firebase - 限制 Firebase 存储路径中的文件数

Question

我想限制用户可以上传到 Firebase 存储路径的文件数量。这是我的 Firebase 存储规则:

   service firebase.storage {
  match /b/jobsdbn.appspot.com/o {
    match /images/Business/{userId}/{imageId} {
       allow read
       allow write: if request.auth.uid == userId && (request.resource == null || ( (list(/images/Business/$(username)).size() <= 5) && imageId.size() < 50 && request.resource.size < 10 * 1024 * 1024 && request.resource.contentType.matches('image/.*')))

    }
  }
}

我添加了这篇文章中的 list(/images/Business/$(username)).size() <= 5:https://groups.google.com/forum/#!topic/firebase-talk/ZtJPcEJr0Mc

但我总是得到 403 并且不确定“用户名”是否是全局变量但我使用了不同的变量但仍然无法使其工作。

Answer 1

如果有人需要答案，我通过使用 firebase 云函数找到了解决方案:

exports.getNumOfFile = functions.storage.object().onChange(event => {
    const object = event.data; // The Storage object.
    const fileBucket = object.bucket; // The Storage bucket that contains the file.
    const bucket = gcs.bucket(fileBucket);
    bucket.getFiles({
        prefix: "[path]", //Path like what you use to get reference of your files in storage 
    }, (error, files) => {
        console.log(files.length);
    });
});

您可以在此处找到更多选项:

https://googlecloudplatform.github.io/google-cloud-node/#/docs/storage/1.1.0/storage/bucket?method=getFiles