We are on 1.2, with plans to move to 2.0 in the next few months.
- We really want to simply fail and return nothing back to the sender,
i.e., reset the connection in effect. The sending system will retry, and
we'll refail again until we regain a db connection. etc...
- I am not sure about your comment regarding DOS attacks, plus we are
within a secured intranet only in a datacenter, so i do not believe this
to be a risk.
- I am not sure either what you mean by "being brought up to code". We
are listening on a port and processing messages. It is possible that a
catastrophic failure occurs which causes us to be unable to process the
message: we cannot guarantee (nobody could) 100% success. Our problem is
that the HL7 gateway (Cloverleaf in this case) has been configured on
premise to always assume success whether ACKs or NACKs were received,
thus eating out messages that we may not have properly processed. We
cannot make changes to that configuration unfortunately. The only
option, and what the hospital system we work with has standardized upon,
is for the consuming system to simply return nothing and close the
connection. Being a large hospital system, i figured this was a fairly
standard and accepted process... :) Silly me! :)
Thank you,
------------------------------------------------------------------------
*Laurent Hasson*
Co-Founder, 360Fresh.com <https://360Fresh.com>
Cellphone: 646-283-2186
This email and any attachments thereto may contain private,
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On 12/3/2012 06:02, Christian Ohr wrote:
Laurent,
What version of HAPI are you using? Internals of the whole app
framework changed quite a bit in 2.0.
If I understood you correctly, you need to close the socket on an
erroneous message and you are well aware of the fact that you expose
yourself to DOS attacks by doing so - anyway.
In general, HAPI application objects don't know about the connection
from where the message came from. In general the socket can of course
be shared by more than one client. If your system environment allows
for closing a dedicated connection anyway, you can do this:
1. Let your Application class implement
ca.uhn.hl7v2.app.ConnectionListener and remember the connection
received in the connectionReceived() if it was initiated by your
client.
2. In the Application's process method, call call the close() method
on the connection you remembered. This will immediately close the
underlying socket and nothing gets returned either.
Even so, I wouldn't recommend this in production systems and rather
that client should be brought up to code!
Christian
2012/12/3 Jens Kristian Villadsen <j...@c3a.dk>:
from within the Application.processMessage() method, that is
2012/12/3 Jens Kristian Villadsen <j...@c3a.dk>
throw an Error instead of an Exception - that makes the HAPI thread choke
and nothing will be returned and the entire framework still lives on. That
sounds like its a proper solution for you.
2012/12/2 LDH <l...@360fresh.com>
I have performed some stress testing this weekend. One test is to kill
our database, which causes our HAPI code that ingests messages to fail. Our
strategy so far was simply to return a NACK, but we discovered that the
system that is sending us messages is taking ANY response as a success
indicator, thus swallowing the message and causing message loss. The sending
system expects the socket connection to simply be terminated. We have tried
a number of strategies such as:
- throwing an exception from the Application.processMessage() method
- returning NULL from the method
- implementing our own PipeParser and overriding the encode() method
to return "" when the message source was null
- etc....
All those strategies have failed because at the end of the day, the
sending system still receives something. Unfortunately, we are not able to
modify the sending system, and so, we have to fix this on our end and we are
not sure how to make HAPI simply drop the connection and not send ANYTHING
back.
Any advice?
Thank you,
________________________________
Laurent Hasson
Co-Founder, 360Fresh.com
Cellphone: 646-283-2186
This email and any attachments thereto may contain private, confidential,
and privileged material for the sole use of the intended recipient. Any
review, copying, or distribution of this email (or any attachments thereto)
by others is strictly prohibited. If you are not the intended recipient,
please contact the sender immediately and permanently delete the original
and any copies of this email and any attachments thereto.
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Med venlig hilsen / Kind regards
Jens Kristian Villadsen
cand.polyt
Systemudvikler / System developer
IM (Skype): j.kidd.o
Cetrea A/S, Denmark
phone : +45 38 40 05 81
address: Brendstrupgårdsvej 21F, DK-8200 Aarhus N.
e-mail : j...@cetrea.com
w^3 : http://www.cetrea.com/
--
Med venlig hilsen / Kind regards
Jens Kristian Villadsen
cand.polyt
Systemudvikler / System developer
IM (Skype): j.kidd.o
Cetrea A/S, Denmark
phone : +45 38 40 05 81
address: Brendstrupgårdsvej 21F, DK-8200 Aarhus N.
e-mail : j...@cetrea.com
w^3 : http://www.cetrea.com/
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