Chanaka Fernando and Ishan Jayawardena are presenting on RESTful integration with WSO2 Enterprise Service Bus (ESB). Chanaka is a Technical Lead and Ishan is a Senior Software Engineer at WSO2. They will discuss configuring REST APIs and resources with WSO2 ESB, extended JSON support for RESTful integrations, and designing APIs with URI templates. They will also present a use case example of building a RESTful API for a pizza shop ordering system using WSO2 ESB.

1. Chanaka Fernando
Technical Lead
Ishan Jayawardena
Senior Software Engineer
May 29 2014
RESTful Integration with WSO2 ESB

2. About the Presenters
๏ Chanaka Fernando - chanakaf@wso2.com
Chanaka joined WSO2 in January 2013. He is a Technical Lead in the WSO2 Enterprise Service
Bus team. In addition to his product development efforts he has also provided technology
consulting on customer engagements, including customer QuickStart programs. Chanaka has
also published numerous articles on WSO2 products which are available in the WSO2 library.
๏ Ishan Jayawardena - ishan@wso2.com
Ishan is a Senior Software Engineer in the integration technologies team where he mainly
focuses on the WSO2 Enterprise Service Bus. In addition to his product development efforts
he has also provided technology consulting on customer engagements, including customer
QuickStart programs focused on Enterprise Application Integration projects.

3. About WSO2
๏ Global enterprise, founded in 2005 by
acknowledged leaders in XML, web
services technologies, standards and
open source
๏ Provides only open source platform-as-a-
service for private, public and hybrid cloud
deployments
๏ All WSO2 products are 100% open source
and released under the Apache License
Version 2.0.
๏ Is an Active Member of OASIS, Cloud
Security Alliance, OSGi Alliance, AMQP
Working Group, OpenID Foundation and
W3C.
๏ Driven by Innovation
๏ Launched first open source API
Management solution in 2012
๏ Launched App Factory in 2Q 2013
๏ Launched Enterprise Store and first
open source Mobile solution in 4Q 2013

4. What WSO2 delivers

5. Agenda
๏ What is WSO2 Enterprise Service Bus (ESB)
๏ The importance of REST
๏ Configuring REST APIs and resources with WSO2 ESB
๏ Extended JSON support for RESTful integrations
๏ Designing APIs with uri-templates and url-mapping techniques
๏ Use Case : Pizza Shop

6. *
WSO2 Enterprise Service Bus
๏ A lightweight, high performance ESB
๏ Comprehensive REST, SOAP, WS-* support
๏ 100% compliant with all EIPs (Enterprise Integration
Patterns)
๏ Connectors (Salesforce, Twilio and many more)
๏ SAP, FIX, HL7 - Domain specific solutions
๏ Zero Code/Configuration driven
๏ Extensible and Scalable

7. WSO2 Enterprise Service Bus
๏ Under the hood: Apache Synapse
๏ A lightweight, open source ESB implementation from the ASF :http:
//synapse.apache.org
๏ Makes up the mediation engine of WSO2 ESB
๏ Multithreaded and asynchronous message processing core
๏ Based on a number of well known open source projects (eg: Axis2, Http Core)

8. What is REST?
๏ REpresentational State Transfer
๏ An architectural Style – Not a Standard
๏ REST uses HTTP for CRUD (Create/Read/Update/Delete) operations
๏ RESTful applications use HTTP requests to
• post data (create and/or update)
• read data (e.g., make queries)
• Delete data.

9. Trend towards REST
๏ Amazon AWS (Over 90% of the clients use RESTful API)
๏ Google Maps
๏ Yahoo
๏ Ebay
๏ Twitter

10. ESB REST APIs
๏ Similar to a web application hosted on the ESB
๏ Anchored at a specific URL path (context)
๏ Eg: /news
๏ Can be bound to a specific hostname:port
๏ Contains one or more Resources

11. ESB REST APIs
๏ Exposes RESTful APIs
๏ REST → SOAP conversion
๏ SOAP → REST conversion
๏ REST → REST conversion

12. ESB REST APIs
๏ Creating a REST API...

13. ESB REST APIs : Resources
๏ A RESTful resource exposed over HTTP
Eg: /news/latest
๏ Similar to a proxy service but focuses on REST
๏ Can be associated with
๏ A set of HTTP verbs
๏ A specific content type
๏ A particular class of clients (user agents)

