Developing WCF Restful Services with GET and POST Methods

Introduction

In this article, we will see how to create WCF REST based service. In this example, we will define two methods, GetSampleMethod (method type is GET) & PostSampleMethod (method type is POST).

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

Note: One should have basic knowledge of 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 WCF Service
1. Define Interface
2. Define Class
3. Implement POST & GET methods
2. Define Configuration for WCF Service
1. Service Configuration
2. Behavior Configuration
3. Smoke test WCF service (before client uses it)
4. Implement client code to use WCF service

Define 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:
1. OperationContract: PostSampleMethod
2. WebInvoke Method Type = POST as we are implementing POST
3. URI Template defines 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
4. 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);

5. OperationContract name: GetSampleMethod
6. WebGet attribute defined method type is GET
7. Need to include below namespaces:

System.ServiceModel.Web;

System.ServiceModel

System.Runtime.Serialization

System.IO

    [OperationContract(Name = “GetSampleMethod”)]

        [WebGet(UriTemplate = “GetSampleMethod/inputStr/{name}”)]

        string GetSampleMethod(string name);

4.      Open MyService.cs class and provide implementation for the methods defined in IMyService Interface as shown below:

public string 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 define webHttpBinding & mexHttpBinding.
2. In System.ServiceModel defined configuration as shown below. To know details about the below config configuration, check out the URL: https://ch1blogs.cognizant.com/blogs/279850/2011/10/18/service-end-point-not-found/.

<services>

      <service name=”WcfRestBased.MyService” 

  behaviorConfiguration=”myServiceBehavior” >

        <endpoint name=”webHttpBinding”

                  address=”"

                  binding=”webHttpBinding”

                  contract=”WcfRestBased.IMyService”

                  behaviorConfiguration=”webHttp”

                  >

                </endpoint>

        <endpoint name=”mexHttpBinding”

                  address=”mex”

                  binding=”mexHttpBinding”

                  contract=”IMetadataExchange”

                  />

      </service>

    </services>

Service Name: To find what's to be given, right click the service & select ViewMarkup option.

Example, 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 my case, it is wcfRestBased.IMyService
• behaviorConfiguration: should be webHttp

EndPoint for mexHttpBinding

These values should be same as shown above.

3. Now define Service behavior as shown below in System.ServiceModel. “mySeriveBehavior” name should match 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, let's 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 shows up data as “You have entered userName as suryaprakash”.
4. By this, we can confirm our service is working fine.

Implement Client Code to Use WCF Service

1. Create 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>”, “”);

            strResult = strResult.Substring(strResult.LastIndexOf(’>

4. Now let's go ahead and implement code to call GETSAMPLEMETHOD from client application. The 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 the above methods to see the output of each method.

Happy coding… hope this helps!

 http://www.codeproject.com/KB/WCF/DevelopWCFRestfulServices.aspx