RSS 0.91 Spec, revision 3

5 views

Skip to first unread message

Flowers In December

unread,

Sep 15, 2005, 11:10:54 AM9/15/05

to Flowers in December

RSS 0.91 Spec, revision 3
Netscape Communications
Primary Author: Dan Libby
July 10, 1999
Notes
Files must be 100% valid XML. We're trying to move towards a more
standard format, and to this end we have included several tags from the
popular <scriptingNews> format. We have also ensured that this version
is 100% valid XML. We did this by requiring that a DOCTYPE tag be
included, and validating each RSS document against that DTD. This means
that it is not enough for an RSS document to be "well-formed". It must
also be "valid" with respect to its DTD.

No mixed content tags. We are specifically not including any tags that
contain mixed content in RSS 0.91. This means that each tag either
contains sub-tags only, or text only, not a combination. This is both
because we want to keep the format simple, and because our current
validation system is not able to handle this type of tag. We also are
not allowing any HTML markup beyond the commonly used entities such as
" A full list of these are defined in the RSS 0.91 DTD.

New tags for syndication community. Our validator will now allow
several new tags through the system, though most of them will not
actually be used by Netcenter. However, these may work when syndicating
content to other sites. These tags are noted explicitly in the spec as
"ignored."

RDF references removed. RSS was originally conceived as a metadata
format providing a summary of a website. Two things have become clear:
the first is that providers want more of a syndication format than a
metadata format. The structure of an RDF file is very precise and must
conform to the RDF data model in order to be valid. This is not easily
human-understandable and can make it difficult to create useful RDF
files. The second is that few tools are available for RDF generation,
validation and processing. For these reasons, we have decided to go
with a standard XML approach.

Specification
Tags in alphabetical order.

<channel>
Description
information about a particular channel. Everything pertaining to an
individual channel is contained within this tag.

Netcenter Usage
Currently displayed on "My Netscape". May use in other locations in the
future.

Attributes
none

Sub-elements:
required:
description
language
link
title
optional:
copyright
docs
image
item
lastBuildDate
managingEditor
pubDate
rating
skipDays
skipHours
textinput
webMaster
Examples
See example 1
--------------------------------------------------------------------------------

<copyright>
Description
copyright string

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<day>
Description
The day of the week, spelled out in English.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<description>
Description
a plain text description of an item, channel, image, or textinput.

Netcenter Usage
displayed as appropriate depending on context.

Attributes
none

Sub-elements:
none

Examples
See example channels
--------------------------------------------------------------------------------

<docs>
Description
This tag should contain a URL that references a description of the
channel.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<!DOCTYPE>
Description
Document Type Identifier. This is an XML tag that identifies where to
find the definition for this format. It should follow the xml tag. The
full DTD is here.

Netcenter Usage
required to ensure document validity

Attributes
1 of these two formats is required:
rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN" ""
rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN"
"http://my.netscape.com/publish/formats/rss-0.91.dtd"
Sub-elements:
none

Examples
<!DOCTYPE rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN"
"http://my.netscape.com/publish/formats/rss-0.91.dtd">

<!DOCTYPE rss PUBLIC "-//Netscape Communications//DTD RSS 0.91//EN" "">

--------------------------------------------------------------------------------

<height>
Description
Specifies the height of an image. Should be an integer value.

Netcenter Usage
The value must be between 1 and 400. If ommitted, the default value is
31.

Attributes
none

Sub-elements:
none

Examples
See image
--------------------------------------------------------------------------------

<hour>
Description
Specifies an hour of the day. Should be an integer value between 0 and
23. See skipHours.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See skipHours
--------------------------------------------------------------------------------

<image>
Description
Specifies an image associated with a channel.

Netcenter Usage
Optionally (user preference) display an image along with the channel
content.

Attributes
none

Sub-elements:
required:
url
link
title
optional:
description
width
height
Examples
<image>
<url>http://my.site.com/images/1.gif</url>
<link>http://my.site.com/index.html</link>
<title>my image alt text</title>
</image>

<image>
<url>http://my.site.com/images/1.gif</url>
<link>http://my.site.com/index.html</link>
<title>my image alt text</title>
<width>120</width>
<height>200</height>
</image>

--------------------------------------------------------------------------------

<item>
Description
An item that is associated with a channel. The item should represent a
web-page, or subsection within a web page. It should have a unique URL
associated with it. Each item must contain a title and a link. A
description is optional.

Netcenter Usage
generates a list of links. The description, if supplied, may optionally
be viewed by the user as plain text beneath the link. Also, a maximum
of 15 items per channel is enforced at this time.

