Developing WCF Restful Services with GET and POST Methods

Here you will see how to create a WCF REST based service. In this example we will define 2 methods GetSampleMethod (method type is GET) & PostSampleMethod (method type is POST).

• GET method will take an input as String & returns a formatted String
• POST method will take an input as XML (user registration) & return a status string

Note: One should have basic knowledge on what is WCF, Why WCF & My article will discuss HOW to use WCF with webHttpBinding

We will divide this article into the below sections

1. Define the WCF Service
   
   • Define Interface
   • Define Class
   • Implement POST & GET methods
2. Define a Configuration for the WCF Service
   
   • Service Configuration
   • Behavior Configuration
3. Smoke test WCF service (before Client uses it)
4. Implement client code to use WCF Service

Define the WCF Service

1. Open VS 2010 & Select new Project, then select WCF & select WCF Service Application & name it as WCF Rest Based.
2. Now add new Service Class to this application as "MyService.svc"
3. Open interface IMservice.cs & add the below code
   
   • perationContract: PostSampleMethod
   • WebInvoke Method Type = POST as we are implementing POST
   • URI Template define the url format by which this method is identified / linked. Note: MethodName, URI Template name & Operation Contract names may not be same means, they can be different
   • PostSampleMethod will accept XML string as input in POST method. Using Stream as input parameter we can de-serialize input data before using it
     
   • 
     [OperationContract(Name = "PostSampleMethod")]
     
   [WebInvoke(Method = "POST",
   
   UriTemplate = "PostSampleMethod/New")]
   
   string PostSampleMethod(Stream data);
   
   
   
   • OpetaionContract name : GetSampleMethod
   • WebGet attribute defined method type is GET
   • Need to include below name spaces
    
       using System.ServiceModel.Web;
       using System.ServiceModel
       using System.Runtime.Serialization
       using System.IO
       [OperationContract(Name = "GetSampleMethod")]
       [WebGet(UriTemplate = "GetSampleMethod/inputStr/{name}")]
       string GetSampleMethod(string name);
    

4. Open the MyService.cs class and provide implementation for the methods defined in IMyService Interface as shown below
   
       publicstring PostSampleMethod(Stream data)
       {
       // convert Stream Data to StreamReader
       StreamReader reader =new StreamReader(data);
      
       // Read StreamReader data as string
       string xmlString = reader.ReadToEnd();
       string returnValue = xmlString;
      
       // return the XMLString data
       return returnValue;
       }
       public string GetSampleMethod(string strUserName)
       {
           StringBuilder strReturnValue = new StringBuilder();
           // return username prefixed as shown below
           strReturnValue.Append(string.Format("You have entered userName as {0}", strUserName));
           return strReturnValue.ToString();
       }

Define Configuration for WCF Service

1. Open web.config as we need to define configuration for our WCF Service. If you want our service to be accessed as part of webHttp then we need to defined webHttpBinding & mexHttpBinding.
2. In System.ServiceModel defined configuration as shown below. 

   <services>
         <servicename="WcfRestBased.MyService"
            behaviorConfiguration="myServiceBehavior">
           <endpointname="webHttpBinding"
                     address=""
                     binding="webHttpBinding"
                     contract="WcfRestBased.IMyService"
                     behaviorConfiguration="webHttp"
                     >
                   </endpoint>
           <endpointname="mexHttpBinding"
                     address="mex"
                     binding="mexHttpBinding"
                     contract="IMetadataExchange"
                     />
         </service>
    </services>

   Service Name: To find what to be given, then right click the service & select ViewMarkup option.eg in my case it is MyService.svc, look for Service attribute & use the complete string in my case it is Service="WcfRestBased.MyService"behaviorConfiguration: can be any name but this will be again used when we define behavior settings in my case it is myServiceBehavior
   
   Endpoint for webHttpBinding
   
   endpoint name: should be webHttpBinding if you are configuring for web access
   
   address: we can leave it empty
   
   binding: should be webHttpBinding
   
   contract: should be Namespace.Interfacename. In mycase it is wcfRestBased.IMyService
   
   behaviorConfiguration: should be webHttp
   
   EndPoint for mexHttpBinding
   
   These values should be same as shown above
    

3. Now define the Service behavior as shown below in System.ServiceModel. "mySeriveBehavior" name should match to behaviorConfiguration name defined in Service tag ( shown above)
    

