WCF With JSONP

Before start with JSONP we should know what is REST ? and how it differ from other protocols? - Learn REST

What is JSONP ?

 JSONP or "JSON with padding" is a communication technique used in JavaScript. It provides a method to request data from a server in a different domain, something prohibited by typical web browsers because of the same origin policy.

By default WCF Services will not return JSON objects as result. if we want to get JSON objects , we have to define at Service implementation level.

If you are new to WCF , check this to get basic understanding about WCF!!!  -  Simple Steps to create the WCF Service

1.  Create WCF Library (WCF Service Library Template)

      a. Create Service contracts

          [OperationContract]
          [WebGet(ResponseFormat = WebMessageFormat.Json)]
          [JSONPBehavior(callback = "method")]
      
          EmployeeWorkDto GetEmployeMoreDetailsByUserName(string logInName);
       

      b. Create Service Implementations (Check this for more details)

Create Business object (employee), Data transfer objects (employeeDto), Data access objects  (employeeDao) , object mapper class(CoreObjectMapper) and mapping   functions(EmployeeDaoToDto).

"GetEmployeByUserName" is the function do all processing and return the result as "employee". then mapper function maps the "employee" object with "employeeDto". finally "employeeDto" will be send as response of that Service call.

         public EmployeeWorkDto GetEmployeMoreDetailsByUserName(string logInName)
        {
              // Do all Your implementation here, but return as "EmployeeWorkDto" Data transfer object
              EmployeeDao empDao = new EmployeeDao();
              return  CoreObjectMapper.EmployeeDaoToDto(empDao.GetEmployeByUserName(logInName));

        }

2. Create WCF Hosting Application (WCF Service Application Template)

      a. Modify Web.config

     i. create new end point

      <endpoint address="jsp"
          binding="customBinding"
          bindingConfiguration="jsonpBinding"
          behaviorConfiguration="restBehavior"
          contract="CoreService.IEmployeeService" />

     and specify binding , binding configuration and behavior configuration

     <endpointBehaviors>
           <behavior name="restBehavior">
              <webHttp />
          </behavior>        
    </endpointBehaviors>

    <customBinding>
           <binding name="jsonpBinding" >
               <jsonpMessageEncoding />
              <httpTransport manualAddressing="true"/>
          </binding>
   </customBinding>

and Host the Service and Check whether it is working or not by invoking the services in Browser.
Use the breakpoints for debug the application (Attach appropriate Processes - IIS App pool process and w3wp.exe  )

Service Url: 
http://ServerName:portNumber/Service.svc/jsp/GetEmployeMoreDetailsByUserName?method=JsonPCallBack&logInName=User1

Result :

JsonPCallBack(
{
    "DateOfBirth":"\/Date(969042600000+0530)\/",
    "AboutMe":"This is about Me ",
    "CurrentATC":"CMB ATC",
    "Department":"Delivery",
    "Experience":8.3,
    "Interests":["UX Design","SharePoint","Photography"],
    "Languages":[""],
    "NoofPastProjects":16,
    "PermanentATC":"CMB ATC",
    "ReportingManager":"Domain\\UserName",
    "Tier":2,
    "Since":"\/Date(852057000000+0530)\/"
}
);