Web Services: Using Web Services
Web services involve using web applications that can be viewed in any browser. Web services go far beyond standard HTML web pages, in that they can be coded to solve problems, transport data, and connect different platforms. Web services can be released either privately or publicly. For example, if a gaming company wishes to prevent users from accessing or editing the source code in the game, they would release it privately. Other companies may choose to release the source code publicly so that its users can modify the code to meet their own preferences.
The basic web services platforms elements are SOAP, WSDL, and UDDI. SOAP stands for Simple Object Access Protocol. It is a communications protocol formatted for sending messages over the internet. SOAP is language and platform independent. WSDL is an acronym for Web Services Description Language. The language is based on XML and is used to locate and describe web services. UDDI is an acronym for Universal Description, Discovery and Integration. It is a service that businesses can register and search for web services. It is basically a directory of web service interfaces.
There are many different platforms that can be used to develop web applications. ASP.Net is an increasingly popular platform for developing because it automatically handles the SOAP, WSDL, and UDDI elements for you. ASP stands for Active Server Pages. It also allows the programmer to create web services and applications with any .Net supported language. Two common languages used in ASP.Net are C# and Visual Basic. ASP.Net allows for true object-oriented applications to work within a web page.
Web services have become increasingly popular because of the many advantages that come along with them. One of the biggest advantages is reusability. One company can develop an application to solve a certain problem or accomplish a certain task and can then make the application available for others to use in their own web sites. One popular example of this is mapping web applications. Developing a web application can take some time and be quite tedious for someone working alone but many web service providers will allow you to use their applications as long as you place their ad on your page.
Another advantage of web services is the ability to communicate and transfer data between different applications, platforms, and browsers. XML is the standard for storing and transporting data in web services. It is similar to HTML in the sense that it uses opening and closing tags and the tags must be properly nested. However, XML is much simpler to learn because there are no predefined tags. For example, if you are storing data that contains information about a set of books, you could use the tags <title> and <author>. Once the XML is created, it then transported over the HTTP protocol.
There are some cons of web services also. Because web services run on plain text protocols, a very large web application could experience problems when being used with a low speed or very busy internet connection. Another disadvantage of web services is that the HTTP protocol is not the best protocol for running long term sessions. Some extra coding would be required by the programmer to make up for the downfalls of the HTTP protocol.
Another disadvantage of web services is that because web services are actually software created to be used on the internet, they are susceptible to software bugs and viruses. It is important for the programmers to debug their applications just as they would a normal Windows from application. This includes checking for tainted variables and logistics errors as well as validating user input.