Is it possible for web service to send random notification to web service consumer?

  • Thread starter Thread starter Michael Fan
  • Start date Start date
M

Michael Fan

I am a newbie for web servcie and want to write a web service which
monitors the certain field in the database. Once it exceeds the
certain value, web service will send out notification to web service
consumer who will take action on it.

Is it possible? If yes, how to implement? If possible, please provide
me the link.

Thanks lot.

Michael
 
No. The protocol is based on the consumer making a request to the service,
therefore your consumer must periodically poll the service.

--
Regards

John Timney
Microsoft Regional Director
Microsoft MVP
 
Hi Michael

I only ask this because you say you are a newbie. When you say consumer, do
you mean a system consumer?
If you just wanted to notify an indivdual then you could easily send an
email?

Richard
 
Hi,
For your requirement, you can write a windows service which will monitor the
database and send out notifications.

Webservices will be created when you want to share your data,
procedures/alogorithms/application as a service to other departments,
customers and suppliers.

Regards,
R.Balaji
 
Thanks John,

Is SOA(Service Oriented Achitecture) helpful for solving this issue? Thanks,

Michael
 
Unfortunatly not - by its very natue a web client/web srevice request is
basically SOA.

Your problem is one of protocol - you make a request, the service responds -
the request is ended. Your client needs to make another request. Its not
the fault of the client - its basically how web servers work.

--
Regards

John Timney
Microsoft Regional Director
Microsoft MVP
 
You can take a look at remoting. With it you can fire events to the
connected client(s).

Sunny
 
Thanks John,

I read some documents about WSE(web service enhancement). Do you think
that might be useful for my issue?

Thanks,

Michael
 
I'm not really up on WSE2, but you might have read something about abstract
patterns which alludes somewhere to it doing a server push. I think what it
actually is is a stream of SOAP requests that the client sends - rather than
just one called a SequenceAcknowledgement chain. This topic is definately
one for the webservices public group, your heading into advanced territory
and I've not read up on WSE2 for a few months..

However, as someone else has suggested there is nothing to stop you using
remoting which could give you that type of connectivity. As it is your
limited by the HTTP protocol which is a disconnected protocol.

--
Regards

John Timney
Microsoft Regional Director
Microsoft MVP
 
Clear enough. Thanks John and everyone contributed your thougths for
this issue. Have a good day.

Michael
 
Hi Sunny,

Could you give me some links which introduce what is remoting and how
it works? Thanks,

Michael
 
Hi,

you may start with MSDN. Just to get the idea, type in "remoting" in the
index of VS.Net help.

http://msdn.microsoft.com/library/en-
us/cpguide/html/cpconaccessingobjectsinotherapplicationdomainsusingnetre
moting.asp

Next step is to get "Advanced remoting" by Ingo Rammer. "Advanced" in
the topic means that he goes very deep, but he starts with the basics,
so it is really great source. I would like to knew that before I lost a
month in pain :)

Reading the posts in .dotnet.remoting newsgroup also helps a lot.

Sunny
 
Michael said:
I am a newbie for web servcie and want to write a web service which
monitors the certain field in the database. Once it exceeds the
certain value, web service will send out notification to web service
consumer who will take action on it.

Is it possible? If yes, how to implement? If possible, please provide
me the link.

Thanks lot.

Michael


If you're willing to use WSE2.0, you can make a web service that accepts
a message that is basically a subscription. This subscription has a
return address of the client (TCP, not HTTP) to which the web service
can send a message.

The hands On Labs for WSE2.0 cover some scenarios where the web service
contacts the client (after an initial client message, but when an event
fires on the server, not in response to the initial client message.) I'd
check them out.

-Ben
 
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