Pure functional HTTP APIs in Scala
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Pure functional HTTP APIs in Scala

About the Book

This book is intended for the intermediate Scala programmer who is interested in functional programming and works mainly on the web service backend side. Ideally she has experience with libraries like Akka HTTP and Slick which are in heavy use in that area.

However maybe you have wondered if we can't do better even though aforementioned projects are battle tested and proven.

The answer to this can be found in this book which is intended to be read from cover to cover in the given order. Within the book the following libraries will be used: Cats, Cats Effect, http4s, Doobie, Refined, fs2, tapir, Monocle and probably others. ;-)

The second edition includes a chapter about migrating the project to Scala 3.

Code and book source can be found in the following repository: https://github.com/jan0sch/pfhais

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    • Functional Programming
    • Scala
    • Computers and Programming
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About the Author

Jens Grassel
Jens Grassel

Jens Grassel is the CTO and founder of Wegtam, a company specialised in data integration and search technology. He is programming in a plethora of languages and engineering software systems since the fall of the Wall. For some years now his focus has shifted to functional programming languages.

He has contributed to numerous free software projects and likes to apply free and open source technologies wherever applicable.

Table of Contents

  • Foreword
      • About this book
      • Copyleft Notice
    • Thanks
  • Our use case
    • Service specification
      • Data model
      • Database
      • HTTP API
  • The state of the art
    • Problems
  • Maybe there is another way
    • Impure implementation
      • Models
      • Database layer
      • Akka-HTTP routes
    • Pure implementation
      • Pure configuration handling
      • Models
      • Database layer
      • http4s routes
    • What about tests?
      • Testing the impure service
      • Testing the pure service
    • Adding benchmarks
      • Our environment
      • Comparison
      • Summary
    • Documenting your API
      • The lay of the land
      • Using types to describe an API
      • A pure implementation using tapir.
    • Moving to Scala 3…
      • Step 1: Updating to 2.13.x
      • Step 2: Migrating to Scala 3
  • Epilogue
  • Notes

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