Solution

The goal of our solution is to replace existing manual processes with a self-service Web site for employees to use for benefits enrollment. The specific scenario calls for integration of a packaged application, SAP R/3, used for payroll and benefits administration with information maintained by the human resources (HR) or personnel department. This scenario can be visualized as two distinct building blocks that need to be connected as depicted below:

• A Web middleware layer including the Web server, business logic, and other application services to accept and process data from users. This Web tier handles interactive requests from employees using Web browsers (presentation layer) and stores information in separate human resources database. This tier needs the ability to reliably communicate some of this information to the application connector layer.
• An application connector layer handling the interface to a SAP R/3 system using exposed interfaces. This tier uses detailed information on the SAP interfaces to make calls to the SAP system, sending and receiving appropriate information. This tier needs a reliable way to receive communication from the Web middleware layer.

This arrangement with a separate building block for integration with each end-point is typical in many application integration scenarios. These application connectors, the Web middleware for input from Web clients and the SAP connector for integration with the SAP system, provide the specific glue needed to communicate with specific endpoint.

The middleware layer used for providing the self-service Web site is the first major building block in our scenario. A conceptual solution for the Web-based building block is straightforward. Microsoft Internet Information Server (IIS) can be combined with Active Server Pages (ASPs) for the Web-based middleware layer. The business logic is handled by the ASP code located on the server.

Using a Web browser, an employee connects to the benefits Web site to access the benefits Web page. The communication between the Web client and the Web server can use the secure sockets layer (https) to encrypt communication between client and server for compliance with privacy requirements. The Web server would need a public certificate registered by a well-known certificate authority so that the client can be assured of the identity of the server. Using features of Internet Explorer, the Web server can verify the user with Windows authentication.

ASP pages on the Web server implement the business logic for processing employee data entry. The application code can be written using VBScript, JavaScript, ISAPI, or other scripting languages. The ASP code can also make calls out to other components, Windows services, and applications. When information is received by the Web middleware layer, the database used by the human resources department needs to be updated. A subset of this information also needs to be written to the SAP system. The ASP pages need to coordinate a distributed transaction that will write information to the HR SQL Server 2000 data tables and at the same time send a limited subset of this information to the SAP R/3 system. ADO can be used from the ASP pages using VBScript to access and update the employee's records in the database.

The second building block in this scenario is the application connector layer containing the ability to send information to the SAP system and integrate with the appropriate SAP exposed interfaces. Several different solutions for this building block can be developed with Microsoft technologies and products based on the SAP interface or exchange mechanism to be used. Possible solutions include the following:

• Integration using BAPI methods and RFC methods
• Integration using IDocs

The application connector for integrating with SAP is best if it is loosely coupled with the Web middleware functions. By separating SAP integration from the Web middleware, both processes are isolated from problems resulting from network outages or off-line servers.

In the following sections, two of the approaches for the application connector will be discussed.

Previous  Next