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

Let's successively go through the libraries we will be using in our project with a brief description of each. This is important because these libraries and the functionalities that they offer will come together to become the building blocks of our service.






### 1. `Akka` 

Using Akka, we can build highly concurrent, distributed, and resilient message-driven applications for Scala. We will also
be using Akka-HTTP, which provides a full server- and client-side HTTP stack, and Akka-Streams, whose purpose is to offer a safe way to formulate stream processing setups.
### 2. `Slick` 

Slick will be our database layer. We are using this specifically to make our job easier as we will write our database queries in Scala instead of SQL.

### 3. `Flyway`

We will employ Flyway for database migrations. Database migrations help move in a deterministic way from a current version of the database to a newer one. Database migrations are stored according to their version number in Flyway, which automatically updates them. 

### 4. _`Circe`_

_Circe_ is a JSON library for Scala that employs Cats and only has a dependency on Cats. Alongside this, we will be using akka-http-json as a wrapper.

### 5. `Refined`

We will use Refined to employ refined types. This library is a port of a [Haskell](https://www.haskell.org/) library, and the aim is to help developers constrain types.

### 6. `PostgreSQL JDBC driver` 
PostgreSQL JDBC is an open-source driver that allows Java programs to connect to a PostgreSQL database using standard, database-independent Java code.





## 1. `Akka` 

Using Akka, we can build highly concurrent, distributed, and resilient message-driven applications for Scala. We will also
be using Akka-HTTP, which provides a full server- and client-side HTTP stack, and Akka-Streams, whose purpose is to offer a safe way to formulate stream processing setups.
## 2. `Slick` 

Slick will be our database layer. We are using this specifically to make our job easier as we will write our database queries in Scala instead of SQL.

## 3. `Flyway`

We will employ Flyway for database migrations. Database migrations help move in a deterministic way from a current version of the database to a newer one. Database migrations are stored according to their version number in Flyway, which automatically updates them. 

## 4. _`Circe`_

_Circe_ is a JSON library for Scala that employs Cats and only has a dependency on Cats. Alongside this, we will be using akka-http-json as a wrapper.

## 5. `Refined`

We will use Refined to employ refined types. This library is a port of a [Haskell](https://www.haskell.org/) library, and the aim is to help developers constrain types.

## 6. `PostgreSQL JDBC driver` 
PostgreSQL JDBC is an open-source driver that allows Java programs to connect to a PostgreSQL database using standard, database-independent Java code.

Get introduced to the building blocks of the impure service.

Introduction

Impure Implementation

Pure Implementation

Testing Impure Services

Testing Pure Services

Benchmarks

Documentation

Epilogue

Getting Started

Libraries used

1. `Akka`

Getting Started

Libraries used

1. Akka

1. `Akka`