the web information system for the italian national institute for

The Web Information system for the Italian National Institute forAstrophysics: the experience by using the Zope/Plone framework

Serena Pastore, Caterina BoccatoINAF-Astronomical Observatory of Padova

National Institute of AstrophysicsVicolo Osservatorio 5 – 35122 - PADOVA

ITALY

Abstract: - The complexity of modern web information systems is steadily increasing; the provision ofplatform where the flow of information may be easily managed and controlled by actors (creators, editors andreviewers of content) and where additional techniques may improve collaboration and online informationsharing is a key requirement for modern web system. The paper describes the design and implementation of aweb information system for the INAF research institution that, in the same multi-tiered framework that keepscontent, presentation and logic separate, joins both the requirement of a flexible and multiuser publicationtool for web actors and users demand on additional services. The software solution adopted is mainly basedon Plone open source software, an application of the Zope web application server that, together with othersproducts, allows to create an integrated environment where information process is highly supported. Wedescribe specifically the membership and workflow systems of the framework that help to design the systeminformation flow and control the quality of information given to site visitors. Furthermore we analyze thetechniques used to provide additional services (i.e. news and searching systems, web feeds) that, added tosatisfy user needs, may enhance every portal.

Key-Words: - Content Management System, Three-tier architecture, web application server, membership andworkflow system, content lifecycle, web feeds

1 IntroductionThe complexity of web information systems [1]used in information-intensive domains is steadilyincreasing. Initially such information join together aweb page that was very concretely mapped tospecific file, located at specific place in the filesystem: this approach do not scale managing a lot ofdocuments of different types and the need toprovide in the same system a vast range oftechniques and services (i.e. collaborative websoftware, news and searching systems, web feeds)that is nowadays required by a website to beeffectively useful and visited [2]. Theimplementation should focus on two standpoints: onone hand there are people acting on information thatneed to be published, on the other hand there arefinal users that access that system whose needsshould be evaluate. A web publishing system shouldprovide an easy method, for people acting on it, tofacilitate content creation, editing and management;nevertheless a membership system should guaranteethat actors play a distinct role and have not the samerights in manipulating content. This last requirementgives a control quality on information published.Web Content Management Systems (Web CMS) [3]have been developed to address these requirements:

with CMSs, the content is not typed into a file withHTML/XML tags, but is inserted in a database. TheCMS produces a web page on the fly that looks likeones handmade, while is a web page generator thattakes an index into the database, retrieves thecontent for that index and uses it to populate theweb page it’s going to create. CMS is a solution forweb sites that have lots of frequently changing itemsFor users instead, it is necessary that theinformation system provide a series of services thatallow both a easy retrieving of information (i.e. asearching system, a news service, web feeds) and anactive interaction (i.e. forum, weblogs [4]). In therecent definition this loose collection of conceptsand technologies including weblogs, wikis, podcasts[5], web feeds and other forms of collaborativepublishing is defined as the Web 2.0 world [6].Having all these software available on the sameframework could greatly enhance every portal. Inthis scenario, the paper describes the design andimplementation of the web information system forthe National Institute of Astrophysics (INAF) usersneeds and site objectives. The requirements for asystem that distributes carefully controlledinformation and provides additional services to finalusers both for an optimal site use and for

Proceedings of the 6th WSEAS International Conference on Applied Informatics and Communications, Elounda, Greece, August 18-20, 2006 (pp18-22)

collaborative goal, demand for a multi-tieredframework that host different application. Theadopted solution make use of the Plone software(http://plone.org) that is developed as a CMSapplication within the Zope (http://www.zope.org)application web server, while web hosting is servedby the Apache HTTP server (http://http://httpd.apache.org/) to provide more flexibilityto the entire information system. In the context theCMS application is not only used as a flexible andmultiuser publication tool for web portalmanagement; but as a tool that allows to control thequality of the information. For this aim, amembership and workflow system has beenconfigured for managing each type of content.Furthermore we analyze services, added to thissystem as Zope/Plone products, to satisfy someusers needs.

