Skinny Micro

Skinny Micro is at once a micro Web framework to build Servlet applications in Scala and the core part of Skinny Framework.

Skinny Micro started as a fork of Scalatra. After that, many improvements have been made to be safer and more efficient when working with Scala Future values upon it.

Basically, Skinny Micro's DSLs are source compatible with Scalatra 2.3's ones. But names of base traits and packages are mostly renamed and the structure of internal modules are re-designed.

Getting Started

Taking a look at skinny-micro-heroku-example first would be helpful to understand what you need to do. samples and scalas-samples in this repository are also worth looking at.

Library Dependencies

When you start new sbt project, add the following dependencies:

lazy val skinnyMicroVersion = "2.0.+"

libraryDependencies ++= Seq(
  // micro Web framework
  "org.skinny-framework" %% "skinny-micro"             % skinnyMicroVersion,
  // jackson integration
  "org.skinny-framework" %% "skinny-micro-jackson"     % skinnyMicroVersion,
  "org.skinny-framework" %% "skinny-micro-jackson-xml" % skinnyMicroVersion,
  // json4s integration
  "org.skinny-framework" %% "skinny-micro-json4s"      % skinnyMicroVersion,
  // Scalate integration
  "org.skinny-framework" %% "skinny-micro-scalate"     % skinnyMicroVersion,
  // Standalone Web server (Jetty 9.4 / Servlet 3.1)
  "org.skinny-framework" %% "skinny-micro-server"      % skinnyMicroVersion
)

Minimum Examples

We'd love to show you some simple but working examples briefly.

Please also see more examples under samples and scalas-samples.

Simple Application

The following is a minimum Servlet example. skinny.micro.SkinnyListener initializes Skinny Micro's environment.

As same as Scalatra, _root_.Bootstrap class (instead of _root_.ScalatraBootstrap for Scalatra) is detected by default. If you'd like to change the name of the Bootstrap class, it's also possible by specifying with Servlet's init parameter.

Also take a look at sbt-servlet-plugin. The plugin will help you much when building Servlet applications in Scala.

See samples for more examples.

src/main/scala/app.scala

import javax.servlet._
import skinny.micro._

object Hello extends WebApp {
  get("/say-hello") {
    s"Hello, ${params.getOrElse("name", "Anonymous")}!\n"
  }
}

class Bootstrap extends LifeCycle {
  override def init(ctx: ServletContext) {
    Hello.mount(ctx)
  }
}

src/main/webapp/WEB-INF/web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <listener>
        <listener-class>skinny.micro.SkinnyListener</listener-class>
    </listener>
</web-app>

Async Native Application

Skinny Micro newly privides original base traits that named as AsyncWebApp (AsyncSkinnyMicorFilter) and AsyncSingleWebApp (AsyncSkinnyMicroServlet).

They are natively suitable for building Future-wired async operations. You will no longer unwantedly feel stressed when working with Future-wired operations.

case class Message(id: Long, text: String)

object Messages {
  def search(keyword: Option[String])(implicit ctx: ExecutionContext): Future[Seq[Message]]
}

object AsyncMessagesApp extends AsyncWebApp with JSONSupport {

  post("/messages/search") { implicit ctx =>
    // You don't need to explicitly wrap results with AsyncResult
    // Of course, doing so is also fine
    Messages.search(params.get("keyword"))
      .map(ms => Ok(toJSONString(ms))) // returns Future[ActionResult]
  }
}

Scalas Example

By using scalas, script runnner from sbt, you can easily run small Scala applications.

http://www.scala-sbt.org/0.13/docs/Scripts.html

#!/usr/bin/env scalas
// or ./scalas app.scala
/***
scalaVersion := "2.12.10"
libraryDependencies += "org.skinny-framework" %% "skinny-micro-server" % "2.0.+"
*/
import skinny.micro._
object HelloApp extends WebApp {
  get("/say-hello") {
    s"Hello, ${params.getOrElse("name", "Anonymous")}!\n"
  }
}
WebServer.mount(HelloApp).port(4567).start()

println
println("Try: curl -v 'localhost:4567/say-hello?name=Martin'")
println

Other Examples

More working examples are available under samples and scalas-samples.

License

(The BSD 2-Clause License)

skinny-framework/skinny-micro