Attributes
none

Sub-elements:
required:
title
link
optional:
description
Examples
<item>
<title>Item #1</title>
<link>http://my.site.com/story1/index.html</link>
</item>

<item>
<title>Item #2</title>
<link>http://my.site.com/story2/index.html</link>
<description>Some stuff about this item</description>
</item>

--------------------------------------------------------------------------------

<language>
Description
Specifies the language of a channel. See supported language codes

Netcenter Usage
used to assist user with determining correct page encoding

Attributes
none

Sub-elements:
none

Examples
See example 1
--------------------------------------------------------------------------------

<lastBuildDate>
Description
The last time the channel was modified.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

Netcenter Usage
must start with either "http://" or "ftp://". All other urls are
considered invalid.

Attributes
none

Sub-elements:
none

Examples
See examples
--------------------------------------------------------------------------------

<managingEditor>
Description
The email address of the managing editor of the site, the person to
contact for editorial inquiries

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<name>
Description
The name of an object, corresponding to the "name" attribute of an HTML
<INPUT> element. Currently, this only applies to textinput.

Netcenter Usage
generates "name" attribute in html form

Attributes
none

Sub-elements:
none

Examples
See textinput
--------------------------------------------------------------------------------

<pubDate>
Description
Date when channel was published.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<rating>
Description
recommended links rating agencies:
http://www.w3.org/PICS/raters.htm (W3 maintained list of rating agency
links)
RSACi http://www.rsac.org (Click on 'register' link)
SafeSurf http://www.safesurf.com/
http://www.safesurf.com/classify/index.html (direct)
User actions:
Obtain a rating for your site from a well-known rating agency (eg
RSACi, SafeSurf)
Copy rating data into RSS file. Include only the data within the
'content=' attribute.
Expected format:
starts with "(PICS-1.1"
Netcenter Usage
ignored. May use in the future to dynamically decide page rating.

Attributes
none

Sub-elements:
none

Examples
Tag obtained from rating agency: <META http-equiv="PICS-Label"
content='(PICS-1.1 "http://www.classify.org/safesurf/" l r (SS~~000
1))'>
RSS Rating tag: <rating>(PICS-1.1
"http://www.classify.org/safesurf/" l r (SS~~000 1))</rating>

--------------------------------------------------------------------------------

<rss>
Description
Identifies begin and end of rss content.

Netcenter Usage
identifies content type

Attributes
required:
version (must be 0.91)
Sub-elements:
required:
channel
Examples
<rss version="0.91">
<channel>
...
</channel>
</rss>

--------------------------------------------------------------------------------

<skipDays>
Description
A list of <day>s of the week, in English, indicating the days of the
week when your channel will not be updated. As with activeHours, if you
know your channel will never be updated on Saturday or Sunday, for
example

Netcenter Usage
ignored

Attributes
none

Sub-elements:
required:
day
Examples
<skipDays>
<day>Saturday</day>
<day>Sunday</day>
</skipDays>

--------------------------------------------------------------------------------

<skipHours>
Description
A list of <hour>s indicating the hours in the day, GMT, when the
channel is unlikely to be updated. If this sub-item is omitted, the
channel is assumed to be updated hourly.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
required:
hour
Examples
<skipHours>
<hour>6</hour>
<hour>7</hour>
<hour>8</hour>
<hour>9</hour>
<hour>10</hour>
<hour>11</hour>
</skipHours>

--------------------------------------------------------------------------------

<textinput>
Description
An input field for the purpose of allowing users to submit queries back
to the publisher's site. This element should have a title, a link (to a
cgi or other processor), a description containing some instructions,
and a name, to be used as the name in the HTML tag <input type=text
name="[name]">

Netcenter Usage
Displays form for submission back to publisher.

Attributes
none

Sub-elements:
required:
title
link
description
name
Examples
<textinput>
<title>Search Now!</title>
<description>Enter your search <terms></description>
<name>find</name>
<link>http://my.site.com/search.cgi</link>
</textinput>

--------------------------------------------------------------------------------

<title>
Description
An identifying string for a resource. When used in an item, this is the
name of the item's link. When used in an image, this is the Alt text
for the image. When used in a channel, this is the channel's title.
When used in a textinput, this is the the textinput's title.

Netcenter Usage
displayed as appropriate depending on context.

Attributes
none

Sub-elements:
none

Examples
See examples
--------------------------------------------------------------------------------

<url>
Description
Location to load a resource from. Note that this is slightly different
from the link tag, which specifies where a user should be re-directed
to if a resource is selected.

