Web Services

Web services are actually the services that usually includes some combination of programmes and data, but possibly including human resources as well.

It is a collection of open protocols and standards such as TCP/IP, HTTP, Java, HTML, and XML which is used for exchanging data between applications or systems. Web services are built on the top of these open standards. Software applications written in various programming languages and running on various platforms can use web services to exchange data over computer networks like the Internet in a similar way as inter-process communicates on a single computer.It allows interoperability.

This interoperability (e.g., between Java and Python, or Windows and Linux applications) is due to the use of open standards. Sometimes called as application services.They are made available from a business's Web server for Web users or other Web-connected programs.

• Repository: They are a basic part of Web Services. Once a Web Service found in a repository, the repository also describes how to use the Web Service.
• Message: It is an abstract definition of the data. Message are presented either as an entire document or as an arguments.
• Service: They are what you connect together using Web Services. A service is the endpoint of a connection.

Basically Webservices have many component, but we define two types of webservices as given below.

1. SOAP: SOAP Web Services are standard-based and supported by almost every software platform. They rely heavily in XML and support transactions, security, asynchronous messages and many other issues. SOAP based Web Services is a great solution when you need- 
• Asynchronous Processing
• Reliability
• Stateful operations

For example: you store information/data on a request and use that stored data on the next on.

2. REST: REST services relies on HTTP protocol.Based on HTTP protocol its methods are mainly PUT, GET, POST, and DELETE. These web services are better integrated with HTTP than SOAP-based services.
• It is a pretty simple and elegant architectural approach.
• The Full Form of REST is Representational State Transfer. It is neither a standard nor a protocol.

Security is critical to web services. However, neither the XML-RPC nor SOAP specifications make any explicit security or authentication requirements.

1. Confidentiality
2. Authentication
3. Network Security

Transports: BEEP, the Blocks Extensible Exchange Protocol (formerly referred to as BXXP), is a framework for building application protocols.

Messaging: The messaging standards and specifications are intended to give a framework for exchanging information in a decentralized, distributed environment. The different standard of Messaging are as given below.

• SOAP 1.1
• SOAP 1.2
• Web Services Attachments Profile 1.0

Description and discovery: Web services are meaningful only if users may find information i.e, sufficient to permit their execution. The focus of these specifications and standards is the definition of a set of services supporting the description and discovery of businesses, organizations, and other Web services providers. The different standard of Description and discovery are as given below.

• UDDI 3.0
• WSDL 1.1
• WSDL 1.2
• WSDL 2.0

Management: In web services manageability means a set of capabilities for discovering the existence, availability, performance, usage, as well as the control and configuration of a Web service within the Web services architecture.

• Web Services Distributed Management(WSDM).