I'm evaluating the possibility of using Play2-mini with Scala to develop a service that will sit between a mobile client and existing web service. I'm looking for the simplest possible example of a piece of code where Play2-mini implements a server and a client. Ideally the client will use Akka2 actors.
With this question, I'm trying to find out how it is done, but also to see how Play2-Mini and Akka2 should co-operate. Since Play2-Mini appears to be the replacement for the Akka HTTP modules.
Play2-mini contains the following code example, in which I created two TODO's. If someone can help me with some sample code to get started, I will be really grateful.
package com.example
import com.typesafe.play.mini._
import play.api.mvc._
import play.api.mvc.Results._
object App extends Application {
def route = {
case GET(Path("/testservice")) & QueryString(qs) => Action{ request=>
println(request.body)
//TODO Take parameter and content from the request them pass it to the back-end server
//TODO Receive a response from the back-end server and pass it back as a response
Ok(<h1>Server response: String {result}</h1>).as("text/html")
}
}
}
Here's the implementation of your example.
Add the following imports:
import play.api.libs.ws.WS
import play.api.mvc.BodyParsers.parse
import scala.xml.XML
Add the following route:
case GET(Path("/testservice")) & QueryString(qs) => Action{ request =>
Async {
val backendUrl = QueryString(qs,"target") map (_.get(0)) getOrElse("http://localhost:8080/api/token")
val tokenData = QueryString(qs,"data") map (_.get(0)) getOrElse("<auth>john</auth>")
WS.url(backendUrl).post(XML loadString tokenData).map { response =>
Ok(<html><h1>Posted to {backendUrl}</h1>
<body>
<div><p><b>Request body:</b></p>{tokenData}</div>
<div><p><b>Response body:</b></p>{response.body}</div>
</body></html>).as("text/html") }
}
}
All it does, is forwarding a GET request to a back-end serivce as a POST request. The back-end service is specified in the request parameter as target and the body for the POST request is specified in the request parameter as data (must be valid XML). As a bonus the request is handled asynchronously (hence Async). Once the response from the back-end service is received the front-end service responds with some basic HTML showing the back-end service response.
If you wanted to use request body, I would suggest adding the following POST route rather than GET (again, in this implementation body must be a valid XML):
case POST(Path("/testservice")) & QueryString(qs) => Action(parse.tolerantXml){ request =>
Async {
val backendUrl = QueryString(qs,"target") map (_.get(0)) getOrElse("http://localhost:8080/api/token")
WS.url(backendUrl).post(request.body).map { response =>
Ok(<html><h1>Posted to {backendUrl}</h1>
<body>
<div><p><b>Request body:</b></p>{request.body}</div>
<div><p><b>Response body:</b></p>{response.body}</div>
</body></html>).as("text/html") }
}
}
So as you can see, for your HTTP Gateway you can use Async and play.api.libs.ws.WS with Akka under the hood working to provide asynchronous handling (no explicit Actors required). Good luck with your Play2/Akka2 project.
Great answer by romusz
Another way to make a (blocking) HTTP GET request:
import play.api.libs.ws.WS.WSRequestHolder
import play.api.libs.ws.WS.url
import play.api.libs.concurrent.Promise
import play.api.libs.ws.Response
val wsRequestHolder: WSRequestHolder = url("http://yourservice.com")
val promiseResponse: Promise[Response] = wsRequestHolder.get()
val response = promiseResponse.await.get
println("HTTP status code: " + response.status)
println("HTTP body: " + response.body)
Related
i want to write code which will refresh cookie (via set-cookie http header) in Lagom.
For clarification Cookie is an encoded string (for example AES).
Lets take lagom service call composition for authentication from Implementing services and edit it
def authenticated[Request, Response](
serviceCall: User => ServerServiceCall[Request, Response]
) = ServerServiceCall.composeAsync { requestHeader =>
//Get cookie from header and decode it
val cookie = decodeCookie(requestHeader)
//Get user based on cookie decode function
val userLookup = getUser(cookie)
userLookup.map {
case Some(user) =>
serviceCall(user)
case None => throw Forbidden("User must be authenticated")
}
}
It is possible to manipulate serviceCall(user) response headers?
I tried something like this:
serviceCall( employee ).handleResponseHeader { case (responseHeader, response) =>
responseHeader.withHeader("Set-Cookie",encodeCookie("NewCookieStringExample")) // Add header
response
}
But function handleResponseHeader requires only response[T] as result and header would not be changed because is immutable.
