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

[Christian G. <chr...@gm...>]

2013/3/13 Artyom Beilis <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.
>

Maybe I could "store it" in kind of pointer address :)

>
>>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);
>    });
>

okay got it...

>>
>
>>
>>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.
>

Sounds like a good idea. The only thing that comes to my mind is: where to store
the hashmap from key to sse object? Is there a concept for global
available data?
In theory a singleton class/object should to it.

thanks
--
Christian Gmeiner, MSc