View source for WDDX

'''WDDX''' (Web Distributed Data eXchange) is a [[programming language]]-, platform- and [[transport protocol|transport]]-neutral data interchange mechanism designed to pass data between different environments and different computers.

==History==
WDDX was created by Simeon Simeonov of [[Allaire Corporation]] in 1998,<ref name="sim">{{cite web  | last = Simeonov
  | first = Simeon  | title = WDDX: Distributed Data for the Web  | url= https://www.infoloom.com/media/gcaconfs/WEB/chicago98/simeonov.HTM
  | accessdate = 2007-02-05 }}</ref> initially for the [[ColdFusion]] server environment. WDDX was open-sourced later that year.<ref name=itoi>{{Cite news|last=Itoi |first=Nikki Goth |title=Syndicating the Web: Businesses are hoping that the ICE protocol will reduce the Web's content-sharing hassles |work=Red Herring |date=February 1999 |url=http://redherring.com/mag/issue63/news-syndication.html |url-status=dead |archiveurl=https://web.archive.org/web/19991013102610/http://redherring.com/mag/issue63/news-syndication.html |archivedate=October 13, 1999 }}</ref>  

==Usage==
WDDX is functionally comparable to [[XML-RPC]] and [[WIDL (Internet Standard)|WIDL]].<ref>{{Cite news|last=Udell |first=Jon |title=Exploring XML-RPC: DCOM? CORBA? RMI? Why Not Just XML-RPC? |work=Byte |accessdate=2015-11-17 |date=1999-06-07 |url=http://www.byte.com/features/1999/06/0607XML_RPC5.html |url-status=dead |archiveurl=https://web.archive.org/web/20000304171225/http://www.byte.com/features/1999/06/0607XML_RPC5.html |archivedate=March 4, 2000 }}</ref> The specification supports simple data types such as number, [[string (computing)|string]], [[boolean data type|boolean]], etc., and complex aggregates of these in forms such as [[record (computer science)|structures]], [[array data type|arrays]] and recordsets (row/column data, typically coming from database queries).

The data is encoded into [[XML]] using an XML 1.0 [[Document Type Definition|DTD]], producing a platform-independent but relatively bulky representation.<ref>{{Cite web|url=http://xml.coverpages.org/allaireWP-cfm.html|title = WDDX White Paper by Jeremy Allaire}}</ref> The  XML-encoded data can then be sent to another computer using [[HTTP]], [[File Transfer Protocol|FTP]], or other transmission mechanism.  The receiving computer must have WDDX-aware software to translate the encoded data into the receiver's native data representation.  WDDX can also be used to [[serialization|serialize data structures]] to storage (file system or database). Many applications use WDDX to pass complex data to browsers where it can be manipulated with [[JavaScript]], as an alternative to [[JSON]].

Example from  [[php.net]]:<ref>{{Cite web|url=https://www.php.net/wddx|title=PHP: WDDX - Manual|website=www.php.net}}</ref>
<syntaxhighlight lang="xml">
<wddxPacket version='1.0'>
  <header comment='PHP'/>
  <data>
    <struct>
      <var name='pi'>
        <number>3.1415926</number>
      </var>
      <var name='cities'>
        <array length='3'>
          <string>Austin</string>
          <string>Novato</string>
          <string>Seattle</string>
        </array>
      </var>
    </struct>
  </data>
</wddxPacket>
</syntaxhighlight>


==Adoption==
WDDX is mainly used by [[ColdFusion]] and, as February 2022, still supported by Adobe.

Outside ColdFusion, libraries exist to read or write this format, [[Ruby (programming language)|Ruby]],<ref>{{Cite web |date=January 31, 2007 |title=Rails WDDX Request |url=http://www.juretta.com/log/2007/01/31/rails_wddx_request/ |access-date=July 26, 2025 |website=www.juretta.com}}</ref> [[Python (programming language)|Python]],<ref>[https://pypi.python.org/pypi/wddx Using WDDX with Python]</ref> [[PHP]], [[Java (programming language)|Java]], [[C++]], [[Microsoft .NET|.NET]],<ref>[https://github.com/Bilal-S/WDDX.net .NET platform WDDX project]</ref> [[ActionScript]],<ref>[http://blog.bigsource.de/index.php/2007/11/01/as3-wddx-class/ Using WDDX with Flex and AS3]</ref> [[Lisp programming language|lisp]], [[Haskell (programming language)|Haskell]], [[Perl]].

PHP used to offer a comprehensive support for WDDX, which could be used as a format to store session information<ref>Andrew Stopford, ''PHP Programming for Windows'', Landmark, New Riders, 2002.</ref> until the version 7.4. It has been removed since from the base language, but still available through PECL.<ref>{{Cite web|url=https://www.php.net/manual/en/migration74.removed-extensions.php|title = PHP: Removed Extensions - Manual}}</ref> The rationale was a lack of standardization of the  format, and new formats like JSON more mainstream.<ref>{{Cite web|url=https://wiki.php.net/rfc/deprecate-and-remove-ext-wddx|title=PHP: RFC:deprecate-and-remove-ext-WDDX}}</ref> A vulnerability was fixed in 2007.{{vague|reason=No information given about what kind of vulnerability it is or how severe.|date=February 2025}}<ref>{{Cite web|url=https://cve.mitre.org/cgi-bin/cvename.cgi?name=2007-0908|title = Cve - Cve-2007-0908}}</ref>

==Notes==
{{reflist}}

==External links==
*[https://web.archive.org/web/20060719125042/http://www.infoloom.com/gcaconfs/WEB/chicago98/simeonov.HTM GCA98 WDDX Presentation]
*[https://web.archive.org/web/20060717205519/http://www.xml.com/pub/r/1266 Using WDDX with Flash]

[[Category:XML-based standards]]
[[Category:Markup languages]]
[[Category:Data serialization formats]]


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