How to Have Firebase Automatically Delete Values Older Than 30 Minutes

How to have Firebase automatically delete values older than 30 minutes

You can use Cloud Functions for Firebase and set up a cron job that runs, say, every five minutes and checks for timestamps older than 30 minutes.

As Will commented, that blog post is useful to learn about scheduling Cloud Functions. Here are some other useful resources to get you started:

Getting Started with Cloud Functions for Firebase - YouTube

Cloud Functions for Firebase Documentation

Cloud Functions Samples

Timing Cloud Functions for Firebase using an HTTP Trigger and Cron - YouTube

How to create an auto delete mechanism for firestore? (deleting data after time period)

Since late 2022 Firestore supports configuring a time-to-live policy on collections. See the documentation on managing data retention with TTL policies for full details.

I left my previous answer below, just in case somebody wants to roll their own solution.

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The below is outdated, and just left for reference. For the latest, see /p>

There is no built-in time-to-live mechanism in Cloud Firestore. The common approach is to run a piece of code at an interval, e.g. a Cloud Function triggered by something like cron-job.org.

Have a look at these questions for samples:

• Delete firebase data older than 2 hours
• How to delete firebase data after "n" days
• Impelementing aging in a Firebase real time database
• How to schedule a Cloud Functions to run in the future in order to build a Firestore document TTL

While these are for the Firebase Realtime Database, the same approach applies to Cloud Firestore.

How to delete firebase data after n days

Say that you have a data structure with nodes line this:

-KItqNxLqzQoLnUCb9sJaddclose
  time: "Thu Apr 28 17:12:05 PDT 2016"
  timestamp: 1461888725444

Each such node has a timestamp property that indicates when it was created. Preferably you'd set this property using Server Timestamp.

With this data structure, you can easily build a query that returns only the items older than 30 days and removes them:

long cutoff = new Date().getTime() - TimeUnit.MILLISECONDS.convert(30, TimeUnit.DAYS);
Query oldItems = ttlRef.orderByChild("timestamp").endAt(cutoff);
oldItems.addListenerForSingleValueEvent(new ValueEventListener() {
    @Override
    public void onDataChange(DataSnapshot snapshot) {
        for (DataSnapshot itemSnapshot: snapshot.getChildren()) {
            itemSnapshot.getRef().removeValue();
        }
    }

    @Override
    public void onCancelled(DatabaseError databaseError) {
        throw databaseError.toException();
    }
});

How to auto delete messages on firebase

It looks like you're trying to deploy code that require Node 8 (since it uses => notation) to an environment that doesn't support it.

On solution is to upgrade the environment to support Node 8. The alternative is to modify the code to not require Node 8 anymore, which can be done with:

exports.deleteOldItems = functions.database.ref('/mensagens/{idone}/{idtwo}/{pushid}').onWrite(function(change) {
  var ref = change.after.ref.parent; // reference to the parent
  var now = Date.now();
  var cutoff = now - CUT_OFF_TIME;
  var oldItemsQuery = ref.orderByChild('timestamp').endAt(cutoff);
  return oldItemsQuery.once('value').then(function(snapshot) {
    // create a map with all children that need to be removed
    var updates = {};
    snapshot.forEach(function(child) {
      updates[child.key] = null;
    });
    // execute all updates in one go and return the result to end the function
    return ref.update(updates);
  });
});

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This type of rewrite is fairly common in modern JavaScript, so I assume you're new to this. If you are new to JavaScript, Cloud Functions for Firebase is not the best way to learn it. I recommend first reading the Firebase documentation for Web developers and/or taking the Firebase codelab for Web developer. They cover many basic JavaScript, Web and Firebase interactions. You could also use the Admin SDK in a local Node.js process, which can be debugged with a local debugger. After those you'll be much better equipped to write code for Cloud Functions too.

Deleting Firebase data after a certain time

The orderByChild() sorting method is very forgiving. The children being sorted are not required to have a member with the specified field name. The documentation explains that those children are assigned a null value and appear first in the sort. Thus, if the reference used to create a query is incorrectly located, the query doesn't fail and instead will typically return all the children of that location.

You created your oldBug query using mDatabase where:

DatabaseReference mDatabase = FirebaseDatabase.getInstance().getReference();

This is one level too high. It should be:

 Query oldBug = mDatabase.child("Users").orderByChild("timeStamp").endAt(cutoff);

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