Android HTTP Codelab

• Codelab to demonstrate networking on Android and JVM using OkHttp and Retrofit.

What will you learn?

• OkHttp and Retrofit libraries
  • Basics of HTTP - headers, path, queries, timeouts
  • Modifying requests by interceptors
  • Authentication, SSL, Certificate Pinning
  • OkHttp internals and philosophy
• Caching
  • Cache-Control Headers and their use cases
  • Etag usage
• Testing Networking code
  • Using MockWebServer
  • Testing whole repositories
  • Complex networking scenarios with parallel requests
• Client network strategies
  • Simple retries
  • Exponential backoff
  • Network throttling

How to use the Codelab

• All code is in the default branch.
• You can find the unit tests within the codelab directory in the format Test{Number}{Topic}
• Each test has comments with instructions and references to guide to the solution.
• There is a solution package having identical Test{Number}{Topic} name with working code.
• Other key classes to look at are: HttpModule, HttpBinClient, GitHubUsersClient
• Most of the methods use the Retrofit Call and we move to Coroutines suspend functions through the codelab.

References

• HTTP in a Hostile World, Slides
• Okio powering OkHttp I/O
• Android Studio Network Inspector
• Cache-Control & ETag, OkHttp Caching
• Gzip, Content-Length header
• Exponential Backoff
• OkHttp retries requests by default
• URL encoding
• Client network throttling
• Bearer authentication
• Android Network Config certificate pinning