Building RESTful Services with WCF 4.0
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The document provides an overview of building RESTful services with WCF, highlighting the simplicity and interoperability of REST compared to SOAP. It discusses how to configure WCF for REST using the web programming model and various attributes like WebGet and WebInvoke. Additionally, it touches on improvements in WCF 4.0, including automatic help pages and HTTP caching support.
![WebGetAttribute
WebGetAttribute maps HTTP GET requests to a WCF method
Supply a UriTemplate to defining URI mapping
The UriTemplate variables map to method parameters by name
BodyStyle property controls bare vs. wrapped
Request/ResponseFormat control body format
URI template
[ServiceContract]
public interface IEvalService
{
[WebGet(UriTemplate="evals?name={name}&score={score}")]
[OperationContract]
List<Eval> GetEvals(string name, int score);
...](https://image.slidesharecdn.com/gids2011restinwcfaskonnardpluralsight-120311000028-phpapp01/85/Building-RESTful-Services-with-WCF-4-0-13-320.jpg)
![WebInvokeAttribute
WebInvokeAttribute maps all other HTTP verbs to WCF
methods
Adds a Method property for specifying the verb (default is POST)
Allows mapping UriTemplate variables
Specify which
Body is deserialized into remaining parameter HTTP verb this
responds to
[ServiceContract]
public interface IEvals
{
[WebInvoke(UriTemplate ="/evals?name={name}",Method="PUT")]
[OperationContract]
void SubmitEval(string name, Eval eval /* body */);
...](https://image.slidesharecdn.com/gids2011restinwcfaskonnardpluralsight-120311000028-phpapp01/85/Building-RESTful-Services-with-WCF-4-0-14-320.jpg)
![WebMessageFormat
WCF provides support for two primary Web formats: XML &
JSON
You control the format via RequestFormat and ResponseFormat
[ServiceContract]
public interface IEvals
{
[WebGet(UriTemplate = "/evals?name={nameFilter}",
ResponseFormat = WebMessageFormat.Json)]
[OperationContract]
List<Eval> GetCurrentEvals(string nameFilter);
...
Specify the message format](https://image.slidesharecdn.com/gids2011restinwcfaskonnardpluralsight-120311000028-phpapp01/85/Building-RESTful-Services-with-WCF-4-0-16-320.jpg)
![Syndication programming model
WCF comes with a simplified syndication programming model
The logical data model for a feed is SyndicationFeed
You can use it to produce/consume feeds in a variety of formats
You use a SyndicationFeedFormatter to work with a specific
format
Use Atom10FeedFormatter or RSS20FeedFormatter today
[ServiceKnownType(typeof(Atom10FeedFormatter))]
[ServiceKnownType(typeof(Rss20FeedFormatter))]
[ServiceContract]
public interface IEvalService {
[WebGet(UriTemplate = "evalsfeed")]
[OperationContract]
allows you to return
SyndicationFeedFormatter GetEvalsFeed();
an Atom or RSS feed ...
}](https://image.slidesharecdn.com/gids2011restinwcfaskonnardpluralsight-120311000028-phpapp01/85/Building-RESTful-Services-with-WCF-4-0-17-320.jpg)
![Http caching support
WCF 4 provides a simpler model for managing HTTP caching
They built on the ASP.NET caching profile architecture
You define an [AspNetCacheProfile] for your GET operations
Shields you from dealing with HTTP caching headers yourself
[AspNetCacheProfile("CacheFor60Seconds")]
[WebGet(UriTemplate=XmlItemTemplate)]
[OperationContract]
public Counter GetItemInXml()
{
return HandleGet();
}](https://image.slidesharecdn.com/gids2011restinwcfaskonnardpluralsight-120311000028-phpapp01/85/Building-RESTful-Services-with-WCF-4-0-22-320.jpg)
Building RESTful Services with WCF 4.0
- 1. Building RESTful Services with WCF Aaron Skonnard Cofounder, Pluralsight
- 2. Overview
- 3. Why REST?
- 4. Why REST? 1. Most folks don't need SOAP's key features Transport-neutrality Advanced WS-* protocols Basic SOAP is just like REST but w/out the benefits
- 5. Why REST? 2. REST is simple and the interface is uniform It's just HTTP + XML/JSON/XHTML Uniform interface that everyone understands Therefore, it’s more interoperable!
- 6. REST is not RPC SOAP emphasizes verbs while REST emphasizes nouns or "resources" SOAP REST With REST, you define resources, getUser() and use a uniform interface to addUser() User { } operate on them (HTTP verbs) removeUser() Location { } ... getLocation() XML representation addLocation() ... <user> <name>Jane User</name> With SOAP, you define <gender>female</gender> custom operations (new <location href="http://example.org/locations/us/ny/nyc" >New York City, NY, US</location> verbs), tunnels through </user> POST
- 7. Is REST too simple for complex systems?
