }
 
    /**
     * Write to stream
     * @param resource $stream
     * @param array $record
     */
    protected function streamWrite($stream, array $record)
    {
        fwrite($stream, (string) $record['formatted']);
    }
 
    private function customErrorHandler($code, $msg)
    {
        $this->errorMessage = preg_replace('{^(fopen|mkdir)\(.*?\): }', '', $msg);
    }

 *
 * @author Jordi Boggiano <j.boggiano@seld.be>
 * @author Christophe Coevoet <stof@notk.org>
 */
abstract class AbstractProcessingHandler extends AbstractHandler
{
    /**
     * {@inheritdoc}
     */
    public function handle(array $record)
    {
        if (!$this->isHandling($record)) {
            return false;
        }
 
        $record = $this->processRecord($record);
 
        $record['formatted'] = $this->getFormatter()->format($record);
 
        $this->write($record);
 
        return false === $this->bubble;
    }
 
    /**
     * Writes the record down to the log of the implementing handler
     *
     * @param  array $record
     * @return void
     */
    abstract protected function write(array $record);
 
    /**
     * Processes a record.
     *
     * @param  array $record
     * @return array
     */
    protected function processRecord(array $record)
    {

        }
        $ts->setTimezone(static::$timezone);
 
        $record = array(
            'message' => (string) $message,
            'context' => $context,
            'level' => $level,
            'level_name' => $levelName,
            'channel' => $this->name,
            'datetime' => $ts,
            'extra' => array(),
        );
 
        try {
            foreach ($this->processors as $processor) {
                $record = call_user_func($processor, $record);
            }
 
            while ($handler = current($this->handlers)) {
                if (true === $handler->handle($record)) {
                    break;
                }
 
                next($this->handlers);
            }
        } catch (Exception $e) {
            $this->handleException($e, $record);
        }
 
        return true;
    }
 
    /**
     * Ends a log cycle and frees all resources used by handlers.
     *
     * Closing a Handler means flushing all buffers and freeing any open resources/handles.
     * Handlers that have been closed should be able to accept log records again and re-open
     * themselves on demand, but this may not always be possible depending on implementation.
     *
     * This is useful at the end of a request and will be called automatically on every handler

     * @param  array  $context The log context
     * @return bool   Whether the record has been processed
     */
    public function err($message, array $context = array())
    {
        return $this->addRecord(static::ERROR, $message, $context);
    }
 
    /**
     * Adds a log record at the ERROR level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string $message The log message
     * @param  array  $context The log context
     * @return bool   Whether the record has been processed
     */
    public function error($message, array $context = array())
    {
        return $this->addRecord(static::ERROR, $message, $context);
    }
 
    /**
     * Adds a log record at the CRITICAL level.
     *
     * This method allows for compatibility with common interfaces.
     *
     * @param  string $message The log message
     * @param  array  $context The log context
     * @return bool   Whether the record has been processed
     */
    public function crit($message, array $context = array())
    {
        return $this->addRecord(static::CRITICAL, $message, $context);
    }
 
    /**
     * Adds a log record at the CRITICAL level.
     *
     * This method allows for compatibility with common interfaces.

     * @return void
     */
    public function write($level, $message, array $context = [])
    {
        $this->writeLog($level, $message, $context);
    }
 
    /**
     * Write a message to Monolog.
     *
     * @param  string  $level
     * @param  string  $message
     * @param  array  $context
     * @return void
     */
    protected function writeLog($level, $message, $context)
    {
        $this->fireLogEvent($level, $message = $this->formatMessage($message), $context);
 
        $this->monolog->{$level}($message, $context);
    }
 
    /**
     * Register a file log handler.
     *
     * @param  string  $path
     * @param  string  $level
     * @return void
     */
    public function useFiles($path, $level = 'debug')
    {
        $this->monolog->pushHandler($handler = new StreamHandler($path, $this->parseLevel($level)));
 
        $handler->setFormatter($this->getDefaultFormatter());
    }
 
    /**
     * Register a daily file log handler.
     *
     * @param  string  $path

     *
     * @param  string  $message
     * @param  array  $context
     * @return void
     */
    public function critical($message, array $context = [])
    {
        $this->writeLog(__FUNCTION__, $message, $context);
    }
 
    /**
     * Log an error message to the logs.
     *
     * @param  string  $message
     * @param  array  $context
     * @return void
     */
    public function error($message, array $context = [])
    {
        $this->writeLog(__FUNCTION__, $message, $context);
    }
 
    /**
     * Log a warning message to the logs.
     *
     * @param  string  $message
     * @param  array  $context
     * @return void
     */
    public function warning($message, array $context = [])
    {
        $this->writeLog(__FUNCTION__, $message, $context);
    }
 
    /**
     * Log a notice to the logs.
     *
     * @param  string  $message
     * @param  array  $context
     * @return void

     */
    public function report(Exception $e)
    {
        if ($this->shouldntReport($e)) {
            return;
        }
 
        if (method_exists($e, 'report')) {
            return $e->report();
        }
 
        try {
            $logger = $this->container->make(LoggerInterface::class);
        } catch (Exception $ex) {
            throw $e; // throw the original exception
        }
 
        $logger->error(
            $e->getMessage(),
            array_merge($this->context(), ['exception' => $e]
        ));
    }
 
    /**
     * Determine if the exception should be reported.
     *
     * @param  \Exception  $e
     * @return bool
     */
    public function shouldReport(Exception $e)
    {
        return ! $this->shouldntReport($e);
    }
 
    /**
     * Determine if the exception is in the "do not report" list.
     *
     * @param  \Exception  $e
     * @return bool
     */

     * A list of the inputs that are never flashed for validation exceptions.
     *
     * @var array
     */
    protected $dontFlash = [
        'password',
        'password_confirmation',
    ];

    /**
     * Report or log an exception.
     *
     * This is a great spot to send exceptions to Sentry, Bugsnag, etc.
     *
     * @param  \Exception  $exception
     * @return void
     */
    public function report(Exception $exception)
    {
        parent::report($exception);
    }

    /**
     * Render an exception into an HTTP response.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Exception  $exception
     * @return \Illuminate\Http\Response
     */
    public function render($request, Exception $exception)
    {
        $url=URL::previous();
        if($this->isHttpException($exception))
        {
            if ( isset(Auth::user()->id) && (Auth::user()->hasRole(['admin', 'sub admin']))) {

                switch ($exception->getStatusCode()) {
                    // not found
                    case 401:
                          return response()->view('admin.errors.401',compact('url'));

    }
 
    /**
     * Handle an uncaught exception from the application.
     *
     * Note: Most exceptions can be handled via the try / catch block in
     * the HTTP and Console kernels. But, fatal error exceptions must
     * be handled differently since they are not normal exceptions.
     *
     * @param  \Throwable  $e
     * @return void
     */
    public function handleException($e)
    {
        if (! $e instanceof Exception) {
            $e = new FatalThrowableError($e);
        }
 
        try {
            $this->getExceptionHandler()->report($e);
        } catch (Exception $e) {
            //
        }
 
        if ($this->app->runningInConsole()) {
            $this->renderForConsole($e);
        } else {
            $this->renderHttpResponse($e);
        }
    }
 
    /**
     * Render an exception to the console.
     *
     * @param  \Exception  $e
     * @return void
     */
    protected function renderForConsole(Exception $e)
    {
        $this->getExceptionHandler()->renderForConsole(new ConsoleOutput, $e);