Device token management in Firebase - Step-by-Step Execution

Process Flow - Device token management

App starts

↓

Request device token

↓

Receive token from Firebase

↓

Store token in database

↓

Use token to send notifications

↓

Token refresh event?

Yes→Get new token

↓

Update token in database

↓

End

The app requests a device token from Firebase, stores it, uses it for notifications, and updates it when refreshed.

Execution Sample

Firebase

firebase.messaging().getToken()
  .then(token => {
    saveTokenToDatabase(token);
  });

This code gets the device token from Firebase and saves it to the database.

Process Table

Step	Action	Firebase Response	Database Action	Result
1	App requests device token	Token requested	No action yet	Waiting for token
2	Firebase returns token	Token: abc123xyz	No action yet	Token received
3	Save token to database	N/A	Store token abc123xyz	Token stored
4	Send notification using token	N/A	Use token abc123xyz	Notification sent
5	Token refresh event occurs	New token requested	No action yet	Waiting for new token
6	Firebase returns new token	Token: def456uvw	No action yet	New token received
7	Update token in database	N/A	Replace old token with def456uvw	Token updated
8	No further refresh	N/A	No action	Process ends

💡 No token refresh event, process ends

Status Tracker

Variable	Start	After Step 2	After Step 3	After Step 6	After Step 7	Final
deviceToken	null	abc123xyz	abc123xyz	def456uvw	def456uvw	def456uvw
databaseToken	null	null	abc123xyz	abc123xyz	def456uvw	def456uvw

Key Moments - 2 Insights

Why do we need to update the token in the database after a refresh?

Because the token changes (see Step 6 and 7 in execution_table), and the database must have the current token to send notifications correctly.

What happens if the app does not request a new token after refresh?

Notifications will fail because the old token becomes invalid (refer to Step 5 and 6 where a new token is needed).

Visual Quiz - 3 Questions

Look at the execution_table, what is the device token after Step 3?

A null

B abc123xyz

C def456uvw

D Token not received yet

💡 Hint

Check the 'deviceToken' value after Step 3 in variable_tracker.

At which step does the token get updated in the database?

A Step 7

B Step 3

C Step 2

D Step 5

💡 Hint

Look at the 'Database Action' column in execution_table for token update.

If the token refresh event never occurs, what happens to the token in the database?

A It changes automatically

B It gets deleted

C It stays the same

D It causes an error

💡 Hint

Refer to the exit_note and final variable values in variable_tracker.

Concept Snapshot

Device token management in Firebase:
- Request token with getToken()
- Store token in database
- Use token to send notifications
- Listen for token refresh
- Update database with new token
- Keep tokens current for reliable messaging

Full Transcript

Device token management in Firebase involves the app requesting a unique token from Firebase Messaging. This token identifies the device for sending notifications. Once received, the token is saved in a database. The app uses this token to send notifications to the device. When Firebase refreshes the token, the app must get the new token and update it in the database to keep notifications working. If the token is not updated, notifications will fail. This process ensures reliable delivery of messages to the device.