Integrating the Google Web Service Into ASP.NET
Google now offers the functionality of its search engine through a Web service.Over the past couple years, Google has become the most popular search engine used on the Web. Building upon its popularity, Google has developed additional search accessories and interfaces for both personal and commercial use. The most powerful interface offered by Google is exposure of its database and search capabilities through the use of a Web service.
If you're not already familiar with Google, it is located at http://www.google.com/ and is commonly known for its creative display logos. According to the Neilson NetRatings of January 2003, Google is rated as the top search engine on the Web with a 29.5% share of the market followed by Yahoo and MSN. In addition to an extremely robust standard search service, Google offers searches in various categories including images, groups, directory, and news. Figure 1 shows the Google home page.
Figure 1. The Google home page.
One extremely popular accessory that Google developed to extend its search capabilities is the Google toolbar (Figure 2). The Google toolbar is designed to work with Microsoft Internet Explorer 5 or higher and makes most of the Google functionality available directly in the browser regardless of the current page being displayed. The Google toolbar also includes a built in popup killer. For more information on the Google Toolbar and other accessories, visit http://www.google.com/options/.
Figure 2. The Google Toolbar in Microsoft Internet Explorer 6.
Traditionally, applications were processed over the Web via HTML pages that users interacted with. A Web service is an application that does not have a visual interface for users to interact with. Instead, Web services are designed for other applications to interact with programmatically. A Web service is a component that interfaces with other applications, devices, and clients through standardized, non-proprietary, and uniform protocols.
Using the beta version of the Google Web service API, the service will return only 10 results per search processed although the estimated total number of results may be greater than 10.
A Web service resides on a Web server and, as such, you can code a Web service using many different technologies including all of the .NET compliant languages as well as Java. At a high level, the protocols and technologies utilized by a Web service include the Web Services Description Language (WSDL), Web Services Discovery documents (DISCO), Universal Description, Discovery, and Integration (UDDI), and Simple Object Access Protocol (SOAP). These technologies are all created using standardized XML grammars.
- WSDL documents describe a Web service, the methods available to be called, and the protocols that the Web service supports.
- DISCO documents describe where the Web service is located.
- UDDI is the online catalog of Web services that are available for use and consumption.
- SOAP is the protocol that is used to pass data back and forth between applications and Web services.
You'll find the UDDI directory located at http://www.uddi.org/. The Wide Web Consortium (W3C) (located at http://www.w3.org) governs the remainder of the technologies listed above.
By: Shannon A Horn
Shannon Horn is the co-founder and chief software architect of WebGeniuses Corporation (http://www.webgeniuses.com). He is a Microsoft Certified Application Developer (MCAD), Microsoft Certified Solution Developer (MCSD) and a Microsoft Certified Trainer (MCT) who has been developing Microsoft Windows and Web-based solutions as well as training for over 12 years. He has been a featured speaker at many industry events including Microsoft DevDays and the ASP.NET and Web Services Solutions conference produced by asp.netPRO. He is a published author on several subjects including XML, the migration from Visual Basic 6 to VB.NET, JScript.NET, C#, and ASP.NET.
Shannon speaks and trains for companies such as AppDev (http://www.appdev.com) and LearnIt (http://www.learnit.com) and has been a featured speaker in training videos with LearnKey. He has also worked with large corporate clients including Microsoft, Universal Studios, MGM Studios, Monster.com/FlipDog.com, Intel, Polygram Pictures, Prudential, Micro Accounting Systems, Sky Harbor International Airport, and Southern Automated Systems on projects using Microsoft technologies such as Visual FoxPro, Visual Studio.NET, C#, ADO.NET, and ASP.NET. Shannon lives in Glendale, AZ, and is married with two daughters and a son.
The power of the most popular search engine on the Web is readily and easily available through the use of the Google Web service API.