Firebase-如何查找所有具有自动生成的ID（值为false）的匹配项

Question

Following the techniques on https://www.firebase.com/docs/web/guide/structuring-data.html

Given the url root is: https://myApp.firebaseio.com

And the data is:

  // Tracking two-way relationships between users and groups
  {
    "users": {
      "mchen": {
        "name": "Mary Chen",
        "groups": {
           "alpha": true,
           "bob": false, // <- I want this
           "charlie": true,
           "dave": false // <- I want this
        }
      },
      ...
    },
    "groups": {
      "alpha": {
        "name": "Alpha Group",
        "members": {
          "mchen": true,
          "hmadi": true
        }
      },
      ...
    }
  }

Is it possible to construct a Firebase query to find all the groups that have the value 'false' for user "mchen" (basically I want bob and dave)? How?

eg new Firebase(' https://myApp.firebaseio.com/users/mchen/groups ') ...

In my real code, alpha, bob, charlie and dave are Firebase auto-generated keys, but the same query should solve my problem. (I'm using Firebase Web version)

Thanks in advance.

Answer 1

Finally got it working. I'm not an expert, but I hope this helps anybody not familiar with Firebase:

If you only use Firebase:

var ref = new Firebase('https://myApp.firebaseio.com/users/mchen/groups');
ref.orderByValue().equalTo(false).on('value', function(data){
  console.log(data.val());
})

If you use AngularFire:

var ref = new Firebase('https://myApp.firebaseio.com/users/mchen/groups');
$firebaseArray(ref.orderByValue().equalTo(false)).$loaded().then(function(data){
  console.log(data);
});

Note:

• orderByValue() is the one to use without knowing the keys
• Use equalTo(false), not equalTo('false')
• $firebaseArray is the one that returns multi items, not $firebaseObject

A rule is also required for performance:

{
  "rules": {
    "users": {
      "$userName": { // A better way would be using an auto-generated ID in here
        "groups": {
          ".indexOn" : ".value" // add index on the value - notice it's .value
        }
      }
    }
  }
}