使用Firebase RuleDataSnapshot方法访问用户数据 [英] Using Firebase RuleDataSnapshot Methods to access user data

问题描述

  root {
 PrivateRooms {
< PrivateRoomName> {
 ... 
} 
} 
用户{
  {
 permissionFrom {
< PrivateRoomName>：value is不是私人房间名称
} 
 ... 
} 
} 
} 
  

...我如何编写规则来授予对<

 rules：{
PrivateRooms：{
$ roomName：{
.read：root.child（'users' ）.child（auth.uid）.child（'permissionFrom'）。hasChild（'$ roomName'）== true，
.write：root.child（'users'）。child .child（'permissionFrom'）。hasChild（'$ roomName'）== true

}，
users：{
.read ：true，
.write：true 
} 
} 
} 
  

...但是在跳过这个数据快照的时候，规则必然是错的：

  var testRef = new Firebase（'https://my.firebaseio.com/privateRooms/<privateRoomName>/privRoomChild'）; 
 testRef.once（value，function（snapshot）{
 var testVal = snapshot.val（）; 
 console.log（testVal）; 
}）; 
  

解决方案

 $ roomName： {
.read：root.child（'users'）。child（auth.uid）.child（'permissionFrom'）。hasChild（$ roomName），
.write： hasChild（$ roomName）
} 
   
If I have data like this:
        root{
           PrivateRooms{
             <PrivateRoomName>{
               ...
             }
           }
           users{
             <uid>{
               permissionFrom{
                   <PrivateRoomName>:value is not private room name 
               }
                ...
             }
           }
         }
...how do I write rules to grant access to < PrivateRoomName > based on the user's permissionFrom children?

I thought this would work: 
{
  "rules": {
    "PrivateRooms" : {
      "$roomName":{
        ".read" : "root.child('users').child(auth.uid).child('permissionFrom').hasChild('$roomName') == true",
        ".write" : "root.child('users').child(auth.uid).child('permissionFrom').hasChild('$roomName') == true"
      }
    },
    "users" : {
      ".read" : true,
      ".write" : true
    }
  }
}
...but something must be wrong with the rules as this data snapshot is skipped over:
var testRef = new Firebase('https://my.firebaseio.com/privateRooms/<privateRoomName>/privRoomChild');
testRef.once("value", function(snapshot){
    var testVal = snapshot.val();
    console.log(testVal);
});

解决方案
In your rules, $roomName is a variable, so it should not be wrapped in quotes.
  "$roomName":{
    ".read" : "root.child('users').child(auth.uid).child('permissionFrom').hasChild($roomName)",
    ".write" : "root.child('users').child(auth.uid).child('permissionFrom').hasChild($roomName)"
  }


                        
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