Firebase data is stored in a NoSQL database and only available as a cloud service. It is a typical JSON tree database similar to many other NoSQL databases like MongoDB, Redis, or Casandra. However, there is a specific feature which differentiates Firebase from others.
Real-time Database
To understand the benefits of Firebase, imagine that you are developing a chatting app. As users add comments in a topic, the app will retrieve comments (in order) from a remote server where the chat database resides. When the user is inactive in the chat room, the app still needs to retrieve other users’ comments as they occur, as long as the user remains in that chat room. There are many challenges with building this type of periodic synchronization from scratch, and Firebase offers a solution. When you point your app to the proper data source in Firebase, it will retrieve the data in real-time. This will save a tremendous amount of custom development time.
The Firebase real-time database feature can be used for any of the following.
- Chatting
- Push notification
- News feed
- Any type of data storage that requires realtime sync
There are some other advantages to using Firebase:
- Cross-platform
- Cloud-based messaging service
- Authentication
Sample Code
The sample code below is written for Android, but iOS usage is very similar.
Initialization
Add a dependency in your build.gradle file. This is all that is needed to use Firebase.
compile 'com.google.firebase:firebase-database:9.6.1'
Next, you can initialize Firebase in your code and point it to the right database.
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("messages");Structure Database
Building upon the chatting app, you can structure the message database as below. Let’s simplify things by assuming that the message node contains all the message from the users. This will continuously grow as users add more comments.
"messages": {
{"message":"This is a test message"},{"message":"How are you?"}
}Read Data
The following method will be called once with the initial value and whenever data at this location is updated.
// Read from the database. Called whenever it's updated.
myRef.child("message").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
String value = dataSnapshot.getValue(String.class);
Log.d(TAG, "Value is: " + value);
}
@Override
public void onCancelled(DatabaseError error) {
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());
}
});Write Data
The write function is simple as shown below.
myRef.child("message").setValue("Hello, World!");There are more features in Firebase that can be leveraged in your app development. For more information, check out the documentation from the following reference: https://firebase.google.com/docs/
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