Web  development tools: a survey

Abstract

In this paper we review, classify, and assess 33 existing commercial products in the light of  evaluation criteria based on the impact on the application development process, architecture, and user-perceived quality. From this review we draw requirements for new-generation development tools and show how current solutions match different application domains. The full version of the paper  is available at  URL: http://www.elet.polimi.it/~fraterna/www7/webtools.html

Keywords

Web development; CASE tools; Authoring tools; Database gateways

1. Motivations

• vendors of productivity tools for the Web have started  integrating database connectivity and object-based components into their authoring environments;
• database vendors have provided facilities for exporting database content in Web-compatible format and for translating proprietary client–server applications for Web execution;
• hypermedia authoring tools are being extended to add both Web-compatible export capabilities and database connectivity.

2. Categories of Web development tools

Visual HTML editors and site managers are authoring and site management environments originally conceived to alleviate the complexity of writing HTML code and of maintaining the pages of a Web site in the file system. In a typical configuration these products bundle a WYSIWYG HTML editor, which permits the user to design sophisticated HTML pages without programming, and a visual site manager, which displays in a graphical way the content of a Web site and supports functions like page upload,deletion, and renaming, and broken link detection and repair.
Among the  products in this category there are Adobe SiteMill and PageMill, NetObject Inc.'s Fusion, SoftQuad's HotMetal,   Microsoft's FrontPage, and many others.  These tool are an excellent solution for small- to medium-sized applications, where publishing database content is not the major issue. The lack of a schema of the application, i.e., of an abstract representation independent of content, forces the definition of the application features instance-by-instance and is a major obstacle to scale-up.

Hypermedia  tools share the same focus on authoring as visual HTML editors but have a different origin,  off-line hypermedia  publishing. These products  entered the market of Web-database development very recently and the interest in them is motivated by their non-conventional approach to application design and specific focus on navigation and presentation. The best known representatives of this class of products are: Asymetrix's Toolbook, Macromedia's Director and Authorware, Formula Graphics Multimedia 97, and several others.  Although architecturally immature, hypermedia tools permit designers to deliver very sophisticated user interfaces, which exhibit a degree of control over graphic accuracy and multimedia synchronization hardly available with other means. The inherent navigational design paradigm, coupled to very effective aids like guided tours and flexible access indices contribute to the deployment of applications which are close to the kind of communication found in high quality, hand-developed Web sites.

HTML-DBPL integrators explicitly address the merge of Web and databases and are very powerful, yet basic, products which can be used to implement applications on top of large information bases; on the other hand, their use typically requires a substantial development effort.  The exising solutions propose different ways of integrating HTML with a full-fledged database programming language (DBPL), yielding an intermediate application programming language. Examples of HTML extensions include:  Cold Fusion by Allaire Inc., Microsoft's Active Server Pages (ASP) and Internet Database Connector (IDC), StoryServer by Vignette Corporation. HTML-DBPL integrators are comparable to traditional client/server 4GLs, because they provide a high level programming interface masking lower-level architectural details;  as such, they are often used to build more sophisticated products.

Web form editors, report writers, and database publishing wizards take quite a database-centric approach to Web-database integration, by addressing the migration of client/server, form-based application to the Web; these tools aim at augmenting the implementor's productivity in such tasks as form editing, report writing, and event-based programming; they offer a higher level of support with respect to HTML-DBPL integrators, but still concentrate only on the implementation phase. Among the reviewed products, we cite: Microsoft's Visual InterDev, Visual Basic 5, and Access97, Oracle Developer 2000, Borland's IntraBuilder, Sybase's PowerBuilder, Apple's WebObjects, NetDynamics, Asymetrix SuperCede Database Edition, and Allaire's Cold Fusion Application Wizards.

Finally, Model-driven Web generators  are those products (actually one product!) that provide a complete  coverage of all the development activities, from analysis to implementation, by leveraging state-of-the-art software engineering techniques. An outstanding representative of this category is the Oracle Web Development Suite, which comprises Designer 2000, a CASE tool for generating Web applications from augmented Entity–Relationship diagrams. Other examples of this approach are a few research prototypes, namely Autoweb [FP97], HSDL [Kes95], RMC [DI*95], and OOHDM [SR95].

The situation for Web development that emerges from the review is typical of a not yet mature technology (it could be easily compared to the OO tool market in the eighties): most products have a limited focus (implementation, with some provision for design); a few tools are trying to cover the lifecycle in a broader way, but they do so by approaching development from an innatural angle, typically using models and abstractions drawn from other fields, notably databases.
 
This scenario opens many research opportunities:

• Conceptual modelling: a conceptual model for a Web application should give peer dignity to structure, behavior, navigation, and presentation. These perspectives should remain orthogonal.
• CASE support: with the proper models, a higher level of assistance could be reached. Among the missing features we mention: mapping Web conceptual models (not only structure) to database schemata, reverse-engineering database applications into Web applications (not only forms),  language- and device-independent application generation, model-level reuse.
• Restructuring: application customization and evolution requires mechanisms to restructure existing Web applications to adapt them to different users or to changes in the requirements; restructuring  is a well-known issue in the database field, but is still not fully understood for Web applications. In principle, Web conceptual models and tools could be extended to support a  notion of view suited to Web applications, which should allow restructuring  presentation and navigation, as well as structure.

  3. Conclusions

• Small scale business-to-user applications: this category includes such applications as companies' points of presence, infocenters, and so on. Visual editors and site managers seem the appropriate solution, because they  ensure the high-level of visual accuracy necessary for  targeting  the general public, coupled to productivity tools reducing the development effort. This role could be undermined in the near future by hypermedia authoring tools, which share the same focus on presentation quality and are even more effective in the design of navigational and multimedia interfaces. The current limit to the applicability of both these classes of solutions is the size of the information base; if this has to be kept in a database, then presently these tools do not provide the adequate means to integrate database and Web design, implementation and maintenance.
• Intra-business or business-to-business applications: this category comprises all legacy information systems and EDI applications and is characterized by  users already trained to the transactional and form-based interaction paradigm.  Web form editors and database publishing wizards offer a powerful opportunity for migrating existing applications to Intranets, and this technical advantage largely balances the limited exploitation of the communication capabilities of the Web.
• Large scale business-to-user applications: this is the most challenging area, comprising such applications as electronic commerce and virtual libraries. Presently, no specific product is fully addressing the analysis, design, implementation and evolution of this kind of application, which require the same communication paradigm and interface quality as small scale user-oriented applications and the same performance and scalability as intranet applications. In this scenario, neutral, implementation-oriented products like HTML-DBPL integrators seem the most adequate choice, although  development and maintenance  with these tools still requires a substantial coding effort.

References

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