2 Collaboration and final usersdemandsThe design of the web information system requiresseveral steps that starting from its strategy andscope define its structure (figure 1).

Figure 1: Structural model of a web information systemand a three-layer architecture

We refer to a three-layer architecture model thatkeeps content, logic and presentation separate: thishelps to implements the two main goal of oursystem that are a web publishing system fordifferent actors and a set of additional tools for finalusers needs.

2.1 Web CMS: a collaborative approachContent management, as a series of technologiesand processes that supports the lifecycle of digitalcontent created by more people, has many facets. Aweb CMS, besides providing document and contentmanagement through the web by essentially using abrowser, may assist in automating various aspects ofweb publishing and managing. Addressing the mainsteps of managing content (creation, update,publish, storage and use), the collaborative processmay be based on the following roles and privileges:

author (which is responsible of content creation),editor (which controls the formal aspect of content,style and representation), reviewer which controlsthe quality of information, publisher whichpublishes information and administrator thatmanage the entire system. The main functions thatneed to be provided for our informationmanagement process are: - the creation of new or editing of existinginformation as part of a controlled generation andpublishing process: this implies user and rolesidentification in content production and delivery andthe definition of the workflow for the different typesof content; - the secure separation of access to public and non-public information; - the automatic conversion for various displayformats with specific visualization for internetpresentation (browser, HTML, XML, etc.) by usinga templating method. The aim is to provide anenvironment where web actors actively collaborateto create, edit, manage and upgrade content, butwhere each one follows its specific role andpermission to avoid inconsistency, wrong data andgeneral problems that may arise when this securityfeatures is not implemented.

2.2 Additional servicesFinal users needs to have information available indifferent way and format: besides a specificnavigation tool and visual design that may easilydirect them to the information, other tools should beavaible to facilitate their retrieval.

2.2.1 Searching system, news services and webfeedsA main tool of an information system is a searchengine software utility that can be used to indexinformation, making it easier for visitors to findwhat they are looking. Moreover since providing alot of new information is a primary requirement,managing news and similar techniques are a way tokeep updated users. A news systems is an easy wayto put small information directly available. A webfeed is a document (XML-based) based on a simpledata format (i.e. RSS – really simple syndication)[5] used to inform visitors or other sites aboutheadlines or content. Syndication is used to describethe action of making available a feed for aninformation source. Users may use feed readers tobe constantly in contact with a specific site. It maybe used to be informed about upgrades of sitesections or for site news to reduce the time andeffort to regularly check it.


3 Software Solution: the Plone/ZopeframeworkThe adopted solution that aims to give an integratedenvironment able to provide all these features, isbased on Plone software [], a CMS applicationwritten in Python language (http://www.python.org)hosted in the Zope framework. The Zopeapplication server infrastructure [] is an object-oriented platform that offers to its applications basicand advanced functionalities (i.e. user services,security): all data (content, HTML templates,scripts, the search engine and code) are store asobjects in a transactional object database (calledZope Object database or ZODB) that can use thefile system as its backing store. Numerous products(plug-in Zope components) are available to extendthe basic set of tools through the “Products” toolwhich consists of packages of Python files put into aspecific location. Plone itself comes as a set ofproducts: it is built on a Zope application calledCMF (content management framework) thatprovides many of the architectural elements that ituses: skins, tools, content definition and a webinterface.

