Web Services

Web Services

Web services are application components Web services communicate using open protocols Web services are self-contained and self-describing Web services can be discovered using UDDI Web services can be used by other applications HTTP and XML is the basis for Web services Web services are web application components. Web services can be published, found, and used on the Web. It can be exposed and used by any technology and any platform

Interoperability has Highest Priority

When all major platforms could access the Web using Web browsers, different platforms couldn't interact. For these platforms to work together, Web-applications were developed.Web-applications are simply applications that run on the web. These are built around the Web browser standards and can be used by any browser on any platform.

Web Services take Web-applications to the Next Level

By using Web services, your application can publish its function or message to the rest of the world.Web services use XML to code and to decode data, and SOAP to transport it (using open protocols).

Web Services have Two Types of Uses

1. Reusable application-components.Web services can offer application-components like: currency conversion, weather reports, or even language translation as services.

2. Connect existing software.Web services can help to solve the interoperability problem by giving different applications a way to link their data.With Web services you can exchange data between different applications and different

platforms.

Web Services

What are Web Services ? A web service is any piece of software that makes itself available over the Internet

and uses a standardized XML messaging system.

XML is used to encode all communications to a web service. For example, a client

invokes a web service by sending an XML message, then waits for a corresponding XML

response. Because all communication is in XML, web services are not tied to any one operating

system or programming language--Java can talk with Perl; Windows applications can talk with Unix applications.

Web services are XML-based information exchange systems that use the Internet for

direct application-to-application interaction.

Best Definition :

Is available over the Internet or private (Intranet) networks

Uses a standardized XML messaging system

Is not tied to any one operating system or programming language

Is self-describing via a common XML grammar Is discoverable via a simple find mechanism

Components of Web Services?The basic Web services platform is XML + HTTP. All the standard Web Services works using following components

1. SOAP (Simple Object Access Protocol)2. UDDI (Universal Description, Discovery and Integration)3. WSDL (Web Services Description Language)

Benefits of using Web Services

Exposing the existing function on to network:A Web service is a unit of managed code that can be remotely invoked using HTTP, that is, it can be activated using HTTP requests. So, Web Services allows you to expose the functionality of your existing code over the network. Once

Web Services

it is exposed on the network, other application can use the functionality of your program.

Connecting Different Applications ie Interoperability:Web Services allows different applications to talk to each other and share data and services

among themselves. Other applications can also use the services of the web services. For example VB or .NET application can talk to JAVA web services and vice versa. So, Web services is used to make the application platform and technology independent.

Standardized Protocol:Web Services uses standardized industry standard protocol for the communication. All the four layers (Service Transport, XML Messaging, Service Description and Service Discovery layers) uses the well defined protocol in the Web Services protocol stack. This standardization of protocol stack gives the business many advantages like wide range of choices, reduction in the cost due to competition and increase in the quality.

Low Cost of communication:Web Services uses SOAP over HTTP protocol for the communication, so you can use your existing low cost Internet for implementing Web Services. This solution is much less costly compared to proprietary solutions like EDI/B2B. Beside SOAP over HTTP, Web Services can also be implemented on other reliable transport mechanisms like FTP etc.

Web Service RolesThere are three major roles within the web service architecture:Service providerThis is the provider of the web service. The service provider implements the service and makes it available on the Internet.Service requesterThis is any consumer of the web service. The requester utilizes an existing web service by opening a network connection and sending an XML request.

Web Services

Service registryThis is a logically centralized directory of services. The registry provides a central place where developers can publish new services or find existing ones. It therefore serves as a centralized clearinghouse for companies and their services.

2. Web Service Protocol StackA second option for viewing the web service architecture is to examine the emerging web service protocol stack. The stack is still evolving, but currently has four main layers.

Service transportThis layer is responsible for transporting messages between applications. Currently, this layer includes hypertext transfer protocol (HTTP), Simple Mail Transfer Protocol (SMTP), file transfer protocol (FTP), and newer protocols, such as Blocks Extensible Exchange Protocol (BEEP).

XML messagingThis layer is responsible for encoding messages in a common XML format so that messages

can be understood at either end. Currently, this layer includes XML-RPC and SOAP.

Service descriptionThis layer is responsible for describing the public interface to a specific web service. Currently, service description is handled via the Web Service Description Language (WSDL).

Service discoveryThis layer is responsible for centralizing services into a common registry, and providing easy

publish/find functionality. Currently, service discovery is handled via Universal Description, Discovery, and Integration (UDDI).

WSDL

What is WSDL?

WSDL stands for Web Services Description Language WSDL is written in XML WSDL is an XML document

Web Services

WSDL is used to describe Web services WSDL is also used to locate Web services WSDL is a W3C recommendation

UDDI

Universal Description, Discovery and Integration (UDDI) is a directory service where businesses can register and search for Web services.

What is UDDI

UDDI is a platform-independent framework for describing services, discovering businesses, and integrating business services by using the Internet.

UDDI stands for Universal Description, Discovery and Integration UDDI is a directory for storing information about web services UDDI is a directory of web service interfaces described by WSDL UDDI communicates via SOAP UDDI is built into the Microsoft .NET platform

SOAP

SOAP stands for Simple Object Access Protocol. SOAP is a protocol for accessing web services. SOAP is based on XML.

What is SOAP?

SOAP stands for Simple Object Access Protocol SOAP is a communication protocol SOAP is for communication between applications SOAP is a format for sending messages SOAP communicates via Internet SOAP is platform independent SOAP is language independent SOAP is based on XML SOAP is simple and extensible

Web Services

SOAP allows you to get around firewalls SOAP is a W3C recommendation

Web ServicesWeb ServicesInteroperability has Highest PriorityWeb Services take Web-applications to the Next LevelWeb Services have Two Types of UsesComponents of Web Services?Exposing the existing function on to network:Connecting Different Applications ie Interoperability:Standardized Protocol:Low Cost of communication:Web Service Roles2. Web Service Protocol StackWhat is WSDL?What is UDDIWhat is SOAP?