W3CArchitecture Domain Web Services

SOAP Version 1.2 - Frequently Asked Questions

This document lists some frequently asked questions about the SOAP Version 1.2 specifications and provides answers to those questions. For more information about SOAP Version 1.2, see the Working Group Home Page.

  1. What is SOAP Version 1.2?
  2. Who has implemented SOAP Version 1.2?
  3. Where can I find an introduction to SOAP Version 1.2?
  4. What is new in SOAP Version 1.2?
  5. Why switch to SOAP Version 1.2?
  6. How can I be sure my implementation is interoperable?
  7. Is SOAP Version 1.2 secure?
  8. Can I use SOAP Version 1.2 without WSDL?
  9. So, when do I need WSDL?
  10. What are my options if I want to use WSDL?
  11. Is SOAP Version 1.2 internationalized?
  12. Can I use other underlying transport protocols in SOAP Version 1.2?
  13. Will my SOAP Version 1.2 implementation work with SOAP/1.1 clients?

What is SOAP Version 1.2?

SOAP Version 1.2 is a messaging framework with a set of extensions. The specification is in three distinct documents:

Who has implemented SOAP Version 1.2?

The SOAP Version 1.2 Implementation Report has a list of implementors known to the XML Protocol Working Group, as well as a status of their implementation. The list is not exhaustive.

Where can I find an introduction to SOAP Version 1.2?

The SOAP Version 1.2 Primer gives a good introduction to SOAP 1.2, and is recommended reading.

What is new in SOAP Version 1.2?

SOAP Version 1.2 is based on a layered and extensible model.

  1. Over 400 issues raised both in the SOAP 1.1 and early SOAP 1.2 specifications have been resolved.
  2. SOAP version 1.2 supports Web standards such as XML Schema and XML Infoset.
  3. The "transport" layer makes it easy to switch between protocols like HTTP, BEEP and others to fit your application needs.
  4. Extensions and the processing of those extensions has been improved and clarified, to ensure more extensibility and interoperability.
  5. Error reporting has been improved.

For more technical details, the SOAP Version 1.2 Part 0 (Primer) has a complete list of changes from SOAP/1.1 to SOAP Version 1.2

Why switch to SOAP Version 1.2?

SOAP Version 1.2 provides more - and proven - interoperability, support for Web standards, and an easier way to extend and update your applications. It also allows you to define applications that can scale better through a more effective use of Web infrastructure - namely with the option of using the HTTP binding. For a more complete reply, see From SOAP/1.1 to SOAP Version 1.2 in 9 points.

How can I be sure my implementation is interoperable?

You should see the SOAP Version 1.2 Specification Assertions and Test Collection, and contact the implementers listed in the implementation report to set up tests.

Is SOAP Version 1.2 secure?

An application is as secure as its design is. SOAP Version 1.2 may use some security features, but in the end, like in all current distributed applications, it is up to the application itself to take care of security (buffer overflow, denial of services...)

Can I use SOAP Version 1.2 without WSDL?

Yes, SOAP 1.2 is not dependent on WSDL (Web Services Description Language). There are many interesting situations in which SOAP can be used without WSDL. Indeed, early adopters of SOAP used it for many months before languages similar to WSDL became available.

So, when do I need WSDL?

WSDL is used primarily as a means of documenting, in machine readable form, the details of particular SOAP-based protocols. Many WSDL-enabled tools can use these descriptions to help you build SOAP applications. Without WSDL, you may have to tailor more of your code by hand.

What are my options if I want to use WSDL?

Several options are available:

Is SOAP Version 1.2 internationalized?

SOAP Version 1.2 has provisions for internationalization, including the ability to provide multiple error messages in different languages, encodings, character sets. Applications themselves still have to be internationalized, but that is a separate matter. SOAP Version 1.2 itself puts no restriction to a particular language.

Can I use other underlying transport protocols in SOAP Version 1.2?

One of the goals of SOAP Version 1.2 was to develop a clean way to change the underlying transport. Part 2 Adjuncts defines a rather complete mapping to HTTP, but you can define your own mapping to whatever protocol, using the SOAP Protocol Binding Framework defined in Part 1, Section 4.

Will my SOAP Version 1.2 implementation work with SOAP/1.1 clients?

Yes, but not directly. The client application will be notified that the current version being used is SOAP Version 1.2. The client application may switch to SOAP Version 1.2 for subsequent requests. See Part 1, Section 5.4.7


Yves Lafon, Carine Bournez
Revision: $Date: 2003/06/24 12:17:56 $