Supporting device independent and accessible authoring by a next generation Web Publishing Framework
Yehya Mohamad and Carlos A. Velasco
Fraunhofer Institute for Applied Information Technology
BIKA Competence Center
Schloss Birlinghoven, D53757 Sankt Augustin (Germany)
W3C Workshop on Device Independent Authoring Techniques, St. Leon-Rot, Germany
access information systems with a variety of devices, and with different
interaction modes that depend on personal characteristics (including disabilities)
and on the context of usage. Content and information providers must deal
with this demand and search for the ideal of authoring once, delivering for
multiple profiles. The authors will present in the paper a conceptual development
in which an Open Source Web Publishing Framework (Apache Cocoon)
that supports Separation of Concerns, can be used to simplify device independent
web authoring in conjunction with user/device profiles implemented as Web
Authoring for device independence and, multimodality and accessibility
authoring is no longer reduced to the maintainance of a set of HTML pages
to keep some Internet presence for any given institution. The growth in the
number of devices able to access the Internet, together with the growing
complexity of Internet applications (e-commerce, portals, web syndication,
etc.), demands from information providers a great effort to maintain different
versions of their Internet offer.
The old paradigm "program
once, run anywhere" can be now be translated to "author once, present anywhere".
There are different types of roles (Mazzocchi, 2000; Lewis, 2002, presents a similar approach) when creating web content:
- Content authors;
- Style authors (information presentation and layout, look & feel, etc.); and
- Logic authors (user interaction, data storage).
Figure 1. Separation of Concerns in Cocoon (after Mazzocchi, 2000).
Content Management Systems (CMS) partially support information providers
in their tasks. However, they still present several limitations (we will
not consider the issue of growth saturation in web development, see for instance
Mazzocchi, 2001, for a discussion on the topic):
rely on HTML or proprietary XML vocabularies that are not in general adaptable
to customer needs. Furthermore, most of the designed XML vocabularies do
not follow the XML Accessibility Guidelines (XAG), or the tool itself is not compliant with the Authoring Tool Accessibility Guidelines (ATAG).
- Most of them are tied to traditional web server tools that do not support content adaptation.
- They do not support cleanly the aforementioned Separation of Concerns for authoring.
Bearing in mind the previously listed limitations, these are the requirements for device independent and accessible authoring:
flexible XML vocabulary design approach that supports customer requirements
for information storage and manipulation. This affects content authoring;
the rest of the authoring roles are normally device dependent, although a
flexible publishing framework allows the reuse of components.
vocabulary must support multimodality and comply with the XML Accessibility
Guidelines. The support of multimodality must come in the authoring process
mainly through the provision of alternative versions, especially for media
content. It is also important to consider ATAG-compliant environments.
to a web publishing framework that supports Separation of Concerns. From
our point of view, device independent authoring cannot be separated from
the publishing process. The role of the publishing framework is to further
support accessible authoring practices by incorporating user and device profiles
in the publishing process.
Implementation in a web publishing framework
The proposed implementation is achieved through an Open Source Web Publishing Framework from the Apache Foundation called Cocoon.
Cocoon is a powerful Java Servlet framework that allows the server-side transformation
of XML documents via pipelined SAX events. Cocoon can also interact with
also any data source: filesystems, RDBMS, native XML databases, LDAP, WebDAV,
etc. The list of technologies supported by Cocoon include, among others:
XSL-FO, XSLT, SVG, CC/PP, XForms, and of course, Web Services.
The integration follows this scheme:
- Content authoring is performed via XForms
interacting with any data source. XForms is an XML application that can be
neatly integrated into Cocoon because it separates content from presentation,
supports device independence, multimodal interaction and reduces the need
for scripting (type/error checking). It is also easily integrated into any
markup language. XForms combined with WebDAV, LDAP or native XML databases
is a reliable and powerful commercial solution.
- Style and
logic authoring is independent of the content authoring process and must
consider different user and device profile stereotypes.
- The publishing framework handles the business logic and pipeline processing.
The implementation of user/device profiles has been discussed by the authors elsewhere (Velasco and Mohamad, 2002). It shall be stressed that whereas for device profiling, an acknowledged recommendation (CC/PP) exists, that is not the case for user profiling, with the exception of the Platform for Privacy Preferences, P3P.
This is particularly important when considering users with disabilities,
where the application of device profiling techniques fails short. The authors
are investigating a profiling «cascading model» for content delivery
similar to CSS where user profiles have higher priority than device profiles
We want to highlight that ATAG-compliance
not only implies that the produced content is accessible, but also that the
authoring environment must be accessible to authors with disabilities. With
Cocoon and XForms it is feasible to implement this essential requirement.
The discussed approach presents a set of benefits for content providers:
- It provides a clean integration of the authoring and the publishing process.
- Content authoring is device independent.
and logic are not generally device independent, but a flexible publishing
framework that allows for the reuse of components, reduces costs.
- Accessibility issues are better addressed through common sets of stylesheets and user profiles.
- Accessible web-based authoring interfaces could be designed.
- Dardailler, D.; Palmer, S.B.; McCathieNevile, C. (Eds.) (2002). XML Accessibility Guidelines, W3C Working Draft 17 June 2002. Available at: http://www.w3.org/WAI/PF/XML/
- Lewis, R. (2002). Authoring Scenarios for Device Independence, Informal public draft of possible W3C Note 29 July 2002. Available at:
- Mazzocchi, S. (2000). Adding XML Capabilities With Cocoon. Apache Conference, Orlando, Florida. Available online at: http://www.apache.org/~stefano/papers/cocoon.pdf
- Mazzocchi, S. (2001). Reducing The Effects Of Growth Saturation With The Adoption Of A Publishing Framework Based On XML Technologies (PhD Thesis). University of Pavia. Available online at: http://www.apache.org/~stefano/papers/thesis.pdf
- Treviranus, J.; McCathieNevile, C.; Jacobs, I.; Richards, J. (Eds.) (2000). Authoring Tool Accessibility Guidelines 1.0, W3C Recommendation 3 February 2000. Available at:
- Velasco, C.A.; Mohamad, Y. (2002). Web Services and User/Device Profiling for Accessible Internet Services Provision.
Proceedings of CSUN's Seventeenth Annual International Conference «Technology
and Persons with Disabilities» (Los Angeles, USA). Available at: http://www.csun.edu/cod/conf/2002/proceedings/217.htm.