Refactor to be generic to the server type

.scalafmt.conf

@@ -21,5 +21,3 @@ rewrite.rules = [RedundantBraces, SortImports, PreferCurlyFors]
 
 docstrings = JavaDoc
 importSelectors = singleLine
-
-newlines.alwaysBeforeTopLevelStatements = true

build.sbt

@@ -1,9 +1,32 @@
 lazy val commonSettings = Seq(
   organization := "io.github.howardjohn",
-  scalaVersion := "2.12.4"
+  scalaVersion := "2.12.6"
 )
 
-lazy val core = project
+lazy val root = project
+  .in(file("."))
+  .settings(commonSettings)
+  .settings(noPublishSettings)
+  .aggregate(http4s, exampleHttp4s)
+
+lazy val CirceVersion = "0.9.0"
+lazy val ScalaTestVersion = "3.0.4"
+
+lazy val common = project
+  .in(file("common"))
+  .settings(commonSettings)
+  .settings(noPublishSettings)
+  .settings(
+    moduleName := "common",
+    libraryDependencies ++=
+      Seq(
+        "io.circe" %% "circe-generic" % CirceVersion,
+        "io.circe" %% "circe-parser" % CirceVersion,
+        "org.scalatest" %% "scalatest" % ScalaTestVersion % "test"
+      )
+  )
+
+lazy val http4s = project
   .in(file("http4s-lambda"))
   .settings(publishSettings)
   .settings(commonSettings)
@@ -13,37 +36,31 @@ lazy val core = project
     moduleName := "http4s-lambda",
     scalacOptions ++= Seq("-Ypartial-unification"),
     libraryDependencies ++= {
-      val Http4sVersion = "0.18.0-M8"
-      val CirceVersion = "0.9.0"
+      val Http4sVersion = "0.18.10"
       Seq(
         "org.http4s" %% "http4s-core" % Http4sVersion,
         "org.http4s" %% "http4s-circe" % Http4sVersion,
         "io.circe" %% "circe-parser" % CirceVersion,
         "io.circe" %% "circe-generic" % CirceVersion,
-        "org.scalatest" %% "scalatest" % "3.0.4" % "test",
+        "org.scalatest" %% "scalatest" % ScalaTestVersion % "test",
         "org.http4s" %% "http4s-dsl" % Http4sVersion % "test"
       )
     }
   )
+  .dependsOn(common)
 
-lazy val example = project
-  .in(file("example"))
+lazy val exampleHttp4s = project
+  .in(file("example-http4s"))
   .settings(noPublishSettings)
   .settings(commonSettings)
   .settings(
-    moduleName := "example",
-    assemblyJarName in assembly := "example.jar",
+    moduleName := "example-http4s",
+    assemblyJarName in assembly := "example-http4s.jar",
     libraryDependencies ++= Seq(
       "org.http4s" %% "http4s-dsl" % "0.18.0-M8"
     )
   )
-  .dependsOn(core)
-
-lazy val root = project
-  .in(file("."))
-  .settings(commonSettings)
-  .settings(noPublishSettings)
-  .aggregate(core, example)
+  .dependsOn(http4s)
 
 lazy val noPublishSettings = Seq(
   publish := {},

common/src/main/scala/io/github/howardjohn/lambda/Encoding.scala

@@ -0,0 +1,41 @@
+package io.github.howardjohn.lambda
+
+import io.circe
+import io.circe.generic.auto._
+import io.circe.parser.decode
+import io.circe.syntax._
+
+object Encoding {
+  case class ProxyRequest(
+    httpMethod: String,
+    path: String,
+    headers: Option[Map[String, String]],
+    body: Option[String],
+    queryStringParameters: Option[Map[String, String]]
+  )
+
+  case class ProxyResponse(
+    statusCode: Int,
+    headers: Map[String, String],
+    body: String
+  )
+
+  def parseRequest(rawInput: String): Either[circe.Error, ProxyRequest] = decode[ProxyRequest](rawInput)
+
+  def encodeResponse(response: ProxyResponse): String =
+    response.asJson.noSpaces
+
+  def reconstructPath(request: ProxyRequest): String = {
+    val requestString = request.queryStringParameters
+      .map {
+        _.map {
+          case (k, v) => s"$k=$v"
+        }.mkString("&")
+      }
+      .map { qs =>
+        if (qs.isEmpty) "" else "?" + qs
+      }
+      .getOrElse("")
+    request.path + requestString
+  }
+}

http4s-lambda/src/main/scala/io/github/howardjohn/http4s/lambda/IOStreamOps.scala → common/src/main/scala/io/github/howardjohn/lambda/IOStreamOps.scala

