Exception handling

/*
 * Configure error reporting
 */
if (is_webserver()) {
    /* running under a web server */
    ini_set('html_errors', '1');
    ini_set('display_errors', defined('APPLICATION_DEVENV') ? '1' : '0');
} else {
    /* Command Line Interface (CLI) */
    ini_set('html_errors', '0');
    ini_set('display_errors', 'stderr');
}

ini_set('log_errors', '0');
ini_set('error_log', <path to directory> . '\error.log'));

/* define the default exception handler */
set_exception_handler('exception_handler');

/* convert errors to exceptions (fatal errors are not handled by a user-defined error handler) */
set_error_handler(function (int $err_type, string $err_message, string $err_file = '', int $err_line = 0) {
    throw new ErrorException($err_message, 0, $err_type, $err_file, $err_line);
});

/* handle fatal errors */
register_shutdown_function(function () {
    /* only unhandled errors (ie fatal errors) should have the last error set */
    if (! is_null($err = error_get_last())) {
        if (in_array($err['type'], [E_ERROR, E_CORE_ERROR, E_COMPILE_ERROR])) {
            /* execution halted - record the error information on the error log */
            error_log(sprintf('Fatal error: %s in %s: %d',
                              $err['message'], $err['file'], $err['line']));
        } else {
            /* convert fatal errors to a CALL to the default exception handler */
            $e = new ErrorException($err['message'], 0, $err['type'], $err['file'], $err['line']);
            exception_handler($e);
        }
    }
});



/**
 * Default exception handler if an exception is not caught in a try/catch block.
 *
 * @param \Throwable $t Exception/Error
 *
 * @return void
 */
function exception_handler(\Throwable $t): void
{
    ... filter out missing web assets, renew session, determine http code, etc ...

    /* record the exception on the error log */
    error_log(sprintf('%s: %s in %s: %d',
                      get_class($t), $t->getMessage(), $t->getFile(), $t->getLine()));

    /*
     * Display the exception
     */
    if (filter_var(ini_get('html_errors'), FILTER_VALIDATE_BOOL)) {
        http_response_code($http_code);

        if (filter_var(ini_get('display_errors'), FILTER_VALIDATE_BOOL)) {
            /* generate stack trace (development environment) */
            exception_stacktrace($t);
        } else {
            /* generate user friendly exception page */
            exception_infopage($t);
        }
    } else {
        echo PHP_EOL, $t->getMessage(), PHP_EOL;
    }
}



/**
 * Determine whether running under a web server.
 *
 * @return bool Indicates whether running under a web server
 */
function is_webserver(): bool
{
    return ! (defined('STDIN') || ! empty($_SERVER['argc']));
}