Netcenter Usage
must start with either "http://" or "ftp://". All other urls are
considered invalid.

Attributes
none

Sub-elements:
none

Examples
See image
--------------------------------------------------------------------------------

<webMaster>
Description
The email address of the webmaster for the site, the person to contact
if there are technical problems with the channel.

Netcenter Usage
ignored

Attributes
none

Sub-elements:
none

Examples
See example 2
--------------------------------------------------------------------------------

<width>
Description
Specifies the width of an image. Should be an integer value.

Netcenter Usage
The value must be between 1 and 144. If ommitted, the default value is
88.

Attributes
none

Sub-elements:
none

Examples
See image
--------------------------------------------------------------------------------

<?xml?>
Description
Identifies this as an XML document and specifies encoding. see w3c Note
that this must be on the first line of the document.

Netcenter Usage
required for XML compliance.

Attributes
version: must be "1.0"
encoding: see list
Sub-elements:
none

Example usage:
<?xml version="1.0"?>
<?xml version="1.0" encoding="utf-8"?>
<?xml version="1.0" encoding="Shift_JIS"?>

--------------------------------------------------------------------------------

Example 1 - Simple
<?xml version="1.0"?>
<!DOCTYPE rss SYSTEM
"http://my.netscape.com/publish/formats/rss-0.91.dtd">
<rss version="0.91">
<channel>
<language>en</language>
<description>News and commentary from the cross-platform scripting
community.</description>
<link>http://www.scripting.com/</link>
<title>Scripting News</title>
<image>
<link>http://www.scripting.com/</link>
<title>Scripting News</title>
<url>http://www.scripting.com/gifs/tinyScriptingNews.gif</url>
</image>
</channel>
</rss>

Example 2 - Complete
<?xml version="1.0"?>
<!DOCTYPE rss SYSTEM
"http://my.netscape.com/publish/formats/rss-0.91.dtd">
<rss version="0.91">
<channel>
<copyright>Copyright 1997-1999 UserLand Software, Inc.</copyright>
<pubDate>Thu, 08 Jul 1999 07:00:00 GMT</pubDate>
<lastBuildDate>Thu, 08 Jul 1999 16:20:26 GMT</lastBuildDate>
<docs>http://my.userland.com/stories/storyReader$11</docs>
<description>News and commentary from the cross-platform scripting
community.</description>
<link>http://www.scripting.com/</link>
<title>Scripting News</title>
<image>
<link>http://www.scripting.com/</link>
<title>Scripting News</title>
<url>http://www.scripting.com/gifs/tinyScriptingNews.gif</url>
<height>40</height>
<width>78</width>
<description>What is this used for?</description>
</image>
<managingEditor>da...@userland.com (Dave Winer)</managingEditor>
<webMaster>da...@userland.com (Dave Winer)</webMaster>
<language>en-us</language>
<skipHours>
<hour>6</hour>
<hour>7</hour>
<hour>8</hour>
<hour>9</hour>
<hour>10</hour>
<hour>11</hour>
</skipHours>
<skipDays>
<day>Sunday</day>
</skipDays>
<rating>(PICS-1.1 "http://www.rsac.org/ratingsv01.html" l gen true
comment "RSACi North America Server" for "http://www.rsac.org" on
"1996.04.16T08:15-0500" r (n 0 s 0 v 0 l 0))</rating>
<item>
<title>stuff</title>
<link>http://bar</link>
<description>This is an article about some stuff</description>
</item>
<textinput>
<title>Search Now!</title>
<description>Enter your search <terms></description>
<name>find</name>
<link>http://my.site.com/search.cgi</link>
</textinput>
</channel>
</rss>

