The .Net Odyseey
By Vijay Mukhi, Vikram Ramchand and Sonal Mukhi
This book offers you the most opportune moment to set sail on a voyage of discovery, during which, you shall visit the topics of XML Web Services and the Simple Object Access Protocol, SOAP. It proceeds according to a coherent roadmap, to ensure that each topic builds up incrementally on its predecessor.
You should assimilate what has been presented in a specific chapter, before venturing on to the next one. We have essayed at quelling the general fear of learning a new language by clearly explaining all the complex topics. We have re-visited some topics to ensure that you have a lucid understanding of the intricate concepts, even though we are aware that reiterations could result in ennui. We have included a vast array of examples, which strip the sheen of complexity in which most concepts are generally ensconced.
XML Web services are the fundamental building blocks in the transition towards Distributed Computing on the Internet. XML Web Services are fast becoming the standard for application interaction. An XML Web Service is a standard way of exposing services to a large number of users.
An XML Web service is a function that is exposed, so that other applications on the Web can exploit its inherent capabilities. By using XML Web services, application developers can converge their creative energies on the unique value-added functions that they wish to provide. XML Web services are modular and extensible. However, there are a number of features that have been left to the developer for implementation.
SOAP, Simple Object Access Protocol, is described as a communications protocol. It is a specification that defines the XML format for messages. The SOAP specification defines the structure of an XML document, which can be used to exchange data between two applications. It expounds a way to represent programming language specific datatypes, in XML.
The most compelling feature of SOAP is that, it has been implemented on many different hardware and software platforms. This implies that SOAP can be used to link disparate systems both, within and outside your organization. SOAP is primarily used to facilitate communication between different programs. These programs may have been written in different languages, and could be running on different platforms.
SOAP is extremely popular and has become the de facto industry standard, as it facilitates interoperability between assorted environments, and it uses HTTP as the transport mechanism.
You would acquiesce that our book titled 'XML Web Services and SOAP' is not meant for the technically naïve. The reader must have sufficient knowledge of C# and ASP.Net, before launching forth with this book. The primary assumption is that you have either read our book on C#, ASP.NET, or any one of the other innumerable books on this topic, strewn all over the market.
We have adopted a step-by-step approach wherein, we first acquaint you with the smallest Web Service. Once you are at ease with it and can create a webservice effortlessly, we progress on to examining the packets that are sent across by the client to the server, and vice-versa. We have based our theory on the packets that have been trapped, using the Trace Utility from the Microsoft SOAP Toolkit, 2.0.
The XML Web Services are built on WSDL, SOAP, XML and UDDI specifications. The second chapter introduces us to WSDL. We have even endeavored to explicate the code generated by the wsdl program. While doing so, we realized that we had to devote an entire chapter to the different data types. We also had to analyze the changes that occur, when data is sent across from client to server and vice-versa. This eventually directed us on to the next chapter of DataSet, since a DataSet is a collection of DataTable objects that embody data. Following this, we attempt to perceive how a web service can be called, using Javascript in an html file.
Then, we proceed on a sojourn to the SOAP packets, which are our next area of interest. Here, we begin with the SOAP headers, and learn how to create custom attributes to enhance the capabilities of the Web Service. Once these aspects have been elucidated, we focus on security issues relating to SOAP. Here, we delve upon the processes of encryption and decryption of data, as well as, on compression and decompression of data.
Finally, all miscellaneous attributes relating to Web Services, which were not touched upon earlier, are tackled in the remaining chapters. After discussing the SOAP faults, we move on to an authentication program, where all the knowledge attained by us so far, has been put to use. The topic of Disco has also been attended to, before going into the details of a WSDL file. We have concluded this book with the chapter on Remoting, where our attention rivets around the data and the data types that get generated in the SOAP packets, when functions are called with different types of parameters.
We are sure that if you read this book with earnest, you diligence will definitely pay off. We exhort you to make the most of this wonderful opportunity. Let the pursuit of knowledge be your lodestar.