HTTP Framework Samples in Scala

Design

All implementations follows below design:

Rest implementation: ☕️ Coffee Shop API

All examples are using coffee-shop static rest service except ZIO Http because of the some bugs. For ZIO, I have implemented a simple Heroku service described here.

Endpoint	Description	Return type	Request example	Return example
/coffee	Returns coffee types	Array[String]	http://localhost:9000/coffee	[ "hots", "iced" ]
/coffee/#category	Drinks in the category	Array[ Drink( title: String, id: Int, description: String, ingredients: List[String] ) ]	http://localhost:9000/coffee/hots	[ { "title": "Black", "id": 1, "description": "Black coffee is as simple as it gets with ground coffee beans steeped in hot water, served warm. And if you want to sound fancy, you can call black coffee by its proper name: cafe noir.", "ingredients": [ "Coffee" ] }, ...

Akka Http

• Functional implementation
• Native Datadog support
• Supports full HTTP protocol
• Detailed documentation: https://doc.akka.io/docs/akka-http/current/index.html

Http4s

• Functional implementation
• Support for effect libraries (cats effect etc)
• Limited Datadog support via third party libraries ( avast/datadog4s, Kamon etc). Integration in progress: DataDog/dd-trace-java#1934
• Supports full HTTP protocol
• Limited documentation: https://http4s.org/v0.23/index.html

ZIO Http

(as of writing this documentation)

• Does not support full Http Protocal
• No native Datadog support yet
• Client has major pitfalls: stable channel does not have Https support. Beta channel has some bugs (removes trailing / in the URLS etc)
• Functional, and follows effect library guides
• Limited documentation (explains just a simple example): https://dream11.github.io/zio-http/docs/index

Finatra

• Play like dependency framework (Guice) support by default
• Supports full HTTP protocol
• Supports both Twitter's Future or Cats effect for processing
• Native Datadog support
• Detailed documentation: https://twitter.github.io/finatra/user-guide/

OpenAPI Endpoint

All tapir implementations exposes documentation automatically on API level.

ReadDoc Web UI: http://localhost:9000/docs

Additionally, tapir-akka-http also implements a way of exporting openapi yaml. A Github Action uses this implementation and publishes a static swagger documentation at http://veysiertekin.github.io/scala-http-framework-samples

Simple Remote Service on Heroku

(This Heroku service has been used in ZIO Http)

1- Go to heroku-coffee-shop-service/ in your terminal.

2- Login to Heroku:

heroku login

3- Create a simple app

heroku create
git push heroku main

4- Start application by scaling it to 1

heroku ps:scale web=1

4- You can view http location of the service by:

heroku open