REST & API Management with the WSO2 ESB
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This document discusses REST, its origins and growth, how it can be implemented using HTTP, and how the WSO2 ESB supports REST. It defines what a RESTful resource is and how resources can represent application state. It also describes how the WSO2 ESB can receive and process REST requests using the same mediators used for SOAP. The document outlines how the WSO2 ESB supports exposing SOAP services via REST and REST/POX services via SOAP. It also discusses how the WSO2 platform can be used to build comprehensive API management solutions.
REST & API Management with the WSO2 ESB
- 1. REST and API Management with Hiranya Jayathilaka Product Manager – WSO2 ESB
- 2. What is REST? ● REpresentational State Transfer ● Lightweight, ClientServer architecture ● Interactions are based on the transfer of resource state representations ● Systems exchange state representations and perform application state transitions ● Mostly implemented using HTTP but can be based on other protocols
- 3. Origin and Growth ● First introduced by Roy Fielding in his doctoral dissertation ● Developed in parallel with HTTP/1.1 ● WWW is the largest known implementation of a RESTful architecture ● Widely used in modern days as an alternative to technologies like CORBA and SOAP
- 4. REST By Example... ● Learning Management System for a school ● A number of fundamental concepts ● Student ● Course ● Teacher ● In a RESTful design these concepts are likely to become the 'resources' managed by the LMS
- 5. The 'Student' Resource State ● Name ● Index number ● Age ● Date of birth ● Contact information ● GPA ● ...
- 8. Application State ● Applications have states ● Number of students in the system ● Number of associations between students and courses ● Number of teachers ● Application state transitions may occur as a result of a resource state transfer ● Application state can also be represented using some data format or hyper text references
- 9. Representational State Transfer ● Clients and servers interact with each other by exchanging ● Resource state representations ● Application state representations ● Other control information
- 11. Why HTTP? ● Rich vocabulary and powerful tools that are ideal for representing resource states, application states and control data ● Application state – Status code + Links ● Resource state – HTTP entity ● Control data – HTTP method ● CRUD operations map nicely into HTTP methods
- 13. Advantages ● Simple and lightweight ● Easy to implement ● Very little processing at the application level ● Small amount of data to pass around ● Support any content type ● Leverage builtin application layer protocol semantics without reinventing the wheel
- 14. Notable Deployments ● Amazon AWS (Over 90% of the clients are using the RESTful API) ● Google Maps ● Yahoo! ● eBay ● Sastry Malladi on service orientation http://www.youtube.com/watch?v=O9osZGXDok
- 15. WSO2 ESB ● A lightweight, highperformance ESB ● Feature rich and standards compliant ● SOAP and WS* standards ● REST support ● Variety of protocols and message formats ● User friendly and highly extensible ● 100% free and open source with commercial support
- 16. Under the Hood ● WSO2 ESB is based on a number of well known Apache projects ● Synapse http://synapse.apache.org ● Axis2 http://axis.apache.org/axis2/java/core ● Web Services http://ws.apache.org ● REST support of WSO2 ESB stems from the REST support offered by Axis2
- 17. REST Support in Axis2 ● Axis2 provides a REST binding for each deployed web service ● This enables clients to invoke any Axis2 service via REST calls ● GET /services/HelloService/sayHello ● GET /services/MathService/add?a=5&b=10
- 18. REST Support in WSO2 ESB ● WSO2 ESB can receive and mediate REST calls just like any other request ● The same mediators that work with SOAP can be used to manipulate REST invocations ● Log, Send, Filter, Switch, XSLT, DBLookup.... ● Additional handles provided by the ESB in the form of properties ● Easily switch between SOAP and REST
- 21. Exposing a REST/POX Service via SOAP
- 23. Exercising More Control Over REST ● Manipulate REST calls based on ● HTTP method ● Status code ● Content type ● HTTP headers
- 25. Examples
- 27. Examples
- 29. Examples
- 30. REST APIs ● An API is similar to a web application hosted on the ESB ● Anchored at a specific URL path (context) ● /test ● /dictionary ● /foo/bar ● Can be bound to a specific host and a port ● Contains one or more resources
- 31. Resources ● A RESTful resource exposed over HTTP ● Similar to a proxy service but focuses on REST ● Can be associated with ● A set of HTTP methods – GET only, GET and POST only, All HTTP methods ● A specific content type – application/xml, application/json ● A particular class of clients (user agents)
- 32. Dispatching Requests to a Resource ● URL patterns ● RegEx match (/test/*) ● Extension match (*.jsp) ● Exact match (/test/index.jsp) ● URI templates ● /dictionary/{character}/{word} ● /accounts/{accountId}/{operation}
- 35. API Example
- 36. APIs in Action
- 37. API Management Goals ● Service provider objectives ● Define APIs ● Define security requirements and SLAs ● Monitor API usage and SLAs ● Service consumer objectives ● Discover and browse APIs ● Sign up and obtain API keys ● Consume APIs using the obtained keys ● Monitor API usage and SLAs
- 40. Summary and Recap ● REST is a lightweight, clientserver architecture for building distributed systems ● RESTful designs are concerned with resources, states and transfer of representational state between systems ● WSO2 ESB provides excellent support for receiving, processing and intermediating REST (HTTP) calls ● The new API concept is a powerful feature which allows developers to define REST APIs in the ESB without writing any additional code ● WSO2 platform is ideally suited for developing comprehensive and flexible API management solutions based on open standards
- 41. Questions?
- 43. WSO2 Engagement Model ● Quick Start ● Development Support ● Development Services ● Production Support ● Turnkey Solutions ● WSO2 Mobile Services Solution ● WSO2 FIX Gateway Solution ● WSO2 SAP Gateway Solution
- 44. Thank You