Example 3 - International
<?xml version="1.0" encoding="EuC-JP"?>
<!DOCTYPE rss SYSTEM
"http://my.netscape.com/publish/formats/rss-0.91.dtd">
<rss version="0.91">
<channel>
<title>è†®ŸÛë´é´Ì´×´è´ŒÁ¹´Õ</title>
<link>http://www.mozilla.org</link>
<description>è†®ŸÛë´é´Ì´×´è´ŒÁ¹´Õ</description>
<language>ja</language> 
<item>
<title>NYÒ™Á¢¸»ÌêÛì15285.25´ƒ´'Á£´Û´-´ÀÁ¹´ê´Ì´éÒ™Ûì¡êçÒÕ‰ÌêÁ£</title>
<link>http://www.mozilla.org/status/</link>
<description>This is an item description...</description>
</item>
<item>
<title>,§±Çç¡ËßÛÂÒ éøÓ¸Á£Ë²®Ÿè†Ûèå ±ÇÌ'¡Íæ-éøë‡Á£</title>
<link>http://www.mozilla.org/status/</link>
<description>This is an item description...</description>
</item>
<item>
<title>ËÜË" ïÌëÈšÁ¢È†Ë§æàÀè±ŽË‰Û,Á¢Ë,åÜ¼šÛ˜íËüËÁ£</title>
<link>http://www.mozilla.org/status/</link>
<description>This is an item description...</description>
</item>
<item>
<title>2000,øíŠå Á¢«'¦éÛë¹ Û çéÛ§ÛÂè†ÒæÓ¸Á£Ì¾«...æ-ÕÝéøƒ¸Á£</title>
<link>http://www.mozilla.org/status/</link>
<description>This is an item description...</description>
</item>
</channel>
</rss>

Supported languages
Why these?
These are the language codes that are accepted by Netcenter. Other
language codes may be available as specified by the w3c, but these are
guaranteed to work with most browsers. Netcenter will currently reject
other language codes, however other sites may accept them.

Codes
af # Afrikaans
sq # Albanian
eu # Basque
be # Belarusian
bg # Bulgarian
ca # Catalan
zh-cn # Chinese (Simplified)
zh-tw # Chinese (Traditional)
hr # Croatian
cs # Czech
da # Danish
nl # Dutch
nl-be # Dutch (Belgium)
nl-nl # Dutch (Netherlands)
en # English
en-au # English (Australia)
en-bz # English (Belize)
en-ca # English (Canada)
en-ie # English (Ireland)
en-jm # English (Jamaica)
en-nz # English (New Zealand)
en-ph # English (Phillipines)
en-za # English (South Africa)
en-tt # English (Trinidad)
en-gb # English (United Kingdom)
en-us # English (United States)
en-zw # English (Zimbabwe)
fo # Faeroese
fi # Finnish
fr # French
fr-be # French (Belgium)
fr-ca # French (Canada)
fr-fr # French (France)
fr-lu # French (Luxembourg)
fr-mc # French (Monaco)
fr-ch # French (Switzerland)
gl # Galician
gd # Gaelic
de # German
de-at # German (Austria)
de-de # German (Germany)
de-li # German (Liechtenstein)
de-lu # German (Luxembourg)
de-ch # German (Switzerland)
el # Greek
hu # Hungarian
is # Icelandic
id # Indonesian
ga # Irish
it # Italian
it-it # Italian (Italy)
it-ch # Italian (Switzerland)
ja # Japanese
ko # Korean
mk # Macedonian
no # Norwegian
pl # Polish
pt # Portuguese
pt-br # Portuguese (Brazil)
pt-pt # Portuguese (Portugal)
ro # Romanian
ro-mo # Romanian (Moldova)
ro-ro # Romanian (Romania)
ru # Russian
ru-mo # Russian (Moldova)
ru-ru # Russian (Russia)
sr # Serbian
sk # Slovak
sl # Slovenian
es # Spanish
es-ar # Spanish (Argentina)
es-bo # Spanish (Bolivia)
es-cl # Spanish (Chile)
es-co # Spanish (Colombia)
es-cr # Spanish (Costa Rica)
es-do # Spanish (Dominican Republic)
es-ec # Spanish (Ecuador)
es-sv # Spanish (El Salvador)
es-gt # Spanish (Guatemala)
es-hn # Spanish (Honduras)
es-mx # Spanish (Mexico)
es-ni # Spanish (Nicaragua)
es-pa # Spanish (Panama)
es-py # Spanish (Paraguay)
es-pe # Spanish (Peru)
es-pr # Spanish (Puerto Rico)
es-es # Spanish (Spain)
es-uy # Spanish (Uruguay)
es-ve # Spanish (Venezuela)
sv # Swedish
sv-fi # Swedish (Finland)
sv-se # Swedish (Sweden)
tr # Turkish
uk # Ukranian

Supported encodings
Note: these are not case sensitive
IANA standard name MIME prefered name (if different from IANA)
ANSI_X3.4-1968 US-ASCII
ISO_8859-1:1987 ISO-8859-1
ISO_8859-2:1987 ISO-8859-2
ISO_8859-5:1988 ISO-8859-5
ISO_8859-7:1987 ISO-8859-7
ISO_8859-9:1989 ISO-8859-9
Shift_JIS
Extended_UNIX_Code_Packed_Format_for_Japanese EUC-JP
GB2312
EUC-KR
Big5
windows-1250
windows-1251
UTF-8
x-mac-roman

