[Libwebsockets] How to send data asynchronously to the client?
bas at appelo.nl
Fri Jun 20 14:29:48 CEST 2014
libwebsocket_service(context, LARGE_NUMBER); //blocks
libwebsocket_cancel_service(context); // wakes up thread-1
libwebsocket_service(context, LARGE_NUMBER); //blocks <= will call
Now you will receive a callback, it works like a charm.
So to write data you'll need to be in a callback, but the way above
shows you how to get there/enforce one.
On 06/20/2014 02:18 PM, Mike M wrote:
> >>/ Hi,
> />>/ 1)Is there a way to asynchronously send the data to the client? That is,
> />>/ without being in a callback, server spontaneously initiating data
> />>/ transfer to the client..!!
> >Libwebsockets is basically single-threaded. But, with care from another
> >server thread, you can call either
> >libwebsocket_callback_on_writable(), or
> >but you need to manage your own list of live wsi / connections with the
> >first option (by tracking their creating and destruction in the
> >ESTABLISHED and CLOSED callbacks).
> >You will get a LWS_CALLBACK_SERVER_WRITABLE as soon as it's possible to
> >write on that connection then, and you should figure out what to write
> >and write it from there.
> I am doing exactly this, but it doesn't work.
> I have a thread that calls libwebsocket_service with a huge timeout.
> Writes, etc, are only ever done from within the callback. When I need
> to write something from another thread, I queue up the message that
> needs to be written and then immediately call
> libwebsocket_callback_on_writeable_all_protocol on the proto I'm
> writing for.
> Unfortunately, I never get LWS_CALLBACK_SERVER_WRITEABLE until the
> libwebsocket_service times out and gets called again. This is totally
> broken. I saw a trac issue (#56) about using ppoll. Unfortunately,
> the version of the library we're using doesn't seem to have that code
> in it. Any ideas?
> Libwebsockets mailing list
> Libwebsockets at ml.libwebsockets.org
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