I have a project that involves parsing wddx webservice responses. The DOM DocumentBuilder is throwing an exception that the XML is malformed as it does not reference a dtd. I inserted a DOCTYPE statement and now it is throwing an exception malformed - cannot find the protocol. I am quite certain it is my reference to the DTD and I now need a local copy. I thought it would be a simple surf to get the DTD from wddx.org, however, that has not been successful.
Not sure if it is up-to-date, but I found this reference on xml.coverpages.org, which linked to a local archive copy of the DTD
WDDX DTD From: http://www.codebits.com/wddx/wddx_0090.dtd.txt Date: 1998-09-28
<!-- ************************************************************************
WDDX DTD:
Author: Simeon Simeonov (simeons@allaire.com)
Copyright (c) 1998 Allaire Corp. http://www.allaire.com
-->
<!-- ************************************************************************
Introductory Notes:
What is WDDX:
WDDX stands for Web Distributed Data eXchange. WDDX is a mechanism for
exchanging complex data structures between programming languages. It
has been designed with web applications in mind. WDDX consists of a
language-independent representation of instantiated data based on
XML 1.0 (which is defined using this DTD) and a set of serializer/
deserializer modules for every language/technology that uses WDDX.
The WDDX DTD:
The WDDX DTD can be used to validate WDDX packets. Packets are
representations of instantiated data structures in programming
languages. The following is an example of a WDDX packet:
<?xml version='1.0'?>
<!DOCTYPE wddxPacket SYSTEM 'wddx_0090.dtd'>
<wddxPacket version='0.9'>
<header/>
<data>
<struct>
<var name='s'>
<string>a string</string>
</var>
<var name='n'>
<number>-12.456</number>
</var>
<var name='d'>
<dateTime>1998-06-12T04:32:12</dateTime>
</var>
<var name='b'>
<boolean value='true'/>
</var>
<var name='a'>
<array length='2'>
<number>10</number>
<string>second element</string>
</array>
</var>
<var name='obj'>
<struct>
<var name='s'>
<string>a string</string>
</var>
<var name='n'>
<number>-12.456</number>
</var>
</struct>
</var>
<var name='r'>
<recordset rowCount='2' fieldNames='NAME,AGE'>
<field name='NAME'>
<string>John Doe</string>
<string>Jane Doe</string>
</field>
<field name='AGE'>
<number>34</number>
<number>31</number>
</field>
</recordset>
</var>
</struct>
</data>
</wddxPacket>
It defines a root level object that is a structure (also known as
an associative array) of six properties:
- s which is the string 'a string',
- n which is the number -12.456,
- d which is the date-time value June 12, 1998 4:32:12am,
- b which is the boolean value true,
- a which is an array of two elements (10 and 'second element'),
- obj which is a structure with two properties s and n, and
- r which is a recordset of two rows with fields NAME and AGE.
Basic data types:
WDDX supports the following basic data types: boolean (true/false),
number, date-time, and string.
Numbers are internally represented with floating point numbers. Because
of differences between WDDX-enabled languages, the range of numbers has
been restricted to 3.4E+/-38. The precision has been restricted to 7
digits after the decimal point. These requirements are consistent with
a 4-byte floating point representation.
Date-time values are encoded according to the full form of ISO8601.
Timezone information will be successfully parsed and used to convert to
a local data-time value. Efforts should me made to ensure that the
internal representation of date-time values does not suffer from Y2K
problems and covers a sufficient range of date-time values.
Strings can be of arbitrary length and must not contain embedded nulls.
Complex data types:
WDDX supports the following complex data types: arrays, structures, and
recordsets.
Arrays are integer-indexed collections of objects of arbitrary type.
The starting index value is usually 0 with the notable exception of
CFML whose arrays have an initial index value of 1. Because of these
differences working with array indices can lead to non-portable data.
Structures are string-indexed collections of object of arbitrary type.
In many languages they are known as associative arrays. Structures
contain one or more variables. Because some of the languages supported
by WDDX are not case-sensitive, no two variable names can differ only
by their case.
Recordsets are tabular data encapsulations: a set of named fields with
the same number of rows of data. Only simple data types can be stored in
recordsets. For tabular data storage of complex data types, an array of
structures should be used. Because some of the languages supported by
WDDX are not case-sensitive, no two field names can differ only by
their case.
Data type comparisons:
The following table compares the basic WDDX data types with those of
languages/technologies commonly used on the Web.
WDDX Type COM Java Type ECMAScript Type
************** ************* **************** ***************
boolean boolean boolean boolean
number float? float? number
dateTime DATE ?? Date
string BSTR java.lang.String string
array VARIANT array ?? Array
struct IWDDXStruct ?? Object
recordset IWDDXRecordset ?? WddxRecordset
More on data types:
WDDX provides no notion of a null object. Null objects should be
serialized to empty strings. Upon deserialization it is up to the
component performing the operation to determine whether and where
should empty strings be deserialized to null values.
WDDX serializes data using a model of pure aggregation. It has no
mechanism for handling object references. Aliased references will
result in multiple object instances being deserialized. WDDX
serialization applied to a data structure that has cyclical references
will most likely result in infinite iteration/recursion, depending on
the serializer implementation.
-->
<!ELEMENT wddxPacket (header, data)>
<!ATTLIST wddxPacket
version CDATA #FIXED "0.9">
<!ELEMENT header (comment?)>
<!ELEMENT comment (#PCDATA)>
<!ELEMENT data (boolean | number | dateTime | string | array | struct | recordset)*>
<!ELEMENT boolean EMPTY>
<!ATTLIST boolean
value (true | false) #REQUIRED>
<!ELEMENT string (#PCDATA)>
<!ELEMENT number (#PCDATA)>
<!ELEMENT dateTime (#PCDATA)>
<!ELEMENT array (boolean | number | dateTime | string | array | struct | recordset)*>
<!ATTLIST array
length CDATA #REQUIRED>
<!ELEMENT struct (var*)>
<!ELEMENT var (boolean | number | dateTime | string | array | struct | recordset)>
<!ATTLIST var
name CDATA #REQUIRED>
<!ELEMENT recordset (field*)>
<!ATTLIST recordset
rowCount CDATA #REQUIRED
fieldNames CDATA #REQUIRED>
<!ELEMENT field (boolean | number | dateTime | string)*>
<!ATTLIST field
name CDATA #REQUIRED>