Akka-stream: source are closed on tailable cursor when using ResponseStage

[reactivemongo]

Akka-stream: source are closed on tailable cursor when using ResponseStage

[cchantep]

Will have a look. A test must be failing.

[vdebergue]

I created a small play app to reproduce the behaviour: https://github.com/vdebergue/reactivemongo-test

• Using documentSource, it's ok with chunked and streamed entity:

% curl -v http://localhost:9000/source
> GET /source HTTP/1.1
> Host: localhost:9000
>
< HTTP/1.1 200 OK
< Transfer-Encoding: chunked
< Content-Type: text/plain; charset=utf-8
< Date: Sun, 13 Nov 2016 21:54:58 GMT
<
1
2
3
# // connection stays opened

% curl -v http://localhost:9000/sourceStr
> GET /sourceStr HTTP/1.1
> Host: localhost:9000
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=utf-8
< Date: Sun, 13 Nov 2016 22:07:32 GMT
< Connection: close
<
1
2
3
# Connection kept opened

• Using bulkSource and Ok.chunked, connection is closed:

% curl -v http://localhost:9000/bulk
> GET /bulk HTTP/1.1
> Host: localhost:9000
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Transfer-Encoding: chunked
< Content-Type: text/plain; charset=utf-8
< Date: Sun, 13 Nov 2016 22:00:35 GMT
<
* transfer closed with outstanding read data remaining
* Closing connection 0
curl: (18) transfer closed with outstanding read data remaining

• Using bulkSource and a HttpEntity.Streamed, connection is kept opened but nothing is sent:

% curl -v http://localhost:9000/stream
*   Trying ::1...
* Connected to localhost (::1) port 9000 (#0)
> GET /stream HTTP/1.1
> Host: localhost:9000
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: text/plain; charset=utf-8
< Date: Sun, 13 Nov 2016 22:02:09 GMT
< Connection: close
<
// kept opened

And in the console, the line Got 0 ids keeps getting printed:

Got 0 ids
Got 0 ids
...

[cchantep]

To avoid having an empty chunk (from an empty result bulk) interpreted as LastChunk, can you try the following.

  def tailBulk = Action {
    val source = cursor()
      .bulkSource()
      .map { ids =>
        println(s"Got ${ids.size} ids")
        "X" + ids.mkString("\n")
    }

    Ok.chunked(source)
  }

[vdebergue]

Seems to be an issue in play framework that doesn't interpret correctly Seq.empty