Streaming content every X seconds

[jaume-pinyol]

Hello,

I don't know if it's the place to ask but I need to have a endpoint that streams data every 2 seconds without closing the connection and in different chunks. I'm struggling a little to find a solution for this case.

Is it posible to stream self-generated data in different chunks with Finatra?

Best Regards,
Jaume Pinyol

[scosenza]

Hi Jaume,

You have two options for streaming HTTP responses:

• Return an AsyncStream
• Return a finagle-httpx Response with setChunked(true)

The following controller demonstrates some streaming HTTP responses:
https://github.com/twitter/finatra/blob/master/http/src/test/scala/com/twitter/finatra/http/integration/tweetexample/main/controllers/TweetsController.scala

See also Future#sleep to wait without blocking.

On Thu, Sep 17, 2015 at 8:25 AM, Jaume Pinyol Vilardell <
notifications@github.com> wrote:

Hello,

I don't know if it's the place to ask but I need to have a endpoint that
streams data every 2 seconds without closing the connection. And I'm
struggling to find a solution for this case.

Is it posible to stream self-generated data with Finatra?

Best Regards,
Jaume Pinyol

—
Reply to this email directly or view it on GitHub
#250.

[jaume-pinyol]

Hi @scosenza,

Thank you very much for you're help.

I almost have it, but the only problem is that if I use AsyncStream it wraps the requests with []

what I need to sent is

data: {some content}

data:{some other content}

but with AsyncStream it wraps the content with

[[
data: {some content},
data:{some other content}
]]

Which using Streaming response, I get the expected output but I don't see how to add headers to the response (I guess I'm too new at finatra, or scala)

get("/test.stream") { request: Request =>
    StreamingResponse(Buf.Utf8.apply) {
      streamContent(1)
    }
  }

I've also tried with setChunked to true, hoping for more flexibility

get("/tweets/streaming_manual_writes") { request: Request =>
    val response = Response()
    response.setChunked(true)

    response.writer.write(Buf.Utf8("hello")) before {
      response.writer.write(Buf.Utf8("world")) ensure {
        response.close()
      }
    }
    Future(response)
  }

But I always get and error message saying:

com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of com.twitter.finagle.httpx.Request, problem: abstract types either need to be mapped to concrete types, have custom deserializer, or be instantiated with additional type information

[jaume-pinyol]

Hi @scosenza,

I've already solved the problem, I ended up modifying the StreamingResponse class to allow custom headers and onFailure and onCompleted callbacks.

I'll do a PR with the changes, maybe someone is interested too

Thank you very much for the help!