Does Firebase Realtime Database REST API support multi path updates at different entity locations?

Question

I am using the REST API of Firebase Realtime Database from an AppEngine Standard project with Java. I am able to successfully put data under different locations, however I don't know how I could ensure atomic updates to different paths. To put some data separately at a specific location I am doing:

requestFactory.buildPutRequest("dbUrl/path1/17/", new ByteArrayContent("application/json", json1.getBytes())).execute();

requestFactory.buildPutRequest("dbUrl/path2/1733455/", new ByteArrayContent("application/json", json2.getBytes())).execute();

Now to ensure that when saving a /path1/17/ a /path2/1733455/ is also saved, I've been looking into multi path updates and batched updates (https://firebase.google.com/docs/firestore/manage-data/transactions#batched-writes, only available in Cloud Firestore?) However, I did not find whether this feature is available for the REST API of the Firebase Realtime Database as well or only through the Firebase Admin SDK.

The example here shows how to do a multi path update at two locations under the "users" node.

curl -X PATCH -d '{
  "alanisawesome/nickname": "Alan The Machine",
  "gracehopper/nickname": "Amazing Grace"
}' \
  'https://docs-examples.firebaseio.com/rest/saving-data/users.json'

But I don't have a common upper node for path1 and path2. Tried setting as the url as the database url without any nodes (https://db.firebaseio.com.json) and adding the nodes in the json object sent, but I get an error: nodename nor servname provided, or not known.

This would be possible with the Admin SDK I think, according to this blog post: https://firebase.googleblog.com/2015/09/introducing-multi-location-updates-and_86.html

Any ideas if these atomic writes can be achieved with the REST API? Thank you!

Interesting question. As far as i know this is possible for all the other firebase API's (web, android, ios, c++ and unity) — André Kool

Frank van Puffelen Frank van Puffelen · Accepted Answer · 2018-04-18T14:30:17

If the updates are going to a single database, there is always a common path.

In your case you'll run the PATCH command against the root of the database:

curl -X PATCH -d '{
  "path1/17": json1,
  "path2/1733455": json2
}' 'https://yourdatabase.firebaseio.com/.json'

The key difference with your URL seems to be the / before .json. Without that you're trying to connect to a domain on the json TLD, which doesn't exist (yet) afaik.

Note that the documentation link you provide for Batched Updates is for Cloud Firestore, which is a completely separate database from the Firebase Realtime Database.

Does Firebase Realtime Database REST API support multi path updates at different entity locations?

1 Answers