Sample activated application

re: Sample activated application

Fernando — Tue, 12 Mar 2013 03:54:07 GMT

Hello,

I tried a similar application (created by myself) which will create a new file when the service activate it. But I never see any new file. Can you please provide a complete sample?

re: Sample activated application

jgauffin — Mon, 11 Feb 2013 11:34:54 GMT

I get a 404 page when trying to download the sample

re: Sample activated application

MR — Tue, 17 Jan 2012 16:39:37 GMT

Can you please provide a step by step sample that includes settting up the queues in database and receiving the message using External Activator?

re: Sample activated application

mark — Sat, 24 Dec 2011 18:03:26 GMT

Following on my previous comment, can you please explain and share the code on how to write a custom external activator *listener*?

re: Sample activated application

mark — Sat, 24 Dec 2011 17:49:06 GMT

I’m hesitant in using this since the activated application is required to be a console application.

How would this behave in a non-interactive server environment where there is no logged-on user? Will there be a pop-up command window if there is an interactive user? Will they see a cmd window? what if they close it by-mistake? Furthermore, how can an infinite dequeue loop be avoid in case of failure, I mean what is the exact condition for future activation, the activated application can exit for a variety of reasons, what are your criteria for consecutive activations?

It seems that a DLL hosting environment would be more appropriate for this…

re: Sample activated application

yevlempy — Thu, 03 Mar 2011 10:10:41 GMT

Can you provide step by step configuration of external activation in sql server 2005

re: Sample activated application

Pawel Marciniak — Wed, 12 Jan 2011 19:10:32 GMT

@Mark Freeman

When the ProcessMessage fails, it will/should throw an exception, which will bubble up and eventually leave the "using(SqlTransaction)" block. That will cause the transaction to be rolled back on the server, effectively putting the received message back into the queue. Of course, the error should not crash the app as it does in the sample, but specific error handling is a business logic that cannot be included in a generic sample. The message, however, will not be lost as you're implying.

re: Sample activated application

Mark Freeman — Tue, 04 Jan 2011 19:13:33 GMT

One significant omission from this sample is handling of a failure in the ProcessMessage method. If that method were to call a web service that was down or otherwise ran into trouble, there is no code to rollback the transaction (to effectively "un-receive" the message so it isn't lost.

re: Sample activated application

Pawel Marciniak — Mon, 22 Nov 2010 17:52:37 GMT

@Stacy:

This pattern is useful when you need the external processing (i/o, web request) to be done transactionally with regard to receiving the message. In order to free the connection before proceeding to do the real work, you would have to commit the receive. What if the external processing fails - there's no easy way to put the message back in the queue for a retry. If you keep the transaction open, you can just do a rollback in such situation and the message is not lost.

Of course feel free to change the pattern if your particular circumstances don't require these guarantees - the code was provided for the most common case, but is by no means perfect for all use cases.

re: Sample activated application

Stacy — Sat, 20 Nov 2010 22:29:41 GMT

Since the payload processing is done inside the reader loop, does the the db connection stay open all that time? What if processing takes time, like doing file i/o or a web request, is this the appropriate pattern to use?