@@ -1,29 +1,23 @@
-package io.github.howardjohn.http4s.lambda
+package io.github.howardjohn.lambda
 
 import java.io.{InputStream, OutputStream}
 import java.nio.charset.StandardCharsets
 
-import cats.effect.IO
-
 import scala.io.Source
 
-object IOStreamOps {
+object StreamOps {
   implicit class InputStreamOps(val is: InputStream) extends AnyVal {
-
-    def consume(): IO[String] = IO {
+    def consume(): String = {
       val contents = Source.fromInputStream(is).mkString
       is.close()
       contents
     }
-
   }
 
   implicit class OutputStreamOps(val os: OutputStream) extends AnyVal {
-
-    def writeAndClose(contents: String): IO[Unit] = IO {
+    def writeAndClose(contents: String): Unit = {
       os.write(contents.getBytes(StandardCharsets.UTF_8))
       os.close()
     }
-
   }
 }

common/src/main/scala/io/github/howardjohn/lambda/LambdaHandler.scala

@@ -0,0 +1,21 @@
+package io.github.howardjohn.lambda
+
+import java.io.{InputStream, OutputStream}
+
+import io.github.howardjohn.lambda.Encoding._
+import io.github.howardjohn.lambda.StreamOps._
+
+trait LambdaHandler {
+  def handleRequest(request: ProxyRequest): ProxyResponse
+
+  def handle(is: InputStream, os: OutputStream): Unit = {
+    val rawInput = is.consume()
+    val request = parseRequest(rawInput).fold(
+      e => throw e,
+      identity
+    )
+    val rawResponse = handleRequest(request)
+    val response = encodeResponse(rawResponse)
+    os.writeAndClose(response)
+  }
+}

example-http4s/serverless.yml

@@ -0,0 +1,25 @@
+service: example-http4s
+
+provider:
+  name: aws
+  runtime: java8
+  region: us-west-2
+  stage: dev
+
+package:
+  artifact: target/scala-2.12/example-http4s.jar
+
+functions:
+  api:
+    handler: io.github.howardjohn.lambda.http4s.example.Route$EntryPoint::handle
+    events:
+      - http:
+          path: "{proxy+}"
+          method: any
+          cors: true
+#      Uncomment below to keep the application warm
+#      - schedule:
+#          rate: rate(4 minutes)
+#          input:
+#            httpMethod: GET
+#            path: /hello/keepWarm

example/src/main/scala/io/github/howardjohn/http4s/lambda/example/Route.scala → example-http4s/src/main/scala/io/github/howardjohn/lambda/http4s/example/Route.scala

@@ -1,14 +1,14 @@
-package io.github.howardjohn.http4s.lambda.example
+package io.github.howardjohn.lambda.http4s.example
 
 import cats.effect.IO
+import io.github.howardjohn.lambda.http4s.Http4sLambdaHandler
+import org.http4s.HttpService
+import org.http4s.circe.jsonOf
 import io.circe.generic.auto._
-import io.github.howardjohn.http4s.lambda.LambdaHandler
-import org.http4s._
-import org.http4s.circe._
 import org.http4s.dsl.io._
 
 object Route {
-  implicit val InputDecoder = jsonOf[IO, Input]
+  implicit val inputDecoder = jsonOf[IO, Input]
 
   // Set up the route
   val service: HttpService[IO] = HttpService[IO] {
@@ -23,7 +23,7 @@ object Route {
 
   // Define the entry point for Lambda
   // Referenced as ` io.github.howardjohn.http4s.lambda.example$Route::handler` in Lambda
-  class EntryPoint extends LambdaHandler(service)
+  class EntryPoint extends Http4sLambdaHandler(service)
 
   case class Input(
     name: String,