Adding Value with XML Web Services

Although Web services do not actually have a graphical user interface, it is still possible to add value to their interface ”that is, their application interface. When you think about it, its very name , "service," implies added value. You could then say that developing XML Web services that provide valuable services to Web service consumers is a reasonable requirement. The following discussion should help jump start your journey toward satisfying the requirement to develop value-added XML Web services.

It just so happens that an excellent example of Web services adding value for a group of end users is right at your fingertips: VS .NET. Recall that Chapter 5 introduced several features on the VS .NET Start Page that require an Internet connection.

Those VS .NET features include the following: What's New, Online Community, Headlines, Search Online, Downloads, XML Web Services, and Web Hosting . In each case, the VS .NET application seamlessly integrates with an online source of data (a Web service) to add value to you, the VS .NET end user. Microsoft's example provides guidance as to how XML Web services and a value-added service can be brought together. Where, then, are other examples of XML Web services adding value? What else is available to help you develop the XML Web services of tomorrow?

Cross-Reference  

You too can tap into VS .NET, integrating other Web service data sources. Recall that Chapter 5 introduced you to the opportunities exposed in VS .NET's object model.

To help answer these questions, you can monitor the current events surrounding XML Web services. As it turns out, Microsoft and several other vendors recently announced the availability of software development kits, toolkits, application programming interfaces (APIs), and other software ^[8] to serve as conduits for the creation of many value-added XML Web services. I provide the following list of recent XML Web service advances to possibly inform those involved in value-added XML Web service development:

• Microsoft Web Services Enhancements 1.0 for Microsoft .NET (WSE)

• Microsoft .NET Services and .NET Messenger Service APIs

• Microsoft MapPoint .NET XML Web service

• Microsoft Universal Description, Discovery, and Integration .NET Software Development Kit (UDDI .NET SDK)

• Microsoft Office XP Web Services Toolkit 2.0

• Microsoft SQL Server 2000 Web Services Toolkit (Microsoft .NET Enterprise Servers)

• Amazon.com Web services developer's kit

• Google Web APIs developer's kit

You can download each of the development kits in the preceding list to obtain the respective SDKs and APIs. Please refer to the "To Learn More" section located at the end of this chapter for the relevant URLs. The following sections will provide you with an overview of each XML Web service offering. In each case, try to see the connection between the service's use and the possible value being added for your end users.

Note  

Keep in mind that this is just a partial list of Web services opportunities that are available. These Web service products, those from other vendors not mentioned here, as well as the ones that you will create yourself, are all acknowledged .

Microsoft Web Services Enhancements 1.0 for Microsoft .NET

You will recall that there was a brief discussion of the Web Services Interoperability Organization (WS-I) and the Global XML Web Services Architecture (GXA) in the previous chapter. WSE is the first set of APIs to be officially released to enable XML Web service development using several of the WS Specifications (WS-Security, WS-Routing, DIME, and WS-Attachments). Essentially, WSE is a .NET class library, an extension to the existing .NET Framework (class library).

Microsoft .NET Services

Originally marketed as a set of subscription-based XML Web services called .NET My Services, this product offering has been recently streamlined by Microsoft (and the term "my" has been removed). The toolset offering, .NET Services, now includes two sets of subscription-based XML Web services: .NET Passport and .NET Alerts. This means that you can seamlessly integrate the authentication features of .NET Passport or the notification features of .NET Alerts directly into your own application.

Downloads are available for the respective SDKs and related documentation. Microsoft also has an SDK available (for download) called the .NET Messenger Service APIs. This SDK exposes instant messaging types of functionalities.

Microsoft MapPoint .NET XML Web Service

This Web service offering exposes Web methods that you can integrate into your own application. You can then enhance your user interface by providing maps, driving directions, opportunities to calculate distances, and proximity searches. Obviously, if your user interface is appropriate for this type of functionality, this would be an added value to your end users. An SDK is also available for this Web service offering.

