Challenges of Web Part Design

This section reviews the particular challenges of designing and deploying Web Parts for business applications within a digital dashboard framework.

Ensuring Authentication

Most business and legacy applications use accounts for authentication into the system separate from those used for Windows authentication. This becomes a challenge for the Web Part builder. Users should not have to enter a user name and password to view each different Web Part on a single page. Each business application should request a user's login information only once, especially if the user needs multiple views of the data.

To give the user a single sign-on experience, you should supply a component to translate a user's authenticated user name (NTLM) and map it to the user name and password for the business application. You must use a signed digital certificate to encrypt the transfer of user name and password to keep the process secure. After the server authenticates a user against the business application, the server should not have to re-authenticate the users when they request data from the same business application by using other Web Parts.

Avanade Security Broker is a utility designed to solve the authentication problem. Avanade Security Broker stores encrypted data, mapping NTLM user names to security authorization schemes of business and legacy applications. Using PKI standards to ensure security encrypts all communications between this utility, the user name/password database, and the calling XML Generator.

Figure 19.5. Data tier

Addressing LOB Application API Latency

Given the complexity of business applications, it is no surprise that the APIs for those applications can complicate information retrieval. For example, SAP has a rich set of COM APIs that assist the Windows Developer in accessing data from its popular ERP application, R/3. However, many of the function calls that are made to the system are complex and require a strict order with data from one call feeding into the next.

With such complexity, retrieving summary data quickly is a challenge. In such cases, it is helpful to create a staging database that contains summarized data for quick retrieval. By using this technique, the data-centric component of a Web Part operates more efficiently. Ultimately, this increases the usefulness of the component to the user of the Web Part.

Figure 19.6. Data tier LOB application