TOWARD THE CREATION OF A GREEN CONTENT

MANAGEMENT SYSTEM

Matteo Ciman, Ombretta Gaggi and Marco Sbrignadello

Department of Pure and Applied Mathematics, University of Padua, via Trieste, 63, 35121 Padua, Italy

Keywords:

Content management systems, Web engineering, Green web sites, Accessibility, Green computing.

Abstract:

In this paper we discuss the problem of efﬁcient use of Content Management Systems in the development of

a web site, and we propose a new approach towards the deﬁnition of a Green Content Management System

(GCMS). Our GCMS distinguishes between pages which contain dynamic data and pages which are not sup-

posed to change frequently. This second kind of documents is generated, off-line, every time that a change

occurs, thus avoiding waste of CPU time, and improving the response time of pages. For this reason, we call

our CMS “green”. Moreover, our GCMS supports the creation of fully accessible web sites.

1 INTRODUCTION

A Content Management System (CMS) is a collection

of procedures designed to support the publication of

contents on the web by users without speciﬁc knowl-

edge about web programming. Among others, it al-

lows to control access to information based on the

user role, to reduce data replication (both for input

and output) and to improve the ease of report writing.

The last feature is particularly important in the cre-

ation of a web site since all its pages have many parts

in common, e. g., the header, the footer and the navi-

gation bars. Only the content changes for each page.

This means that a change in the content of one of the

shared components without the help of a CMS, may

require to modify all the pages of the web site, with

waste of time and money. This is one of the main

reasons for authors and designers to adopt a CMS.

On the other hand, the introduction of a CMS in

the management of a web site can have some draw-

backs from the user’s point of view. Let us analyze the

behaviour of a web server when a user that requests a

web page through a browser.

In presence of a CMS, to return the content re-

quired by the user, the server cannot simply retrieve a

ﬁle in its ﬁle system (see Figure 1), but the CMS en-

gine must create the web page, which does not exist

a priori. Therefore the server must receives an URL

from the web browser and requests the corresponding

page to the CMS, which requests the content of the

page to a database, retrieves the content and build up

Figure 1: Web site without a Content Management System.

the page. Then, the web server can return the HTML

code to the browser (see Figure 2).

Figure 2: Web site with a Content Management System.

All these operations require time, therefore, the

use of a CMS is not completely transparent to the user

because it affectsthe response time of the web site, es-

pecially when the size of the site increases, in terms

of number of requested pages and visitors. Moreover,

the introduction of a CMS requires resources (power,

network bandwidth, etc.) to build up each requested

page, which is generated on the ﬂy when a user asks

for it. This approach is not cost-effective when the

content of the page is essentially static, i. e., it does

not change frequently in time. As an example, con-

sider a web site for e-commerce, which can be divided

in pages containing dynamic data like the presence of

products in the stock for which a CMS can help, and

408

Ciman M., Gaggi O. and Sbrignadello M..

TOWARD THE CREATION OF A GREEN CONTENT MANAGEMENT SYSTEM.

DOI: 10.5220/0003340204080412

In Proceedings of the 7th International Conference on Web Information Systems and Technologies (WEBIST-2011), pages 408-412

ISBN: 978-989-8425-51-5

 2011 SCITEPRESS (Science and Technology Publications, Lda.)

static pages (e. g., information about seller) for which

the use of a CMS wastes time and resources.

Another problem is that modern CMSs often do

not generate accessible web pages. A web page is

accessible if all users can use it, despite their operat-

ing systems, browsers, devices and user capabilities.

Web Accessibility means that people with disabilities

can perceive, understand, navigate, and interact with

the page. Accessibility does not beneﬁts only people

with disabilities because search engines can be com-

pared to users visually impaired, therefore accessible

web pages usually obtain a better rank.

