Refactor to be generic to the server type

Author: howardjohn

.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 renamed to 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 renamed to 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,