WCF Rest Services

When we are designing processes which expose data across multi-platform and systems, we have to consider the implementation of REST Services

REST stands for Representational State Transfer. In RESTful systems, servers expose resources using a URI, and clients access these resources using the four HTTP verbs

GET: used exclusively to retrieve data

DELETE: used for deleting resources

PUT: used to add or change a resource

POST: used to modify and update a resource

In this example, we will develop a REST Service with Xml and Json responses, using WCF, and will make the whole circuit to the call

The first step is beginning a new WCF Application. This is the implementation of the interface with the definition of the service contract

 
	namespace RestWCFService
    {
        [ServiceContract]
        public interface IRestService
        {
            [OperationContract]
            [WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Xml,
                BodyStyle = WebMessageBodyStyle.Wrapped, UriTemplate = "getXml/{id}")]
            string XmlElement(string id);

            [OperationContract]
            [WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Json,
                BodyStyle = WebMessageBodyStyle.Wrapped, UriTemplate = "getJson/{id}")]
            string JsonElement(string id);
        }
    }
    

The next step is implementing the service contract

 
	public class RestService : IRestService
    {
        public string XmlElement(string atomicSymbol)
        {
            return getElement(atomicSymbol);
        }

        public string JsonElement(string atomicSymbol)
        {
            return getElement(atomicSymbol);
        }

        private string getElement(string aSymbol)
        {
            Dictionary<string, string> Elements = getElementsTable();

            if (Elements.Keys.Contains(aSymbol))
                return "the element is " + Elements[aSymbol];
            else
                return "there is no match for " + aSymbol;
        }
    }

Now we have to set up the web.config file, changing the next sections:

 
	<services>
      <service name="RestWCFService.RestService" behaviorConfiguration="ServiceBehavior">
        <endpoint binding="webHttpBinding" contract="RestWCFService.IRestService" 
            behaviorConfiguration="web">
        </endpoint>
      </service>
    </services>
    
    <behaviors>
      <serviceBehaviors>
        <behavior name="ServiceBehavior">
          <!-- To avoid disclosing metadata information, set the value below to false 
           and remove the metadata endpoint above before deployment -->
          <serviceMetadata httpGetEnabled="true"/>
          <!-- To receive exception details in faults for debugging purposes, 
           set the value below to true. Set to false before deployment 
           to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
      <endpointBehaviors>
        <behavior name="web">
          <webHttp helpEnabled="true" faultExceptionEnabled="true"/>
        </behavior>
      </endpointBehaviors>
    </behaviors>

- The 'services' section will point to our service contract definition, and the 'behaviors' section will enable the http get method

Now we publish the service and check it from the browser

http://localhost:9479/RestService.svc/getXml/O

http://localhost:9479/RestService.svc/getJson/K

To call this service from the client layer we can make use of jQuery Ajax, the code is the next

 
	function getChemical(atomicSymbol) {

        $.ajax({
            url: "http://localhost:9479/RestService.svc/getJson/" + atomicSymbol,
            type: "GET",
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            data: {},
            processdata: true,
            success: function (response) {

                var element = response.JsonElementResult;
                $('#lblElement').html(element);
            },

            error: function (e) {
                alert(e.status + ". " + e.statusText);
            }
        });
    }

<METHOD SOFTWARE © 2013>

Adding HTML5 Intellisense

When we develop web applications with HTML5 API, we can add HTML5 Intellisense, here is the link to download the installer for Visual Studio and Visual Web Developer 2010 and 2008

HTML 5 Intellisense for Visual Studio 2010 and 2008

We just have to install and the option for HTML5 validation code will appear automatically in our tool bar

Now we will see how the Intellisense displays with HTML5 tags

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