DTD
Location
Public ID: -//Netscape Communications//DTD RSS 0.91//EN
System ID: http://my.netscape.com/publish/formats/rss-0.91.dtd
The DTD itself

<!ELEMENT rss (channel)>
<!ATTLIST rss
version CDATA #REQUIRED> 
<!ELEMENT channel (title | description | link | language | item+ |
rating? | image? | textinput? | copyright? | pubDate? | lastBuildDate?
| docs? | managingEditor? | webMaster? | skipHours? | skipDays?)*>
<!ELEMENT title (#PCDATA)>
<!ELEMENT description (#PCDATA)>
<!ELEMENT link (#PCDATA)>
<!ELEMENT image (title | url | link | width? | height? |
description?)*>
<!ELEMENT url (#PCDATA)>
<!ELEMENT item (title | link | description)*>
<!ELEMENT textinput (title | description | name | link)*>
<!ELEMENT name (#PCDATA)>
<!ELEMENT rating (#PCDATA)>
<!ELEMENT language (#PCDATA)>
<!ELEMENT width (#PCDATA)>
<!ELEMENT height (#PCDATA)>
<!ELEMENT copyright (#PCDATA)>
<!ELEMENT pubDate (#PCDATA)>
<!ELEMENT lastBuildDate (#PCDATA)>
<!ELEMENT docs (#PCDATA)>
<!ELEMENT managingEditor (#PCDATA)>
<!ELEMENT webMaster (#PCDATA)>
<!ELEMENT hour (#PCDATA)>
<!ELEMENT day (#PCDATA)>
<!ELEMENT skipHours (hour+)>
<!ELEMENT skipDays (day+)>



<!ENTITY nbsp " "> 
<!ENTITY iexcl "¡"> 
<!ENTITY cent "¢"> 
<!ENTITY pound "£"> 
<!ENTITY curren "¤"> 
<!ENTITY yen "¥"> 
<!ENTITY brvbar "¦"> 
<!ENTITY sect "§"> 
<!ENTITY uml "¨"> 
<!ENTITY copy "©"> 
<!ENTITY ordf "ª"> 
<!ENTITY laquo "«"> 
<!ENTITY not "¬"> 
<!ENTITY shy ""> 
<!ENTITY reg "®"> 
<!ENTITY macr "¯"> 
<!ENTITY deg "°"> 
<!ENTITY plusmn "±"> 
<!ENTITY sup2 "²"> 
<!ENTITY sup3 "³"> 
<!ENTITY acute "´"> 
<!ENTITY micro "µ"> 
<!ENTITY para "¶"> 
<!ENTITY middot "·"> 
<!ENTITY cedil "¸"> 
<!ENTITY sup1 "¹"> 
<!ENTITY ordm "º"> 
<!ENTITY raquo "»"> 
<!ENTITY frac14 "¼"> 
<!ENTITY frac12 "½"> 
<!ENTITY frac34 "¾"> 
<!ENTITY iquest "¿"> 
<!ENTITY Agrave "À"> 
<!ENTITY Aacute "Á"> 
<!ENTITY Acirc "Â"> 
<!ENTITY Atilde "Ã"> 
<!ENTITY Auml "Ä"> 
<!ENTITY Aring "Å"> 
<!ENTITY AElig "Æ"> 
<!ENTITY Ccedil "Ç"> 
<!ENTITY Egrave "È"> 
<!ENTITY Eacute "É"> 
<!ENTITY Ecirc "Ê"> 
<!ENTITY Euml "Ë"> 
<!ENTITY Igrave "Ì"> 
<!ENTITY Iacute "Í"> 
<!ENTITY Icirc "Î"> 
<!ENTITY Iuml "Ï"> 
<!ENTITY ETH "Ð"> 
<!ENTITY Ntilde "Ñ"> 
<!ENTITY Ograve "Ò"> 
<!ENTITY Oacute "Ó"> 
<!ENTITY Ocirc "Ô"> 
<!ENTITY Otilde "Õ"> 
<!ENTITY Ouml "Ö"> 
<!ENTITY times "×"> 
<!ENTITY Oslash "Ø"> 
<!ENTITY Ugrave "Ù"> 
<!ENTITY Uacute "Ú"> 
<!ENTITY Ucirc "Û"> 
<!ENTITY Uuml "Ü"> 
<!ENTITY Yacute "Ý"> 
<!ENTITY THORN "Þ"> 
<!ENTITY szlig "ß"> 
<!ENTITY agrave "à"> 
<!ENTITY aacute "á"> 
<!ENTITY acirc "â"> 
<!ENTITY atilde "ã"> 
<!ENTITY auml "ä"> 
<!ENTITY aring "å"> 
<!ENTITY aelig "æ"> 
<!ENTITY ccedil "ç"> 
<!ENTITY egrave "è"> 
<!ENTITY eacute "é"> 
<!ENTITY ecirc "ê"> 
<!ENTITY euml "ë"> 
<!ENTITY igrave "ì"> 
<!ENTITY iacute "í"> 
<!ENTITY icirc "î"> 
<!ENTITY iuml "ï"> 
<!ENTITY eth "ð"> 
<!ENTITY ntilde "ñ"> 
<!ENTITY ograve "ò"> 
<!ENTITY oacute "ó"> 
<!ENTITY ocirc "ô"> 
<!ENTITY otilde "õ"> 
<!ENTITY ouml "ö"> 
<!ENTITY divide "÷"> 
<!ENTITY oslash "ø"> 
<!ENTITY ugrave "ù"> 
<!ENTITY uacute "ú"> 
<!ENTITY ucirc "û"> 
<!ENTITY uuml "ü"> 
<!ENTITY yacute "ý"> 
<!ENTITY thorn "þ"> 
<!ENTITY yuml "ÿ">