In this paper we discuss the problem of the efﬁ-

cient use of CMSs, and propose a new approach to-

wards the creation of a Green Content Management

System (GCMS) which preserves CPU resources and

response time. Our GCMS allows to divide layout

from content structure in order to allow the easily

change of the shared components of a web site, but it

distinguishes between pages which contain dynamic

data and pages which are not supposed to change fre-

quently. This second kind of documents is generated,

off-line, every time that a change occurs and not ev-

ery time a user ask for it, thus avoiding waste of CPU

time, and improving the response time of pages with

static data. For this reason, we call our CMS “green”.

The GCMS in this paper is intended for expert

web designers and authors, therefore it does not pro-

vide a graphic interface to avoid writing XHTML

code, since many solutions to address accessibility is-

sues require the full control of the page code. Our

aims is to help this kind of users to divide the shared

parts of a web page from the real content of the page

to avoid data replication, but preserving efﬁciency.

This approach has been tested in the web site of

the ﬁrst and second level degree in Computer Sci-

ence of the University of Padua in Italy (University

of Padua, 2010) with positive results.

2 RELATED WORK

Green computing, or Green IT, is a set of principles,

procedures and policies to improve the efﬁciency of

computing resources, in order to reduce the envi-

ronmental impact of their utilization (Rajguru et al.,

2010). Just as we need to plant a new tree for each cut

tree, power consumption strategies must maximize

the conservation of energy until renewable forms be-

come more readily available and the same for other

resources like network bandwidth, paper and so on.

Internet may help to reduce paper waste or people

movement, thus reducing air pollution, but its power

consumption for web sites is quickly increasing in

such a way that it is not clear whether energy sav-

ing through ICT overbalance its energy consumption,

or not (Coroama and Hilty, 2009). Therefore, it is an

important issue to enhance the energy efﬁciency of

Internet and in particular of the Web.

Many works address this problem. Dick et al de-

ﬁne the Green Web Engineering as “. . . the art of de-

veloping, designing, maintaining, administrating, and

using a website in such a manner, that direct and indi-

rect energy consumption within the complete life cy-

cle of a website is reduced”. In (Dick et al., 2010) they

deﬁned a framework with 12 web engineering princi-

ples which suggest, the use of virtualization strate-

gies, correct conﬁguration of cache expiration, opti-

mization of CSS and a correct use of format and qual-

ity of multimedia elements.

One of the principles of green computing is the

so called “Re-duce, Re-use, Re-cycle” philosophy,

where the word “reduce” aims at minimizing the set

of needed resources. Abaza and Allemby (Abaza and

Allenby, 2009) explore the use of virtualization to du-

plicate hardware with software. They combined the

virtualization and green computing to develop a pro-

duction model for virtual desktop environments.

Among CMSs let us analyze a set of open source

solutions. Joomla! (joomla.org, 2010) is an open

source CMS, based on Apache server. It provides

a WYSIWYG interface to edit web content, an ad-

vanced caching strategy, and partial support of UTF-8

charset. Moreover many predeﬁned layout are avail-

able to easily create a web site from scratch. Unfortu-

nately, it neither produces a valid XHTML code, nor

supports the production of accessible web pages.

A step towards the realization of a CMS producing

XHTML-complaint web site is represented by Drupal

(drupal.org, 2010). Drupal allows to realize valid web

pages. The produced code tends to remain clean and

light but it requires to install many plugins. Drupal is

intended for expert developers, and not for all the pos-

sible users. Unfortunately, the tests done show that its

support for accessibility is still limited.

TYPO3 (Typo3 Association, 2010) is an open

source CMS that declares to provide a full support for

the development of accessible web site. TYPO3 is a

user-friendly, intuitive tool, allowing content editors

to produce and maintain web pages, using sophisti-

cated functions. TYPO3 allows a complete separation

of design and content and does not limit the design

options expected by professional website designers.

