RE: [wsbpel] Issue - 87 - Optional SOAP Headers

Hi 
Yaron,

 

Thank you for 
creating a new issue separated from 77. I think it will simplify our 
discussions. Intermediaries have always been a favorite subject of mine, so I'll 
give you my feedback on this one ;-).

 

I can understand 
this issue in two different ways:

 

1. The issue is not 
limited to SOAP headers and to the presence of SOAP 
intermediaries.

 

This is just the way 
WSDL 1.1 is defined. Any part of an abstract interface is optional when it comes 
to binding (and limiting the definition of abstract interface to the portType, 
by the way, does not change this fact a single bit).

 

I am not sure we 
need to do anything here. BP 1.0, sec. 5.3.3, gives a specific recommendation in 
the case of portType parts (but, as I mentioned in the past, it is just a 
SHOULD, so even BP 1.0 compliant deployments can have this problem). So we could 
say that if a WSDL/BPEL designer follows BP 1.0, then the problem would not 
appear with parts from the portType. Otherwise, the developer must be 
prepared to have undefined/unused parts at runtime.

 

2. The issue should 
be understood only in the specific context of SOAP 
intermediaries.

 

In other words, 
because of the existence of intermediaries along the SOAP path, some headers are 
not intended for a particular end point (either a service port or a service 
client) and are never going to appear at that end point (they are only used 
in other segments of the path which do not touch that end 
point).

 

This is a 
manifestation of a much serious problem with WSDL 1.1: it simply cannot handle 
SOAP intermediaries in the general case. Whenever intermediaries are 
present, there is simply no way to specify in WSDL to which 
segment of the overall SOAP path a binding refers to. This issue applies to 
intermediaries as they are described by the binding, but it also applies to the 
protocol chosen by the binding and to the address associated with the port. 
(The protocol and address problems, of course, do not appear at the BPEL 
language level, but they are part of the same basic problem WSDL 1.1 has when 
dealing with intermediaries).

 

 

Ugo