As the name "Web Services" suggests, it is a method for communicating between two electronic devices over the web (internet).
A web service is not a website that a human reads. It is not anything with which an end user would directly interact. A web service is a standard platform for building interoperable distributed applications. It allows you as a developer, to interact with other information providers without worrying about what they are running either at the backend or even their front-end.
Points to remember:
1. Web Service is small units of code.
2. Web Service is small unit of codes that is designed to handle a limited set of tasks. For example, online payment system communicates using Web Services.
3. Web Service is independent of OS and Programming Languages.
4. Web Service is not limited to OS type or Programming Languages as it communicates using open protocol systems.
5. Web Service is designed to handle a limited set of tasks.
6. The main point is that they are designed to handle limited sets of tasks, like a payment gateway connects to a server for some time interval.
7. Web Service connects to different systems and devices.
Another point is that it can establish communication with different types of systems; for example, a mobile device can also use banking or stock prices.
Benefits of Web Services:
Web Services creates new possibilities for many businesses because they provide easy ways to distribute information to a large number of consumers. For example, ticket reservation systems, payment systems, stock market etc. Here is the list of benefits.
1. Distribute information to more consumers
2. Reuse existing services
3. Communicate between applications
4. Rapid developments etc.
Web service uses the standard web protocols to establish communication between different types of systems (open standard) like XML, HTTP, SOAP, WSDL and UDDI.
XML was designed to transport and store data and in WS we take its advantage to transport the data.
HTTP (Hyper Text Transfer Protocol)
The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web.
SOAP (Simple Object Access Protocol):
SOAP is a simple XML-based protocol to let applications exchange information over HTTP. Or more simply, SOAP is a protocol for accessing a Web Service. In other words, SOAP provides a way to communicate between applications running on different operating systems, with different technologies and programming languages.
WSDL (Web Services Description Language):
WSDL (Web Services Description Language) is an XML-based language for describing Web services and how to access them.
WSDL is a document written in XML. The document describes a Web service. It specifies the location of the service and the operations (or methods) the service exposes.
Universal Description, Discovery and Integration (UDDI):
Universal Description, Discovery and Integration (UDDI) are a directory service where businesses can register and search for Web services. It is platform-independent framework for describing services, discovering businesses, and integrating business services by using the Internet.
Developing Web Services and Consuming Web Services:
I am an ASP.NET guy, so I'll prefer to use it in the Web Service developments. Keep in mind, there are two separate developments involved in Web Services:
1. Developing Web Services
2. Consuming Web Services