Proprietary Schema (Validation Rules)
Explanation
XML currently provides a limited amount of validation via DTD's.
However, DTD's do not provide any support for common validation
requirements, such as data types, length of strings, number of
sub-elements, or pattern matching.

A standard has been proposed to solve this problem. XML Schemas looks
like it will do all of this and more. Unfortunately, there are few, if
any parsers available today that understand them.

As a proprietary, interim only solution, we have developed a very
simplistic schema format that performs a second level of validation
after the parser has read the XML document into memory. We are listing
the schema used to validate RSS 0.91 files, so that there will be no
ambiguity when validation fails.

Here are the basic rules:

Each XML element must be defined by an <Element> tag.
Each Element definition must have a unique id attribute and a type
attribute.
Each Attribute of an Element must be referenced by an <Attrib> tag
Each sub-Element of an Element of type container must be referenced by
<Contains> tag.
Each Element may have a type associated with it. Currently supported
types are:
container: this Element contains other Elements only.
string: this Element contains text data.
int: this Element contains an integer.
Each string or int Element may contain a matching rule, specified via
<Matches>
Each string or int Element may specify a minimum and maximum number of
characters (or value if type int) via min, max, and exactly.
Each XML attribute must be defined by an <Attribute> tag.
Each Attribute definition must have a unique id attribute and a type
attribute.
Each Attribute may be of type string or int.
Each Attribute may contain a matching rule, specified via <Matches>
Each Attribute may specify a minimum and maximum number of characters
(or value if type int) via min, max, and exactly.
Each <Contains> and <Attrib> definition must contain a 'ref' attribute
that refers to a uniquely defined Element or Attribute with the value
of 'ref' as its id.
Each <Contains> and <Attrib> definition may contain min, max, or
exactly attributes to define the number of Elements or Attributes
required.
Each <Matches> must contain a valid regular expression, against which
the corresponding Element or Attribute will be evaluated.
Schema
Here is the schema for RSS 0.91.

