Slides from a lunchtime talk at Adastral Park, 18 March 2008. Won't make much sense on their own, I'm afraid.

1. REST
Putting the web back into web services
kerry.buckley@bt.com

2. The Web
(for humans)

3. The Web
(for machines)

4. SOAP

5. Web Services Standards Overview Dependencies
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Messaging Specifications
SOAP 1.1
Interoperability Business Process Specifications Management Specifications Presentation
SOAP 1.2
SOAP Message Transmission Optimization Mechanism
Issues Specifications
WS-Notification
Business Process Execution WS-Choreography Model Web Service Choreography Web Service Choreography Management Using Web Management Of WS-BaseNotification
WS-Management
Metadata
Resource
Security
Language for Web Services 1.1 Overview Interface Description Language Services (WSDM-MUWS) Web Services (WSDM-MOWS) AMD, Dell, Intel, Microsoft and Sun WS-Topics
(BPEL4WS) · 1.1 · BEA Systems, IBM, (WSCI) · 1.0 · W3C 1.0 1.0 Microsystems
1.0 · W3C (CDL4WS) · 1.0 · W3C WS-BrokeredNotification
Microsoft, SAP, Sun Microsystems, SAP, BEA Systems OASIS OASIS Published Specification Web Services for Remote
Working Draft Candidate Recommendation
Basic Profile Siebel Systems · OASIS-Standard and Intalio · Note OASIS-Standard OASIS-Standard
Portlets (WSRP) WS-Addressing – Core
1.1
WS-I Business Process Execution Language for Web Services WS-Choreography Model Overview defines the format Web Service Choreography Interface (WSCI) describes Web Service Choreography Description Language Web Service Distributed Management: Management Using Web Service Distributed Management: Management Of WS-Management describes a general SOAP-based 2.0 WS-Addressing – WSDL Binding
1.1(BPEL4WS) provides a language for the formal and structure of the (SOAP) messages that are exchanged, how Web Service operations can be choreographed in the (CDL4WS) is to specify a declarative, XML based language Web Services (WSDM-MUWS) defines how an IT resource Web Services (WSDM-MOWS) addresses management of protocol for managing systems such as PCs, servers, OASIS
Final Specification specification of business processes and business interaction and the sequence and conditions in which the messages context of a message exchange in which the Web Service that defines from a global viewpoint the common and connected to a network provides manageability interfaces the components that form the network, the Web services devices, Web services and other applications, and other
protocols using Web Services. are exchanged. participates. complementary observable behaviour, where message such that the IT resource can be managed locally and from endpoints, using Web services protocols. manageable entities. Committee Draft WS-Addressing – SOAP Binding
exchanges occur, and when the jointly agreed ordering remote locations using Web services technologies.
Basic Profile – The Basic Profile 1.1 provides rules are satisfied. Web Services for Remote Portlets (WSRP) defines a WS-Eventing
implementation guidelines for how related set of non-
proprietary Web Service specifications should be used Business Process Execution Business Process Management XML Process Definition
set of interfaces and related semantics which standardize
interactions with components providing user-facing WS-Enumeration
together for best interoperability. Language for Web Services 2.0 Language (BPML) Language (XPDL) Service Modeling Language markup, including the processing of user interactions with
that markup.
(BPEL4WS) · 2.0 1.1 IBM, BEA, BMC, Cisco, Dell, HP, Intel,
Metadata Specifications
2.0
OASIS, BEA Systems, IBM, Microsoft, SAP, BPMI.org Microsoft, Sun
Final
Siebel Systems · Committee Draft Final Draft Draft Specification
Basic Profile
1.2 Business Process Execution Language for Web Services Business Process Management Language (BPML) XML Process Definition Language (XPDL) provides an WS-Policy
2.0 (BPEL4WS) provides a language for the formal provides a meta-language for expressing business XML file format that can be used to interchange process Servcie Modeling Language (SML) is used to model
WS-I specification of business processes and business interaction processes and supporting entities. models between tools. complex IT services and systems, including their structure, WS-PolicyAssertions
Working Group Draft protocols using Web Services.
Security
constraints, policies, and best practices.
WS-PolicyAttachment
Basic Profile – The Basic Profile 1.2 builds on Basic Profile
Messaging
1.1 by incorporating Basic Profile 1.1 errata, requirements WS-Discovery
from Simple SOAP Binding Profile 1.0, and adding support
for WS-Addressing and MTOM. WS-MetadataExchange
Universal Description, Discovery and Integration
Web Service Description Language 1.1
Basic Profile
Web Service Description Language 2.0 Core
Metadata Specifications Reliability Security Specifications Transaction Resource
2.0
WS-I
Working Group Draft Web Service Description Language 2.0 SOAP Binding
Basic Profile – The Basic Profile 2.0 is an update of WS-I
BP that includes a profile of SOAP 1.2.
WS-Policy WS-PolicyAssertions Specifications WS-Security WS-SecurityPolicy Specifications Specifications Security Specifications
1.1 1.1 WS-Security
1.5 1.1
BEA Systems, IBM, Microsoft,
W3C
IBM, Microsoft, SAP
OASIS
RSA Security, VeriSign WS-Coordination Web Services WS-Security: SOAP Message Security
Attachments Profile Working Draft
Public Draft WS-ReliableMessaging OASIS-Standard
Public Draft 1.1 Resource Framework (WSRF)
1.0 1.1 OASIS WS-Security: Kerberos Binding
1.2
WS-I OASIS Working Draft
WS-Policy describes the capabilities and constraints of WS-PolicyAssertions provides an initial set of assertions WS-Security is a communications protocol providing a WS-SecurityPolicy defines how to describe policies related OASIS
Final Specification the policies on intermediaries and endpoints (e.g. business to address some common needs of Web Services Committee Draft means for applying security to Web Services. to various features defined in the WS-Security specification. WS-Security: SAML Token Profile
Messaging
OASIS-Standard
Reliability
Metadata
rules, required security tokens, supported encryption applications. WS-Coordination describes an extensible framework for providing
algorithms, privacy rules). protocols that coordinate the actions of distributed applications. Web Services Resource Framework (WSRF) defines a family of WS-Security: X.509 Certificate Token Profile
Attachments Profile – The Attachment Profile 1.0 specifications for accessing stateful resources using Web Services.
complements the Basic Profile 1.1 to add support WS-ReliableMessaging describes a protocol that allows
WS-Business Activity WS-Security: Username Token Profile
for interoperable SOAP Messages with attachments-based
Web Services.
Web services to communicate reliable in the presence of
software component, system, or network failures. It defines WS-Security: WS-Security: 1.1 WS-BaseFaults (WSRF) WS-SecurityPolicy
a SOAP binding that is required for interoperability. SOAP Message Security Username Token Profile OASIS 1.2
WS-PolicyAttachment WS-Discovery 1.1 1.1 Working Draft OASIS WS-Trust
1.2 Microsoft, BEA Systems, Canon, OASIS OASIS Working Draft
Simple SOAP W3C Intel and webMethods WS-Reliable Messaging Public Review Draft Public Review Draft
WS-Business Activity provides the definition of the business activity
coordination type that is to be used with the extensible coordination WS-Federation
WS-BaseFaults (WSRF) defines a base set of information
Binding Profile W3C Member Submission Draft Policy Assertion (WS-RM Policy) framework described in the WS-Coordination specification. that may appear in fault messages. WS-BaseFaults defines an WS-SecureConversation
1.0 WS-Security: SOAP Message Security describes WS-Security: Username Token Profile describes how XML schema type for base faults, along with rules for how
1.1
WS-I
WS-PolicyAttachment defines two general-purpose WS-Discovery defines a multicast discovery protocol for OASIS
enhancements to SOAP messaging to provide message
integrity and confidentiality. Specifically, this specification
a Web Service consumer can supply a Username Token as a
means of identifying the requestor by username, and
WS-Atomic Transaction this base fault type is used and extended by Web Services.
Final Specification
Simple SOAP Binding Profile – The Simple SOAP Binding
mechanisms for associating policies with the subjects to
which they apply; the policies may be defined as part
of existing metadata about the subject or the policies may
dynamic discovery of services on ad-hoc and managed
networks.