Despite this CMS represents the ﬁrst real tentative to

automatically create accessible web pages, the tests

done reported a set of bugs. As an example, TYPO3

does not allow to mark words in a language that is dif-

ferent from the one deﬁned in the page header. More-

TOWARD THE CREATION OF A GREEN CONTENT MANAGEMENT SYSTEM

409

Table 1: Comparison of most important Content Manage-

ment Systems: Joomla!, Drupal and TYPO3. FA = Free

Add On; L = Limited support.

WYSIWYG

Editor

UTF-8

Content

Reuse

Valid

XHTML

WCAG

Compliant

Joomla! Yes L Yes No No

Drupal FA Yes L Yes L

TYPO3 Yes Yes Yes Yes L FA

over, there are some errors also in the management

of list, so that the requirement of generation of valid

XHTML code sometimes is rejected.

Table 1 summarizes some features of the exam-

ined CMSs. Summing up, the tests made report that

it does not exists a CMS which is able to produce,

contemporarily, an accessible and XHTML-valid web

site. The solutions that try to address these issues in-

evitably end up creating software that is not so user-

friendly. Moreover, the produced code, even if the

CMS uses some optimization techniques, is far away

from the quality that can be obtained by a web devel-

oper, both in terms of efﬁciency (number of bits) and

in terms of clearness and maintainability of the code.

3 A Greeen CMS

As discussed in the introduction, the use of a CMS

simpliﬁes the management of a web site but it can

also affect its response time. Our solution has 3 goals:

to improve the management of a web site support-

ing easily modiﬁcation of common parts, to be com-

pletely transparent to the users, i.e., it should not in-

crease time needed to receive a page and GCMS must

support accessibility. The last two points are not cur-

rently fulﬁlled by any other CMS.

The solution adopted was to create an evolution

of CMSs, which allows to minimize the work of the

server and transmission of data, thus reducing time

needed to process any request. Our GCMS satisﬁes

this goal lowering the number of dynamic requests.

The idea is to classify content in two categories,

on the basis of who can modify it and its update fre-

quency. Data are originally stored in one, or more,

databases (relational databases or XML ﬁles) or in

XHTML pages. If a web pages is modiﬁed only by

expert authors at predeﬁned date, we ask to the au-

thors to force the off-line generation of that page after

any change. We apply the same strategy to data stored

in databases which are seldom modiﬁed and with a

predeﬁned schedule. In this way, the web server

stores and retrieves this content from static XHTML

ﬁles, thus improving its performances. If the content

of a web page is modiﬁed by non expert authors, e.g.

the administrative staff of a company, or it is not pos-

sible to determine when and with what frequency it

changes, data are collected into a database, and the

page is generated on-line each time it is visited.

Our system was implemented in Perl and it is

based on an Apache Web Server and MySql Database

Server. The architecture of the system was studied to

combine positive aspects of a pure web serverwith the

improvements brought by CMSs: from a visitor per-

spective, the system behaves exactly as a web server

which returns static web pages; from a web developer

point of view instead, GCMS manages the presence

of shared parts in a web page like a traditional CMS.

Our site generation system organizes data in fold-

ers where each folder represents a section of the

site. Global information common to all HTML

pages, such as top-level menus or the ﬁles containing

header and footer, are collected into a folder, called

globalDetails.

This information must be available

for all languages used in the web site. New pages or

entire sections can be added at any time.

Each folder related to a speciﬁc section of the site

contains a subfolder

source

with the source code of

the web pages and two XML ﬁles: the list of pages

that must be generated for that section and some par-

ticular information about them (e.g., metatags, title of

the pages, etc.), and the second level menu within that

section. This second XML ﬁle is optional, since, very

simple sections can be composed of a single page.

Each XML ﬁle, when applicable, must be present for

each language for which web pages are available.

Each XHTML ﬁle inside folders

source

is a tem-

plate which represents a page that will be created.

This ﬁle contains only the content of the page and a

set of XML tags that are placeholders for that parts

of the web page which are in common with all the

pages of the web site and will be composed during

the off-line generation, replacing these tags with the

appropriate HTML code. As an example, the tag

is replaced with the content of

the XML ﬁle containing the ﬁrst level menu.

