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
   

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2. Network is
   important!
   

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3. Network means a lot of things
   @ddinorahtovar
   

   Data Layer
   Network
   

   Presentation Layer
   UI
   Models
   
   
   Entities
   Domain Layer
   

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4. Network means a lot of things
   @ddinorahtovar
   •Concurrency
   •Clients
   •Connections (WIFI, Cell)
   •Http versions and frames
   

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5. Network means a lot of things
   @ddinorahtovar
   Request
   Response
   Click Origin Server
   

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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
   

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7. Network means a lot of things
   @ddinorahtovar
   Uniform Resource Locator
   Headers
   Body
   

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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
   

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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
   

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10. Http and Network Clients
    

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11. Http Methods
    @ddinorahtovar
    GET
    PATCH
    DELETE
    POST
    PUT
    

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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
    

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13. HttpClient
    @ddinorahtovar
    •HttpClient are clases to handle Http connection,
    methods and frames of data
    

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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
    

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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
    

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16. Cache policies
    @ddinorahtovar
    •Cache file and policies
    

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17. Cache
    @ddinorahtovar
    •To force a full refresh, add the noCache()
    

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18. TSL, Certificates and
    Pinning
    

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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
    

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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
    

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21. TSL depends of HTTPs
    @ddinorahtovar
    HTTP/1.1
    

    TCP streams and
    packets
    HTTP/2
    

    Frames division
    HTTP/3
    

    QUIC streams
    

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22. TSL
    @ddinorahtovar
    •Using HTTPS in our servers is enough?
    •Want to be safe? Then, lets talk about
    encryption
    •Short Answer: No
    

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23. Your App
    
    TSL
    @ddinorahtovar
    Origin Server
    
    Encrypted Certificates
    
    TSL/SSL
    
    

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24. TSL in your HTTP client
    @ddinorahtovar
    

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25. TSL
    @ddinorahtovar
    •What is a cipherSuite?
    val cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
    Schema
    Model
    Padding
    

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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
    

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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
    

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28. Certificates
    @ddinorahtovar
    CER (.CRT
    )
    
    PFX
    

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29. Certificates
    @ddinorahtovar
    

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30. Security is important
    @ddinorahtovar
    •You can check “Modern security for Android
    developers”
    

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31. Authenticators &
    Interceptors
    

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32. Interceptors are amazing!
    @ddinorahtovar
    Your App
    OkHttp
    

    Core
    Internet
    Loggin
    Interceptor
    Network
    Interceptor
    

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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
    

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34. Loggin interceptors
    @ddinorahtovar
    

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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!
    

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36. Network interceptor
    @ddinorahtovar
    

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37. Network interceptors
    @ddinorahtovar
    •Do we need it like that?
    •Let’s do it in a cool way
    ->
    •Short Answer: well, maybe no
    

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38. Network Interceptor
    @ddinorahtovar
    

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39. Interceptor.Chain
    @ddinorahtovar
    •We need to talk about Interceptor.Chain
    •Specially about RealInterceptorChain
    

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40. Interceptor.Chain
    @ddinorahtovar
    •Here is where all the HTTP work happens
    

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41. Network Interceptor
    @ddinorahtovar
    

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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
    

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43. Authenticator
    @ddinorahtovar
    Your App Authenticator Your server
    401
    Try to
    access
    Refresh
    Refresh
    Normal
    request
    Normal
    request
    

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44. Authenticators
    @ddinorahtovar
    

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45. A tip for OkHttpClient
    

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46. OkHttpClient and Start up time
    @ddinorahtovar
    •Slow the times of creating
    

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47. @ddinorahtovar
    •Dagger Party tricks by Zac Sweers
    OkHttpClient and Start up time
    

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48. Performance
    

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49. Performance!
    @ddinorahtovar
    •Depends of many things
    •Redundancy
    •Concurrency
    •OkHttpClient*
    

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50. Concurrency
    @ddinorahtovar
    •Is not proper mobile but is important!
    Fault tolerance
    High Availability
    

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51. Concurrency
    @ddinorahtovar
    Pools
    Threading
    •Is about three things
    Coroutines*
    

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52. Threading
    @ddinorahtovar
    UI Thread
    Dispatcher IO
    

    Suspendable action
    

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53. Connection Pool
    @ddinorahtovar
    CPU operation
    like Files
    Databases
    Network
    

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54. Testing
    

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55. Testing should be simpl
    @ddinorahtovar
    Your App MockResponse MockWebServer
    Intercept
    call
    Normal
    request
    Mocked
    response
    Normal
    request
    

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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
    

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57. MockWebServer
    @ddinorahtovar
    •Simple setup
    

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58. MockWebServer
    @ddinorahtovar
    •Adding responses is pretty simple!
    

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59. MockWebServer
    @ddinorahtovar
    

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60. Practical Network for
    Android Developers
    Dinorah Tova
    r
    
    Google Developer Expert

    Platform Mobile Engineer

    @ konfío.mx
    @ddinorahtovar
    @ddinorahtovar
    

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