Serena Pastore
INAF - Astronomical Observatory of Padova, vicolo Osservatorio 5 – 35122 – Padova, Italy
Keywords: Content syndication, RSS specification, ATOM standards, XML technologies, web feeds, Ajax.
Abstract: Content syndication is a widely used method to distribute information as web feeds. It is an easy way of
reaching the greatest number of end users requiring immediate access. Content syndication is essentially
based on XML technology, is easily distributed and possesses a high level of interoperability across
platforms. Both the website providing information with an up-to-date structure regardless of the different
techniques to stored and manage content and the website consuming information benefit from such
technology. Several different specifications and standards have been developed to support syndication, all
used in every context. The paper describes how syndication technology has been used to distribute centrally
located INAF information to each organizational entity’s local Web site. It describes technological choices
done both for producing and distributing the feed to each local website presenting it as a specific section of
the home page. Feeds are produced according to different formats, and technologies and standards used are
specific Web technologies collectively known as Web 2.0 applications.
Content syndication technologies are essentially
XML-based technologies (Moller A., et al. 2006)
used to aggregate and distribute information, making
it more accessible to users. Syndication differs only
nominally from publishing methods using dynamic
content management systems (CMS). It includes
standardized protocols which permit the use of a
site’s data in other contexts such as other websites,
browser plug-ins or a separate desktop application. It
is an application of the kind collectively known as
Web 2.0 applications (Murugesan, S. 2007). Web
mashups are also Web 2.0 applications that combine
information and services from several sources.
Mashups could be used with syndication to create an
improved user interface to view data. Information
arrives to the user in a pull method rather then a
push one in a specific format, called feed, which
summarize different content giving only some items
and usually a link to the place where to deepen into
the topic. From the provider side, delivering feeds
usually means providing information wrapped in an
XML-based file. Such file is then shared and
processed by many client applications such as feed
readers and web aggregators as specific software
that collects the feed and visualizes it inside a
specific application or in a single Web page.
However sometimes it is useful not only to design an
application able to produce web content in a feed
format, but also to provide a method to process it
and visualize in an appealing way by using the
interactive web technologies This paper describes
how syndication and rich internet technologies have
been used to distribute information, which, even if
already aggregated in a system (Boccato, C.,
Pastore, S. 2006), needs to be interactively delivered
to specific users. The Italian National Institute for
Astrophysics (INAF, is
composed of one headquarters and 19 satellite
organizations mainly in Italy. Its Web site is
basically designed to act as a reference source of
astrophysical information for end users. However, a
study has revealed that the majority of users prefer
their local Web sites and do not take advantage
either of the INAF Web site, which they visit only
few times a week, or of other applications such as
feed aggregators. It is therefore necessary to find a
more effective information distribution method.
Syndication and Web 2.0 technologies have thus
been chosen as the way to collect, distribute and
process updated information in order to be viewed
Pastore S. (2008).
In Proceedings of the Fourth International Conference on Web Information Systems and Technologies, pages 228-231
DOI: 10.5220/0001518702280231
from each local Institute’s Web site integrated on the
home page. The main issues involved in this solution
include: 1) the heterogeneous structure of
information that derives from different logical and
physical sources; 2) the existence of different
syndication specifications and standards, each one
having strengths and benefits and 3) the need to
provide an application as a package to be easily
included in each Web site independently of the
technologies used by each webmaster. Standard web
technologies (XHTML, CSS, Javascript, XML) and
web programming languages which are the basis of
the Web 2.0 technology paradigm, have been used to
develop a solution for creating, processing and
publishing information in the form of a feed.
The initial problem is how best to distribute specific
information that, although available on the INAF
Web site, is not being accessed by potential users.
The distribution approach could be divided into
three phases: definition of publishing content,
creation of the feed and its visualization.
2.1 Content Selection
The main data to be published (Figure 1) concerns
different aspects of the Institute and astrophysics in
general and could be practically divided according to
their structure.
Figure 1: The main problem is how to aggregate and
publish information coming from different sources and
display them in a single web feed.
