WCF REST - Adnan Masood
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Transcript WCF REST - Adnan Masood
WCF 3.5, REST ET AL. HOW TO?
Adnan Masood
www.AdnanMasood.com
ABOUT ME
AKA.
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SHAMELESS SELF PROMOTION
Sr. Software Engineer / Tech Lead for Green Dot Corp. (Financial
Institution)
Design and Develop Connected Systems
Involved with SoCal Dev community, co-founded San Gabriel Valley
.NET Developers Group. Published author and speaker.
MS. Computer Science, MCPD (Enterprise Developer), MCT,
MCSD.NET
Doctoral Student - Areas of Interest: Machine learning, Bayesian
Inference, Data Mining, Collaborative Filtering, Recommender
Systems.
Contact at [email protected]
Read my Blog at www.AdnanMasood.com
Doing a session in IASA 2008 in San Francisco on Aspect Oriented
Programming; for details visit http://www.iasaconnections.com
AGENDA
Overview of SOA, Web Services, Design Patterns
What’s new in WCF 3.5
Discuss what is REST?
How to Implement REST using WCF?
What are UriTemplates?
How to use them in .NET 3.5?
ARCHITECT IQ TEST
What are the four tenants of SOA?
TENANTS OF SOA
1. Boundaries are explicit
2. Services are Autonomous
3. Services share Schema and Contract, not Class
4. Compatibility is based upon Policy
ABBR./ACRONYMS 101
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REST
SOAP
JSON
POX
RSS
ATOM
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Representational State Transfer
Simple Object Access Protocol
Javascript Object Notation
Plain Old XML
Really Simple Syndication
WHAT IS REST?
• REST is a term coined by Roy
Fielding in his Ph.D dissertation [1] to
describe an architecture style of
networked systems.
[1] http://www.ebuilt.com/fielding/pubs/dissertation/top.htm
REST
Representational
There
State Transfer
are REST-Services and “REST-like”
services which use XML and HTTP but not the
underlying philosophy of REST
REST
outlines the philosophy of mapping
HTTP verbs to the
Create/Retrieve/Update/Delete philosophy of
APIs as discussed in a PhD thesis by Roy Fielding
Examples
• http://example.com/users/
http://example.com/users/{user} (one for each user)
http://example.com/findUserForm
http://example.com/locations/
http://example.com/locations/{location} (one for
each location)
http://example.com/findLocationForm
WCF SUPPORT TO REST
WebHttpBinding: Sends information directly
over HTTP or HTTPS—no SOAP envelope is
created. This binding is new with the .NET
Framework 3.5 version of WCF, and it’s the right
choice for RESTful communication and other
situations where SOAP isn’t required. The
binding offers three options for representing
content: text-based XML encoding, JavaScript
Object Notation (JSON) encoding, and opaque
binary encoding.
“REPRESENTATION STATE TRANSFER” IS THE
IDEA BEHIND RESOURCE ORIENTED
ARCHITECTURE
http://www.myblog.com/{year}/{month}/{day}
Resource
Client
Blog Posts for the day
Posts 01012008 – a view and not a physical file
The Client references a Web resource using a URL. A representation
of the resource is returned which can be rendered as an HTML.
MOTIVATION FOR REST
"The motivation for developing REST was to create an
architectural model for how the Web should work, such that
it could serve as the guiding framework for the Web protocol
standards.
REST has been applied to describe the desired Web
architecture, help identify existing problems, compare
alternative solutions, and ensure that protocol extensions
would not violate the core constraints that make the Web
successful."
- Roy Fielding
REST VS. SOAP
– Enhanced Caching
– Invocation vs. Resource
– Bloat vs. Simplicity
– Proxy Servers
– Web evolution (semantic Web)
– Generic Uri based interface via
UriTemplates (versus custom SOAP
interface)
– Interoperability
RESTFUL ARCHITECTURE BEST PRACTICES*
1. Prefer HTTP-GET over POST when a information resource URI is exposed.
2. Publish a logical URI for every programmable resource being exposed in the
service.
3. Logical URI are preferred over the physical URL. The logical URL (such as :
http://www.myblog.com/2008/7/2/) is better than physical URI.
(http://www.myblog.com/20080702.html)
4. Create and Follow URI Template rules; this way logical URIs can modify
the implementation without impacting client applications.
5. REST services focus on representing resources as "things" and not "actions".
The REST Uri’s are the nouns, not verbs.
*Roger L. Costello XML technologies course also discusses some of these points.
RESTFUL ARCHITECTURE BEST PRACTICES
(CONT.)
6. Design functional oriented read methods i.e. the GET methods should be
side-effect free.
7. Use the extended information links in the responses to allow the
consuming application to follow the next steps if further actions are needed.
8. As a corollary to item 6, use the extended information links for workflow
actions to allow the atomic unfolding based on the current state.
9. Meaningful Uri templates are more effective than Query strings; for
instance http://www.myblog.com/2008/7/2/ is more appropriate REST
pattern than http://www.myblog.com/page.aspx?pageid=20080702)
10. The URL delimiter “/” should be used to represent the inheritance or
“part of” relationship in the logical hierarchy. For instance
http://www.myblog.com/{year}/{month}/{day}/ is more effective than
http://www.myblog.com/{day}/{month}/{year}.
QUESTIONS
REFERENCES
• HTTP Programming with WCF and the .NET Framework 3.5 Justin Smith
http://msdn.microsoft.com/msdnmag/issues/08/01/WCFinOrcas/d
efault.aspx
• What's New for WCF in Visual Studio 2008 – Juval Lowy
http://msdn.microsoft.com/msdnmag/issues/08/02/Foundations/d
efault.aspx
• RESTful Web Services By Leonard Richardson, Sam Ruby
http://www.amazon.com/RESTful-Web-Services-LeonardRichardson/dp/0596529260
• Mix 2007 Talk by Don Box and Steve Maine “DEV03 Navigating the Programmable Web”
http://sessions.visitmix.com/default.asp?event=1011&session=20
12&pid=DEV03&disc=&id=1512&year=2007&search=DEV03
REFERENCES
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Paul Prescod has written several excellent articles on REST:
– Second Generation Web Services
• http://www.xml.com/pub/a/2002/02/06/rest.html
– REST and the Real World
• http://www.xml.com/pub/a/2002/02/20/rest.html
– SOAP, REST and Interoperability
• http://www.prescod.net/rest/standardization.html
– Evaluating XML for Protocol Control Data
• http://www.prescod.net/xml/envelopes/
• Wikipedia Entry on REST
• http://en.wikipedia.org/wiki/Representational_State_Transfer
• Publishing RSS and ATOM Feeds using WCF 3.5 Syndication Libraries
• http://www.codeproject.com/KB/WCF/WCF35RSSATOM.aspx
• Exploring WCF 3.5 Tools - WcfSvcHost and WcfTestClient
• http://www.codeproject.com/KB/WCF/WCF35Utils.aspx
• Web Service Studio
• http://www.codeplex.com/WebserviceStudio
• JSON
• http://en.wikipedia.org/wiki/JSON
CONCLUDING REMARKS
REST is a “new” paradigm for .NET Developers;
a new way to think about programming web
services but it’s not really new since we have
been using it for a long time over the web.
Any Questions / Comments … feel free to contact
[email protected]
Visit www.AdnanMasood.com