Where can I find a copy of the wddx.dtd?
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 开发者_JS百科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>
Sorry to jump on an old thread but this kept coming up when I was searching for the wddx.dtd. The version in the previous answer is version 0.9 which probably will not help most people because version 1.0 has been in use for at least 5 years or so.
I am faced with converting an old legacy app which is using wddx for serializing data. I thought I would post it here in case anybody else faced the same issue. A lot of posts here have helped me out greatly in the past so why not return the favour.
In the end I managed to get my hands on the file by using the way back machine (waybackmachine.org) and feeding in this URL - http://www.openwddx.org/downloads/dtd/wddx_dtd_10.txt. When I was trying openwddx.org never worked. All hail the way back machine!
From the archived copy:
<!-- ************************************************************************
WDDX DTD
Editor: Simeon Simeonov (simeons@allaire.com)
Contributing authors: Hussain Chinoy (hussain@granularity.com)
Nate Weiss (nweiss@icesinc.com)
Last modified: October 19, 1999
Copyright (c) 1998, 1999 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 application environments. It
has been designed with web applications in mind. WDDX consists of a
language and platform neutral representation of instantiated data based
on XML 1.0 (which is defined using this DTD) and a set of serializer/
deserializer modules for every environment that uses WDDX. The process
of creating an XML representation of application data is called
serialization. The process of instantiating application data from a
WDDX XML representation is called deserialization.
WDDX packets:
The WDDX DTD can be used to validate WDDX packets. Packets are
representations of instantiated data structures in application
environments. The following is an example of a WDDX packet:
<?xml version='1.0'?>
<!DOCTYPE wddxPacket SYSTEM 'wddx_0100.dtd'>
<wddxPacket version='1.0'>
<header/>
<data>
<struct>
<var name='aNull'>
<null/>
</var>
<var name='aString'>
<string>a string</string>
</var>
<var name='aNumber'>
<number>-12.456</number>
</var>
<var name='aDateTime'>
<dateTime>1998-06-12T04:32:12</dateTime>
</var>
<var name='aBoolean'>
<boolean value='true'/>
</var>
<var name='anArray'>
<array length='2'>
<number>10</number>
<string>second element</string>
</array>
</var>
<var name='aBinary'>
<binary length='8'>MIIBJASHETASV==</binary>
</var>
<var name='anObject'>
<struct>
<var name='s'>
<string>a string</string>
</var>
<var name='n'>
<number>-12.456</number>
</var>
</struct>
</var>
<var name='aRecordset'>
<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 eight properties:
- aNull which is a null value,
- aString which is the string 'a string',
- aNumber which is the number -12.456,
- aDateTime which is the date-time value June 12, 1998 4:32:12am,
- aBoolean which is the boolean value true,
- anArray which is an array of two elements (10 and 'second element'),
- aBinary which contains 8 bytes of binary data encoded in base64,
- anObject which is a structure with two properties s and n, and
- aRecordset which is a recordset of two rows with fields NAME and AGE.
Basic data types:
WDDX supports the following basic data types: null, boolean (true/false),
number, date-time, and string.
Null-
Null values in WDDX are not associated with a type such as number or
string. Languages that do not have the concept of a null value should
deserialize nulls as empty strings.
Numbers-
Numbers are internally represented with floating point numbers. Because
of differences between WDDX-enabled languages, the range of numbers has
been restricted to +/-1.7E+/-308. The precision has been restricted to
15 digits after the decimal point. These requirements are consistent
with an 8-byte floating-point representation.
Date-time values-
Date-time values are encoded according to the full form of ISO8601,
e.g., 1998-9-15T09:05:32+4:0. Note that single-digit values for months,
days, hours, minutes, or seconds do not need to be zero-prefixed.
While timezone information is optional, it must be successfully parsed
and used to convert to local date-time values. 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 dates. In
particular, years must always be represented with four digits.
Strings-
Strings can be of arbitrary length and must not contain embedded nulls.
To facilitate the inclusion of control characters in strings, the
<string> element can contain <char code='??'/> elements. The value of
the code attribute is a two-character representation of the UTF-8 hex
code for a given control character. For example, <char code='0C'/>
represents the form feed character. Control characters are characters
in the UTF-8 range 00-1F. Note that tab (09) and newline (0A) characters
can be included directly in XML text. The XML 1.0 specification Section
2.11 requires XML processors to not pass carriage return (0D) characters
to applications.
Note on end-of-line handling-
End-of-line characters have platform and programming language specific
representations. Different application environments may use either a
single newline (0A), a single carriage return (0D), or a carriage return
and newline combination (0D0A). For the purposes of successful data
encoding and translation the elements <char code='0A'/> and
<char code='0D'/> must be used to encode newline and carriage return
characters when they should be preserved in the deserialized string.
Note that Section 2.11 of the XML 1.0 specification requires XML
processors to translate all occurrences of carriage returns and the
carriage return, newline combination to a single newline character.
Therefore, for the purposes of XML, end-of-line is represented by a
single newline character.
Complex data types:
WDDX supports the following complex data types: arrays, structures,
recordsets, and binary.
Arrays-
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-
Structures are string-indexed collections of objects of arbitrary type.
In many languages they are known as associative arrays, dictionaries, or
maps. 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. In the case where two variables have the
same names or differ only by their case the final deserialized value would
be the value of the last variable.
