Introduction to ZIO Http

ZIO Http is a scala library for building http apps. It is powered by ZIO and netty and aims at being the defacto solution for writing, highly scalable and performant web applications using idiomatic scala.

Installation

Setup via build.sbt:

libraryDependencies += "dev.zio" %% "zio-http" % "3.0.0-RC2"

NOTES ON VERSIONING:

• Older library versions 1.x or 2.x with organization io.d11 of ZIO Http are derived from Dream11, the organization that donated ZIO Http to the ZIO organization in 2022.
• Newer library versions, starting in 2023 and resulting from the ZIO organization (dev.zio) started with 0.0.x, reaching 1.0.0 release candidates in April of 2023

Getting Started

A simple Http server can be built using a few lines of code.

import zio._
import zio.http._

object HelloWorld extends ZIOAppDefault {

  val app: App[Any] = 
    Http.collect[Request] {
      case Method.GET -> Root / "text" => Response.text("Hello World!")
    }

  override val run =
    Server.serve(app).provide(Server.default)
}

Steps to run an example

1. Edit the RunSettings - modify className to the example you'd like to run.
2. From sbt shell, run ~example/reStart. You should see Server started on port: 8080.
3. Send curl request for defined http Routes, for eg : curl -i "http://localhost:8080/text" for example.HelloWorld.

Watch Mode

You can use the sbt-revolver plugin to start the server and run it in watch mode using ~ reStart command on the SBT console.