Subject Line: .NET UPDATE, May 15, 2003
.NET UPDATE--brought to you by the Windows & .NET Magazine Network http://www.winnetmag.com
~~~~ THIS ISSUE SPONSORED BY ~~~~
Windows & .NET Magazine http://www.winnetmag.com/rd.cfm?code=edwi203dup
* ROLES IN SOAP 1.2 The World Wide Web Consortium (W3C) has released a proposed recommendation for the next version of Simple Object Access Protocol (SOAP) 1.2. Although most of the proposed changes probably won't affect non-developers, the use of roles and the introduction of new roles in this version of the protocol can help you understand how the message-passing works.
SOAP is the protocol that .NET applications use to pass XML messages. The specification describes how the protocol should work. The protocol uses remote procedure calls (RPCs) over HTTP (SOAP is a high-level protocol, not a transport protocol like TCP/IP), but it can also cooperate with a couple of other protocols.
Each time a SOAP node processes a message--either passing it on to another node or keeping it, as the final destination--that SOAP node adopts a particular role to let it process the message accordingly. Roles aren't new to the most recent version of SOAP, but SOAP 1.2 defines two new roles, introduces a new sub-element used to explicitly define the roles, and provides a more detailed processing model for how roles affect message processing.
SOAP 1.2 has three roles--"none," "next," and "ultimate receiver"--which are used in SOAP message headers or the message body. The values aren't recorded as "none" and so forth but as Uniform Resource Identifiers (URIs) pointing to the appropriate definition on the W3 Web site.
If a message header's role has the "none" attribute, then no SOAP node should process the contents. This rule doesn't preclude a node examining the content of a message if another message header points to the content, but it does mean that the node should not alter the data.
If a node receives a message containing a header with the "next" value as its role, then that node must be able to process the message if necessary. Therefore, intermediaries along the path from the message's originator to its final destination always play the "next" role.
The "ultimate receiver" role isn't defined in the message header but in the body of the message where the payload resides. This role is implied rather than explicit. The role of the node can be explicitly stated in the body of the message, but it's not necessary--if no role is listed, then the "ultimate receiver" role is the default. Also, you can't leave a role undefined but with an empty value--that is, instead of "next" the role is "". In that case, the Uniform Resource Identifier (URI) defining the role is the base URI for that SOAP message. SOAP 1.2 doesn't define the mechanics of deriving the base URI, but HTTP, the protocol on which SOAP depends, does.
A SOAP node can act in multiple roles. In fact, in the case of the ultimate receiver, it always will, because the node must both be able to process the headers and receive the body of the message. The SOAP node that originally sent the message has no defined role.
Roles let a SOAP message know what it's supposed to do with a message and provide pointers to explicit instructions for how to process it. Any SOAP node that receives a message for processing--either to give to another node or to process itself--will use roles defined in the header or defined implicitly or explicitly in the body of the message.
* GET THE EBOOK THAT WILL HELP YOU GET CERTIFIED! The "Insider's Guide to IT Certification," from the Windows & .NET Magazine Network, has one goal: to help you save time and money on your quest for certification. Find out how to choose the best study guides, save hundreds of dollars, and be successful as an IT professional. The amount of time you spend reading this book will be more than made up by the time you save preparing for your certification exams. Order your copy today! http://winnet.bookaisle.com/ebookcover.asp?ebookid=13475
* CAST YOUR VOTE IN OUR ANNUAL READERS' CHOICE AWARDS! Which companies and products are the best on the market? Tell us by nominating your favorites in the annual Windows & .NET Magazine Readers' Choice Awards survey. Click here! http://www.winnetmag.com/readerschoice
* USE .NET CONTROLS IN ASP .NET APPLICATIONS Platte Canyon released Web Player, a .NET control for developers to embed either a Windows Media Player, Flash Player, RealPlayer, or plain text into ASP.NET applications. The Web Player enables a user to play sound, video, and animated files in ASP.NET applications. The developer can set the URL to the desired media or let the user turn off the media and display closed-captions. Web Player costs $145. Contact Platte Canyon at 888-866-5251 or [email protected] http://www.plattecanyon.com
* ABOUT THE COMMENTARY -- [email protected]
* ABOUT THE NEWSLETTER IN GENERAL -- [email protected] (please include the newsletter name in the subject line)
* TECHNICAL QUESTIONS -- http://www.winnetmag.com/forums
* PRODUCT NEWS -- [email protected]
* QUESTIONS ABOUT YOUR .NET UPDATE SUBSCRIPTION? Customer Support -- [email protected]
* WANT TO SPONSOR .NET UPDATE? [email protected]
This biweekly email newsletter is brought to you by Windows & .NET Magazine, the leading publication for Windows professionals who want to learn more and perform better. Subscribe today. http://www.winnetmag.com/sub.cfm?code=wswi201x1z
Receive the latest information about the Windows and .NET topics of your choice. Subscribe to our other FREE email newsletters. http://www.winnetmag.com/email
Thank you for reading .NET UPDATE.
You are subscribed as #EmailAddr#.
MANAGE YOUR ACCOUNT You can manage your entire Windows & .NET Magazine Network email newsletter account on our Web site. Simply log on and you can change your email address, update your profile information, and subscribe or unsubscribe to any of our email newsletters all in one place. http://www.winnetmag.com/email
Thank you! _________________________________________________________ Copyright 2003, Penton Media, Inc.