Content may be organized in a relational
database and managed by a LAMP (Linux,
PHP/MySQL) platform (Davis, M.E., Philips, J.A.,
2007). Alternately, content could be organized in an
object database and managed through a CMS such
as the Plone/Zope/Python environment (Boccato, C,
et al. 2006) or it could simply be stored as
XHTML/HTML pages and thus organized
hierarchically by tags. The goal is to create a unique
feed containing items coming from various sources
and distributing it to each institution to reside on
their home pages. Every publishing system
frequently makes available a library of automatic
feed creation tools, and there are many scrapers
which extract web page content and create feeds. In
these ways, each produced feed may be merged with
others to produce a solution, just as happens in many
on-line web site aggregators.
Unfortunately such an approach involves
incompatible feed formats and therefore requires
further processing. The solution is thus to collect all
the information to be published in a unique database
from which data can be extracted to create the
requested feed according to the format. This
approach implies that information is twice
published, but it provides more flexibility in
successive feed processing.
2.2 Feed Creation: Syndication
Specifications and Standards
Content syndication has various implementations
and there is no ruling body. It is therefore necessary
to choose the standard which suits the need. Each
implementation however shares a common logical
structure following an XML syntax. Content is
organized into a so-called “channel”, an entity to
which refers as information provider. Each channel
consists of single chunks of information (the so-
called item), each one possessing attributes (title,
description, a reference to the information, etc.). The
main technology used is RSS. This consists of
specifications developed by specific groups of
interested people (as in the case of RSS version 1.0, or by organizations
(as in the case of RSS version 2.0, The Atom 1.0
syndication format (
html.charters/atompub-charter.html) grew out of
RSS and is a standard developed by the Internet
Engineering Task Force (IETF). Moreover,
Microsoft has introduced Simple Sharing Extensions
(SSE) (http://msdn2. en-gb/xml/
bb510102.aspx ), which extends the Atom 1.0 and
RSS 2.0 specifications, while Javascript Object
Notation (JSON, is a data-
interchange format used by Google as another feed
format. A comparison of the different attributes used
by the main feed specifications is shown in figure 2.
Figure 2: A comparison between RSS and Atom formats.
2.2.1 RSS 1.0, RSS 2.0 and ATOM 1
Despite having the same acronym, RSS 1.0 and RSS
2.0 are distinct and incompatible formats. RSS 1.0
stands for RDF Site Summary and incorporates the
Resource Description Framework (RDF, and its tags and attributes
to better describe resources. The basic structure of
RSS 1.0 involves wrapping the entire feed in the
<rdf:RDF> element which contains the
definition, attributes and list of items of a
<channel> (the source of information) and each
item and its attributes specifically described in the
<item>. Specification flexibility allows the use of
metadata to attach information to the feed by
integrating other standards (i.e. the Dublin Core, useful for semantic
processing, even if they are a bit verbose. RSS 2.0,
which follows on from various RSS 0.9x
specifications, was developed by Netscape and later
by Useland. It stands for Really Simple Syndication
to emphasize its ease of use. According to this
format, the feed is described inside the <rss> tag
and includes a <channel> metadata with a set of
attributes (which contain more information than in
the previous format) and then the list of items and
their attributes (i.e. standard as link, title and
description metadata and other facilities like
enclosure which allows attachments to be
automatically downloaded, or a <guid> element
that identifies the item uniquely). Finally Atom, as
defined by IETF in the last 1.0 version, is a standard
which defines both a feed representation format (the
Atom Syndication Format, RFC 4287, and an
interaction protocol (the Atom Syndication Format
an internet drafts,
drafts/draft-ietf-atompub-protocol-17.txt) with
enhanced interoperability. In the Atom format, the
feed is specified by the <feed> metadata that
initially describes the channel (even if it does not
associate it with a specific tag) and its attributes and
then specifies each item inside the <entry> tag.
Most client feed applications deal with each format.
A web application which creates syntactically
corrected and validated feeds following the different
formats, may however guarantee a spread
information delivering.
