This document compares SOAP and REST web services. SOAP uses XML and relies on complex specifications, while REST uses simple HTTP requests and aims to be lightweight. REST has advantages for simplicity, bandwidth usage, caching and statelessness. SOAP may be better for complex transactions that require ACID properties and reliable messaging. Factors like security requirements, scalability, and programming language support also influence the choice of protocol.

1. SOAP vs REST
Presentation by Mario Almeida

2. Index
● What is a webservice?
● Services interoperability
● What is SOAP?
● What is REST?
● Peek at competition
● Characteristics
○ Popularity
○ Simplicity
○ Bandwidth
○ Security
○ Caching
○ State
● Problems
● Conclusion

3. What is a Webservice?
"Software system designed to support
interoperable machine-to-machine interaction
over a network" - W3C

4. Services interoperability!
Systems interact with the web service using
messages sent through HTTP generally with an
XML serialization.

5. What is SOAP?
Simple Object Access Protocol

6. What is REST?
Representational State Transfer

7. Lets take a peek on the competition!
● Yahoo and all its services such as Flickr and
deli.ici.ous use REST
● Amazon and Ebay provide both though
Amazon's internal usage is nearly all REST.
● Google used to provide SOAP for all their
services, but in 2006 they deprecated in
favor of REST.

8. Characteristics: Simplicity
REST:
● Is easy to build - no toolkits required!
● Just figure how to create and modify the URI
to access different web resources!
SOAP:
● Requires a toolkit to form requests and
parse results!
● Requires specific knowledge of a new XML
specification.

9. Characteristics: Bandwidth!
REST:
● can be short!
SOAP:
● requires an XML wrapper around every
request and response
● once namespaces and typing are declared
can take 10 times as many bytes as the
same message in REST.

10. Characteristics: Security!
REST:
● easy to analyze the intent of each message by checking
the HTTP command!
● Certificates and LDAP can delegate authentication and
authorization to the network layer.
● Secure data should never be sent as parameters in the
URI.
SOAP:
● Needs to look into SOAP envelope!
● Authentication and authorization in the application layer.

11. Characteristics: Caching!
Caching?
● take advantage of all the caching infrastructure that is
built into the Web infrastructure.

12. Characteristics: State!
Session State is Evil! (SOAP)
● Enormous impact on scalability and avalability.

13. Other problems?
● Banking transactions?
○ ACID properties!
○ Reliable messaging!
○ Enterprise security features!
● Language support? (SOAP)
○ Good: .NET, Java (Axis)
○ Ok: C++ (gSOAP), PERL (SOAP::Lite)
○ Poor: Phyton (SOAPpy, ZSI, PHP
● File transfers?

14. Conclusion: What purpose?
How important are the ACID properties?
What security measures?
Scalability? Availability?

15. Conclusion: How fast?
What is the Learning curve?
How is the Testing?
How is the Error Handling?

16. Future?
● SOAP has been evolving in a way that it is
more similar to REST by allowing other
HTTP commands.
● Hypermedia as the engine of application
state.
● Uniform interfaces
● Stateless communications between servers
and clients.

17. References
● http://geeknizer.com/rest-vs-soap-using-http-choosing-the-right-
webservice-protocol/
● http://davidvancouvering.blogspot.com/2007/09/session-state-is-evil.html
● http://www.javaworld.com/javaworld/jw-03-2002/jw-0308-soap.html -
caching SOAP services on client side
● http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven
● http://tomayko.com/writings/rest-to-my-wife
● http://www.25hoursaday.
com/weblog/2005/03/17/ETech2005TripReportBuildingANewWebServiceA
tGoogle.aspx

18. Images
All of the following images have creative common rights:
● http://www.flickr.com/photos/ahmadnawawi/3808452611 - stock market
● www.flickr.com/photos/soldiersmediacenter/4723608143 - handshake
● http://www.flickr.com/photos/oceanflynn/6638184545 - networks
● http://www.flickr.com/photos/mybloodyself/5659661793 - clock
● http://www.flickr.com/photos/tim_norris/2789759648 - snail
● http://www.flickr.com/photos/garrette/53235940/ - pc
● http://www.flickr.com/photos/legofenris/5410534167 - darth vader