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Remko,
If you're working with the low-level API, then I
guess you need to construct your SOAP fault manually (someone correct me if I'm
wrong). A SOAP fault element must be the first and only child of the SOAP body
element. You want to use addFault () to create a SOAPFault object and add
it to the SOAPBody. Then you want to set the fault code and fault string and add
the detail.
(This is using the SAAJ API).
Anne
----- Original Message -----
Sent: Friday, June 27, 2003 2:29 PM
Subject: Re: Exception handling strategy
question
Response:
Anne, thanks for your response. The reason
why I am returning a Document is because I need to return XML, this is just
the way I defined/need to format my response(1). Because I must also be able
to be invoked from all languages, I can't expect the clients to catch the Java
Exceptions(2).
For these two reasons, I am trying to solve it by
appending the mapped SOAPFault (created when the Exception was thrown) to the
Document to be returned.
Question:
But how to append the
SOAPFault object with 'appendChild(Node f)' which takes a Node?
I keep
getting castExceptions when I try to cast the SOAPFault.
or maybe I am
on the wrong track here, and this isn't the way to do
it?
remko
Anne Thomas Manes wrote:
Remko,
You don't have to return a Document in order to
ensure language-neutrality. The whole point of SOAP and WSDL is to provide a
layer of abstraction between your object model and your message structure
that ensures language-neutrality. Axis lets you return whatever your
application would like to return, and then Axis will convert that return
into a document for you. No matter how you define your service (RPC or
Document -- whether you marshal the message or you let Axis marshal the
message), the client SOAP processing engine (e.g., .NET, MS SOAP,
PocketSOAP, SOAP::Lite, Axis, etc) will receive a document, and that SOAP
processing engine can automatically transform that document into the
appropriate language objects on the client side (VB, C#, Java, Perl,
etc).
It's fine if you want your application to work
directly with the XML -- the Axis Messaging style lets you do so -- but I
want to make sure that you understand that you don't have to do so to ensure
language-neutrality.
When you return a fault, you don't return a
response message -- you return a fault message. Axis can automatically
capture an exception and return that exception to the client in a fault
message, but that doesn't help much if the client isn't Java. Therefore you
need to define a fault message for each of your exceptions, and then tell
Axis to map the exceptions to the faults accordingly.
Anne
-----
Original Message -----
Sent:
Friday, June 27, 2003 1:31 PM
Subject:
Re: Exception handling strategy question
Situation:
OK, so far this helped, and pointed
out the right direction in which to go. I had seen the SOAP Faults and
understand now when to use them.
I use the document/literal or
message style of web services in axis, since I am sending XML only.
I
use the
'public Document method(Document doc)'
signature,
and I need to be language neutral, and therefor have to return a Document
regardless. The Java Exceptions are indeed caught by the client, but I
can't use this method.
I managed to add a Fault to the SOAPBody object
from the MessageContext and set its parameters, but as mentioned I need to
return the Document, eg responseDoc, so the/any client can query this for
Faults.... or do I have to deal with it
differently??
Question:
How do I append the Fault object
to the Document to be returned??
Anne Thomas
Manes wrote:
There are four defined reasons to return a SOAP fault [1]:
- VersionMismatch: the request didn't specify the correct SOAP namespace
- MustUnderstand: a SOAP node did not understand a SOAP header that said
mustUnderstand='1'
- Client: the request failed either because it was malformed or contained
invalid data
- Server: the request failed because of some type of server error
Remko's example requires an error code of Client. The error report should be
returned in the fault <details> element. As long as you have Java on both
sides of the wire, the SOAP system on the client should be able to simply
rethrow the original exception (assuming that it has the exception class
installed). But if you intend to support non-Java clients, you should map
your various exceptions to specific SOAP fault messages.
[1] http://www.w3.org/TR/SOAP/#_Toc478383510
Regards,
Anne
----- Original Message -----
From: "George Jagodzinski" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Tuesday, June 24, 2003 3:22 PM
Subject: RE: Exception handling strategy question
if you are refering to business logic that happens after the request has
been accepted I would say that the best way is to return some type of
error
report. I could be wrong but it seems like soap fault should only be
thrown
if there was a conformance issue. Someone please correct me if I am wrong.
--George
-----Original Message-----
From: remko de knikker [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 24, 2003 3:22 PM
To: [EMAIL PROTECTED]
Subject: Exception handling strategy question
when implementing a web service and a ws client, what is the general
design principle for exception handling, when
1. when user entered a non-valid input value, for instance it doesn't
exist in the database?
Do I simply through a SOAPFault or is it better to append my own
<doesnotexist> tag?
2. as a client, do I catch an xxxxException/Fault, do I look for the
soapenv:Fault tag or do I have to look the webservice specific <wserror>
tag??
What is the best design strategy here??
thanks,
r
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