I have clients connecting to the database with javascript. I also have code running on my server and I'm trying to do a transaction following example as shown here: https://firebase.google.com/docs/database/server/save-data#section-transactions
Here's a simplified structure of my data
users:
userguid
resource : "room1"
printer : "printer1"
resources
rooms
room1
printers
printer1
counter : 15
The web client would write a request to their own node under "users".
The server is watching for those request and updates the counter for that resource.
If i have the transaction watching for child added I get null for counter so I can't increment the number. If I also watch for child modified the I will get the correct counter value.
I understand from the documentation that the value in transaction can be null but I'm not sure how I can fix my use case to do what I need.
Basically I don't want the client touching the counter, I want the server to read and update that value.
I've gone thru this post Firebase runTransaction not working but I'm not clear on how to structure my code to deal with this.
