Jump into cross-platform development with Firebase - GDG Kharkiv-Center

Brief intro to Firebase, with examples of Dynamic database and Authentication, made on the GDG Kharkiv-Center meetup

1. Jump into cross-platform development with Firebase Dynamic Database, Authentication and much more... Constantine Mars Team Lead, Senior Developer @ DataArt Organizer @ GDG Dnipro-Art
2. GDG First - about this day
3. #gdg_kharkiv_center What is a GDG? Google Developer Groups (GDGs) are for developers who are interested in Google's developer technology; everything from the Android, App Engine, and Google Chrome platforms, to product APIs like the Maps API, YouTube API and Google Calendar API. A GDG can take many forms -- from just a few people getting together to watch our latest video, to large gatherings with demos and tech talks, to events like code sprints and hackathons. However, at the core, GDGs are focused on developers and technical content, and the core audience should be developers.
4. #gdg_kharkiv_center A GDG is • Run by passionate individuals in the developer community • A place to learn about Google Technologies and Tools for developers. • A place to see what local companies and developers are doing with these technologies • Focused on developers and educational technical content • Open to the public with a public membership • A place to meet cool and smart people in tech :)
5. #gdg_kharkiv_center A GDG is NOT • Run by a corporation • A place to hear a very salesy pitch at any time • Focused on end users or consumer content • A closed group
6. #gdg_kharkiv_center Worldwide GDG Community
7. #gdg_kharkiv_center GDG in Ukraine
8. #gdg_kharkiv_center Upcoming Events - GDG DevFest Ukraine
9. #gdg_kharkiv_center Upcoming Events - Google I/O
10. #gdg_kharkiv_center Upcoming Events - Google Developer Day
11. Firebase Overview
12. #gdg_kharkiv_center History September 2011 - James Tamplin and Andrew Lee founded Envolve, that provided developers an API that let them integrate online chat into their websites April 2012 - Tamplin and Lee decided to separate the chat system and the real-time architecture that powered it, founding Firebase as a separate company 21 October 2014 - Firebase announced it had been acquired by Google
13. #gdg_kharkiv_center History February 16, 2016 - David East announced Firecasts video series for Firebase developers May 18, 2016 - James Tamplin and Francis Ma present Firebase Overview on Google I/O ‘16 January 18, 2017 - Google announced that it signed an agreement to acquire Fabric and Crashlytics from Twitter, and that those services would join the Firebase team.
14. #gdg_kharkiv_center Overview
15. Project setup Click-click-boom
16. #gdg_kharkiv_center Project setup in console
17. #gdg_kharkiv_center Project setup in console
18. #gdg_kharkiv_center Project setup in console
19. #gdg_kharkiv_center Project setup in console
20. #gdg_kharkiv_center Project setup in console
21. #gdg_kharkiv_center Android Studio Assistant
22. #gdg_kharkiv_center Android Studio Assistant
23. #gdg_kharkiv_center Android Studio Assistant
24. #gdg_kharkiv_center Android Studio Assistant
25. Authentication Be together, not the same!
26. #gdg_kharkiv_center Authentication
27. #gdg_kharkiv_center Enable Authentication types
28. #gdg_kharkiv_center @Override public void onActivityResult(int requestCode, int resultCode, Intent data) { … if (requestCode == RC_SIGN_IN) { GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data); if (result.isSuccess()) { // Google Sign In was successful, authenticate with Firebase GoogleSignInAccount account = result.getSignInAccount(); firebaseAuthWithGoogle(account); } else { // Google Sign In failed, update UI appropriately // ... } } } Authentication (Google Sign In)
29. #gdg_kharkiv_center AuthCredential credential = GoogleAuthProvider.getCredential(acct.getIdToken(), null); mAuth.signInWithCredential(credential) .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() { @Override public void onComplete(@NonNull Task<AuthResult> task) { Log.d(TAG, "signInWithCredential:onComplete:" + task.isSuccessful()); // If sign in fails, display a message to the user. If sign in succeeds // the auth state listener will be notified and logic to handle the // signed in user can be handled in the listener. if (!task.isSuccessful()) { Log.w(TAG, "signInWithCredential", task.getException()); Toast.makeText(GoogleSignInActivity.this, "Authentication failed.", Toast.LENGTH_SHORT).show(); } // ... } }); Authentication (Google Sign In)
30. #gdg_kharkiv_center FirebaseAuth.getInstance().signOut(); Sign out
31. #gdg_kharkiv_center Rules
32. Firebase Database, pt1 Basics
33. #gdg_kharkiv_center With FirebaseDatabase private DatabaseReference mDatabase; // ... mDatabase = FirebaseDatabase.getInstance().getReference(); Get Database reference
34. #gdg_kharkiv_center public class BatteryStatus { public int level; public int status; public BatteryStatus() { } public BatteryStatus(int level, int status) { this.level = level; this.status = status; } } Use POJOs or primitive types