Figure 2: web information system hierarchy andarchitecture

Specifically the framework includes a Zope corewhich provide the basic platform and severalpossible instances: an instance contains data andsoftware that make a running Zope server unique.Each web request is treated as a separate transactionby the object database. It includes its own HTTPserving capabilities (called ZServer), even if theintegration into Apache web server is to prefer. APlone site stands as a hierarchy of objects inside theZope structure: the Zope administration interface(called Zope Management Interface or ZMI)provides a way to view and manage all the objectsthat make up a site (figure 3). Besides the specificfolder which constitute the site section with thespecific content inserted by web actors, there are themain portal_* objects, called tools, which providedifferent features and behavior of the site (figure 3).The Plone web interface has a default layout, buteverything may be customizable. Content (inside

portal_types tool) that may be of different types, isseparate from logic which is provided by pythonscripts and in turn by the content presentation that isprovided by templating languages (insideportal_skins). Layout and appearance is almostdecided by Cascading Style Sheet (CSS).

Figure 3: the ZMI interface for managing and viewing thesite

The main features is that every customization interms of the three layers is done by adding specificobject in the custom sub-object of the portal_skinstool without modifying source code. The resultinglayout is shown in figure 4.

Figure 4: A screenshot for resulting site layout

Administrators are the only authorized to make suchmodifications, together with the management of siteproperties, users and products management . In factweb actors may act only on content and not on thesite behavior, layout or properties. The end result isa site on which content can be maintained entirelyover the web; web pages are generated by uniquecombination of plaintext authoring, clever plug-insand site-wide style.

4 Membership managementand workflow system

The key aspect of such information system is thesetting of the content publishing process: thisrequires the establishment of specific actors to


distinguish who can create content and who canapprove whoever content actually gets publishedand the implementation of a workflow on content.Zope implements the delegation of editing orauthoring responsibilities of a section of publicationto others: its security architecture, built around theconcept of “safe delegation of control”, allows toturn control over parts of a site to others. Objectsprovides a much richer set of possible permissionsthan a conventional file-based system: permissionsvary by object type based on capabilities of thatobjects. We can set restriction so that a user canonly create certain kinds of objects. Plone provides a membership system so that userscan have a specific identity on the site: such identitymay be used to make sure that only authorizedpeople can act on certain content. Moreover user areprovided a place to work keeping track of changeswithout touching the site. Respect the basic usermanagement that allows for users to join in the site,in this system users are added only by siteadministrators that also set their properties in termof rights and group membership. Figure 5 shows theinterface used to configure users.

Figure5. The Plone interface to manage users

With this configuration each users has a securitypolicy that is set by his/her role in terms of a set ofpermissions that are assigned either for the site ingeneral or for specific content. Basic securitymechanism lies on user credentials (a login andpassword to access the system), even if the systemrecognize a special user called anonymous andspecial roles (anonymous and authenticated) thathelp to discriminate about certain actions done inthe system. Every action is guarded by apermissions: they are named after the action theycontrol and are assigned to roles. Permissions canbe viewed and set in a special tab (called security)of any ZMI object (figure 6). Advantaging of this feature, we have defined a setof new roles to have different permissions ondifferent section of the system besides the ones ofPlone that are manager, owner, member andreviewer.

Figure 6. ZMI interface to manage global role andpermissions.

Roles can be assigned across the entire site (globalrole) or on a per-object basis (local role) to set amuch finer control over access to content orfeatures. Global roles are assigned as seen throughthe ZMI interface checking the action in specificsection of the site, while local roles are set insidethe Plone interface by using a specific tab calledsharing that allows another person to act with aspecific role in that section. Finally users can becollected in groups: a group can have roles, can owncontent and can otherwise act like a member. Agroup is created to collect the same permissions. Auser interacting with the system has his/her ownspace and interface (figure 7): after the login, he/sheworks with content by using a set of actions andtools included in toolbars or buttons.

Figure 7: Actions and tabs available to authenticated users

But a CMS allows to manage the lifecycle of acontent and a workflow system may be applied toautomate the process that applying to contentdifferent access policies based upon certain criteria,makes content to follow a progression throughvarious steps. Workflow are set by content type.Furthermore users have different rights on thecontent and their lifecycle: different workflows areavailable for folder and other contents. The centralconcept is the content objects have a state thatdetermines how permissions are set on that contentobject and the states to which the content can movethrough the transitions. For example in ourimplementation (figure 8), that differs from thedefault one in the actors involved and in the scriptdeveloped for specific tasks, we have some contentcreators works in their workspace addinginformation as different types of format (web pages,files, images, etc). Their number coincides with the


sections in which the site is structure and are relatedto the institution organization.

