Re: [Caml-list] Async Server not executing

[Kenneth Adam Miller <kennethadammiller@gmail.com>]

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Ah. Well I think I can incorporate from that what I can, but my unit tests
need to be reflective of the use case I have. I'm sending protobuf encoded
messages between two processes on one machine-whatever the size of the
message, that's the size that should be received on the other end (I've
read about the returning partial bytes, I can't decode a part of a proto
message, it has to be the right size).

I can't use write_line, I'll have to find a way to delimit the messages
based on size. I think I'll just prepend every message with the size that
it should expect, and then read a integer off the stream and then that many
bytes.

On Tue, Jun 16, 2015 at 11:41 AM, David House <dhouse@janestreet.com> wrote:

> Ah, now I read your code in more detail I think I see why.
>
> Reader.contents on the server side will block until eof. The client side
> sends some stuff, but does not close the writer, so the server never sees
> eof. (Recall that sockets are not like files: it's possible to read all of
> the available data right now, but not reach eof.)
>
> Network protocols normally have some explicit "this is the end of one
> message" marker, like a newline or something similar. Then the server just
> reads chunks until it sees that marker, at which point it can put the
> message together and to something with it.
>
> For example, you could use Writer.write_line on the client side and
> Reader.read_line on the server side.
>
> On 16 June 2015 at 16:36, Kenneth Adam Miller <kennethadammiller@gmail.com
> > wrote:
>
>> So, now I can get server received if I add that into the callback, but at
>> "writing shutdown to server" I don't see response received or even
>> something for Eof.
>>
>> On Tue, Jun 16, 2015 at 11:09 AM, David House <dhouse@janestreet.com>
>> wrote:
>>
>>> The first thing to try is to make sure that everything is getting
>>> flushed. For temporary debugging messages I strongly recommend just using
>>> [Core.Std.eprintf "<message>\n%!"].
>>>
>>> On 16 June 2015 at 16:03, Kenneth Adam Miller <
>>> kennethadammiller@gmail.com> wrote:
>>>
>>>> I'm having trouble with OCaml Async. I wrote a small server with it,
>>>> and right now I'm trying to unit test that server. Here's my code for the
>>>> server:
>>>>
>>>>
>>>> let _main ()=
>>>>   print_endline "Server running";
>>>>   let handler = print_endline in
>>>>   let socket = Tcp.on_port 5554 in
>>>>   let server = Tcp.Server.create socket (fun addr r w ->
>>>>       (Reader.contents r) >>| handler; (Writer.write w "got it")) in
>>>>   server
>>>>
>>>>
>>>>
>>>> In my unit test code I have:
>>>>
>>>> let test_shutdown test_ctxt = Thread_safe.block_on_async_exn (fun () ->
>>>>  (
>>>>       print_endline "test_shutdown";
>>>>       let server = Server._main () in
>>>>       server >>= fun server ->
>>>>       let where = Tcp.to_host_and_port "127.0.0.1" 5554 in
>>>>       Tcp.connect where >>= fun s ->
>>>>         let socket, r, w = s in
>>>>         ignore (Writer.write w "kill");
>>>>         ignore (Writer.flushed w);
>>>>         (Reader.recv r >>> function
>>>>           | `Ok result ->  print_endline ("writing shutdown to server"
>>>> ^ result)
>>>>           | `Eof -> ());
>>>>         return ()
>>>>     )); ()
>>>>
>>>>
>>>>
>>>> I see test_shutdown and Server running, but not sign of "writing
>>>> shutdown to server" or even "got it"; why isn't my server or even any of
>>>> the connection executing?
>>>>
>>>
>>>
>>
>

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