REST which stands for Representational State Transfer is a way of sending data over the Internet without an additional message layer. Standard web services use soap for there message header. In this example we will create a service that uses the northwind database to send a list of the products for a category.
Lets start by create a new VB web application. In that web application add a Ado.Net Entities data model. In that class add the northwind database's product class.
Now add a service named Service1 to the web application. Lets start by modify the web.config for the service to support rest. First remove the ServiceBehavior section and add a endpointBehaviors section for webHttp. In the endpoint we have to change the binding to webHttpBinding and the behaviorConfiguration to the webBehavior we created.
<system.serviceModel>
<behaviors>
<endpointBehaviors>
<behavior name="webBehavior">
<webHttp/>
</behavior>
</endpointBehaviors>
</behaviors>
<serviceHostingEnvironment aspNetCompatibilityEnabled="True"></serviceHostingEnvironment>
<services>
<service name="RestTest.Service1">
<endpoint address="" behaviorConfiguration="webBehavior" binding="webHttpBinding" bindingConfiguration="" contract="RestTest.IService1">
</endpoint>
</service>
</services>
</system.serviceModel>
When we added the service we got 2 items the wcf service and an interface for the service. Before we go any further we need to add a reference to system.servicebehavior.web
In the Interface we need to define the how the categoryId is passed to the service. In this example it expects product/categoryID in the url for the service
Imports System.ServiceModel
Imports System.ServiceModel.Web
<ServiceContract()> _
Public Interface IService1
<OperationContract()> _
<WebGet(UriTemplate:="Product/{categoryID}", ResponseFormat:=WebMessageFormat.Xml, BodyStyle:=WebMessageBodyStyle.Bare)> _
Function GetProducts(ByVal categoryId As String) As List(Of Products)
End Interface
In the service we need to set the AspNetCompatibilityMode and write some code to return the products
Imports System.ServiceModel.Activation
<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)> _
Public Class Service1
Implements IService1
Public Function GetProducts(ByVal categoryId As String) As System.Collections.Generic.List(Of Products) Implements IService1.GetProducts
Dim dc As New NorthwindEntities
Dim q = From p In dc.Products Select p Where p.CategoryID = CInt(categoryId)
Return q.ToList
End Function
End Class
To call the service you would use a url like http://localhost:2050/Service1.svc/Product/7
you will get an xml file like this returned
