Firebase 数据库规则：未知变量“$memberId1”

Question

我有以下 Firebase 数据库：

我想添加数据库规则以保护只有适当的用户才能访问他们的消息。

当我添加以下内容时，出现错误：

谁能给点建议？

谢谢

更新

findMessages(chatItem: any): Observable<any[]> { // populates the firelist
    return this.af.database.list('/message/', {
        query: {
            orderByChild: 'negativtimestamp'
        }
    }).map(items => {
        const filtered = items.filter(
            item => ((item.memberId1 === chatItem.memberId1 && item.memberId2 === chatItem.memberId2)
                || (item.memberId1 === chatItem.memberId2 && item.memberId2 === chatItem.memberId1))
        );
        return filtered;
    });
}

Answer 1

在.read 规则的表达式中，以$ 开头的变量代表路径中的键。

但是，成员 ID 不是键；他们是数据成员。要在表达式中使用它们，您可以使用data 快照的child 和val 方法。像这样：

{
  "rules": {
    "message": {
      "$key": {
        ".read": "data.child('memberId1').val() === auth.uid || data.child('memberId2').val() === auth.uid"
      }
    }
  }
}

Answer 2

您应该有定义成员的变量，然后引用这些变量。

这是来自Firebase security docs的聊天示例。

{
  "rules": {
    "room_names": {
      // any logged in user can get a list of room names
      ".read": "auth !== null",
  "$room_id": {
    // this is just for documenting the structure of rooms, since
    // they are read-only and no write rule allows this to be set
    ".validate": "newData.isString()"
  }
},

"members": {
   // I can join or leave any room (otherwise it would be a boring demo)
   // I can have a different name in each room just for fun
   "$room_id": {
      // any member can read the list of member names
      ".read": "data.child(auth.uid).exists()",

      // room must already exist to add a member
      ".validate": "root.child('room_names/'+$room_id).exists()",

      "$user_id": {
         ".write": "auth.uid === $user_id",
         ".validate": "newData.isString() && newData.val().length > 0 && newData.val().length < 20"
      }
   }
},

"messages": {
  "$room_id": {
    // the list of messages for a room can be read by any member
    ".read": "root.child('members/'+$room_id+'/'+auth.uid).exists()",

    // room we want to write a message to must be valid
    ".validate": "root.child('room_names/'+$room_id).exists()",

    "$message_id": {
      // a new message can be created if it does not exist, but it
      // cannot be modified or deleted
      // any member of a room can write a new message
      ".write": "root.child('members/'+$room_id+'/'+auth.uid).exists() && !data.exists() && newData.exists()",

      // the room attribute must be a valid key in room_names/ (the room must exist)
      // the object to write must have a name, message, and timestamp
      ".validate": "newData.hasChildren(['user', 'message', 'timestamp'])",

      // the message must be written by logged in user
      "user": {
         ".validate": "newData.val() === auth.uid"
      },

      // the message must be longer than 0 chars and less than 50
      "message": { ".validate": "newData.isString() && newData.val().length > 0 && newData.val().length < 50" },

      // messages cannot be added in the past or the future
      // clients should use firebase.database.ServerValue.TIMESTAMP
      // to ensure accurate timestamps
      "timestamp": { ".validate": "newData.val() <= now" },

      // no other fields can be included in a message
      "$other": { ".validate": false }
    }
  }
}

} }