How can I enable more output formats in addition to the default XML?

Question

When debugging a web service, I can test the functions using the default WSDL interface that is provided that lets me input some values for the parameters. This is very handy but outputs only XML. Is it possible to enable more options at this stage? (JSON, CSV)

Or if that is not possible, I would like to add an extra parameter to the API call, filetype=[json,csv] but how would I write this back in that format? Do I pass it as a string?

Answer 1

I am assuming you are using WCF. There are a couple of simple ways you can choose between XML or JSON results. One is to have different endpoints, and the other is to have different methods. The second option caters for your request to include a parameter on the API call, but I will briefly describe both. Consider the endpoints below:

    <endpoint address="/rest/" behaviorConfiguration="web" binding="webHttpBinding" contract="WebApplication1.Interface.ITestRest" />
    <endpoint address="/json/" behaviorConfiguration="web" binding="webHttpBinding" contract="WebApplication1.Interface.ITestJson" />
    <endpoint address="" behaviorConfiguration="web" binding="webHttpBinding" contract="WebApplication1.Interface.ITestBoth" />

The first two relate to option 1 to differentiate by endpoint (either /rest/ or /json/ will be in the url before the method, and both interfaces can define the same signature so it can just be implemented once). The last one relates to option 2 to have two methods on the interface. Here is a sample set of interfaces for the above:

[ServiceContract]
public interface ITestJson
{
  [OperationContract, WebInvoke(Method = "GET", UriTemplate = "/Echo/{Text}",
    RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
  string Echo(string Text);
}

[ServiceContract]
public interface ITestRest
{
  [OperationContract, WebInvoke(Method = "GET", UriTemplate = "/Echo/{Text}",
    RequestFormat = WebMessageFormat.Xml, ResponseFormat = WebMessageFormat.Xml)]
  string Echo(string Text);
}

[ServiceContract]
public interface ITestBoth
{
  [OperationContract, WebInvoke(Method = "GET", UriTemplate = "/Echo?Text={Text}&Format=json",
    RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]
  string EchoJ(string Text);
  [OperationContract, WebInvoke(Method = "GET", UriTemplate = "/Echo?Text={Text}&Format=xml",
    RequestFormat = WebMessageFormat.Xml, ResponseFormat = WebMessageFormat.Xml)]
  string EchoR(string Text);
}

Then a class that implements this:

public class Signature : ITestJson, ITestRest, ITestBoth
{
  public string Echo(string Text)
  {
    return Text;
  }

  public string EchoR(string Text)
  {
    return Text;
  }

  public string EchoJ(string Text)
  {
    return Text;
  }

Now you can use this in the following ways:

Service1.svc/json/echo/xxx
Service1.svc/rest/echo/xxx

Service1.svc/echo?Text=xxx&Format=json
Service1.svc/echo?Text=xxx&Format=rest

As I said at the start, these are a couple of simple ways to choose XML or Json. Your request asked for CSV as well. Currently there is no simple way to return CSV. I did find this project on CodePlex that can return TXT, but I have not checked it out.