Web Services, SOAP, and WSDL CSCI 4300

Web Services for B2B communication

Technology involved for remote procedure call Web Service Description Language is the API SOAP is the message envelope HTTP is the transport layer

Remote Method Invocation Low-level Requires all parts written in Java CORBA is one attempt to get around this issue

JAX RPC layered over RMI

Simple SOAP message

SOAP headers and body Headers: Security credentials Transaction IDS Routing instructions Payment tokens Etc. etc. Body: Actual message content

Application-specific header example

A security header

Processing SOAP messages In particular, JAX-RPC implements remote procedure calls by exchanging SOAP messages

Modular processing

Message passing: multiple actors

Who processes the headers? A node which has identified itself with this processing role will process this header.

SOAP use case

Sequential processing Processing nodes can add and remove headers The Inventory node can add an authentication header and force the next node to process it

Web Services Description Language

“portType”: a service access point

Operation types

WSDL – SOAP binding The binding determines the format of the SOAP message that will transport a service

UDDI: the Yellow Pages

Acknowledgements Auto parts example: mple.html mple.html