Functions-samples: Firebase search by child value?

[beratuslu]

Hello guys,

I am trying to get "pushToken" value by searching child value called "deviceUid". Since my query returning null, I cant send notification to user..

Here is my db and I cant get push token value with following code;

Thank you..

  const deviceUID = event.params.deviceUID;
  console.log("deviceUID: ", deviceUID);
  //deviceUID: 1f2d34d

  const getpushTokenPromise = admin.database().ref('/users').child('pushToken').orderByChild('deviceUid').equalTo(deviceUID).once('value');

  getpushTokenPromise.then(pushTokenSnapshot => {
    const token = pushTokenSnapshot.val();
    console.log("token:" ,token);
    //token: null
  });

[davvit]

here is a quick sample

firebase().database().ref('/app-users/users/').orderByChild("email").equalTo('[email protected]').on('value', function (snapshot) {
       //snapshot would have list of NODES that satisfies the condition
    console.log(snapshot.val())
        console.log('-----------');

       //go through each item found and print out the emails
       snapshot.forEach(function(childSnapshot) {

       var key = childSnapshot.key;
      var childData = childSnapshot.val();

        //this will be the actual email value found
         console.log(childData.email);
  });

});

in your case
_childData.email_ would be childData.pushToken
_orderByChild("email")_ would be orderByChild("deviceUid")

[inlined]

It looks like @davvit solved your problem before we could get to it. To make sure your query is efficient, also add this to your firebase database rules:

{
  "users": {
    "$userId": {
      ".indexOn": "deviceUid"
    }
  }
}

[alanscarpa]

Hi @inlined , I'm just wondering what the database rule that you listed does in this situation?

[inlined]

It allows you to (efficiently) use orderByChild('deviceUid'). When the Firebase Realtime Database loads your node, it will keep a view of that data in deviceUid order.

Also, if you need complex querying, consider using Cloud Firestore.