Microsoft Universal Description, Discovery, and Integration .NET Software Development Kit

Microsoft has made available the Universal Description, Discovery, and Integration .NET Software Development Kit (UDDI .NET SDK). You can use the UDDI .NET SDK to integrate the features of the UDDI (enabling others to dynamically find your Web service) directly into your application. This would be similar to the UDDI feature that is exposed in the VS .NET IDE.

Cross-Reference  

I briefly discussed the UDDI in Chapter 13 in the section "XML Web Services Continue to Evolve."

Microsoft Office XP Web Services Toolkit 2.0

Those who have a need to develop using the Visual Basic for Applications (VBA) development model will be delighted with the Office XP Web Services Toolkit 2.0. Using this free toolkit, the Microsoft Office XP family of products (Word 2002, Excel 2002, and so forth) can now consume XML Web services. You can now enable your VBA application to use either the UDDI or Web Services Description Language (WSDL) approach to locate, reference, and consume XML data from XML Web services.

Imagine that: external data from the Web, programmatically integrated right into a Word document or an Excel spreadsheet. Your end users are sure to see this as a value-added feature.

Microsoft SQL Server 2000 Web Services Toolkit

Using this toolkit, you can create XML Web services directly from SQL Server stored procedures. If this fits the development architecture that you are seeking, using this free toolkit could be an easy opportunity to add value to your application. When you download this toolkit, you will also download the software package known as SQLXML 3.0. As you may recall, I introduced SQLXML 3.0 in Chapter 12.

A reference is provided in the "To Learn More" section to help get you started with your SQL Server “based XML Web service. After you successfully create your Web service, your client application (or the client applications of others) can then reference and consume the XML delivered from your XML Web service.

Amazon.com Web Services Developer's Kit

Say that you develop an ASP.NET Web application and plan to add a hyperlink that your users can use to surf over to Amazon.com. Perhaps this is beneficial because of a product that you are selling on Amazon.com. Your concern, though, is making it as easy as possible for your users to navigate back to your site when they have completed shopping on Amazon.com.

Well, Amazon.com has listened and created a free Web services developer's kit. Using this SDK, you can reference and consume data from the Amazon.com XML Web service. Then, you display the received content on your Web site. In other words, your users will remain parked on your application while you programmatically deliver Amazon.com product information to them. Over time, I expect many other vendors to follow Amazon.com's lead. This is yet another opportunity to add value to your own application by taking advantage of XML Web services.

Google Web APIs Developer's Kit

Have you ever used the fantastic Internet search engine, Google ( http://www.google.com )? Maybe not, huh? Have you ever used the Yahoo! ( http://www.yahoo.com ) or Netscape ( http://www.netscape.com ) search engines? Yes? Well, then you actually have used Google's search engine. That is right. Google's search engine works so well that other companies have contracted with Google to use its search engine behind the scenes on their own Web sites.

Now you too can add Google's searching power to your own Web or Windows application. To do this, you need to download the Google Web APIs. Currently, the API is considered a beta version, restricts you to 1,000 daily searches, and is free of charge. The API enables you to reference and consume the Google Web service. Their Web service exposes a set of members to enable you to send in "search criteria" and receive XML representing the returned search results. The nice thing is that the Search input field and the returned search results delivered to your end users are seamlessly integrated into your own value-added Web user interface. Nice, very nice!

Consider letting the Microsoft, Amazon.com, and Google XML Web service examples inspire you to create your own XML Web services. You too can create value-added APIs as these vendors have. Optionally, you can use the XML Web services offered by these software vendors ^[9] and others. As a Web service consumer, you can seamlessly integrate the exposed advanced functionality into your application. In other words, you can use these Web service opportunities to easily add value to your user and application interfaces.

^[8] Most of the software development kits (SDKs) and toolkits are free to download and "experiment" with.

^[9] There is generally a subscription fee associated with XML Web services offered by most software vendors.