#define WANT_TRACE

// 
// MagicContentTypeSelectingServiceHost.cs
//
// This service host automagically allows content-type selection by URL, for all WebGet
// operations that do not have the ResponseFormat explicitly set (to WebMessageFormat.Xml or 
// WebMessageFormat.Json), and which are decorated with a special attribute 
// (ionic.samples.WcfRest.DynamicContentType). 
//
// The host does this by cloning the OperationDescription for all operations in the service contract
// that do not have an ResponseFormat explicitly specified, and then setting one of the clones
// to WebMessageFormat.Xml and the other to WebMessageFormat.Json.  Both clones point to the 
// same method in the service class, so there is no duplication of application code . 
//
// Wed, 02 Apr 2008  15:51
//


using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.ServiceModel.Description;


// If your original .svc file was:
// <%@ ServiceHost Language="C#" Debug="true" 
//     Service="CommunicationService" 
//     CodeBehind="~/App_Code/CommunicationService.cs" %>
//
// Then, to use this custom ServiceHost, specify this in your .svc file
// <%@ ServiceHost Language="C#" Debug="true" 
//     Factory="ionic.samples.WcfRest.MagicContentTypeSelectingServiceHostFactory"
//     Service="CommunicationService" 
//     CodeBehind="~/App_Code/CommunicationService.cs"  %>
//


namespace ionic.samples.WcfRest
{

  public class MagicContentTypeSelectingServiceHost : ServiceHost
  {

    public MagicContentTypeSelectingServiceHost(Type t, params Uri[] baseAddrs) : base(t, baseAddrs) { }


    public MagicContentTypeSelectingServiceHost(object singletonInstance, params Uri[] baseAddresses)
      : base(singletonInstance, baseAddresses) { }


    public MagicContentTypeSelectingServiceHost() : base() { }


    protected override void OnOpening()
    {
      TraceMe("");
      TraceMe("");
      ServiceEndpointCollection sec = this.Description.Endpoints;
      foreach (ServiceEndpoint se in sec)
      {
		TraceMe("Endpoint: ");
		TraceMe("  Address: {0}", se.Address.ToString());
		TraceMe("  Contract: {0}", se.Contract.ToString());

		var opsToAdd= new List<OperationDescription> ();
		foreach (OperationDescription opDesc in se.Contract.Operations)
		{
		  object[] attrs= opDesc.SyncMethod.GetCustomAttributes(typeof(ionic.samples.WcfRest.DynamicContentType), false);
		  if ((attrs != null) && ( attrs.Length == 1)) 
		  {
			TraceMe("  operation: {0}", opDesc.Name);
			TraceMe("    Marked with {0} attribute", typeof(ionic.samples.WcfRest.DynamicContentType));

			System.ServiceModel.Web.WebGetAttribute wga= 
			  opDesc.Behaviors.Find<System.ServiceModel.Web.WebGetAttribute>() ;

			if (wga != null)
			{
			  if (wga.IsResponseFormatSetExplicitly)
			  {
				throw new System.Exception
				  ( String.Format("On method '{0}', there are conflicting attributes. When using the " +
								  "custom service host {1}, on a method that is marked with {2}, the " + 
								  "ResponseFormat in the WebGet attribute must be omitted.", 
								  opDesc.Name, 
								  this.GetType().ToString(), 
								  typeof(ionic.samples.WcfRest.DynamicContentType)));

			  }

			  TraceMe("    Cloning this operation ...");

			  // Now, clone this OperationDescription.
			  // We can copy references to all properties, except those we are changing. 
			  // The only thing that is changing is the WebGetAttribute, so 
			  // we must actually new up one of those. 

			  OperationDescription od= new OperationDescription(opDesc.Name+".clone", opDesc.DeclaringContract);

			  string rootTemplate= wga.UriTemplate;
			  System.ServiceModel.Web.WebGetAttribute wga2= null;
			  foreach (System.ServiceModel.Description.IOperationBehavior b in opDesc.Behaviors) 
			  {
				if ((b as System.ServiceModel.Web.WebGetAttribute) != null)
				{
				  wga2= new System.ServiceModel.Web.WebGetAttribute();
				  if (wga.IsBodyStyleSetExplicitly)
					wga2.BodyStyle = wga.BodyStyle;

				  if (wga.IsRequestFormatSetExplicitly)
					wga2.RequestFormat = wga.RequestFormat;

				  // Now, differentiate the two WebGetAttribute instances with the ResponseFormat.
				  // The original OperationDescription gets XML, the clone gets JSON
				  wga.ResponseFormat = System.ServiceModel.Web.WebMessageFormat.Xml;
				  wga2.ResponseFormat = System.ServiceModel.Web.WebMessageFormat.Json;
				  wga.UriTemplate = rootTemplate + "/xml";
				  wga2.UriTemplate = rootTemplate + "/json";

				  od.Behaviors.Add(wga2);

				}
				else
				  od.Behaviors.Add(b);
			  }

			  foreach (System.ServiceModel.Description.MessageDescription md in opDesc.Messages)
				od.Messages.Add(md);

			  foreach (System.ServiceModel.Description.FaultDescription fd in opDesc.Faults)
				od.Faults.Add(fd);

			  od.SyncMethod= opDesc.SyncMethod;

			  // remember to add this OperationDescription to the service contract
			  opsToAdd.Add(od);
			}
		  }
		}

		// add the cloned operation descriptions to the ServiceContract
		foreach (OperationDescription od in opsToAdd)
		  se.Contract.Operations.Add(od);
      }
      base.OnOpening();

      TraceMe("");
      TraceMe("");
    }




    #if WANT_TRACE
    // this is for tracing within IIS
    private string TraceFilePath = String.Format("c:\\temp\\MagicContentTypeSelectingServiceHost.Log.txt");
    #endif
    private void TraceMe(string s)
    {
      #if WANT_TRACE
      //             using (System.IO.StreamWriter sw = System.IO.File.AppendText(TraceFilePath))
      //             {
      //                 if (s != "")
      //                     sw.Write(DateTime.Now.ToString("dd MMM yyyy HH:mm:ss - "));
      //                 sw.WriteLine(s);
      //             }

      // This is for tracing within a console app. 
      if (s != "")
		Console.WriteLine("{0} - {1}", DateTime.Now.ToString("dd MMM yyyy HH:mm:ss"),s);
      else
		Console.WriteLine(s);

      #endif
    }


    private void TraceMe(string format, params Object[] values)
    {
      #if WANT_TRACE
      String s = String.Format(format, values);
      TraceMe(s);
      #endif
    }

  }

  public class MagicContentTypeSelectingServiceHostFactory : System.ServiceModel.Activation.ServiceHostFactory
  {
    protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
    {
      return new MagicContentTypeSelectingServiceHost(serviceType, baseAddresses);
    }
  }


  // the marker attribute
  [System.AttributeUsage( System.AttributeTargets.Method )]
    class DynamicContentType: System.Attribute
    {
    }

}