ASP.NET Web API is a framework that makes it easy to build HTTP services that reach a broad range of clients, including browsers and mobile devices. ASP.NET Web API is an ideal platform for building RESTful applications on the .NET Framework.

1. ASP.NET Web API
Udaiappa Ramachandran
NHDN-Nashua .NET/Cloud Computing UG Lead
Email: udaiappa@gmail.com
Blog: http://cloudycode.wordpress.com

2. Agenda
 Introduction to Web API
 Web API Routing
 Web API Pipeline
 Dependency Injections and Resolvers
 Model Binding and Media Formats
 Self Hosting
 Deploying Web API into cloud
 References

3. Introduction to Web API
 Next iteration of WCF REST
 Framework for developing REST Services
 Released part of ASP.NET MVC
 Uses HTTP protocol
 Accessible from wide variety of clients
 Http Methods: GET, POST, PUT, DELETE
 URLs and Methods

4. Demo: Web API Basics

5. Web API Routing
 Web API Routing very similar to MVC routing
 Action determined using the HTTP method not the URI path
 Uses “api” in the rout is to avoid collisons with ASP.NET MVC
routing.
 Adds “Controller” to the controller part of the URL
 Default mapping thru global.asax
 Additional URL parameters are mapped as action parameters
 Explicitly specify the HTTP methods for an action by decorating
the action method with HttpGet, HttpPut, HttpPost or
HttpDelete attribute
 Action can be defined thru AcceptVerbs as a method attributes
 Route by Action Name
 Override action name by using ActionName attribute
 Ignore action by NoAction Attribute

6. Demo: Web API Routing

7. Filtering
 Uses OData specific keywords
Directs that related records should be retrieved in the record or collection
$expand
being retrieved.
Specifies an expression or function that must evaluate to ‘true’ for a record to
$filter
be returned in the collection.
$orderby Determines what values are used to order a collection of records.
$select Specifies a sub set of properties to return.
$skip Sets the number of records to skip before it retrieves records in a collection.
$top Determines the maximum number of records to return.
Install-Package Microsoft.AspNet.WebApi.OData -Pre

8. Demo: Web API Filtering

9. Web API Pipeline
 Both Request and Response Model have pipeline
 Web API has client and server side pipelines
 Both Share the common object HttpMessageHandler
 HttpRequestMessage
 Represents all info about http request such as URL, HTTP Methods and
Headers
 HttpResponseMessage
 Represents all the info about the Http Response such as StatusCode,
Success Flag, Original Http Request
 HttpMessageHandler
 Common for both Request and Response
 Most common processing code can be placed here
 Ideal for authentication
 Two Scopes: Global and Per-Route
 Custom Handlers
 Inherit DelegatingHandler
 Custom code to perform any kind of per request functionality

10. Pipeline Elements

11. Pipeline Elements

12. Demo: Web API Pipeline
Demo: Custom Handlers

13. Dependency Resolution
 Service Oriented Architecture for Decoupling the
object
 IoC: The concept of allowing something outside of
system to control it.
 Often done thru DI frameworks
 Unity
 Ninject
 Castle Windsor
 Structure Map
 Spring.net
 Autofac
 Web API provides a hook for us to wire up the
complex dependency

14. Demo: Simple Resolver
Demo: Resolve using DI Framework

15. Data Model and MIME types
 Returning JSON
 Default return format
 Good for mobile apps
 does not require any special code
 Returning XML
 No code change
 Set the request content type as application/xml
 Mime Types:
 return virtually anything that can be sent over the web
 Inherit from BufferedMediaTypeFormatter
 Override key methods
 attach media formatter to configuration

16. Demo: Data Model
Demo: MIME Types

17. Hosting
 IIS
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 Self Hosting
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19. Demo: Self Hosting

20. Resource
 http://cloudycode.wordpress.com
 http://www.asp.net/web-api/overview
 http://code.msdn.microsoft.com/ASPNET-Web-API-Self-
Host-30abca12
 http://msdn.microsoft.com/en-us/library/gg309461.aspx
 http://blogs.msdn.com/b/webdev/archive/2012/08/26/asp-
net-web-api-and-httpclient-samples.aspx

21. Q&A