Web Service Architecture and Models

Web Services Entities
- Provider Agent
- Requester Agent
- Discovery Service

Web Service Architecture Stack


Web Service Models



Service Oriented Model


- Is Concerned with the service provided and the actions necessary to provide it. A service is realized by an agent and used by another agent. Services are mediated by means of the messages exchanged between requester agents and provider agents. A service offers real-world functionality and is owned by a person or organization


Resource Oriented Model


- Is concerned with resources that are available over the Internet. The owners of a resource are responsible for ti. The resource-oriented model specifies the relationship between owners and resources


Policy Oriented Model

- Is concerned with constraining how agents and services behave. Policies are implemented to address concerns about quality of service, security, application, and management.


Message-Oriented Model


- Is concerned with the messages that are exchanged by web service agents. It focuses on their structure and how they are transported. It is not concerned with their significance.


Message Exchange Patterns
- request-response
- one-way request (from requester)
- notification (from provider)
- solicit-response (provider to requester and back)


SOA Roles
- Service Requester
- Service Provider
- Service Register


SOA Operations
- Publish
- Find
- Bind


Web Service Design Stages
- Vision document
- Conceptual Design
- Logical Design
- Physical Design
- Architecture (how to connect and installed)
- Security Design (Authentication, Privacy, Authorization)


Web Service Design Options
- Synchronous or asynchronous Communication
- Session State
- Transactions (actions in a group. Time-stamped data to enable rollback across independent web services)
- Caching (expiration time must be set)