如何将图像上传功能添加到codeigniter中的现有添加/更新功能

Question

我在我的控制器中添加/更新功能，我想为它添加图像上传功能，并将文件路径保存到数据库，而不想显示它，但我不知道在哪里添加文件上传功能 这是代码

public function edit($id = NULL) {
        //Fetch a page or set new one
        if ($id) {
            $this->data['page'] = $this->page_m->get($id);
          count($this->data['page']) || $this->data['errors'][] = 'Page Could not be found';
            }
            else {
                $this->data['page'] = $this->page_m->get_new();
           }
        $id == NULL || $this->data['page'] = $this->page_m->get($id);
        //Pages for dropdown
        $this->data['pages_no_parents'] = $this->page_m->get_no_parents();
        //dump($this->data['pages_no_parents']);
        //Setup form
        $rules = $this->page_m->rules;

        $this->form_validation->set_rules($rules);
        //Process the form

        if ($this->form_validation->run() == TRUE) {
            $data = $this->page_m->array_from_post(array(
                'title',
                'slug',
                'order',
                'body',
                'template',
                'parent_id',
                'filename'
            ));
            $this->page_m->save($data, $id);
            //echo $data->filename;
            redirect('admin/page');
        }
        //Load the view    
        $this->data['subview'] = 'admin/page/edit';
        $this->load->view('admin/_layout_main', $this->data);
    }