Question

我想知道是否有更简单的方法来实现这个规则。刚开始尝试使用firestore。

match /emails/{emailId} {

    allow write: if request.resource.data.attachments.size() == 0
    || request.resource.data.attachments.size() == 1 && request.resource.data.attachments[0].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[0].filetype == 'image/png' || request.resource.data.attachments[0].filetype == 'image/jpg' || request.resource.data.attachments[0].filetype == 'application/vnd.ms-excel')
    || request.resource.data.attachments.size() == 2 && request.resource.data.attachments[0].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[0].filetype == 'image/png' || request.resource.data.attachments[0].filetype == 'image/jpg' || request.resource.data.attachments[0].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[1].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[1].filetype == 'image/png' || request.resource.data.attachments[1].filetype == 'image/jpg' || request.resource.data.attachments[1].filetype == 'application/vnd.ms-excel')
    || request.resource.data.attachments.size() == 3 && request.resource.data.attachments[0].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[0].filetype == 'image/png' || request.resource.data.attachments[0].filetype == 'image/jpg' || request.resource.data.attachments[0].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[1].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[1].filetype == 'image/png' || request.resource.data.attachments[1].filetype == 'image/jpg' || request.resource.data.attachments[1].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[2].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[2].filetype == 'image/png' || request.resource.data.attachments[2].filetype == 'image/jpg' || request.resource.data.attachments[2].filetype == 'application/vnd.ms-excel')
    || request.resource.data.attachments.size() == 4 && request.resource.data.attachments[0].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[0].filetype == 'image/png' || request.resource.data.attachments[0].filetype == 'image/jpg' || request.resource.data.attachments[0].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[1].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[1].filetype == 'image/png' || request.resource.data.attachments[1].filetype == 'image/jpg' || request.resource.data.attachments[1].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[2].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[2].filetype == 'image/png' || request.resource.data.attachments[2].filetype == 'image/jpg' || request.resource.data.attachments[2].filetype == 'application/vnd.ms-excel') && request.resource.data.attachments[3].fileSize < 3 * 1024 * 1024 && (request.resource.data.attachments[3].filetype == 'image/png' || request.resource.data.attachments[3].filetype == 'image/jpg' || request.resource.data.attachments[3].filetype == 'application/vnd.ms-excel');
}

Answer 1

我们不允许在规则中使用循环结构，因为我们依赖于几种更复杂结构更难的优化技术。我们也不会为规则执行收取计算时间，这意味着我们不希望它们过于复杂且可能具有滥用性。

随着规则的重复，我强烈建议使用function（）功能来简化。例如，这是＆lt; 1/3大小：

match /emails/{emailId} {
    function attachments (){
      return request.resource.data.attachments();
    }

    function attach_cnt () {
      return attachments().size();
    }

    function valid_size(attach) {
      return attachments()[attach].fileSize < 3 * 1024 * 1024;
    }

    function valid_type(attach) {
      return (attachments()[attach].filetype == 'image/png' 
         || attachments()[attach].filetype == 'image/jpg'
         || attachments()[attach].filetype == 'application/vnd.ms-excel');
    }

    allow write: (attach_cnt() < 1 || (valid_size(0) && valid_type(0)))
    && (attach_cnt() < 2 || (valid_size(1) && valid_type(1)))
    && (attach_cnt() < 3 || (valid_size(2) && valid_type(2)))
    && (attach_cnt() < 4 || (valid_size(3) && valid_type(3)))
}

以下是我如何简化它（值得仔细检查，因为我可能输入错误）。

我为正在访问的请求数据创建了一个函数attachments，因为它使用了一个聚合 - 这使得很容易浏览规则。
我为附件数量设置了一个函数attach_cnt，因为经过了大量检查。
现在我看到每个附件都有文件大小限制，所以我使用参数valid_size为该测试创建了一个函数attach。
接下来是功能valid_type，其工作方式相同，但检查确保它是有效类型。
现在很明显，对于有2-4个项目的请求，对附件0执行相同的检查等。重新排序某些逻辑使您只能检查每个附件一次。

firestore规则中可用的循环？

1 个答案: