tcp_server + AnyEvent::Handle

[Marc Lehmann]

On Wed, Apr 30, 2014 at 12:12:48AM +0400, Sergei <perllance at yandex.ru> wrote:
> I have a tcp_server and I want to use AnyEvent::Handle to manage the read and write queue.
> My code looks something like this (see below, very simple). The problem is that my read handler is missing some initial data from the $fh.

Missing means?

> Obviously, by the time the $hdl object is instantiated, $fh already contains some data. I can circumvent this by trying to sysread from the $fh first, but the data is not necessarily there, so I'll have to write conditions and callbacks which makes my code clumsy and duplicates AnyEvent::Handle.

What do you mean "contains some data"? $fh doesn't contain any data at
all, it's just a filehandle, and no data has been read into its buffers by
tcp_server (nor will AnyEvent::Handle read any data into its buffer).

> Ideally, AnyEvent::Handle would have some parameter in its constructor which would drain the $fh so that I can rely on AnyEvent::Handle methods only and avoid sysread in my code. Or there is got to be a way to trigger a read event on the $fh which would make AnyEvent::Handle to process whatever was written to the $fh so far.

I am not sure what you mean with "drain", it feels as if draining would be
your problem, not the solution.

In any case, AnyEvent::Handle doesn't have a notion of "initial data",
the data that is still in the kernel sockets buffer will be delivered
normally, while the data already read is not visible to AnyEvent::Handle
at all anymore.

> tcp_server '127.0.0.1', '123', sub {

Your code will likely never call any callback, as it creates and destroys
$hdl instantly.

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