Allow for multiple HTTP headers with same field name in ResponseHeader

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Following up the discussion on glitter channel https://gitter.im/lagom/lagom?at=59bfcc2d7b7d98d30d0d3005

Lagom Version (1.2.x / 1.3.x / etc)

1.4.0-M2

API (Scala / Java / Neither / Both)

Scala

Operating System (Ubuntu 15.10 / MacOS 10.10 / Windows 10)

MacOS 10.12.6 (16G29)

JDK (Oracle 1.8.0_112, OpenJDK 1.8.x, Azul Zing)

Oracle 1.8.0_111

java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)

Expected Behavior

1. Define a service implementation such as

def method: ServerServiceCall[NotUsed, Done] = ServerServiceCall { (_, _) =>
    Future.successful((ResponseHeader.Ok
        .withHeader("Set-Cookie", s"cookie1=One; Path=/;")
        .addHeader("Set-cookie", s"cookie2=Two; Path=/;"),
      Done))
  }

Suspected behavior also appears with this definition

def method: ServerServiceCall[NotUsed, Done] = ServerServiceCall { (_, _) =>
    Future.successful((ResponseHeader.Ok.withHeaders(immutable.Seq(
          ("Set-Cookie", s"cookie1=One; Path=/;"),
          ("Set-cookie", s"cookie2=Two; Path=/;")
      )), 
    Done))
}

1. Wire it as a REST call with the descriptor in the api

override final def descriptor = {
    import Service._
    named("SomeService").withCalls(
      restCall(Method.GET, "/api/method", method _)
    ).withAutoAcl(true)
  }

1. Start lagom server

$ sbt runAll

1. Call the rest endpoint and get both set-cookieheaders in the response

$ curl -v -X GET   http://localhost:9000/api/method
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 9000 (#0)
> PUT /api/logout HTTP/1.1
> Host: localhost:9000
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200 OK
< set-cookie: cookie1=One; Path=/
< set-cookie: cookie2=Two; Path=/
< Date: Mon, 18 Sep 2017 13:39:41 GMT
< Server: akka-http/10.0.9
< Content-Length: 0
<
* Connection #0 to host localhost left intact 

Actual Behavior

$ curl -v -X GET   http://localhost:9000/api/method
*   Trying ::1...
* TCP_NODELAY set
* Connected to localhost (::1) port 9000 (#0)
> PUT /api/logout HTTP/1.1
> Host: localhost:9000
> User-Agent: curl/7.54.0
> Accept: */*
>
< HTTP/1.1 200 OK
< set-cookie: cookie1=One; Path=/
< Date: Mon, 18 Sep 2017 13:39:41 GMT
< Server: akka-http/10.0.9
< Content-Length: 0
<
* Connection #0 to host localhost left intact 

The response HTTP headers only contains one occurence of “set-cookie” header, the first defined.

As RFC 6265 states its required to use multiple occurence of headers with the same field name for set-cookie . Others HTTP headers will probably fall in the same case (most notably those from X- non-standards headers)

[jroper]

I was just about to reply with exactly the same thing. Play unfolds Set-Cookie headers here:

https://github.com/playframework/playframework/blob/8a660fc12d359e8e005ffc368883ee5124262d0e/framework/src/play-server/src/main/scala/play/core/server/common/ServerResultUtils.scala#L237

[gmethvin]

At its core I believe this is a Play issue, not a Lagom one. There is some context here: https://github.com/playframework/playframework/issues/3279

This is not really a problem for Play users because Play already has a high-level API to handle cookies, for example:

Ok("Hello world").withCookies(Cookie("cookie1", "One"), Cookie("cookie2", "Two"))

Lagom has it’s own ResponseHeader that wraps Play’s, and doesn’t have any explicit handling for cookies.

As a workaround, I think it should work to use a single Set-Cookie header with ;; separating the cookies: cookie1=One;Path=/;;cookie2=Two;Path=/. The server should “unfold” those cookies and serve them as separate cookie headers.