Architecture

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The Toi Carz and Toy Car Parts systems use a number of programs to complete the requisition process. Tables 11-1 and 11-2 provide a description of the programs and their purpose. On the companion CD, two directories contain all the programs for Toi Carz (/Samples/Ch11/ToiCarz) and Toy Car Parts (/Samples/Ch11/ToyCarParts).

Table 11-1. Toi Carz programs used in the purchase requisition process.

Program Name	Program Type	Description
prEnter.asp	ASP	This program creates a purchase requisition, connecting to the employee and vendor databases to display a list of all items available for ordering. It is processed by prProcess.asp.
prProcess.asp	ASP	This program processes a purchase requisition. It first checks to see whether an employee has sufficient authority to order the products, and then it assures that the items ordered are not already in stock.
poGen.exe	VB	This purchase order generation program reads the database containing purchase requisitions and generates purchase orders that are sent to the vendors. One of the vendors is Toy Car Parts, which will receive the purchase order. This program uses ROPE to package and send a SOAP document to a SOAP server.
poConfirm.asp	ASP	This program receives the BizTalk document that contains the purchase order confirmation. It updates the purchase order database, indicating that the purchase order has been processed, and then it informs the employees who made the purchase requisitions that their orders have been processed.

Table 11-2. Toy Car Parts programs used in the purchase fulfillment process.

Program Name	Program Type	Description
PlaceOrder.htm	HTML page	Toy Car Parts has an existing legacy application that it uses internally for entering orders. When a purchase order is received, a clerk enters information into this form, which is an HTML document that captures order information.
PlaceOrder.xom	OmniMark	This program acts as a CGI script, which is called as the ACTION method in the FORM element in PlaceOrder.htm. PlaceOrder.xom contains business logic that makes sure the order conforms to internal checks and procedures. After conformity is confirmed, the program inserts the order into the order database. Toy Car Parts does not want to rewrite this system, which has been working fine for years. Its BizTalk server must be able to use this existing system.
BTServer.xom	OmniMark	This OmniMark program, written as a CGI script, first acts as a SOAP server, receiving a SOAP document sent from the ROPE interface in poGen.exe. Then the program turns into a BizTalk server, transforming the XML-based request into a document that pretends to be PlaceOrder.htm. BTServer.xom receives a response from PlaceOrder.xom and creates a BizTalk confirmation message, which BTServer.xom sends directly to Toi Carz as a POST message to an active server page, poConfirm.asp. This program processes the purchase order confirmation and closes the loop.

The entire requisition process is shown in Figure 11-3.

Figure 11-3. The big picture: three BizTalk servers we will build in this chapter.