Access control capability

The portal provides the menu access control. It means if a user has no right to operate a

function, the application link is not visible. For example, administrative staffs cannot

execute the Medical Report Review Services in the HSS group; the service links are not

visible to them. This capability is implemented in configuration files. There is a “check”

property for every menu selection item in the files. The property can control the visibility of

menu linkage. This feature will be discussed in details in the “Content of configuration file”

Section.

4.3.3 DDNM design & implementation

NTUH portal site is designed as hierarchical, drop-down navigation menus (DDNM)

(Goodman, 2003), depicted in Figure 3. The web page only displays in groups initially.

Users first select a group; all the function linkages in the group will be rendered. This

approach makes space usage flexibly as well as enlarges the amount of function linkages

effectively.

Hierarchical DDNM is a client side display mechanism, i.e., this feature executes on user

local machine by web browser. JavaScript is a powerful scripting language running in client

browser, and it has been supported by many websites. Therefore, we choose JavaScript to

implement the client side hierarchical DDNM.

Although the hierarchical DDNM solves the spatial problem of displaying a huge amount of

function linkages (URL links), we quickly face another challenge. Because scripts are

executed at client side, the URL link is normally hard coded in the scripts. Any URL link

modification will cause the server side programs be revised. In addition, if the server side

language is a compiling language, i.e., ASP.NET with C# programming language, the

38 Web Intelligence and Intelligent Agents

program needs to be re-compiled and re-deployed. Therefore, the modification of URL link

is time consuming. In order to solve the problem, the URL link should be retrieved at server

side dynamically and not hard coded in scripts.

At beginning, the server side program retrieves URL links from the configuration files

stored in the servers. A complete DDNM web page embedded with JavaScript is

dynamically generated by the server. Afterwards, the client browser executes the scripts and

displays the hierarchical DDNM. Figure 4 illustrates the concepts of dynamic, hierarchical

DDNM. In the diagram, the users initiate requests; according to the selections, the web

server retrieves the associated configuration files and generates the corresponding web

pages, delivers them to the client side. The browsers render the web page and display the

DDNM. Therefore, if the URL links need to be changed, we only modify the contents of

configuration files. The server side program is independent from URL links. Thus, the URL

links variation cost reduces significantly.

Fig. 4. Concepts of dynamic, hierarchical DDNM