Practical Network for Android Developers

In this talk we are gonna be talking about the Network data layer with a different vision that usually is addressed, cause networking on Android is difficult to work with, with multiples carriers, streaming different and rich contents, and all of this should arrive at our users without missing a single detail.

We will cover the next couple of topics:

Part 1 — HTTP and Network Layer
Part 2 — TLS, Certificates, and Pinning
Part 3 — Authenticators and Interceptors
Part 4 — Performance, Redundancy, and Concurrency
Part 5 — Testing and Integration

Transcript

1. Practical Network for Android Developers Dinorah Tova r Google Developer Expert
 Platform Mobile Engineer
 @ konfío.mx @ddinorahtovar @ddinorahtovar
2. Network is important!
3. Network means a lot of things @ddinorahtovar 
 Data Layer Network 
 Presentation Layer UI Models Entities Domain Layer
4. Network means a lot of things @ddinorahtovar •Concurrency •Clients •Connections (WIFI, Cell) •Http versions and frames
5. Network means a lot of things @ddinorahtovar Request Response Click Origin Server
6. Network means a lot of things @ddinorahtovar •Request — Make an HTTP request to an URL •Response — Will return an error or success •Data that can be parsed — Parsing of a String as response to a Data Class
7. Network means a lot of things @ddinorahtovar Uniform Resource Locator Headers Body
8. Network Errors are for surviving @ddinorahtovar •1xx — Everything is cool, just wait a little bit •2xx — Everything is fine, fully successful •3xx —The response is somewhere else
9. Network Errors are for surviving @ddinorahtovar •4xx— The request by the client is poorly fulfilled, so this is an error from the mobile side •5xx — The server failed to fulfill a correct request, so this is an error from the backend side
10. Http and Network Clients
11. Http Methods @ddinorahtovar GET PATCH DELETE POST PUT
12. Http Methods @ddinorahtovar GET PATCH DELETE POST PUT •GET — Push data from server •POST — Create new resources •PUT — Update resources •PATCH — Update specific resources •DELETE — Delete resources
13. HttpClient @ddinorahtovar •HttpClient are clases to handle Http connection, methods and frames of data
14. Cache @ddinorahtovar •Database Catching — Database provide an impactful factor of your app performance. •CDN — Global network of edge locations to deliver a cached copy of your APIs content •DNS — Every domain request made on the internet essentially queries DNS cache servers in order to resolve the IP address
15. Cache policies @ddinorahtovar •Designed for non suffering and be aware that not everything change in a second •File allocation •max-age [Max time available] •Size space
16. Cache policies @ddinorahtovar •Cache file and policies
17. Cache @ddinorahtovar •To force a full refresh, add the noCache()
18. TSL, Certificates and Pinning
19. Transport Layer Security (TLS) @ddinorahtovar •Transport Layer Security (TLS) is the successor protocol to SSL. TLS is an improved version of SSL. •Depends on HTTP and the multiple flavors available
20. TSL depends of HTTPs @ddinorahtovar Version Content Http/1.1 
 with TLS Http/2 
 with TLS TLS streams, TCP streams & Packages Frames division UDP packages + QUIC streams Http/3 
 with TLS
21. TSL depends of HTTPs @ddinorahtovar HTTP/1.1 
 TCP streams and packets HTTP/2 
 Frames division HTTP/3 
 QUIC streams
22. TSL @ddinorahtovar •Using HTTPS in our servers is enough? •Want to be safe? Then, lets talk about encryption •Short Answer: No
23. Your App TSL @ddinorahtovar Origin Server Encrypted Certificates TSL/SSL
24. TSL in your HTTP client @ddinorahtovar
25. TSL @ddinorahtovar •What is a cipherSuite? val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding") Schema Model Padding
26. TSL @ddinorahtovar •What is a cipherSuite? .cipherSuites( CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA, CipherSuite.TLS_RSA_WITH_AES_128_GCM_SHA256 ) TLS Bulk encryption Key exchange and signature Message auth
27. Certificates @ddinorahtovar •In a typical SSL usage scenario, a server is configured with a certificate containing a public key as well as a matching private key. As part of the handshake between an SSL client and server, the server proves it has the private key by signing its certificate with public-key cryptography
28. Certificates @ddinorahtovar CER (.CRT ) PFX
29. Certificates @ddinorahtovar
30. Security is important @ddinorahtovar •You can check “Modern security for Android developers”
31. Authenticators & Interceptors
32. Interceptors are amazing! @ddinorahtovar Your App OkHttp 
 Core Internet Loggin Interceptor Network Interceptor
33. Loggin interceptors @ddinorahtovar •They give us information about the Headers or Body levels of the request and response •Only Debug •They can leak information
34. Loggin interceptors @ddinorahtovar
35. Network interceptors @ddinorahtovar •They give us the chance to modify request and responses •Can be used in production •Amazing for handling errors like 401!
36. Network interceptor @ddinorahtovar
37. Network interceptors @ddinorahtovar •Do we need it like that? •Let’s do it in a cool way -> •Short Answer: well, maybe no
38. Network Interceptor @ddinorahtovar
39. Interceptor.Chain @ddinorahtovar •We need to talk about Interceptor.Chain •Specially about RealInterceptorChain
40. Interceptor.Chain @ddinorahtovar •Here is where all the HTTP work happens
41. Network Interceptor @ddinorahtovar
42. Authenticator @ddinorahtovar •Returns a request that includes a credential to satisfy an authentication •Authenticate by returning a follow-up request that includes an authorization
43. Authenticator @ddinorahtovar Your App Authenticator Your server 401 Try to access Refresh Refresh Normal request Normal request
44. Authenticators @ddinorahtovar
45. A tip for OkHttpClient
46. OkHttpClient and Start up time @ddinorahtovar •Slow the times of creating
47. @ddinorahtovar •Dagger Party tricks by Zac Sweers OkHttpClient and Start up time
48. Performance
49. Performance! @ddinorahtovar •Depends of many things •Redundancy •Concurrency •OkHttpClient*
50. Concurrency @ddinorahtovar •Is not proper mobile but is important! Fault tolerance High Availability
51. Concurrency @ddinorahtovar Pools Threading •Is about three things Coroutines*
52. Threading @ddinorahtovar UI Thread Dispatcher IO 
 Suspendable action
53. Connection Pool @ddinorahtovar CPU operation like Files Databases Network
54. Testing
55. Testing should be simpl @ddinorahtovar Your App MockResponse MockWebServer Intercept call Normal request Mocked response Normal request
56. MockWebServer @ddinorahtovar •Let you manipulate the responses and let you verify request were made as expected •Testing of: •Request/Response •Body’s responses •Header’s
57. MockWebServer @ddinorahtovar •Simple setup
58. MockWebServer @ddinorahtovar •Adding responses is pretty simple!
59. MockWebServer @ddinorahtovar
60. Practical Network for Android Developers Dinorah Tova r Google Developer Expert
 Platform Mobile Engineer
 @ konfío.mx @ddinorahtovar @ddinorahtovar