   <behaviors>

         <serviceBehaviors>

           <behavior name="myServiceBehavior" >

             <serviceMetadata httpGetEnabled="true"/>

             <serviceDebug includeExceptionDetailInFaults="false" />

           </behavior>

           <behavior>

             <!– 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="webHttp">

             <webHttp/>

           </behavior>

         </endpointBehaviors>
   </behaviors>

Smoke test WCF service

1. Configure WCF Service in IIS
2. To check our WCF service is working properly lets test it by opening MyService.svc in browser in my case it is http://localhost/wcfrestbased/MyService.svc
3. To test our GET method service, you can call it by http://localhost/wcfrestbased/MyService.svc/GetSampleMethod/inputStr/suryaprakash & this show up data as "<string>You have entered userName as suryaprakash</string>"
4. By this we can confirm our service is working fine

Implement client code to use the WCF Service

1. Create a new website application which will act as client to access WCF services
2. Add a textbox to default.aspx page & name it as txtResult & open Default.aspx.cs
3. Define below function which will call rest service to fetch the data. This method will call POSTSAMPLEMETHOD in service (MyService) implemented. Inline code comments are added
    

   void CallPostMethod()

      {

           // Restful service URL

           string url = 

             "http://localhost/wcfrestbased/myservice.svc/PostSampleMethod/New";

           / declare ascii encoding

           ASCIIEncoding encoding = new ASCIIEncoding();

           string strResult = string.Empty;

           // sample xml sent to Service & this data is sent in POST

           string SampleXml = @"<parent>" +

                  "<child>" +

                     "<username>username</username>" +

                       "<password>password</password>" +

                      "</child>" +

                   "</parent>";

           string postData = SampleXml.ToString();

           // convert xmlstring to byte using ascii encoding

           byte[] data = encoding.GetBytes(postData);

           // declare httpwebrequet wrt url defined above

           HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(url);

           // set method as post

           webrequest.Method = "POST";

           // set content type

           webrequest.ContentType = "application/x-www-form-urlencoded";

           // set content length

           webrequest.ContentLength = data.Length;

           // get stream data out of webrequest object

           Stream newStream = webrequest.GetRequestStream();

           newStream.Write(data, 0, data.Length);

           newStream.Close();

           // declare & read response from service

           HttpWebResponse webresponse = (HttpWebResponse)webrequest.GetResponse();

           // set utf8 encoding

           Encoding enc = System.Text.Encoding.GetEncoding("utf-8?);

           // read response stream from response object

           StreamReader loResponseStream = 

               new StreamReader(webresponse.GetResponseStream(), enc);

           // read string from stream data

           strResult = loResponseStream.ReadToEnd();

           // close the stream object

           loResponseStream.Close();

           // close the response object

            webresponse.Close();

           // below steps remove unwanted data from response string

           strResult = strResult.Replace("</string>", "");

4. Now lets go ahead and implement code to call GETSAMPLEMETHOD from client application. Below code has inline comments
   
   

   void CallGetMethod()

       {

           // Restful service URL

           string url = "http://localhost/wcfrestbased/myservice.svc/

                         GetSampleMethod/inputStr/suryaprakash";

           string strResult = string.Empty;

           // declare httpwebrequet wrt url defined above

           HttpWebRequest webrequest = (HttpWebRequest)WebRequest.Create(url);

           // set method as post

           webrequest.Method = "GET";

           // set content type

           webrequest.ContentType = "application/x-www-form-urlencoded";

           // declare & read response from service

           HttpWebResponse webresponse = (HttpWebResponse)webrequest.GetResponse();

           // set utf8 encoding

           Encoding enc = System.Text.Encoding.GetEncoding("utf-8?);

           // read response stream from response object

           StreamReader loResponseStream = new StreamReader

                                 (webresponse.GetResponseStream(), enc);

           // read string from stream data

           strResult = loResponseStream.ReadToEnd();

           // close the stream object

           loResponseStream.Close();

           // close the response object

           webresponse.Close();

           // assign the final result to text box

           txtResult.Text = strResult;

       }

5. Now go ahead and call above methods to see the output of each methods.

Happy coding, Hope this helps!