Figure 8: Lifecycle of a content: states andtransitions

Furthermore each section has an editor which isresponsible of position and layout of the content anda reviewer which is responsible of the contentmeaning. In this way a generic content follows adetail lifecycle that going from its creation to itspublication involves all these actors. In the creationphase content is in the visible state: with the hidetransition, it may be put in a “private” state thatmeans that anyone can see it. This state permitscreator to modify the content. When it is ready to bepublished , creator makes again the “show”transition and then chooses the “submit for review”action to send the content to be reviewed. Thisimplies a changing to a pending state that is addedwith the action to an automatic mail to its referenceeditor. The editor in turn advertise the reviewer thatmay accept the content as it is or reject it to bemodified motivating such action. At this point theeditor has two action: in the first case publishes thecontent which passes to the published state by the“publish” transition, or rejects the submission withthe reject state and the content returns to the visiblestate. As in the submit transition there is the “mail-to” action state, in the publish transition, we haveassociate a “change of owner” action in order thatthe published information may not be modified bycreator.

3 Additional services Among the default content, the news item isspecifically target for such service. Plone provideselements in the site look and feel called portlets toprovide site services: a specific one is dedicated tothe news. Furthermore Zope has a built in searchengine (ZCatalog) that allows to categorize andsearch objects. It provides a fast indexing andsearching with drop-in ZCatalog objects: it allowsindexing of any kind of object. The objects can beindexed by their content as well as properties.Moreover it supports a rich query interface toperform full text-searching and it keeps track ofmeta-data. Finally Plone can generate RSS data for

syndication of the content of the folders that usesRSS 1.0 and RDF-based format. Syndication may beapplied to news, folders and topics, and propertiesmanaged are the time and frequency of update andthe maximum number of items syndicated, : after itsenablement, the object becomes an RSS channel.We have enabled for example channels for news, fornew upgrade in order that RSS readers andaggregators let visitors to be informed about newsand changes.

4 ConclusionThe analyzed Zope/Plone framework has beenrevealed a powerful and extensible web informationsystem for the INAF requirements. The key aspect isthe easy management by web users that hides thecomplexity of the entire system: the possibility thatpeople with no particular technical knowledge canadd information to the system has been veryimportant to guarantee an often updated site thatenhance its usefulness. From a technical point ofview, the system, that up to now has a traffic ofthree thousand hits a day, was deployed in amachine with a 3 GHz processor and 2 GB of RAM:it is stable and robust and helps to keep separateweb editors from administrator roles. Besides it hasrequired a great effort in the first customization oflayout, setting of templates and the workplace forusers. Thanks to its extensibility, we are trying tointegrate other products in the system such as anewsletter and a weblog.

References:[1] Jesse James Garret, The Elements of User

Experience: User-Centered Design for the Web,New Riders Press, 2002

[2] Louis Rosenfeld, Peter Morville, InformationArchitecture for the World Wide Web:Designing Large-Scale Web Sites, O’Reilly,2002

[3] Russel Nakano, Web Content Management: ACollaborative Approach, Addison-WesleyProfessional, 2001

[4] Shelly Powers, et al. Essential Blogging:Selecting and using Weblog Tools, O’Reilly,2002

[5] Will Richardson, Blogs, Wikis, Podcast andother powerful web tools for classrooms, CorwinPress, 2006

[6] Tim O’Reilly, What is Web 2.0, O’Reilly on-line, 2005

[7] Ben Hammersley, Content Syndication withRSS, O’Reilly 2003

[8] Andy McKey, The definitive Guide to Plone,Apress, 2004


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