35. #gdg_kharkiv_center With FirebaseDatabase BatteryStatus batteryStatus = new BatteryStatus(lastBatteryLevel, lastIsChargingStatus); mDatabase.child("battery_status").child("current_status").setVal ue(batteryStatus); mDatabase.child("voting").setValue(lastVote); Write values
36. #gdg_kharkiv_center Written values visible in console
37. #gdg_kharkiv_center mDatabase.child("battery_status").addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { BatteryStatus batteryStatus1 = dataSnapshot.child("current_status").getValue(BatteryStatus.class); lastBatteryLevel = batteryStatus1.level; } @Override public void onCancelled(DatabaseError databaseError) { } }); Read values = listen to changes
38. #gdg_kharkiv_center private void onPerformTransaction(DatabaseReference postRef) { postRef.runTransaction(new Transaction.Handler() { @Override public Transaction.Result doTransaction(MutableData mutableData) { Voting p = mutableData.getValue(Voting.class); if (p == null) { return Transaction.success(mutableData); } p.setValue(true); // Set value and report transaction success mutableData.setValue(p); return Transaction.success(mutableData); } @Override public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot) { // Transaction completed } }); } Transactions
39. Firebase Database, pt2 How to make queries in NoSQL
40. #gdg_kharkiv_center It’s a JSON tree { "users": { "droid_ninja": { "name": "Android Ninja", "battery_status": { "74": true }, }, "raspberry_pike": { ... }, "fire_tamplin": { ... } } } Structure data
41. #gdg_kharkiv_center { // This is a poorly nested data architecture, because iterating the children // of the "chats" node to get a list of conversation titles requires // potentially downloading hundreds of megabytes of messages "chats": { "one": { "title": "Phone battery discussions", "messages": { "m1": { "sender": "droid_ninja", "message": "Looks like Doze Mode doesn’t help" }, "m2": { ... }, // a very long list of messages } }, "two": { ... } } } Avoid nesting
42. #gdg_kharkiv_center // Conversation members are easily accessible // and stored by chat conversation ID "members": { // we'll talk about indices like this below "one": { "droid_ninja": true, "fire_tamplin": true, "raspbery_pike": true }, "two": { ... }, "three": { ... } }, Flatten data structures
43. #gdg_kharkiv_center { // Chats contains only meta info about each conversation // stored under the chats's unique ID "chats": { "one": { "title": "Battery talks", "lastMessage": "ninja: Battery exhausting", "timestamp": 1459361875666 }, "two": { ... }, "three": { ... } }, ... Flatten data structures
44. #gdg_kharkiv_center // An index to track Ada's memberships { "users": { "droid_ninja": { "name": "Droid Ninja", // Index Ada's groups in her profile "groups": { // the value here doesn't matter, just that the key exists "gdg": true, "geeks": true "foreigners": false } }, ... }, Use an index
45. #gdg_kharkiv_center "groups": { "gdg": { "name": "GDG", "members": { "droid_ninja": true, "fire_tamplin": true, "raspberry_pike": true } }, ... } } Use an index
46. #gdg_kharkiv_center firebase.database.Query class
47. #gdg_kharkiv_center ChildEventListener childEventListener = new ChildEventListener() { @Override public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {} @Override public void onChildChanged(DataSnapshot dataSnapshot, String previousChildName) {} @Override public void onChildRemoved(DataSnapshot dataSnapshot) {} ... }; ref.addChildEventListener(childEventListener); Lists Just push()
48. #gdg_kharkiv_center Ordering
49. #gdg_kharkiv_center // My top posts by number of stars String myUserId = getUid(); Query myTopPostsQuery = databaseReference.child("user-posts").child(myUserId) .orderByChild("starCount"); myTopPostsQuery.addChildEventListener(new ChildEventListener() { // TODO: implement the ChildEventListener methods as documented above // ... }); Ordering
50. #gdg_kharkiv_center Filtering
51. #gdg_kharkiv_center / Last 100 posts, these are automatically the 100 most recent // due to sorting by push() keys Query recentPostsQuery = databaseReference.child("posts") .limitToFirst(100); Limit
52. #gdg_kharkiv_center // My top posts by number of stars myTopPostsQuery.addValueEventListener(new ValueEventListener() { @Override public void onDataChange(DataSnapshot dataSnapshot) { for (DataSnapshot postSnapshot: dataSnapshot.getChildren()) { // TODO: handle the post } } @Override public void onCancelled(DatabaseError databaseError) {} }); Filtering example
53. #gdg_kharkiv_center Query biggest value of “weight” ref .orderByChild("weight") .limitToLast(2) .on("child_added", function(snapshot) { console.log(snapshot.key()); }); More query examples
54. And more... There are a lot of tools in the box
55. #gdg_kharkiv_center Samples
56. #gdg_kharkiv_center And even more...
57. #gdg_kharkiv_center Links • Firebase home: https://firebase.google.com/ • Firebase docs: https://firebase.google.com/docs/ • Firebase blog: https://firebase.googleblog.com/ • Firecasts Youtube Channel: https://goo.gl/9giPHG • Firecasts for iOS: https://goo.gl/eNioSp • Firecasts for Android: https://goo.gl/M7UPTv • Firebase for SQL Developers on Youtube: https://youtu.be/WacqhiI-g_o?list=PLl-K7zZEsYLlP-k-RKFa7RyNPa9_wCH2s
58. Constantine Mars @DataArt @ConstantineMars +ConstantineMars Q&A Get ready for more...