Recordsets-
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.
In the case where two fields have the same names or differ only by their
case the final deserialized values will be the values from the last field.
Field names must satisfy the regular expression [_A-Za-z][_.0-9A-Za-z]*
where the '.' stands for a period, not 'any character'.
Binary-
The binary datatype represents strings (blobs) of binary data. The WDDX
DTD allows for multiple encodings of binary data. In this version only
MIME style base64 encoding is supported by the specification. Optionally,
the length of the encoded binary object can be provided as a hint to
WDDX deserializers. It can be used to validate the length of the binary
object after decoding. It can also be used for efficient allocation of
memory during the decoding process.
Data type comparisons:
The following table compares the basic WDDX data types with those of
languages/technologies/specifications commonly used on the Web.
WDDX XMLSchema Java ECMAScript COM Type
************** ************** *************************** ************* ****************
null N/A null null VT_NULL
boolean boolean java.lang.Boolean boolean VT_BOOL
number number java.lang.Double number VT_R8
dateTime dateTime java.lang.Date Date VT_DATE
string string java.lang.String string VT_BSTR
array N/A java.lang.Vector Array VT_ARRAY | VT_VARIANT
struct N/A java.lang.Hashtable Object IWDDXStruct
recordset N/A com.allaire.util.RecordSet WddxRecordset IWDDXRecordset
binary binary com.allaire.util.Binary WddxBinary V_ARRAY | UI1
More on data types:
Reserved properties-
For the purposes of efficiently implementing WDDX platform modules in
a variety of languages, and to facilitate the representation of
arbitrary datatypes, WDDX reserves all object/structure/recordset
property/var/field names beginning with '_wddx'. (The prefix is case-
insensitive because some of the languages WDDX works with are case-
insensitive.) WDDX serializers can treat such names in a special,
language and platform specific manner. WDDX deserializers can do the
same with the name attributes of the var and field elements.
Serialization model-
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. Object references support is another area of
future investigation.
Multiple object types-
WDDX provides no built-in mechanism for representing objects of
arbitrary type. This is done on purpose to enable interoperability
between application environments using a minimal yet functional set of
datatypes. In some special cases, however, particularly when WDDX is
used to exchange data between identical application environments, there
is a need for preserving object type in the serialization/
deserialization process. To facilitate this, the top-level elements
representing all datatypes can have an optional 'type' attribute whose
value is platform-specific. Upon serialization this attribute can be
used to provide information about the type of the serialized object. If
provided, the value of this attribute can be used by a deserializer to
instantiate a particular type of object. To facilitate the
representation of arbitrary objects the _wddx_structAttributes_type
property is reserved to contain the value of the type attribute of the
struct element. Neither sererializers nor deserializers are required to
use or populate this reserved property, but it is recommended that they
provide the capability. However, if they do provide it, it is required
(on both sides) that this behavior is optional and that it defaults to
"Off".
DTD verbosity:
This DTD is purposefully made verbose to aid the readability of WDDX
packets. If packet size becomes an issue, compressing WDDX packets
using an HTTP-safe real time compression algorithm is likely to be a
much more appropriate solution than, for example, a DTD that uses one
character element and attribute names. Some experiments conducted at
Allaire suggest that 5 - 15 fold compression rates are achievable.
-->
<!ELEMENT wddxPacket (header, data)>
<!ATTLIST wddxPacket
version CDATA #FIXED "1.0">
<!ELEMENT header (comment?)>
<!ELEMENT comment (#PCDATA)>
<!ELEMENT data (null | boolean | number | dateTime | string | array | struct | recordset | binary)>
<!ELEMENT null EMPTY>
<!ATTLIST null
type CDATA #IMPLIED>
<!ELEMENT boolean EMPTY>
<!ATTLIST boolean
value (true | false) #REQUIRED
type CDATA #IMPLIED>
<!ELEMENT string (#PCDATA | char)*>
<!ATTLIST string
type CDATA #IMPLIED>
<!ELEMENT char EMPTY>
<!ATTLIST char
code CDATA #REQUIRED>
<!ELEMENT number (#PCDATA)>
<!ATTLIST number
type CDATA #IMPLIED>
<!ELEMENT dateTime (#PCDATA)>
<!ATTLIST dateTime
type CDATA #IMPLIED>
<!ELEMENT array (null | boolean | number | dateTime | string | array | struct | recordset | binary)*>
<!ATTLIST array
length CDATA #REQUIRED
type CDATA #IMPLIED>
<!ELEMENT struct (var*)>
<!ATTLIST struct
type CDATA #IMPLIED>
<!ELEMENT var (null | boolean | number | dateTime | string | array | struct | recordset | binary)>
<!ATTLIST var
name CDATA #REQUIRED>
<!ELEMENT recordset (field*)>
<!ATTLIST recordset
rowCount CDATA #REQUIRED
fieldNames CDATA #REQUIRED
type CDATA #IMPLIED>
<!ELEMENT field (null | boolean | number | dateTime | string | binary)*>
<!ATTLIST field
name CDATA #REQUIRED>
<!ELEMENT binary (#PCDATA)>
<!ATTLIST binary
encoding CDATA #FIXED "base64"
length CDATA #IMPLIED
type CDATA #IMPLIED>
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