Explore creating robust HTTP services in Scala's functional programming paradigm. Gain insights into pure vs. impure implementations, their pros and cons, and effective tool usage.

scala-platform.tar.gz

Scala-Pure

Scala-Impure

Scala-Tapir

Scala-Impure-Test

Scala-Pure-Test

Scala-Tapir-Test

Test

Scala - Run Code Widget 

Scala-Pure-copy

Scala is one of the most popular general-purpose languages that supports both object-oriented and functional programming. In this course, you will learn how to create back-end HTTP services using Scala's functional programming paradigm.

You will also learn how to develop, test, and document the service using both pure and impure ways. You will be exposed to the differences between pure and impure implementation, their respective pros and cons, and how pure implementation can be more robust in terms of performance, understandability, testability, and type safeness. 

By the end of the course, you will have a clear idea of how functional programming works in Scala and how you can use the available tools more effectively.

Pure Functional HTTP APIs in Scala

# Take 1 - Merging products

Because we believe ourselves to be clever, we pick the simple sledgehammer approach and just run some accumulator on the stream. We need a helper function and some code changes on the stream (e.g., in the route). 



def merge(ps: List[Product])(p: Product): List[Product] =
  ps.headOption.fold(List(p)) { h => 
    if (h.id === p.id)
      h.copy(names = h.names ::: p.names) :: ps.drop(1)
    else
      p :: ps
  } 

So this function will take a list (that may be empty) and a `Product`, and will merge the topmost element (the head) of the list with the given `Product`. It will return an updated list that either contains an updated head element or a new head. We may use this method if we temporarily ignore the question of what guarantees that the relevant list element will always be the head. 


Learn how to implement the streaming of our products.

Introduction

Impure Implementation

Pure Implementation

Testing Impure Services

Testing Pure Services

Benchmarks

Documentation

Epilogue

Streaming

Take 1 - Merging products