Examining the wscall Function Block

The previous procedure, Creating a ddtek:wscall Function, provided an example Web service (Swanad Mokashi's StockQuote WSDL ( http://www.swanandmokashi.com/HomePage/WebServices/StockQuotes.asmx?WSDL), and an example of an operation ( GetStockQuotes). This Web service, given a stock ticker value, returns information about that stock, including the company name, a current stock quote, daily high and low values, and related information.

Imagine we chose the GetStockQuotes operation for our wscall. Let's take a closer look at the wscall function block created by Stylus Studio.

As seen in Figure 346, our wscall function block was created with two input ports (we could have created a wscall function block with three input ports), a flow port, and an output port. (See Parts of a Function Block for general information about function blocks in XQuery Mapper.)

Location Input Port

The location input port for the wscall function describes information about the Web service whose operation we selected for the XQuery, including its location (as a URL) and operation (as a SOAP action). This port is on all wscall function blocks.

If you double-click the port, Stylus Studio displays a configurable information box, as shown in Figure 347. (The same is true for other input ports and the output port.)

Figure 347. wscall Location Input Port

If we right-click the address node and choose Set Text Value, the Value dialog box displays the URL for the Swanand Mokashi Web service WSDL, as shown in Figure 348:

Figure 348. Value for wscall location

Similarly, we would see GetStockQuotes if we looked into the soapaction node.

Payload Input Port

The payload input port for the wscall function describes the data the Web service requires in order to execute the SOAP action. This port is on all wscall function blocks. (It is the second input port for functions added to XQuery Mapper using the wscall/2 menu choice. It is the third input port if you used the wscall/3 menu choice.)

The "payload" for the Swanand Mokashi StockQuotes Web service, for example, is a ticker value - PRGS, GOOG, or EBAY, for example.

Figure 349. wscall Payload Input Port

By default, no text value is defined for the payload port.

Header Input Port

The header port for the wscall function appears on function blocks defined using the wscall/3 menu choice. You use the header port to provide authentication and authorization information, like a username and password, for example.

Output Port

The output port for the wscall function displays the output of the Web service represented by the wscall function. In the case of the Swanand Mokashi StockQuote Web service, available output includes company name, stock quote, change, opening price, and so on, as shown in Figure 348.