为什么这个Firebase“.indexOn”不行？ [英] Why does this Firebase ".indexOn" not work?

问题描述

所以我有这样的数据：

  pushNotifications {
 -K  -  RwEgd541PIGNOXXUH：{
消息：Xiaoyu Hugh Hou出价900美元对你的任务：新P ...
 notifyId：facebook：10100683829966199
 relatedTask：-Jzl8XKaxGCv19nIOChm
时间戳：1443594566599 
 $ {
 message：Sam Feldt出价1100美元在你的任务上：New Post g ...
 notifyId：google：1043268349966197
 relatedTask： - Jzl8XKaxGCv19nIOChm
 timestamp：1443594721963 
}  -  K  -  RwuM3  -  0 G0q9I96WHg：{
 message：Sam Feldt在您的任务中出价600美元：NO Firebase ...
 notifyId ：facebook：10100683829966199
 relatedTask：-JzTSk2TIlO46oVqJ1Nn
 timestamp：1443594741347 
} 
} 
  

在我的代码中，我需要将最新的通知传递给某个notifyId。这里是代码：

$ $ p $ $ $ $ c $ ref $（$'$' $ b .limitToLast（1）
.on（child_added，function（snapshot）{
console.log（Found a new notification ...）;
sendPush（snapshot。 val（））;
}）;

在我的firebase安全规则中，我有这个索引规则：

 pushNotifications：{
.read：auth！= null，
.write：auth！= null ，
$ pushId：{
.indexOn：[notifyId，timestamp]，
} 
}，
  

这是Firebase文档所遵循的索引结构：

FIREBASE警告：使用未指定的索引。考虑在/ pushNotifications处添加.indexOn：notifyId到你的安全规则以获得更好的性能

这是没有任何意义的，我已经做到了。请帮忙！

解决方案

您需要将 .indexOn 你做了：
$ b $ pre $ pushNotifications：{
.read：auth！= null，
.write：auth！= null，
.indexOn：[notifyId，timestamp]
}，


作为比较，请查看

 dinosaurs：{$ rel =noreferrer> Firebase关于索引的文档， 
lambeosaurus：{
height：2.1，
length：12.5，
weight：5000 
}，
stegosaurus ：{
height：4，
length：9，
weight：2500 
} 
} 
  
 
 
使用此索引规则：
 
 
  {
rules：{
dinosaurs：{
.indexOn：[height，length] 
} 
} 
} 
  
 
So I have data like so: 
pushNotifications {
    -K - RwEgd541PIGNOXXUH: {
        message: "Xiaoyu Hugh Hou bid at $900 on your task: New P..."
        notifyId: "facebook:10100683829966199"
        relatedTask: "-Jzl8XKaxGCv19nIOChm"
        timestamp: 1443594566599
    } - K - RwpcBlQa04VJT4Bwm: {
        message: "Sam Feldt bid at $1100 on your task: New Post g..."
        notifyId: "google:1043268349966197"
        relatedTask: "-Jzl8XKaxGCv19nIOChm"
        timestamp: 1443594721963
    } - K - RwuM3 - 0 G0q9I96WHg: {
        message: "Sam Feldt bid at $600 on your task: NO Firebase..."
        notifyId: "facebook:10100683829966199"
        relatedTask: "-JzTSk2TIlO46oVqJ1Nn"
        timestamp: 1443594741347
    }
}
In my code, I need to get the latest notification below to a certain "notifyId". Here is the code:
ref.child('pushNotifications')
   .orderByChild("notifyId")
   .limitToLast(1)
   .on("child_added", function (snapshot) {
       console.log("Found a new notification...");
       sendPush(snapshot.val());
   });
In my firebase security rule, I have this index rule: 
 "pushNotifications": {
      ".read": "auth != null",
      ".write": "auth != null",
      "$pushId": {
        ".indexOn": ["notifyId", "timestamp"],
      }
    },
It is the index structure follow by the Firebase docs here: docs

But when I run the code, the console still log 

  
FIREBASE WARNING: Using an unspecified index. Consider adding ".indexOn": "notifyId" at /pushNotifications to your security rules for better performance 
Which does not make any sense since I did that already. Please help! 
解决方案
You need to put the .indexOn one level higher than what you did:
 "pushNotifications": {
    ".read": "auth != null",
    ".write": "auth != null",
    ".indexOn": ["notifyId", "timestamp"]
},
For comparison always look at the Firebase documentation on indexes, which uses this JSON example:
"dinosaurs": {
  "lambeosaurus": {
    "height" : 2.1,
    "length" : 12.5,
    "weight": 5000
  },
  "stegosaurus": {
    "height" : 4,
    "length" : 9,
    "weight" : 2500
  }
}
With this indexing rule:
{
  "rules": {
    "dinosaurs": {
      ".indexOn": ["height", "length"]
    }
  }
}


                        
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