Firebase (2016) Shallow Query

Question

I'm trying out Firebase (since Google's new release).

In the original version of Firebase the parameter shallow=true would return an object with { key: true } for every key at the root of the tree/branch that was requested (and so, rather than children being returned, you would just know the fact that child(ren) exist). This is useful because you don't necessarily want all the data from the child nodes (particularly if there's a lot of it).

Is there a way to do that with Google's new version of Firebase? I'm thinking something like:

firebase.database().ref('/data/?shallow=true').once('value', function(snapshot) {
  // do something with snapshot
}

The above code's snapshot.val() returns null and if I'm reading the docs correctly, it seems this functionality is gone.

Answer 1

The ?shallow=true parameter in Firebase Database 2.x was only available in the REST API. See https://www.firebase.com/docs/rest/guide/retrieving-data.html#section-rest-uri-params.

In the new Firebase Database 3.x, the same parameter is still only available in the REST API. See https://firebase.google.com/docs/database/rest/retrieve-data#shallow

You're using a Firebase SDK (JavaScript from the looks of it), which never supported this parameter.

For more questions that have discussed this in the past, see:

• Firebase retrieve child keys but not values
• Firebase REST API working with shallow data
• How do I do a shallow query on Firebase iOS?
• Get Firebase child nodes' names without getting their children too in Firebase response?

Answer 2

This worked for me based on Frank's answer:

import request from 'request';

request({ url: "https://[YOUR-APP-ID].firebaseio.com/path/to/data/.json?shallow=true" }, (error, response, body) => {
    const shallowData = JSON.parse(body);
    console.log(shallowData);
});

Reference: https://firebase.google.com/docs/database/rest/retrieve-data#shallow