Re: [Cppcms-users] One SSE stream per session

[Artyom B. <art...@ya...>]

>________________________________
> From: Christian Gmeiner <chr...@gm...>
> 
>Hi all.
>
>at the moment I am looking how to have one SSE stream per session. In
>general I would put the SSE stream object into the session storage but
>I am not sure how I could access it from other cppcms-apps.
>

I don't really understand what exactly you are doing as you can't
store "sse" object in session storage as is - you can probably
create its unique identification and store it in session object.

>Here is brief overview:
>
>I have an SSE application mounted at /sse/
>
>        booster::intrusive_ptr<SSE> sse = new SSE(srv);
>        Configuration::instance()->sse = sse.get();
>        srv.applications_pool().mount(sse, cppcms::mount_point("/sse(.*)", 1));
>
>It is possible for all other cppcms apps running to send data via SSE
>to the browser.
>
>        Configuration::instance()->sse->enqueue("event", "data");
>
>

>class SSE : public cppcms::application  {
>public:
>    SSE(cppcms::service &srv);
>
>    void post();
>    void get();
>    void redirect();
>
>    void enqueue(std::string const &event, std::string const &data);
>
>private:
>    booster::shared_ptr<sse::bounded_event_queue> stream_;
>};
>


Yes, however you should remember that SEE object is asynchronous one
and runs in the event loop stream.

That means that you can't just call sse->enqueue("event","data")
from synchronous applications from the other thread
but rather you need to "post" it to event loop's thread:

Using C++11 lambdass:

   std::string message = ...;
   service().post([=]() {
         see->equeue("event",message);
   });

>

>
>At the moment all clients are using the same SSE stream and this is a
>no-go security wise.
>So I want to extend my current approach to have multiple SSE streams -
>for each session one.
>As this "website" is used for embedded device configuration I think I
>will not run into any
>resource problems.
>
>Or is there a better way to deliver each session their own data-packages only?


Use multiple sse stream object and for each one of them create unique id that
would be stored in session and thus if user request sse with some id
give it to him, this way you can even give multiple users same sse stream.

>
>thanks
>--
>Christian Gmeiner, MSc
>


Regards,


Artyom Beilis
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