silverstripe / silverstripe-asset-admin

        /** @var File $file */

        $file = File::get()->byID($id);

        if (!$file->canView()) {

            $this->httpError(403, _t(

                'SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ErrorItemPermissionDenied',

                'You don\'t have the necessary permissions to modify {ObjectTitle}',

                '',

                ['ObjectTitle' => $file->i18n_singular_name()]

            ));

            return null;

        }

        // Pass to form factory

        $augmentedContext = array_merge($context, ['Record' => $file]);

            return $this->httpError(404);

        }

        if (!$file->canView()) {

            $this->httpError(403, _t(

                'SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ErrorItemPermissionDenied',

                'You don\'t have the necessary permissions to modify {ObjectTitle}',

                '',

                ['ObjectTitle' => $file->i18n_singular_name()]

            ));

            return null;

        }

        $effectiveContext = array_merge($context, ['Record' => $file]);

        /** @var FormFactory $scaffolder */

            ));

            return null;

        }

        if (!$record->canView()) {

            $this->httpError(403, _t(

                'SilverStripe\\AssetAdmin\\Controller\\AssetAdmin.ErrorItemPermissionDenied',

                'You don\'t have the necessary permissions to modify {ObjectTitle}',

                '',

                ['ObjectTitle' => $record->i18n_singular_name()]

            ));

            return null;

        }

        $handler = AddToCampaignHandler::create($this, $record, 'addToCampaignForm');

        $form = $handler->Form($record);