In case of dynamic web pages, whose content is

stored in a database, the off-line generation produces

a template containing all the common parts and a

placeholder for the content. This choice helps to re-

duce response time even in this case, since the GCMS

must retrieve on-ﬂy only the content.

In order to support accessibility, each page is val-

idated, contains links to skip the menus, to access the

content and to jump at the top of the page from its

bottom. Moreover, the authors are required to mark

WEBIST 2011 - 7th International Conference on Web Information Systems and Technologies

410

text written in a language different from the one of

the page. This information helps the screen readers.

Our GCMS lacks of a WYSIWYG editor. This

choice can be better explained if we consider the tar-

get. Our system is designed for expert web develop-

ers, i. e., people that deal with the realization of com-

plex web sites, therefore people who know very well

web standards. For this kind of users, the knowledge

of some notion of XHTML, CSS and web accessibil-

ity is not an hard requirement. Many CMSs are avail-

able, but none of them allows the generation of clear,

maintainable code, which is also WCAG complaint.

Therefore, in order to obtain an accessible web page,

web developers must often modify the source code

produced by the CMS.

CMSs are usually not able to generalize. Let as

consider an author who highlights some cells of a ta-

ble with different colors. Using a WYSIWYG editor

of a CMS, she/he chooses a color from a palette and

assigns it to a (set of) cell(s). Then she/he chooses an-

other color and repeats the same operation. The CMS

usually adds the corresponding CSS code to each sin-

gle cell, while the correct approach is to deﬁne a class

with that particular color, and assign it to the cells.

This solution allows to change the color to all the cells

using it with a single operation, the CMS approach

no. Moreover, the solution adopted by CMS does not

separate content from layout and produces much more

verbose and weighty code.

Many other examples are available reporting sim-

ilar problems. For this reason, the current state of art

of the editors does not allow an expert web author to

create a page using only the WYSIWYG interface,

but she/he often need to modify the source code of a

web page, in order to improve its quality and accessi-

bility. Some CMS like TYPO3 makes a step further,

but still limited, in this direction, and we must also

consider that, as soon as the set of features offered by

a CMS increases, also the time needed to learn how it

works increases in such a way to overbalance some-

times the efﬁciency of their use.

This problem does not affect the occasional web

authors for whom traditional CMS are sufﬁcient since

they do not usually consider accessibility and efﬁ-

ciency of web pages as their goals. For this reason,

our GCMS is not intended for non expert users.

We must note here that our approach does not

preclude the use of a conventional HTML editor, it

simply leaves this choice to the author, who can use

a WYSIWYG interface or not according to her/his

goals and preferences. In this sense, the absence of

a visual editor can be positive, because it does not im-

pose to the author to change her /his preferred editor:

we simply force authors to split the page in different

ﬁles, shared parts are stored only once for the entire

site, and single pages contains only their content with-

out header, footer and menus.

We call the proposed CMS “green” because its

off-line generation system allows to reduce energy

consumption and reuse resources since web pages are

created once, and visited many times. GCMS reduces

the response time of the web server minimizing the

number of dynamic pages that must be composed be-

fore visualization thus reducing transmission of data

between the CMS and the database (see Figure 2).

4 CASE STUDY

GCMS was tested during the development of the web

site of the ﬁrst and second level degree in Computer

Science of the University of Padua in Italy (University

of Padua, 2010) in order to verify what type of result

can be reached with the adoption of our GCMS. The

web site is installed on a virtual machine on a Fujitsu

Siemens RX3000 Server with 4 CPU cores Intel(R)

Xeon(R) CPU E5504 @ 2.00GHz with 4GB of RAM,

384MB of which were assigned to the virtual machine

running the web site. The same hardware runs also

other 3 virtual machines with web servers and other

services and this choice helps to reduce power con-

sumption and needed resources (Dick et al., 2010).

