app\controllers\CashbookController::actionUpdate PHP Method

    public function actionUpdate($id)
    {
        $model = $this->findModel($id);
        if ($model->user_id != Yii::$app->user->id) {
            throw new ErrorException(Yii::t('app', 'Forbidden to change entries of other users'));
        }
        $oldFile = $model->getImageFile();
        $oldattachment = $model->attachment;
        $oldFileName = $model->filename;
        $model->edit_datetime = date("Y-m-d H:i:s");
        if ($model->load(Yii::$app->request->post())) {
            // process uploaded image file instance
            $file = $model->uploadImage();
            // revert back if no valid file instance uploaded
            if ($file === false) {
                $model->attachment = $oldattachment;
                $model->filename = $oldFileName;
            }
            if ($model->save()) {
                // upload only if valid uploaded file instance found
                if ($file !== false && unlink($oldFile)) {
                    // delete old and overwrite
                    $path = $model->getImageFile();
                    $file->saveAs($path);
                }
                Yii::$app->session->setFlash("Entry-success", Yii::t("app", "Entry updated"));
                return $this->redirect(['index']);
            } else {
                // error in saving model
            }
        }
        return $this->render('update', ['model' => $model]);
    }