Cloud Firestore on Android

An overview of Cloud Firestore and implementation on Android

Transcript

1. Cloud Firestore on Android @_modge_ Eoin Fogarty
2. # Introduction - Eoin Fogarty - Native Engineer at Cyberagent (REQU). - Android and Flutter developer @_modge_ https://github.com/eoinfogarty
3. # What is Cloud Firestore Cloud Firestore is a flexible, scalable NoSQL cloud database to sync data for client and server-side development. Capabilities - Flexibility - Expressive Querying - Realtime Updates - Offline Support - Designed to Scale
4. # NoSQL vs SQL SQL - Relational Databases (RDBMS); - Table based databases. - Tables which consists of n number of rows of data. - Predefined schema . - Vertically scalable NoSQL - Distributed database. - Document based, key-value pairs, graph databases or wide-column stores. - key-value pair, documents, graph databases or wide-column stores which do not have standard schema definitions which it needs to adhered to ie dynamic schema. - Dynamic schema for unstructured data. - Horizontially scalable
5. # Data Models In Firestore there are no tables or rows. Data is stored in Documents and organized in Collections.
6. # Documents - Stored in Collections - Contains a set of key-value pairs. - Can contain subcollections and nested objects. - Identified by a name. - Supports a variety of data-types eg boolean, string, number etc. - Complex objects can be represented with maps. Example: ❒ _modge_ name: first : "Eoin" last : "Fogarty" born : 1900
7. # Collections - Simply a container for documents. - Cannot contain other collections. - Do not create or delete, its implied. - Contained documents can contain different fields and types. Example: ❒❒ users ❒ _modge_ name: first : "Eoin" last : "Fogarty" ❒ heihei first : "Shawn" last : "Kawano"
8. # Getting Started
9. # Getting Started
10. # Getting Started - Android 1 - Add Firebase to your Android app. 2 - In build.gradle make sure to add google maven repository. 3 - Add firestore dependency. implementation 'com.google.firebase:firebase-firestore-ktx:19.0.0' 4 - Initialize Cloud Firestore. val db = FirebaseFirestore.getInstance()
11. # Add data To create or overwrite a document we use the set method val user = HashMap<String, Any>() user["name"] = "Eoin Fogarty" user["born"] = "1900" db.collection("users").document("_modge_") .set(user) .addOnSuccessListener { Log.d(TAG, "DocumentSnapshot successfully written!") } .addOnFailureListener { e -> Log.w(TAG, "Error writing document", e) } If the document does not exist, it will be created. If the document does exist, its contents will be overwritten with the newly provided data, unless you specify otherwise
12. # Read Data Once We can use the get() method to retrieve an entire collection db.collection("users") .get() .addOnSuccessListener { result -> for (document in result) { Log.d(TAG, "${document.id} => ${document.data}") } } .addOnFailureListener { exception -> Log.w(TAG, "Error getting documents.", exception) }
13. # Realtime Updates We can listen to a document with the onSnapshot() method. val docRef = db.collection("users").document("_modge_") docRef.addSnapshotListener(EventListener<DocumentSnapshot> { snapshot, e -> if (e != null) { Log.w(TAG, "Listen failed.", e) return@EventListener } if (snapshot != null && snapshot.exists()) { Log.d(TAG, "Current data: ${snapshot.data}") } else { Log.d(TAG, "Current data: null") } })
14. # Securing Data All Cloud Firestore Security Rules consist of match statements, which identify documents in your database, and allow expressions, which control access to those documents: // Allow read/write access on all documents to any user signed in to the application service cloud.firestore { match /databases/{database}/documents { match /{document=**} { allow read, write: if request.auth.uid != null; } } }
15. # Extending with Cloud Functions With Cloud Functions, you can deploy Node.js code to handle events triggered by changes in your Cloud Firestore database. The Cloud Functions for Firebase SDK exports a functions.firestore object that allows you to create handlers tied to specific events. - onCreate: when a document is written to for the first time. - onUpdate: when a document already exists and has a value changed. - onDelete: when a document with data is deleted. - onWrite: when onCreate, onUpdate or onDelete is triggered.
16. # Extending with Cloud Functions This will trigger a function to fire any time a new document is created in a collection by using an onCreate() handler with a wildcard exports.createUser = functions.firestore .document('users/{userId}') .onCreate((snap, context) => { // Get an object representing the document // e.g. {'name': 'Eoin', 'age': 119} const newValue = snap.data(); // access a particular field as you would any JS property const name = newValue.name; // perform desired operations eg send push... });
17. # Much More - Simple and compound queries - Order and limit data - Paginate Data - Offline Data Access - Indexes - Transactions and batched writes - Conditional Security Rules - Testing security rules