Dynamic invocation of web services?

[Generic Usenet Account]

Most of the open source web-service products that I am reading about
seem to require generation of client stub and server implementation
ancestor classes from the WSDL file. The client application links in
with the stubs. Like CORBA SII, the client operates on a proxy
(albeit a "service proxy" and not an "object proxy") in its address
space.

This approach seems to limit the scope of web services. Is there an
equivalent of CORBA DII for web services? I believe the UDDI standard
allows clients to invoke services without having compile-time
knowledge of the service description. Is this correct? Also, are
there any open source web-service products that support this
capability?

Thanks in advance.

Bhat

 

[Zahid Faizal]

Most of the open source web-service products that I am reading about
seem to require generation of client stub and server implementation
ancestor classes from the WSDL file. The client application links in
with the stubs. Like CORBA SII, the client operates on a proxy
(albeit a "service proxy" and not an "object proxy") in its address
space.

This approach seems to limit the scope of web services. Is there an
equivalent of CORBA DII for web services? I believe the UDDI standard
allows clients to invoke services without having compile-time
knowledge of the service description. Is this correct? Also, are
there any open source web-service products that support this
capability?

Thanks in advance.

Bhat

The web-services specifications do not preclude the possibility of
"dynamically" discovering the description of a service and then
binding to it, although hardly any of the C++ products that I have
looked at support that capability.

Having said that, I must admit that I feel that the whole notion of
"dynamically" discovering the description of a service and then
binding to it is, like CORBA DII, a pipe-dream. Yeah, you can make it
work in some "toy" applications, but the feasibility of this approach,
in the real world, is questionable. Many times I wish that DII and
dynamic service description discovery were merely described as the
means towards reducing integration time and effort. Remember, unless
you have the "business logic" to process a response from a
service/interface regarding which you had no compile time knowledge,
you cannot get very far and all you can come up with is a "Toy Story".

--ZF