What
is RSS?
It is a format to share
data, defined in Xml
1.0 version. You can deliver information
in this format et one can get this and
other information from various sources,
in this format. Information provided by
a Web site in a xml file is called a rss
feed. Some new browsers can read directly
Rss files, but a rss reader or
aggregator may be used too. |
RSS,
History
Created by Netscape
in 1999. First version is 0.90. The 0.91
version has been improved by the Userland
company in 2000. In 2000 the version 1.0
based on RDF is created and named RDF
Site Summary, it comes from O'Reilly
and is not related to other versions.
RSS 2.0 was defined by Dave Winer (previously
worker at Userland) at Harvard University
in 2002.
Another version is acronym of Rich
Site Summary.
This page is based on the 2.01 specification
from Harvard. |
Why
to use RSS?
To get information or
news provided by Web sites in a format
computers can process. To display it on
a website or to read it yourself.
And for the provider of the content, this
allows it to let known news on its site. |
RSS,
how it works?
The Rss system to publish
articles and news over the web is very
simple:
- There are just simple
web pages, one want to be displayed
by other websites.
This set of pages is the rss feed.
- A xml file that defines
the rss feed. This file holds URL, title
and summary of each page to display.
- A person which want
to read the feed on its computer. He
(she) uses a rss reader and just adds
the feed with the command of the program.
- Or another website
that want to display the feed. It has
to load the Rss file from the provider,
to extract URL of pages, and display
titles and summaries. This may be performed
by a php script.
- When someone visits
the website of the receiver, the scripts
is launched, it recalls the rss file
from the provider website and displays
a list of news from extracted data.
- By a click on a line
of the list, visitors display a page
of the provider.
|
Structure
of a RSS document
It is a Xml file and
the global container is a "rss" tag.
The file holds one chanel at least, this
is the website that provides the information.
The chanel provides some articles or data.
These are web pages from the same or other
websites. |
How
to use RSS?
1 - Using rss on a
desktop
A Rss reader (or
aggregator) must be installed first, compatible
with your operating system (Windows, Linux,
Mac OS, etc...). See in resources. There
is one that is built with XUL.
Accessing the content depends upon the
reader. This may accomplished just by
a click on a "add" button to get the URL
of the rss feed, and let it added to a
list of feeds.
2 - Using a feed on
a website
The Rss feed is displayed
as a list of titles (and optionally summaries).
A click on a title displays the new. Titles
are updated automatically. A script in
Php or other language, builds the list
each time the page is displayed by loading
the Rss file and extracting the data from
it. |
How
to publish news in a RSS feed?
There are several means
to generate Rss feeds.
- Using the rss library
of php. A php script will build the
xml file from titles and descriptions
of pages for from the content of a page.
- Use a specialized
tool to extract the data from a page.
To give acces to
the xml file, a link is displayed:
<a
type="application/rss+xml" href="feed.rss">
RSS feed for this site</a> |
Feeds in Atom
format use the "application/atom+xml" value
instead. |
Vocabulary
- Feed It is
a set of "item" tags, a set of infos
or news.
- Portal A web
page that displays a Rss feed.
- Syndicated
published through a Rss feed.
- Syndication
publishing data by Rss feeds.
|
Main
Rss tags
RSS The global
container.
Channel A distributing chanel. It
has several descriptive tags and holds one
or several items.
| <rss
version="2.0">
<channel>
</channel>
</rss> |
Required tag for the
channel
- title The
title of the channel. Should contains
the name.
- link URL of
the website that provides this channel.
- description
Summary of what the provider is.
- one item tag
at least, for the content.
| <rss
version="2.0">
<channel>
<title>Premier
Directory </title>
<link>http://www.premierdirectory.org/</link>
<description></description>
<item>
</item>
</channel>
</rss> |
Optional tags for the
channel
- language The
human language used for the text.
- docs Where
to find the doc for the format of the
file, may be Harvard.
- webmaster
E-mail.
- pubDate Publishing
date.
- etc... See in the
specification for more.
Articles of the channel
Each item tag
must hold these tags:
- title Title
of the article.
- link The URL
of the page.
- description
Summary of the article.
| <item>
<title>ROR
XML Feed</title>
<link>http://www.premierdirectory.org/rormap.html</link>
<description>...
some text... </description>
</item>
|
And some optional info
for this article
- pubDate Publishing
date.
- guid A string
of character that is unique to designate
this item.
- category The
category of the article.
- etc...
|
Building
its personal Rss feed, step by step
At start, this is
just a simple text file, created with any
text editor. But a Xml editor is more convenient.
(see at the "software" page). The name may
be, for example: "feed.xml".
The overall structure is as that:
<?xml
version="1.0"?>
<rss version="2.0">
<channel>
</channel>
</rss> |
1) Defining the source,
by the channel tag
The channel will be
the same for all your rss feeds. These
tags are required:
- title: the title of your website,
may be the one in the title tag of the
home page.
