Example: Add authentication middleware example (zio#175)

* doc(http): add Authentication Middleware example

* doc: update website

* style(*): scalafmt

* chore: update build

* chore: update build

* chore: update build

README.md

@@ -45,6 +45,7 @@ You can checkout more examples in the examples project —
 - [Streaming Response](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/StreamingResponse.scala)
 - [Simple Client](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/SimpleClient.scala)
 - [File Streaming](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/FileStreaming.scala)
+- [Authentication](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/Authentication.scala)
 
 # Installation
 

build.sbt

@@ -115,7 +115,10 @@ lazy val example = (project in file("./example"))
  .settings(publishSetting(false))
  .settings(
  fork := true,
- Compile / run / mainClass := Option("HelloWorldAdvanced"),
+ Compile / run / mainClass := Option("Authentication"),
+ libraryDependencies ++= Seq(
+ "com.github.jwt-scala" %% "jwt-core" % "7.1.4",
+ ),
  )
  .dependsOn(zhttp)
 

docs/index.md

@@ -103,3 +103,4 @@ A simple Http app that responds with empty content and a `200` status code is de
 - [Streaming Response](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/StreamingResponse.scala)
 - [Simple Client](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/SimpleClient.scala)
 - [File Streaming](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/FileStreaming.scala)
+- [Authentication](https://github.com/dream11/zio-http/blob/main/example/src/main/scala/Authentication.scala)

example/src/main/scala/Authentication.scala

@@ -0,0 +1,58 @@
+import pdi.jwt.{Jwt, JwtAlgorithm, JwtClaim}
+import zhttp.http.{Method, _}
+import zhttp.service.Server
+import zio._
+
+import java.time.Clock
+
+object Authentication extends App {
+ // Secret Authentication key
+ val SECRET_KEY = "secretKey"
+
+ implicit val clock: Clock = Clock.systemUTC
+
+ // Helper to encode the JWT token
+ def jwtEncode(username: String): String = {
+ val json = s"""{"user": "${username}"}"""
+ val claim = JwtClaim { json }.issuedNow.expiresIn(60)
+ Jwt.encode(claim, SECRET_KEY, JwtAlgorithm.HS512)
+ }
+
+ // Helper to decode the JWT token
+ def jwtDecode(token: String): Option[JwtClaim] = {
+ Jwt.decode(token, SECRET_KEY, Seq(JwtAlgorithm.HS512)).toOption
+ }
+
+ // Authentication middleware
+ // Takes in a Failing HttpApp and a Succeed HttpApp which are called based on Authentication success or failure
+ // For each request tries to read the `X-ACCESS-TOKEN` header
+ // Validates JWT Claim
+ def authenticate[R, E](fail: HttpApp[R, E], success: JwtClaim => HttpApp[R, E]): HttpApp[R, E] = Http.flatten {
+ Http
+ .fromFunction[Request] {
+ _.getHeader("X-ACCESS-TOKEN")
+ .flatMap(header => jwtDecode(header.value.toString))
+ .fold[HttpApp[R, E]](fail)(success)
+ }
+ }
+
+ // Http app that requires a JWT claim
+ def user(claim: JwtClaim): UHttpApp = Http.collect[Request] {
+ case Method.GET -> Root / "user" / name / "greet" => Response.text(s"Welcome to the ZIO party! ${name}")
+ case Method.GET -> Root / "user" / "expiration" => Response.text(s"Expires in: ${claim.expiration.getOrElse(-1L)}")
+ }
+
+ // App that let's the user login
+ // Login is successful only if the password is the reverse of the username
+ def login: UHttpApp = Http.collect[Request] { case Method.GET -> Root / "login" / username / password =>
+ if (password.reverse == username) Response.text(jwtEncode(username))
+ else Response.fromHttpError(HttpError.Unauthorized("Invalid username of password\n"))
+ }
+
+ // Composing all the HttpApps together
+ val app: UHttpApp = login +++ authenticate(HttpApp.forbidden("Not allowed!"), user)
+
+ // Run it like any simple app
+ override def run(args: List[String]): URIO[zio.ZEnv, ExitCode] =
+ Server.start(8090, app).exitCode
+}

zio-http/src/main/scala/zhttp/http/HttpApp.scala

@@ -57,4 +57,9 @@ object HttpApp {
  * Creates an HTTP app which always responds with a 200 status code.
  */
  def ok: HttpApp[Any, Nothing] = HttpApp.empty(Status.OK)
+
+ /**
+ * Creates an HTTP app that responds with 403 - Forbidden status code
+ */
+ def forbidden(msg: String): UHttpApp = Http.succeed(HttpError.Forbidden(msg).toResponse)
 }

zio-http/src/main/scala/zhttp/http/package.scala

@@ -7,6 +7,7 @@ import java.nio.charset.Charset
 
 package object http extends PathModule with RequestSyntax {
  type HttpApp[-R, +E] = Http[R, E, Request, Response[R, E]]
+ type UHttpApp = HttpApp[Any, Nothing]
  type RHttpApp[-R] = HttpApp[R, Throwable]
  type Endpoint = (Method, URL)
  type Route = (Method, Path)