The web site was published on July 22

, 2010,

and was accessed by 44,103 visitors in 6 months, for

a total of 223,866 pages views. The web site re-

sponse time was measured with Google Webmaster

Tools Labs, which reports that, on average, the load-

ing of pages takes 0.8 seconds, and that the web site

was faster than 94% of sites accessed by Google

This results can be reached thanks to the features of

our GCMS.

The site underwent two different trials. We check

its accessibility with the help of a group of ex-

pert users and the W3C validators and Total Val-

idator(Total Validator, 2010). The results were pos-

itive. All the pages of the site are complaint to

web standards and WCAG 2.0 AAA recommenda-

tion. Morevore, a totally blind user deeply inspected

the web site and reported very positive comments:

he did not run into any difﬁculties during navigation

and he judges sufﬁcient the navigation aids offered by

all the web pages. Moreover, since accessibility also

helps search engines, the web site results to be the

ﬁrst result returned into the Google responses page

for a set of keywords containing the words “Univer-

We must note here that this tool provided by Google is

an experimental function of Google Labs.

TOWARD THE CREATION OF A GREEN CONTENT MANAGEMENT SYSTEM

411

sity”, “Computer Science” and the name of the city

hosting the courses.

We also ask to visitors to answer a questionnaire,

judging their experience with the site. Fifty students

ﬁlled the questionnaire. Even in this case, the site

reports positive results. In particular,only for the 21%

of visitors, the experience was not positive since they

did not ﬁnd the wanted information. For what relates

the response time of the web site, 69% of visitors gave

a positive score

12% judged it sufﬁciently and 20%

of visitors gave a negative response (i. e., visitors that

did not ﬁnd the information they look for).

5 CONCLUSIONS

In this paper we present a Green Content Manage-

ment System which preserves CPU process time and

the use of network bandwidth. It aims at merging

some positive aspects of traditional CMS (the central-

ized management of the common parts of a web page

like header, footer, menus, etc. in order to facilitate

their change) with some concepts of the “Re-duce,

Re-use, Re-cycle” philosophy. For this reason, dif-

ferently from other CMS, it generates off-line all the

pages that are not subject to frequent changes, even if

they originally retrieve from a database, so that web

pages, whenever possible, are created once and vis-

ited many times.

To better evaluate our work, we have tested the

GCMS in situation of very few resources. We in-

stalled the GCMS over plug computer, in particular

we chose a SheevaPlug, based on a powerful 1.2GHz

Sheeva, ARM-compatible, processor(Marvell, 2010)

with 512 MB of RAM. The SheevaPlug stores data

on a 2GB Secure Digital card and declares a DC Con-

sumption of 15W while traditional computers con-

sume, on average, 250-300W.

The tests reveal that the time need for the off-line

generation of the web site increased of about 40%,

but this performance degradation affects only the au-

thors and not the visitors of a web site, therefore it is

sustainable if we consider the resources used.

Then we organized a second test to verify if the

use of a GCMS is transparent to the visitors even in

case of resources rationing. If this assumption is true,

our approach is really green. We asked to a set of 7

users to navigate through web pages, some of which

resided on the SheevaPlug and some not. Then, we

explained to users the situation and we asked them to

try to identify the sets. The result was very positive

We consider positive only the values excellent (40% of

the feedbacks) and good (29% of the feedbacks).

since all the users reports that there are no substantial

differences in the web servers response times, there-

fore it was not possible to understand where the pages

are placed on. Therefore we can argue that our GCMS

is transparent to the visitors of a web page. Moreover,

it helps to reduce the power consumption and, more

in general, the resources needed by a content manage-

ment system.

Our future work will be devoted to integrate our

GCMS into a traditional CMS in order to solve the

problem of the absence of a WYSIWYG editor for

accessible web pages. Moreover, we want to better

investigates the possibility to produce optimized and

clear code and to automatically identify what sections

of a page are in common with the whole web site.

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