- link: the URL of your website:
example: http://www.premierdirectory.org
- description: description of your
website, about 200 characters, this may
be the text assigned to the content attribute
of the description tag, in the head section
of the home page.
| <channel>
<title>Premier
Directory </title>
<link>http://www.premierdirectory.org/</link>
<description>Free
Web Directory, etc...</description>
</channel>
|
2) Addind an image
This is optional. Design
a small image (64x64 for example) in a
common format (gif, jpg, png) and put
in into the same directory that the rss
file.
The "image" tag is a sub-element of the
channel tag
- url is the address of the image
itself.
- link is the adress of the page
displayed when one clicks on the image.
<channel>
<title>
</title>
<link>
</link>
<image>
<url>http://www.premierdirectory.org/images/logo_head.jpg</url>
<link>http://www.premierdirectory.org/feed.xml</link>
</image>
</channel> |
3) Adding a new
Now, we will add
a web page to display an information.
This is an "item" tag, a sub-element of
channel, and this components are required:
- title: the title of the article.
- link: the URL of the page.
- description: a summary of the
article, about 200 characters.
<item>
<title>News
of today</title>
<link>http://www.premierdirectory.org/feed.xml</link>
<description>All
you need to know about RSS</description>
</item> |
4) Adding more items
More items may be
added to this channel.
5)
Upload the file
Put the feed.xml
file into your website, among other
web pages.
6) Validate the file
 You
may use this online
.
7) Make it available
This is accomplished
by adding a rss button on the home pagel.
A click on the button should display the
xml file you have created.
<a
href="http://www.premierdirectory.org/feed.xml>
<img src="xml.pnj"> </a> |
8) Update the feed
To publish further articles,
you have just to add items, and remove
older ones to keep the number of articles
constant. |
Example:
the complete file
| <?xml version="1.0"?>
<rss version="2.0">
<channel>
<title>Premier Directory</title>
<link>http://www.premierdirectory.org/</link>
<description>Xml graphical interface etc...</description>
<image>
<url>http://www.premierdirectory.org/xul-icon.gif</url>
<link>http://www.premierdirectory.org/index.html</link>
</image>
<item>
<title>News
of today</title>
<link>http://www.premierdirectory.org/xml-rss.html</link>
<description>All
you need to know about RSS</description>
</item>
<item>
<title>News
of tomorrows</title>
<link>http://www.premierdirectory.org/xml-rdf.html</link>
<description>And
now, all about RDF</description>
</item>
</channel>
</rss> |
A
RSS document
You
can Download
the Example and use it as a
template.
|
Dublin
Core and RSS: example in RSS 1.0 (RDF)
On the RDF,
page, the Dublin Core format has been
evocated, about describing work of authors
and other documents.
RSS 1.0 version, based upon RDF is of
course the one used by Dublin Core for
Rss feed.
| <?xml version="1.0"?>
<rdf:RDF
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns="http://purl.org/rss/1.0/"
xmlns:dc="http://purl.org/dc/elements/1.1/">
<channel rdf:about="http://www.premierdirectory.org/authors.rss">
<title>After Gutemberg</title>
<link>http://www.premierdirectory.org/</link>
<items>
<rdf:Seq>
<rdf:li resource="http://www.premierdirectory.org/Dickens/"/>
<rdf:li resource="http://www.premierdirectory.org/Swift/"/>
</rdf:Seq>
</items>
</channel>
<item rdf:about="http://www.premierdirectory.org/Dickens/">
<title>Dickens</title>
<link>http://www.premierdirectory.org/Dickens/</link>
<description>Poor little boy in a very
bad world</description>
</item>
<item rdf:about="http://www.premierdirectory.org/Swift/">
<title>Swift</title>
<link>http://www.premierdirectory.org/Swift/</link>
<dc:date>1712</dc:date>
</item>
</rdf:RDF> |
The difference with RSS 2.0 is in the use
of RDF, that describes firstly the structure
and then describe elements of the structure. |
| |
| |
Specifications
and licence of use
-
Rss 2.0.
-
of RSS 2.0. Is named "Attribution/Share
Alike Creative Commons License".
Tools to generate and
test a RSS feed
-
Online service that uses hints in your
Html code to generate a feed.
-
Tool for scraping web sites using XPath
expressions.
-
enter the URL of your file to check
the feed.
Tools to read RSS feeds
-
A rss readed with a XUL user interface.
-
rss reader for Windows, Linux and Mac.
-
Rss extension for Firefox.
-
Dealing with multiple standards by using
XSLT. Includes JavaScript functions
to extract the info (and create the
list).
Scripts to create a
list on a web page
-
PHP script to extract info from RSS
feeds.
Examples of feeds
-
provides a rss feed to aggregate. Click
on the orange button.
|
Article
Source: http://www.premierdirectory.org/
| About
the Author |
| D.G. Sureau is one of the
most respected Internet Technology specialists
on the web. |
|
|