I know that i can pass cookie to serviceCall(user) and in every service call implementation return tuple with ResponseHeader and Response but this will impact all endpoints and will add much more code.
Use of HeaderFilter is possible too but this would decode and encode cookie twice in one request (in header filter and in authenticated service call composition )
Any tips?
You can return the modified Header and the Response as a Tuple:
serviceCall( employee ).handleResponseHeader((responseHeader, response) => {
val modifiedHeader = responseHeader.withHeader("Set-Cookie",encodeCookie("NewCookieStringExample")) // Add header
(modifiedHeader, response)
})
By the way, The provided example does not compile for me. composeAsync wants a Future[ServerServiceCall[...]].
I'd like to test that a Http4s Client is being called from my class ClassUnderTest (to make a HTTP request) and that the request made contains the headers I expect.
In 0.18.x, I did something like below. Using a side effect to store the value of the headers so that I can make an assertion after the call. In the example below, f.execute(...) is expected to make a PUT with the client instance and I'm trying to record all request handling and storing the headers.
"Request has headers" >> {
var headers = List[String]()
val client = Client[IO](new Kleisli[IO, Request[IO], DisposableResponse[IO]](request => {
headers = request.headers.map(_.name.toString()).toList
Ok().map(DisposableResponse(_, IO.pure(())))
}), IO.pure(()))
val f = ClassUnderTest(client)
f.execute("example")
headers must_== List(
"Content-Type",
"X-Forwarded-For",
"Content-Length"
)
}
The real code is here if you're interested.
ClassUnderTest took a Client[IO] so I could get the above working.
class ClassUnderTest(client: http4s.Client[IO])
In Http4s 0.20.12, I had to change the signature to:
class ClassUnderTest(client: Resource[IO, http4s.Client[IO]])
...and now I can't figure out how to stub out the client for tests. I experimented with JavaNetClientBuilder but that doesn't help because I can get an instance of Client (after .create) and now I need a Resource[IO, http4s.Client[IO]].
How can I use a test double to stand in for the Client / Resource[F, Client[F]] so that I can test the requests it makes?
The testing page on the docs doesn't really help me. I want a test double, not to test all the functionality of the Service (I don't want to startup a server).
I`m trying to send post request to external url using play framework and scala. I want to add some parameters to the body also.
I want to send a post request to "http://www.posonlinedemo.tk" with parameters TransactionNo='T10000' and reqtype='T'
how could i do it?
here is my Action
def test(para:String) = Action {
val url: Option[String] = Some("http://www.posonlinedemo.tk")
url match {
case Some(url) => Redirect(url)
case None => NotFound("This URL leads nowhere. :(")
}
}
You can use the Play WS API.
As you can see in the documentation, it is that simple:
ws
.url(url)
.post(Map(
"TransactionNo" -> Seq("T10000"),
"reqtype" -> Seq("T")))
Don't forget to add ws to your library dependencies.
Spray is hard!! I now know that my knowledge on HTTP protocol is not nearly enough and API design isn't easy. However, I still very much want my practice app to work. I'm writing this authentication for POST/PUT/DELETE method. It appears that there are at least two ways to do this: BasicAuth or write a custom directive.
I found this article:
BasicAuth: https://github.com/jacobus/s4/blob/master/src/main/scala/s4/rest/S4Service.scala
I'm trying it out because it looks simple.
The compile and run stages are fine, and the server runs. However, when I'm trying to send a PUT request to test the implementation (using Python's Httpie: http PUT 127.0.0.1:8080/sec-company/casper username=username token=123), the feedback is:HTTP/1.1 404 Not Found
Here's my route:
pathPrefix("sec-company") {
path("casper") {
//first examine username and token
authenticate(BasicAuth(CustomUserPassAuthenticator, "company-security")) {userProfile =>
post { ctx =>
entity(as[Company.Company]) { company =>
complete {
company
}
}
}
}
Here is my implementation of UserPassAuthenticator:
object CustomUserPassAuthenticator extends UserPassAuthenticator[UserProfile] {
def apply(userPass: Option[UserPass]) = Promise.successful(
userPass match {
case Some(UserPass(user, token)) => getUserProfile(user, token)
case _ => None
}
).future
}
First of all, is this the right way to implement authentication? Second, where does UserPassAuthenticator find the username and password?? Can I send back a better HTTP header other than 404 to indicate failed authentication?
