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

# Provide Swagger UI and documentation

We can now look at documenting our API via OpenAPI using the tooling provided by _tapir_. But first, we should modify our main application entry point to provide the documentation for us.

//...
productRoutes = new ProductRoutes(repo)
productsRoutes = new ProductsRoutes(repo)
docs = List(
    ProductRoutes.getProduct,
    ProductRoutes.updateProduct,
    ProductsRoutes.getProducts,
    ProductsRoutes.createProduct
).toOpenAPI("Pure Tapir API", "1.0.0")
docsRoutes = new SwaggerHttp4s(docs.toYaml)
routes = productRoutes.routes <+> productsRoutes.routes
httpApp = Router(
    "/" -> routes,
    "/docs" -> docsRoutes.routes
).orNotFound
//...

We use the `toOpenAPI` helper provided by _tapir_, which generates a class structure describing our API from a list of given endpoints (**Line 9**). Additionally, we use the `SwaggerHttp4s` helper, which includes the Swagger UI for simple documentation browsing (**Line 10**). All of it is made available under the `/docs` path. The `docs` 
endpoint (**Line 14**) will be exposed on port `57344` and can be accessed by calling `{url}:57344/docs`.

While browsing there, we can see that it provides our models and endpoints but documentation could be better. So what can we do about it?

The answer is simple: Use the helpers provided by _tapir_ to add additional information to our endpoints.


Learn how to modify the main application and document the application via OpenAPI.

Introduction

Impure Implementation

Pure Implementation

Testing Impure Services

Testing Pure Services

Benchmarks

Documentation

Epilogue

Documentation via OpenAPI

Provide Swagger UI and documentation