2.3 Feed Processing
Despite having different standards, feed formats are
XML files and may be managed and processed by
many libraries and tools developed using different
programming languages (i.e. PHP MagPie RSS,, the Java ROME, or Python
( Many are
distributed as on-line tools (for example, a lot of
scraping tools are used as web aggregators like
despite the fact they do not provide a packaged
solution to be delivered to each website. However,
the common underlying concept is the extraction of
information, its formatting according to XML syntax
and the processing and parsing of the visualization
inside a Web page or other application. Focusing on
the visualization inside a Web page, the simplest
way is to include an external feed by pointing to a
RSS parser developed with every language which
processes it and then presents the content according
a specific style through CSS technologies (Schmitt,
C., 2006). The choice of the language and the
platform is subjective.
After the analysis of constraints and issues, the
developed solution has followed the rule of easy
implementation and requires the design of the
content database, the development of a Web
application for producing the feeds and the
establishment of simple visualization procedure as
means of a set of scripts and CSS templates. The
LAMP platform has been chosen for the first two
phases, while other more interactive technologies,
collectively known as the Ajax paradigm (Gross, C.,
2006), have been adopted for the visualization
phase. The MySQL schema design requires more
work to include all the attributes related to each feed
specification needed for successive validation. The
WEBIST 2008 - International Conference on Web Information Systems and Technologies
Web application for producing and publishing the
feed has been developed as a Web form user
interface (Figure 3) used by authors to insert content.
Thus the application, taking advantage of the
FeedCreator.class.php tool
(, creates
the three different validated feeds by extracting the
needed information from the database, according to
RSS 1.0, RSS 2.0 and Atom 1.0 formats and
publishes them in a specific directory of the Web
server. Then the feeds may be distributed as they are
to several Web site to be integrated into the
publishing systems or into another application. The
feeds may also be directly integrated into Web pages
using the <link> tag (inside the <head> section of
the HTML page) and the type specification within
the type attribute (i.e.
type=”application/atom+xml” href=”file).
At this point the methods are different for
visualizing the feeds inside each home page (Figure
3) because they make use of specific produced
stylesheets to tailor the presentation.
Figure 3: Interface of the Web application which creates
the feed and examples of feed visualization.
A first implementation uses a static solution of a
simple list by including a PHP RSS parser inside the
webpage and thus simple HTML/PHP code even if it
requires that the target web server supports PHP
language. Other interactive techniques use Javascript
languages both in a synchronous (client-side) or
asynchronous (server-side), allowing scrolling of the
content (Figure 3). Ajax technology in particular
enhances interactivity and usability, since
information is represented, processed and
dynamically displayed according the Document
Object Model (DOM, and
JavaScript with a fast message exchange with the
server. An example of this technique is the Google’s
Ajax feed API (
apis/ajaxfeeds/), a library which manipulates Atom
or RSS feeds, through an Ajax interface. Its
application requires the creation of a key usable
within all URLs of a site directory where content is
stored and the API invocation is simply included
inside a script tag in the page:
<script type="text/javascript"
<script type="text/javascript">
google.load("feeds", "1");
However, the followed solution gives more freedom
to each local webmaster which could decide to
choice the feed format, a visualization solution or
even use his publishing system.
It is necessity that information to be published and
distributed in a simple, straightforward way to reach
as many end users as possible. This need has led
INAF developers to study methods to display
specific information as feeds in the local Web sites
of its organizational entities. Approaching different
specifications nowadays used to describe
syndication, a specific web application has been
developed which creates web feeds from several
content sources following several formats and
allows their dynamic visualization by adopting
interactivity technologies like Ajax used in the web
2.0 paradigm. Moreover other web 2.0 applications
such as web mashups could be integrated with feeds
to guarantee a better user experience.
Moller A., and Schwartzbach, M., 2006. An Introduction
to XML and Web technologies, Pearson Education.
Murugesan S., 2007. Understanding Web 2.0. IT
Professional, Vol. 9, Issue 4, July-Aug. 07, pp. 34-41.
Boccato, C., Pastore, S., 2006. The Web Information
System of the INAF: different actors contributing to
disseminate information, In Current Research in
Information Sciences and Tech. Multidisciplinary
approaches to global information systems, Volume I,
Open Institute of Knowledge, pp. 507-511.
Davis, M.E., Philips J.A., 2007. Learning PHP & Mysql.
Schmitt, C., 2006. CSS Cookbook. O’Reilly
Gross, C. Ajax Patterns and Best practices. Apress. 2006.