Web client receiving "events" from server side.

[Ricardo Vazquez]

THIS IS MY SCENARIO:
- PBX (a private telephone exchange or switch)
- A Telephony server running on computer "A" (it communicates with the PBX
via IP)
- An ASP.NET application (running on computer "A") for web clients of that
telephony server (running on computer "B", "C", etc.)

THIS IS ALREADY WORKING:
On the client web browser we enter the originating and the destination
extension numbers, we click on button "makecall" and the destination
extension rings, called by the originating one.

THIS IS NOT WORKING YET: THIS IS WHAT I ASK:
If I hook off my telephone, the PBX says to the Telephony server "extension
52 is off hook"; then the Telephony server says to ASP.NET "extension 52 is
off hook". BUT How can I get the ASPNET on the server side notify its web
client this event?
I mean: I need the web page modified, maybe a label, to change from
"disconnected" to "off hook", but it is not a request from the client: there
is no postback. The change is on the server's initivative.
Polling (refresh="2", for instance) is not a good answer, because you need a
more accurate information.

IN OTHER WORDS:
I need not only methods to be invoked from the web client (v.gr. makeCall);
but also events to be received in the web client (v.gr. inboundCall).

Is there any way to do this, or work around it?
Could you please give me some urls to investigate, or some simple code to
get this?

Thank you very much!

Ricardo Vázquez.
Spain.

 

[bruce barker \(sqlwork.com\)]

there are only three options.

1) the bowser can poll (refresh, ajax).
2) the browser hosts a active/x contrl or java applet that maintains a
connection.
3) server push, which is really client pull. the server does not close the
connection and keeps sending data. this is tricky in .net, you need to turn
off buffering and disable timeouts, reconfigure thread pools. also does not
scale well.

if you use 2 or three youu need to reconfigure iis and asp.net or you will
be limited t about 30 users. the max you can get is about 200-250 per
server.

-- bruce (sqlwork.com)

 

[Guest]

Ricardo,
I do a lot of this kind of stuff, and Bruce is correct. I've found the
easiest way is to use an Anthem.net timer control to "poll" a method in the
page on the server that gets updates and refreshes the UI of the page without
any reloads or postbacks.
Peter

 

[Ricardo Vazquez]

Peter! Bruce!

Thank you so much.
Your answers were so complete (a detailed and complete list of possibilities
for me to consider) and also so useful (sharing your experience about these
possibilities to suggest me one of them)!
Now I feel sure to be waking in the right direction.
Thank you very much.

I will try polling to a method via an ajax timer control as you said; the
page reloading was what worried me about polling; but the ajax timer
polling a method will provide a smooth browsing experience: so that's what
I needed!

Greetings from Madrid,

Ricardo.