If this is far from correct, is there any tutorial on authentication that I can follow? TypeSafe's Spray templates are more about overall patterns and less about Spray's functionality!
Thank you!
I had the same problem, even after looking at https://github.com/spray/spray/wiki/Authentication-Authorization (which says it's for an older version of Akka but it still seems to apply) I came up with the following:
trait Authenticator {
def basicUserAuthenticator(implicit ec: ExecutionContext): AuthMagnet[AuthInfo] = {
def validateUser(userPass: Option[UserPass]): Option[AuthInfo] = {
for {
p <- userPass
user <- Repository.apiUsers(p.user)
if user.passwordMatches(p.pass)
} yield AuthInfo(user)
}
def authenticator(userPass: Option[UserPass]): Future[Option[AuthInfo]] = Future { validateUser(userPass) }
BasicAuth(authenticator _, realm = "Private API")
}
}
I mix in this trait into the Actor that runs the routes and then I call it like this:
runRoute(
pathPrefix("api") {
authenticate(basicUserAuthenticator) { authInfo =>
path("private") {
get {
authorize(authInfo.hasPermission("get") {
// ... and so on and so forth
}
}
}
}
}
}
The AuthInfo object returned by the validateUser method is passed as a parameter to the closure given to the authorize method. Here it is:
case class AuthInfo(user: ApiUser) {
def hasPermission(permission: String) = user.hasPermission(permission)
}
In Spray (and HTTP), authentication (determining whether you have a valid user) is separate from authorization (determining whether the user has access to a resource). In the ApiUser class I also store the set of permissions the user has. This is a simplified version, my hasPermission method is a bit more complex since I also parametrize permissions, so it's not just that a particular user has permission to do a get on a resource, he might have permission to read only some parts of that resource. You might make things very simple (any logged-in user can access any resource) or extremely complex, depending on your needs.
As to your question, when using HTTP BASIC authentication (the BasicAuth object), the credentials are passed in the request in an Authorization: header. Your HTTP library should take care of generating that for you. According to the HTTP standard, the server should return a 401 status code if the authentication was incorrect or not provided, or a 403 status code if the authentication was correct but the user doesn't have permissions to view the content.
I'm trying to learn how to use web sockets in Play 2.1, and I'm having trouble getting the web socket URL to work with my app's routing configuration. I started with a new Play application and the Play framework documentation on websockets.
Here is my conf/routes:
# Home page
GET / controllers.Application.index
# Websocket test site
GET /wstest controllers.Application.wstest
Then I added the wstest function to my controller class:
object Application extends Controller {
def index = Action {
Ok(views.html.index("Websocket Test"))
}
def wstest = WebSocket.using[String] { request =>
// Log events to the console
val in = Iteratee.foreach[String](println).mapDone { _ =>
Logger.info("Disconnected")
}
// Send a single 'Hello!' message
val out = Enumerator("Hello!")
(in, out)
}
}
However, so far, I can only access the websocket with the URL ws://localhost:9000/wstest (using the sample code at websocket.org/echo.html). I was looking at the sample/scala/websocket-chat app that comes with the Play framework, and it uses the routing configuration file to reference the websocket, like this:
var WS = window['MozWebSocket'] ? MozWebSocket : WebSocket
var chatSocket = new WS("#routes.Application.chat(username).webSocketURL()")
I tried replacing my websocket URL with #routes.Application.wstest.webSocketURL() and #routes.Application.wstest. The first one doesn't compile. The second one compiles, but the client and server don't exchange any messages.
How can I use my Play routing configuration to access this websocket? What am I doing wrong here?
Edit
Here is a screenshot of my compilation error, "Cannot find any HTTP Request Header here":
Without the compiler error it's hard to guess what might be the problem.
Either you have to use parens because of the implicit request, i.e. #routes.Application.wstest().webSocketURL(), or you have no implicit request in scope which is needed for the webSocketURL call.
Marius is right that there was no implicit request in scope. Here's how to get it in scope:
Update the index function in the controller:
def index = Action { implicit request =>
Ok(views.html.index("Websocket Test"))
}
Add the request as a curried parameter to index.scala.html:
#(message: String)(implicit request: RequestHeader)
#main(message) {
<script>
var output;
function init() {
output = document.getElementById("output");
testWebSocket();
}
function testWebSocket() {
websocket = new WebSocket("#routes.Application.wstest.webSocketURL()");
.
.
.
And now the RequestHeader is in scope.