在PHP中使用文件上传时，CKEditor中缺少上传图像源URL

Question

当我尝试使用CKEditor在PHP中上传图片时，它成功上传了，但是当我按下OK按钮时，它给了我错误upload image source URL is missing，有人可以检查我的代码吗并帮助我如何解决此问题？在这里，我已经放置了整个代码

if($_FILES['upload']['name']) {
    if($_FILES['upload']['error'] == 0) {
        $new_file_name = strtolower($_FILES['upload']['tmp_name']);
        if($_FILES['upload']['size']>300000) {
            echo json_encode(array('status'=>0,'msg'=>"Your file size is to large."));
        } else {
            require_once($_SERVER['DOCUMENT_ROOT'].'/wp-admin/includes/image.php');
            require_once($_SERVER['DOCUMENT_ROOT'].'/wp-admin/includes/file.php');
            require_once($_SERVER['DOCUMENT_ROOT'].'/wp-admin/includes/media.php');
            $file_id = media_handle_upload( 'upload', 0 );
            if(is_wp_error($file_id)) {
                echo json_encode(array('status'=>0,'msg'=>"Error uploading file"));
            } else {
                $image_data = wp_get_attachment_image_src($file_id);
                $image_url = $image_data[0];
                //echo json_encode(array('status'=>1,'msg'=>"",'id'=>$file_id,'url'=>$image_url));
                echo '<script>window.parent.CKEDITOR.tools.callFunction(" + CKEditorFuncNum + ", \"" + url + "\");</script>';
            }
        }
    } else {
        echo json_encode(array('status'=>0,'msg'=>$_FILES['upload']['error']));
    }
}