<?xml version="1.0"?>
<!DOCTYPE Schema PUBLIC "-//Netscape Communications//DTD Schema
1.0//EN" "http://my.netscape.com/publish/formats/schema-1.0.dtd">
<Schema version="DKHXVF 1.0" root="rss" name="RSS 0.91">
<Element id="rss" type="container">
<Contains ref="channel" exactly="1"/>
<Attrib ref="version" exactly="1"/>
</Element>
<Attribute id="version" type="string">
<Matches>0.91</Matches>
</Attribute>
<Element id="channel" type="container">
<Contains ref="description" exactly="1"/>
<Contains ref="image" min="0" max="1"/>
<Contains ref="item" min="0" max="15"/>
<Contains ref="language" exactly="1"/>
<Contains ref="link" exactly="1"/>
<Contains ref="rating" min="0" max="1"/>
<Contains ref="textinput" min="0" max="1"/>
<Contains ref="title" exactly="1"/>
<Contains ref="copyright" min="0" max="1"/>
<Contains ref="pubDate" min="0" max="1"/>
<Contains ref="lastBuildDate" min="0" max="1"/>
<Contains ref="docs" min="0" max="1"/>
<Contains ref="managingEditor" min="0" max="1"/>
<Contains ref="webMaster" min="0" max="1"/>
<Contains ref="skipHours" min="0" max="1"/>
<Contains ref="skipDays" min="0" max="1"/>
</Element>
<Element id="copyright" type="string" max="100"/>
<Element id="pubDate" type="string" max="100"/>
<Element id="lastBuildDate" type="string" max="100"/>
<Element id="docs" type="string" max="500"/>
<Element id="managingEditor" type="string" max="100"/>
<Element id="webMaster" type="string" max="100"/>
<Element id="skipHours" type="container">
<Contains ref="hour" min="0" max="24"/>
</Element>
<Element id="skipDays" type="container">
<Contains ref="day" min="0" max="7"/>
</Element>
<Element id="hour" type="int" min="0" max="24"/>
<Element id="day" type="string" min="0" max="10"/>
<Element id="item" type="container">
<Contains ref="title" exactly="1"/>
<Contains ref="link" exactly="1"/>
<Contains ref="description" min="0" max="1"/>
</Element>
<Element id="image" type="container">
<Contains ref="title" exactly="1"/>
<Contains ref="link" min="0" max="1" />
<Contains ref="url" exactly="1"/>
<Contains ref="width" min="0" max="1"/>
<Contains ref="height" min="0" max="1"/>
<Contains ref="description" min="0" max="1"/>
</Element>
<Element id="textinput" type="container">
<Contains ref="title" exactly="1"/>
<Contains ref="link" exactly="1"/>
<Contains ref="description" exactly="1"/>
<Contains ref="name" exactly="1"/>
</Element>
<Element id="title" type="string" min="1" max="100"/>
<Element id="description" type="string" min="1" max="500"/>
<Element id="url" type="string" min="1" max="500">
<Matches>^(http://|^ftp://)</Matches>
</Element>
<Element id="link" type="string" min="1" max="500">
<Matches>^(http://|^ftp://)</Matches>
</Element>
<Element id="language" type="string" min="2" max="5">
<Matches>
^(af | # Afrikaans
sq | # Albanian
eu | # Basque
be | # Belarusian
bg | # Bulgarian
ca | # Catalan
zh-cn | # Chinese (Simplified)
zh-tw | # Chinese (Traditional)
hr | # Croatian
cs | # Czech
da | # Danish
nl | # Dutch
nl-be | # Dutch (Belgium)
nl-nl | # Dutch (Netherlands)
en | # English
en-au | # English (Australia)
en-bz | # English (Belize)
en-ca | # English (Canada)
en-ie | # English (Ireland)
en-jm | # English (Jamaica)
en-nz | # English (New Zealand)
en-ph | # English (Phillipines)
en-za | # English (South Africa)
en-tt | # English (Trinidad)
en-gb | # English (United Kingdom)
en-us | # English (United States)
en-zw | # English (Zimbabwe)
fo | # Faeroese
fi | # Finnish
fr | # French
fr-be | # French (Belgium)
fr-ca | # French (Canada)
fr-fr | # French (France)
fr-lu | # French (Luxembourg)
fr-mc | # French (Monaco)
fr-ch | # French (Switzerland)
gl | # Galician
gd | # Gaelic
de | # German
de-at | # German (Austria)
de-de | # German (Germany)
de-li | # German (Liechtenstein)
de-lu | # German (Luxembourg)
de-ch | # German (Switzerland)
el | # Greek
hu | # Hungarian
is | # Icelandic
id | # Indonesian
ga | # Irish
it | # Italian
it-it | # Italian (Italy)
it-ch | # Italian (Switzerland)
ja | # Japanese
ko | # Korean
mk | # Macedonian
no | # Norwegian
pl | # Polish
pt | # Portuguese
pt-br | # Portuguese (Brazil)
pt-pt | # Portuguese (Portugal)
ro | # Romanian
ro-mo | # Romanian (Moldova)
ro-ro | # Romanian (Romania)
ru | # Russian
ru-mo | # Russian (Moldova)
ru-ru | # Russian (Russia)
sr | # Serbian
sk | # Slovak
sl | # Slovenian
es | # Spanish
es-ar | # Spanish (Argentina)
es-bo | # Spanish (Bolivia)
es-cl | # Spanish (Chile)
es-co | # Spanish (Colombia)
es-cr | # Spanish (Costa Rica)
es-do | # Spanish (Dominican Republic)
es-ec | # Spanish (Ecuador)
es-sv | # Spanish (El Salvador)
es-gt | # Spanish (Guatemala)
es-hn | # Spanish (Honduras)
es-mx | # Spanish (Mexico)
es-ni | # Spanish (Nicaragua)
es-pa | # Spanish (Panama)
es-py | # Spanish (Paraguay)
es-pe | # Spanish (Peru)
es-pr | # Spanish (Puerto Rico)
es-es | # Spanish (Spain)
es-uy | # Spanish (Uruguay)
es-ve | # Spanish (Venezuela)
sv | # Swedish
sv-fi | # Swedish (Finland)
sv-se | # Swedish (Sweden)
tr | # Turkish
uk # Ukranian
)$
</Matches>
</Element>
<Element id="rating" type="string" min="20" max="500">
<Matches>^\(PICS-1.1</Matches>
</Element>
<Element id="width" type="int" min="1" max="144"/>
<Element id="height" type="int" min="1" max="400"/>
<Element id="name" type="string" min="1" max="20"/>
</Schema>