14. ESB REST APIs : Resources
๏ URL Patterns
๏ Regex match (/news/*)
๏ Extension match (*.jsp)
๏ Exact match (/news/index.jsp)
๏ URI templates
๏ /dictionary/{char}/{word}
๏ HTTP verbs (GET/POST/PUT/DELETE)
๏ A set of HTTP verbs
๏ A specific content type
๏ A particular class of clients (user agents)

15. ESB REST APIs : Resources

16. ESB REST APIs : Resources
/people

17. ESB REST APIs : Resources
/people
GET
/staff/*

18. ESB REST APIs : Resources
/people
GET
/staff/*
POST
/add?name={name}&id={id}

19. ESB REST APIs : Resources

20. HTTPEndpoint
<endpoint xmlns="http://ws.apache.org/ns/synapse"
name="HTTPEndpoint">
<http
uri-template="http://localhost:8080/{uri.var.
companyname}/restapi/{uri.var.servicename}/menu?
category={uri.var.category}"
method="GET">
</http>
</endpoint>
Sample request:
http://localhost:8280/pizza?
companyname=wso2&servicename=lunch&category=vegetable

21. ๏ Data Formats plays a major role in REST integrations
๏ Easy to transform between JSON and XML
๏ Native JSON support for handling JSON only scenarios like mobile
applications
๏ Directly evaluate json message rather than converting to XML
Eg: <filter source="json-eval(pizza.name)" regex="
Meat Sizzler">
JSON Support for REST

22. Use Case : Pizza Shop

23. API - /pizzashop
Resources
๏ Pizza - /api/menu/pizza* [GET]
๏ Order - /api/order* [POST]
๏ Order - /api/order/{orderId} [POST, GET, DELETE, PUT]
๏ Purchase - /api/purchase/{orderId} [POST]
Use Case : Pizza Shop

24. <resource methods="GET"
uri-template="/api/menu/pizza*">
<inSequence>
.......................
</inSequence>
<outSequence>
.......................
</outSequence>
</resource>
sample requests
http://127.0.0.1:8280/pizzashop/api/menu/pizza
http://127.0.0.1:8280/pizzashop/api/menu/pizza?
val=thin&type=crust
Use Case : Pizza Shop

25. <resource methods="POST" uri-template="/api/order*">
<inSequence>
.....................
</inSequence>
<outSequence>
.....................
</outSequence>
</resource>
sample requests
http://127.0.0.1:8280/pizzashop/api/order
{"order": {
"items": [
{"id": 1, "qty": 2},
{"id": 2, "qty": 1}
]
}}
Use Case : Pizza Shop

26. <resource methods="POST GET DELETE PUT"
uri-template="/api/order/{orderId}">
<inSequence>
......................
</inSequence>
<outSequence>
......................
</outSequence>
</resource>
sample requests
http://127.0.0.1:8280/pizzashop/api/order/0001
Use Case : Pizza Shop

27. <resource methods="POST"
uri-template="/api/purchase/{orderId}">
<inSequence>
..............
</inSequence>
<outSequence>
................
</outSequence>
</resource>
sample requests
http://127.0.0.1:8280/pizzashop/api/purchase/0001
{“purchaseInformation”:
{
“amount”: 175.00,
“cc”: "1234-5678-9876-5432"
}
}
Use Case : Pizza Shop

28. Complete sample
http://wso2.com/library/articles/2013/12/restful-integration-with-wso2-esb/
Use Case : Pizza Shop

29. Questions?

30. *
๏ WSO2 ESB
http://wso2.com/products/enterprise-service-bus
๏ WSO2 ESB Documentation
https://docs.wso2.
org/display/ESB481/WSO2+Enterprise+Service+Bus+Documentation
๏ RESTful Integration with WSO2 ESB
http://wso2.com/library/articles/2013/12/restful-integration-with-wso2-
esb/
๏ How to GET a Cup of Coffee the WSO2 Way
http://wso2.com/library/articles/2012/09/get-cup-coffee-wso2-way/
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