19 messages in org.oasis-open.lists.wsbpelRe: [wsbpel] inputVariable optional o...| From | Sent On | Attachments |
|---|---|---|
| Yaron Y. Goland | Jul 16, 2004 9:59 am | |
| Ron Ten-Hove | Jul 16, 2004 11:25 am | |
| Prasad Yendluri | Jul 16, 2004 12:16 pm | |
| Ugo Corda | Jul 16, 2004 1:28 pm | |
| Ron Ten-Hove | Jul 16, 2004 2:40 pm | |
| Prasad Yendluri | Jul 16, 2004 4:20 pm | |
| Prasad Yendluri | Jul 16, 2004 4:28 pm | |
| Ugo Corda | Jul 16, 2004 4:35 pm | |
| Prasad Yendluri | Jul 16, 2004 4:49 pm | |
| Ugo Corda | Jul 16, 2004 5:02 pm | |
| Danny van der Rijn | Jul 16, 2004 5:05 pm | |
| Danny van der Rijn | Jul 16, 2004 5:06 pm | |
| Prasad Yendluri | Jul 16, 2004 5:12 pm | |
| Prasad Yendluri | Jul 16, 2004 5:19 pm | |
| Ron Ten-Hove | Jul 16, 2004 5:35 pm | |
| Yaron Y. Goland | Jul 19, 2004 10:18 am | |
| Prasad Yendluri | Jul 19, 2004 11:29 am | |
| Yaron Y. Goland | Jul 20, 2004 10:07 am | |
| Monica J. Martin | Jul 20, 2004 10:24 am |
| Subject: | Re: [wsbpel] inputVariable optional on Invoke | |
|---|---|---|
| From: | Ron Ten-Hove (Rona...@Sun.COM) | |
| Date: | Jul 16, 2004 2:40:16 pm | |
| List: | org.oasis-open.lists.wsbpel | |
R2202 does indeed allow for an empty soap body. The part I quoted presupposes that wsdl:messages with zero parts are, in fact, legal, lending weight to Yaron's supposition that the schema for WSDL 1.1 trumps the prose.
-Ron
Prasad Yendluri wrote:
Ron,
This is only permits zero parts in the wsdl:message or the soap:body (binding level) being empty. This does not say the wsdl:message or the soap:envelope itself can be totally absent. Hence we can not interpret that to imply the inputVariable can be absent. It can be empty or void of payload (body) content and with WSDL 1.1 headers can be present in the soap:envelope coming from other wsdl:messages etc.
Regards, Prasad ||
Ron Ten-Hove wrote:
When faced with the oddities of WSDL 1.1, I usually consult my copy of the WS-I Basic Profile. Even though it is SOAP-centric, it does have a lot to say about service declarations. The BP 1.0 doesn't recognize (and clarify) the contradiction you found (concerning the cardinality of message parts), but I find this:
From section 5.3.1 (Bindings and Parts):
Use of |wsdl:message| elements with zero parts is permitted in Document styles to permit operations that can send or receive messages with empty |soap:Body|s. Use of |wsdl:message| elements with zero parts is permitted in RPC styles to permit operations that have no (zero) parameters and/or a return value.
I'd say we have the WS-I's blessing on leaving the inputVariable as optional. Other implementations of SOAP may have different interpretations, but allowing the inputVariable to be optional is the most general choice, and will cover such implementations as well.
-Ron
Yaron Y. Goland wrote:
Executive Summary: Antony Miguel, in a private e-mail, pointed out that the inputVariable attribute on invoke is currently optional. In BPEL as it now is specified this doesn't make sense as all operations MUST have a WSDL message associated with them. But if issue 12 passes then the optional inputVariable makes sense in cases where the message has no parts. Unfortunately the WSDL 1.1 spec seems to contradict itself on the legality of partless messages.
Long Winded Version:
Antony Miguel, in a private e-mail with me, pointed out that the inputVariable attribute is optional on invokes. Given that all invoke MEPs MUST have an outgoing message does it make sense to have the attribute be optional?
The only scenario I can come up with where it makes sense to not have an inputVariable attribute is if the outgoing message is 'empty'. This is not a completely insane idea. Some protocols do have 'empty' messages which have an address header but no body. This could be used for things like pings.
But all BPEL messages have to be sent using a WSDL message structure and it isn't possible to define an operation that doesn't point at a message. However it MAY be legal to define a WSDL message with no parts. There is a contradiction between the text in WSDL 1.1 and the schema. The text in section 2.3 says "Messages consist of one or more logical parts.". But the psuedo-schema in 2.3 says:
<definitions .... > <message name="nmtoken"> * <part name="nmtoken" element="qname"? type="qname"?/> * </message> </definitions>
Furthermore the XML Schema in the appendix says:
<complexType name="messageType"> <complexContent> <extension base="wsdl:documented"> <sequence> <element ref="wsdl:part" minOccurs="0" maxOccurs="unbounded"/> </sequence> <attribute name="name" type="NCName" use="required"/> </extension> </complexContent> </complexType>
Assuming the schema triumphs then this means that it is legal to define a message with no parts. An empty message.
But this still leaves the problem that BPEL requires that all messages be contained in a WSDL container. This alone would require that invoke MUST always have an inputVariable attribute.
But, if issue 12 passes, then it would make sense to make inputVariable optional to cover the case where the message for an operation has no parts.
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