![Basic SOA Using REST
âą The focus is âImplementing SOA components using the
REST paradigmâ
âą REST stands for Representational State Transfer. It was
first introduced by Roy Fielding1 in his 2000 doctoral
dissertation [Fielding].
âą For simple applications, REST is an easy way to get
started
âą Simple examples can be worked up, using only HTTP
and servlets, so that learners who are not advanced in
Java can come up the learning curve and get a sense of
the basics before working on the Java Web Services
(JWS) APIs.](https://image.slidesharecdn.com/soa27restandrestfulservices-200520070950/85/Soa-27-rest-and-restful-services-2-320.jpg)
Soa 27 rest and restful services
- 1. Service Oriented Architecture: 27 REST and Restful Services Prof Neeraj Bhargava Vaibhav Khanna Department of Computer Science School of Engineering and Systems Sciences Maharshi Dayanand Saraswati University Ajmer
- 2. Basic SOA Using REST âą The focus is âImplementing SOA components using the REST paradigmâ âą REST stands for Representational State Transfer. It was first introduced by Roy Fielding1 in his 2000 doctoral dissertation [Fielding]. âą For simple applications, REST is an easy way to get started âą Simple examples can be worked up, using only HTTP and servlets, so that learners who are not advanced in Java can come up the learning curve and get a sense of the basics before working on the Java Web Services (JWS) APIs.
- 3. What Is REST âą REST-style services (i.e., RESTful services) adhere to a set of constraints and architectural principles that include the following: âą â RESTful services are stateless. âEach request from client to server must contain all the information necessary to understand the request, and cannot take advantage of any stored context on the server.â âą â RESTful services have a uniform interface. This constraint is usually taken to mean that the only allowed operations are the HTTP operations: GET, POST, PUT, and DELETE. âą â REST-based architectures are built from resources (pieces of information) that are uniquely identified by URIs. For example, in a RESTful purchasing system, each purchase order has a unique URI.
- 4. What Is REST âą â REST components manipulate resources by exchanging representations of the resources. âą Fielding writes that âREST-based architectures communicate primarily through the transfer of representations of resourcesâ âą This is fundamentally different from the Remote Procedure Call (RPC) approach that encapsulates the notion of invoking a procedure on the remote server. âą Hence, RPC messages typically contain information about the procedure to be invoked or action to be taken. This information is referred to as a verb in a Web service request. In the REST model, the only verbs allowed are GET, POST, PUT, and DELETE. âą In the RPC approach, typically many operations are invoked at the same URI. This is to be contrasted with the REST approach of having a unique URI for each resource.
- 5. RESTful Web Services versus SOAP Web Services âą REST uses simple XML over HTTP without a WSDL interface definition. âą XML Schema could be used as an interface definition for RESTful Services âą services.
- 6. SOA-style development for the Enterprise Information System (EIS) âą Structuring EIS Records as XML documents âą â Getting EIS records from a REST service (with and without JWS) âą â Posting EIS records to a REST service (with and without JWS) âą â Basic SOA-style integration of REST services using XSLT for data transformation âą â Deploying a REST service to be used for getting EIS recordsâin other words, an HTTP GET service (with and without JWS) âą â Deploying a REST service to be used for posting EIS recordsâin other words, an HTTP POST service (with and without JWS)
- 7. XML Documents and Schema for EIS Records âą The first step toward implementing an SOA component that consumes or provides EIS records involves formatting the EIS records that need to be exchanged as XML documents. âą This process is formalized by creating an XML Schema to represent the structure of an XML document for a particular EIS record. âą XYZ Corporation has an Order Management System (OMS) that needs to be integrated with a Customer Service System (CSS). âą The OMS should be thought of as an EIS, such as SAP, for taking customer orders and tracking them through delivery. âą The CSS should be thought of as an EIS, such as Oracleâs Siebel Customer Relationship Management Applications, that is used by customer service employees as a tool for handling customer inquiries.
- 8. OMS order record as it appears in the user interface
- 9. An XML Representation of the Order
- 10. A Fragment of the XML Schema for Validating an Order Document
- 12. Assignment âą Explain the usage and benefits of Restful Services for implementing SOA