- 8. Why REST? 3. REST is how the Web works It scales from HTTP's built-in caching mechanisms Caching, bookmarking, navigating/links, SSL, etc You can access most REST services with a browser
- 9. REST in WCF
- 10. Windows Communication Foundation WCF doesn't take sides – it provides a unified programming model And allows you to use SOAP, POX, REST, whatever data format, etc Architecture: SOAP, REST, distributed objects, etc Transport Protocol: HTTP, TCP, MSMQ, etc WCF Message format: XML, RSS, JSON, binary, etc Message protocols: WS-*, none, etc
- 11. WCF programming styles Most of the built-in WCF bindings use SOAP & WS-* by default You have to configure them to disable SOAP WCF 3.5 comes with a new Web (REST) programming model Found in System.ServiceModel.Web.dll Allows you to map HTTP requests to methods via URI templates You enable the Web model with a new binding/behavior Apply to messaging layer using WebHttpBinding Apply to dispatcher using WebHttpBehavior
- 12. WebServiceHost WebServiceHost simplifes hosting Web-based services Derives from ServiceHost and overrides OnOpening Automatically adds endpoint for the base address using WebHttpBinding Automatically adds WebHttpBehavior to the endpoint ... this host WebServiceHost host = new WebServiceHost( adds the typeof(EvalService), Web binding new Uri("http://localhost:8080/evals")); & behavior host.Open(); // service is up and running Console.ReadLine(); // hold process open ... <%@ ServiceHost Language="C#" Service="EvalService" Factory= "System.ServiceModel.Activation.WebScriptServiceFactory" %>
- 13. WebGetAttribute WebGetAttribute maps HTTP GET requests to a WCF method Supply a UriTemplate to defining URI mapping The UriTemplate variables map to method parameters by name BodyStyle property controls bare vs. wrapped Request/ResponseFormat control body format URI template [ServiceContract] public interface IEvalService { [WebGet(UriTemplate="evals?name={name}&score={score}")] [OperationContract] List<Eval> GetEvals(string name, int score); ...
- 14. WebInvokeAttribute WebInvokeAttribute maps all other HTTP verbs to WCF methods Adds a Method property for specifying the verb (default is POST) Allows mapping UriTemplate variables Specify which Body is deserialized into remaining parameter HTTP verb this responds to [ServiceContract] public interface IEvals { [WebInvoke(UriTemplate ="/evals?name={name}",Method="PUT")] [OperationContract] void SubmitEval(string name, Eval eval /* body */); ...
- 15. WebOperationContext Use WebOperationContext to access HTTP specifics within methods To retreived the current context use WebOperationContext.Current Provides properties for incoming/outgoing request/response context Each context object surfaces most common HTTP details URI, ContentLength, ContentType, Headers, ETag, etc
- 16. WebMessageFormat WCF provides support for two primary Web formats: XML & JSON You control the format via RequestFormat and ResponseFormat [ServiceContract] public interface IEvals { [WebGet(UriTemplate = "/evals?name={nameFilter}", ResponseFormat = WebMessageFormat.Json)] [OperationContract] List<Eval> GetCurrentEvals(string nameFilter); ... Specify the message format
- 17. Syndication programming model WCF comes with a simplified syndication programming model The logical data model for a feed is SyndicationFeed You can use it to produce/consume feeds in a variety of formats You use a SyndicationFeedFormatter to work with a specific format Use Atom10FeedFormatter or RSS20FeedFormatter today [ServiceKnownType(typeof(Atom10FeedFormatter))] [ServiceKnownType(typeof(Rss20FeedFormatter))] [ServiceContract] public interface IEvalService { [WebGet(UriTemplate = "evalsfeed")] [OperationContract] allows you to return SyndicationFeedFormatter GetEvalsFeed(); an Atom or RSS feed ... }
- 18. New in 4.0
- 19. Improved REST Support Many features in the WCF REST Starter Kit are now part of WCF 4.0
- 20. Automatic help page WCF 4 provides an automatic help page for REST services Configure the <webHttp> behavior with helpEnabled=“true”
- 21. Message format selection WCF 4 also provides automatic format selection for XML/JSON This feature is built on the HTTP “Accept” headers <configuration> <system.serviceModel> <standardEndpoints> <webHttpEndpoint> <standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="true"/> </webHttpEndpoint> </standardEndpoints> </system.serviceModel> </configuration>
- 22. Http caching support WCF 4 provides a simpler model for managing HTTP caching They built on the ASP.NET caching profile architecture You define an [AspNetCacheProfile] for your GET operations Shields you from dealing with HTTP caching headers yourself [AspNetCacheProfile("CacheFor60Seconds")] [WebGet(UriTemplate=XmlItemTemplate)] [OperationContract] public Counter GetItemInXml() { return HandleGet(); }
- 23. REST project templates Download the new REST project templates via the new Visual Studio 2010 Extension Manager (Tools | Extension Manager)
- 25. WCF Web Api Futures http://wcf.codeplex.com