On 16/03/2010 02:01, Song Thuy Nguyen wrote:
The thing is, I'm using the failover behaviour in Apache Synapse (Enterprise Service
Bus). I can give Synapse a list of web service endpoints that have the same interface.
One is the primary service endpoint and the others are the backups in case the primary
endpoint become unavailable for some reason. Actually there are only 2 general reasons:
the (application) server that provides the services is not running, so the port (lets say
port 80) is closed. Or the second case: the application server is still running, but the
service is made inactive. That means the application server still listens at port 80 but
can't serve request to the mentioned service and answers with the "404 The requested
resource XYZ is not available" response.
Now the problem: Synapse gets this http-404 response, eventhough it can't find
the SOAP envelop it expects it doesn't see the endpoint as faulty and forwards
the 404 message to the caller (web service consumer). The fail-over mechanism
doesn't kick in.... :( But actually it should because the service is not
available anymore, so the request should be send to the backup endpoints.
Ofcourse I tried to make Synapse understand that a 404-response should be
treated the same as a failure. But it can't easily be done. So I thought I
could make Tomcat to receive calls to inactive services, but just drop them
without answering. After some time... synapse will trigger timeout and tries to
call the backup endpoints.
It doesn't matter if the http/tcp connection has been established or not.
So why try to fake a timeout? Presumably there is an error code that
Synapse will recognise as meaning that the service is unavailable, find
out what that is and send that instead. E.g. 503.
You could employ a custom ErrorValve, if you are able to check/intercept
the 404 status that would be returned in the normal case and override it.
p
-----Original Message-----
From: Len Popp [mailto:len.p...@gmail.com]
Sent: Tuesday, March 16, 2010 1:50 AM
To: Tomcat Users List
Subject: Re: How to surpress The requested resource XYZ is not
available - response
I don't think you can do that. After Tomcat accepts the HTTP
connection and decides whether to respond, it's too late to pretend
there's no server there. The user's web browser displays a different
error message for no server (something like "can't establish a
connection") vs. server timeout (something like "the server took too
long to respond") or dropping the connection ("the connection was
reset").
So you might as well just customize the 404 error page to say "There's
no server here" - it'd fool people just as well. :-) Or just return
an empty error page.
--
Len
On Mon, Mar 15, 2010 at 19:26, Song Thuy Nguyen<programm...@biaqua.de>
wrote:
Hello,
usually you will get a "The requested resource /XYZ is not available"
response when you call an
unavailable web service on Apache Tomcat. However, for a special use
case I don't want Tomcat to
answer to requests for a unknown/unavailable web service. I just
want Tomcat to ignore it and "keep
quiet", resulting that the caller will get a timeout and therefore
knows that there is no service behind
this URL. How can I achieve such behaviour?
Best Regards,
Song Thuy Nguyen
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