building restful applications with odata
DESCRIPTION
Applications today are expected to expose their data and consume data-centric services via REST. In this session we discuss what REST is and have an overview of WCF Data Services and see how we can REST enable your data using the Open Data Protocol (OData). Then you will learn how to leverage existing skills related to Visual Studio, LINQ and data access to customize the behavior, control-flow, security model and experience of your data service. We will then see how to enable data-binding to traditional ASP.NET controls as well as Silverlight and Excel PowerPivot. We’ll then turn to consuming SharePoint and other OData based applications in .NET as well as from a non-Microsoft client. This is a very demo intensive session.TRANSCRIPT
Building RESTful Applications Building RESTful Applications with the Open Data Protocolwith the Open Data ProtocolTodd AnglinTodd AnglinChief Evangelist, Telerik
Level: Intermediate
IntroductionsIntroductions
Todd Anglin
Chief Evangelist, TelerikMicrosoft MVP
ASP InsiderPresident NHDNUG & O’Reilly Author
@toddanglin
TelerikWatch.com
The PlanThe Plan
What you should learn today:What you should learn today:
• What is REST/OData• Who created REST/OData• Why use REST/OData• When should you use REST/OData• Where can you find REST/OData
How did we get here?
“There is a vast amount of data available today and data is now being collected and stored at a rate never seen before. Much, if not most, of this data however is locked into specific applications or formats and difficult to access or to integrate into new uses.”
- OData.org
State of Data & ServicesState of Data & Services
Internal SQL
Internal SQL
My App
AppDataAppData
CMSCMS
SharePointSharePoint
CloudCloud
Custom API
SQL
JSON ServicesFBFB
What is REST?What is REST?
• Representational State Transfer
• What is the biggest REST implementation?– World Wide Web!
REST is NOT a standard!(But it uses standards)
HTTP + URLs + XML*
REST PrinciplesREST Principles
REST IllustratedREST Illustrated
Magic Kingdom(Resource)
http://disneyworld.com/parks/magic-kingdomResource URL
Representation
URL Click
(State Transfer)
Representation
RESTful ServicesRESTful Services
• Core idea:
let's have computers use the web the way humans do
Alternatives to RESTAlternatives to REST
• Most common: SOAP and RPC
• Why use SOAP (vs REST)?– Enterprise security features (WS-Security)
– ACID Transactions (WS-AtomicTransaction)
– Message error recovery (WS-ReliableMessaging)
SOAP services focus on exposing application logicREST services focus on exposing “data” (or CRUD operations on data)
SOAP services focus on exposing application logicREST services focus on exposing “data” (or CRUD operations on data)
OData does for data what REST does for services
(Finally!) What is OData?(Finally!) What is OData?
• HTTP– REST-based services
• AtomPub– Data structure
• JSON – Data delivery format
Data silo buster
Why?Why?
• Interoperability– Predictable access to data from any system
• Gaining popularity– SharePoint 2010
– SQL Server 2008 R2
– IBM WebSphere eXtreme Scale
– Azure Table Storage
– Telerik TeamPulse
– …
REST AND ODATA IN REST AND ODATA IN ACTIONACTION
DEMO
Consuming ODataConsuming OData
• Windows Phone 7 / iPhone / Mobile• AJAX / Javascript • PHP / Java / .NET • Silverlight • PowerPivot • Simple HTTP Requests (GET, POST, PUT,
DELETE)• More…
Visual Studio ToolsVisual Studio Tools
• Open Data Protocol Visualizer
CONSUMING EXISTING CONSUMING EXISTING ODATAODATA
DEMO
Creating OData ServiceCreating OData Service
• As simple as returning proper XML/JSON– No specific platform requirements
• Ways to build:– Using Visual Studio tools (WCF Data Services)
– SharePoint Lists
– Azure Table Storage
– Manually produce XML
WCF Data Services (Astoria)WCF Data Services (Astoria)
• Build RESTful services on Microsoft platform– Roots of OData protocol
• Built on WCF– Supports ATOM (XML) and JSON data representations
• Automates REST for data– Anything that implements IQueryable<T> or IUpdatable<T>
– EX: EF, LinqToSQL, 3rd party ORM, etc.
WCF DATA SERVICES WCF DATA SERVICES BASICSBASICS
DEMO
Service OperationsService Operations
• Functions exposed by OData– Similar to RPC
– Accept zero or more primitive type input params
– Can return scalar value
– [WebGet] is used for an addressable query
– [WebInvoke] is used for insert, update, and delete
http://.../OData.svc/GetProductsByRating?rating=5
InterceptorsInterceptors
• Query Interceptors– Logic runs when resource is requested
– Uses: limit the data viewed, log, perform security check
• Change Interceptors– Logic runs when a change (Add/Edit/Delete) request
is made (HTTP PUT/POST/DELETE)
SERVICE OPS & SERVICE OPS & INTERCEPTORSINTERCEPTORS
DEMO
Securing Data ServicesSecuring Data Services
• Remember!– REST is NOT a protocol, it’s a pattern
• Same security that applies to HTTP, AtomPub, JSON
• Other options:– EntitySetRights
– Hiding sensitive data with [IgnoreProperties]
– Infrastructure security – SSL, IP Filtering
– QueryInterceptors
OData & SharePoint 2010OData & SharePoint 2010
• ListData.svc– Out-of-the-box OData access to SharePoint data
– Data is NOT anonymously available!
http://siteurl/_vti_bin/listdata.svc/Announcements
When to REST?When to REST?
1. Stateless web services
2. Scalable web services (via HTTP caching)
3. Mutually understood context (OData)
4. Restricted bandwidth (Mobile)
Always, except when there is a reason NOT to REST
