RESTful services are those which follow the REST (Representational State Transfer) architectural style. Before implementing your first RESTful service, lets first understand the concept behind it. As we know that WCF allows us to make calls and exchange messages using SOAP over a variety of protocols i.e. HTTP, TCP, Named Pipes and MSMQ etc. In a scenario, if we are using SOAP over HTTP, we are just utilizing HTTP as a transport. But HTTP is much more than just a transport. So, when we talk about REST architectural style, it dictates that “Instead of using complex mechanisms like CORBA, RPC or SOAP for communication, simply HTTP should be used for making calls”.
RESTful architecture use HTTP for all CRUD operations like (Read/Create/Update/Delete) using simple HTTP verbs like (GET, POST, PUT, and DELETE).It’s simple as well as lightweight. For the sake of simplicity, I am going to implement only a GET request for which service will return certain types of data (i.e. Product data) in XML format.
- Create a WCF Service Project.
- Preparing the data (e.g. Product) to return
- Creating Service Contract
- Implementing Service
- Configure Service and Behavior
You can download the complete source code for this article here.
- Open Visual Studio.
- From File -> New Project. Select WCF from left and create a new WCF Service Application.
2. Preparing the data to return
- Now add a class to newly created project. Name it to Products.cs.
3. Creating Service Contract
It will add contract as well as service file to project. Following is the code for service contract i.e. IProductRESTService.cs.
IProductRESTService contains only one method i.e. GetProductList. Important points to understand about this method is WebInvoke attribute parameters.
- Method = “GET”, represents an HTTP GET request.
- ResponseFormat = WebMessageFormat.Xml, response format will be XML here but we can return JSON as well by changing its value to WebMessageFormat.json.
- BodyStyle = WebMessageBodyStyle.Bare, indicates neither the request and nor response are wrapped. Other possible values for BodyStyle are Wrapped, WrappedRequest, WrappedResponse.
- UriTemplate = “GetProductList/”, it has two parts, URL path and query.
Don’t forget to add using System.ServiceModel.Web at top.
4. Implementing RESTful Service
In this step we are going to implement the service. Only one method GetProductList is defined in the contract, so implementing service class will be as follows:
5. Configure Service and Behavior
The last step is to configure the service and its behaviors using the configuration file. Following is the complete ServiceModel configuration settings.
Right click ProductRESTService.svc file and click “View in Browser“. You will see the following screen, that means service is fine.
An important point to consider here is that in Service Behavior Configuration, we have setted httpGetEnabled=”true” for serviceMetadata that’s why we are getting above service screen with wsdl option.
This is what we do normally for SOAP-based services. REST-based services only uses HTTP verbs on a resource, so we can disable WSDL in this case by simply setting httpGetEnabled=”false”. Now if we run the service again, we will get the following screen.
Just modify the URL in browser and add “GetProductList/” to it. So, this is the UriTemplete we defined as service contract method.
Hopefully, this simple WCF tutorial will be helpful for the readers. To keep the things simple, I restrict it to just getting records using HTTP GET verb. But you can find a complete implementation for all CRUD (Create, Read, Update, Delete) operations using RESTful service in another WCF RESTful Service tutorial here.
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