Schema DTD
Here is the DTD for the schema format.

<!--
A DTD for Dan's Kinda Hacky XML Validation Format (DKHXVF)
Basically, this format allows us to enforce some additional rules
that DTD's do not. Specifically, we can:
- specify min and max for number of each child element
- specify a regular expression that text elements and attributes must
match
- specify type of text elements and attributes (int, float, string,
timestamp)
- specify min and max for any type. (length compare for strings,
numeric otherwise)
The hope is that this will allow the rapid creation of new formats, and
modification
of existing formats (adding/removing tags, attributes etc), without
requiring
code changes in the validation software.
This is not in any way intended to be an alternative to XML schemas.
In the
absence of code supporting XML schemas, I created this, but it is meant
as
a transitional work only.
For more on XML schemas, see:
http://www.w3.org/1999/05/06-xmlschema-1/ and
http://www.w3.org/1999/05/06-xmlschema-2/
This is also not meant to replace DTDs. There are many things that you
can do
with DTDs that you cannot do with this format. For example, you cannot
declare
entities with this format. You must do that in the DTD. If you want
your
parser to interpret them correctly, you must use a validating parser.
It is possible to use these schemas without DTD validation, however you
may run
into problems with entity expansion and other things.
Dan Libby - da...@netscape.com
$Log: rss-spec-0.91.html,v $
Revision 1.1.2.2 2001/11/09 08:10:07 dprusak
Merged for 6.2

Revision 1.1.2.1 2001/10/17 22:25:28 dprusak
NewMyNetscape
Revision 1.1.2.1 2001/05/03 00:44:50 hoangtv
adding DTD definition
Revision 1.4 1999/09/10 03:01:44 jquach
removed comments
Revision 1.3 1999/09/10 03:01:24 jquach
pulled ref to internal file
Revision 1.2 1999/08/07 04:53:02 danda
'cleaning' (removing useful info) for public release
Revision 1.3 1999/08/07 04:52:12 danda
'cleaning' (removing useful info) for public release
Revision 1.2 1999/07/22 07:09:41 danda
fixing examples, RDF Site Summary -> Rich Site Summary
Revision 1.1 1999/06/09 07:01:29 danda
adding schema and dtd for rss 0.9 and 1.0
-->

<!ELEMENT Schema (Element | Attribute)*>
<!ATTLIST Schema
version CDATA #FIXED "DKHXVF 1.0"
root CDATA #REQUIRED
name CDATA #REQUIRED>

<!ELEMENT Element ((Contains | Attrib)* | Matches?)>
<!ATTLIST Element
id CDATA #REQUIRED
type (int | float | container | string | timestamp) #REQUIRED
min CDATA #IMPLIED
max CDATA #IMPLIED
exactly CDATA #IMPLIED>

<!ELEMENT Contains EMPTY>
<!ATTLIST Contains
ref CDATA #REQUIRED
min CDATA #IMPLIED
max CDATA #IMPLIED
exactly CDATA #IMPLIED>

<!ELEMENT Attrib EMPTY>
<!ATTLIST Attrib
ref CDATA #REQUIRED
min CDATA #IMPLIED
max CDATA #IMPLIED
exactly CDATA #IMPLIED>

<!ELEMENT Attribute (Matches?)>
<!ATTLIST Attribute
id CDATA #REQUIRED
type (int | float | string | timestamp) #REQUIRED
min CDATA #IMPLIED
max CDATA #IMPLIED
exactly CDATA #IMPLIED>

<!ELEMENT Matches (#PCDATA)>

Reply all

Reply to author

Forward

0 new messages