6. WS-*

7. WS-

8. Drawing: Paul Downey (http://flickr.com/photos/psd)

14. http://xkcd.com/386/

15. Photo: Steven Mofacko (http://www.flickr.com/photos/mofacko)

16. REST

18. RFC2616

19. UNIVERSITY OF CALIFORNIA,
IRVINE
Architectural Styles and the Design of Network-based Software Architectures
DISSERTATION
submitted in partial satisfaction of the requirements for the degree of
DOCTOR OF PHILOSOPHY
in Information and Computer Science
by
Roy Thomas Fielding
Dissertation Committee:
Professor Richard N. Taylor, Chair
Professor Mark S. Ackerman
Professor David S. Rosenblum
2000

20. Principles of REST
• Addressable resources
• Generic Interface
• Stateless messages
• Representations

21. Resource

22. Noun

23. URI

24. http://twitter.com/kerryb/
http://twitter.com/kerryb/statuses/773022501
http://www.flickr.com/search/?q=barcamp
http://mojo.bt.com/calls

25. Action

26. Verb

27. HTTP operation

28. Create Read
Update Delete

29. Careful!
POST GET
Safe
Idempotent
PUT DELETE

30. Representation

31. Format

32. http://twitter.com/statuses/user_timeline/kerryb.xml
http://twitter.com/statuses/user_timeline/kerryb.json
http://twitter.com/statuses/user_timeline/kerryb.rss
http://twitter.com/statuses/user_timeline/kerryb.atom

33. That’s all very well, but...

34. Response status
• 200 OK • 404 Not found
• 201 Created • 405 Method Not Allowed
• 202 Accepted • 500 Internal Server Error
• 400 Bad Request • 503 Service Unavailable
• 403 Forbidden • etc...

35. Security
• SSL
• HTTP Basic
• HTTP Digest
• Shared key digest
• Custom

36. Why?
• Simplicity
• Consistency
• Interoperability
• Testability
• Web infrastructure

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