Async WCF interface with T4

T4 template that takes a DLL, pulls out all the WCF interfaces and gives your client development team a proxy class to code against.

namespace ServerInterfaces
{
    [ServiceContract]
    public interface ILoginFacade
    {
        [OperationContract]
        [WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, 
                   Method = "GET", UriTemplate = "/Login")]
        GetLoginResponse GetLogin()

        [OperationContract]
        [WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, 
                   Method = "PUT", UriTemplate = "/Login")]
        UpdateLoginResponse UpdateLogin(UpdateLoginRequest request);

        [OperationContract]
        [WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, 
                   Method = "GET", UriTemplate = "/Login/WriteToLog")]
        void WriteToLog();
    }

    [ServiceContract]
    public interface ITradeFacade
    {
        [OperationContract]
        [WebInvoke(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, 
                   Method = "PUT", UriTemplate = "/Trades")]
        int UpdateTradesDatabase(string userId);
    }
}

Generated Client Proxy

   
/***************************************************************************************
**** GENERATED CODE:  Use t4toolbox & tangiblet4editor to update AsyncInterfaces.tt ****
****************************************************************************************/
using System;
using Newtonsoft.Json;

namespace WcfServiceDirectory
{
    public partial class Services
    {    
        public Services()
        { 
            this.LoginFacade = new LoginFacade(); 
            this.TradeFacade = new TradeFacade(); 
        }

        public LoginFacade LoginFacade { get; set; }
        public TradeFacade TradeFacade { get; set; }
    }    
    
    public class LoginFacade
    {
        private IServiceExecutor serviceExecutor;
            
        public LoginFacade()  { this.serviceExecutor = new ServiceExecutor(); }

        public void GetLogin(Action<CallCompleteEventArgs<DTOs.GetLoginResponse>> callback)
        {
            serviceExecutor.Get<DTOs.GetLoginResponse>("/Login",  callback);
        }

        public void UpdateLogin(DTOs.UpdateLoginRequest request, Action<CallCompleteEventArgs<DTOs.UpdateLoginResponse>> callback)
        {
            serviceExecutor.Put<DTOs.UpdateLoginResponse>("/Login", JsonConvert.SerializeObject(request), callback);
        }

        public void WriteToLog(Action<CallCompleteEventArgs<Object>> callback)
        {
            serviceExecutor.Get<Object>("/Login/WriteToLog",  callback);
        }
    }    
    
    public class TradeFacade
    {
        private IServiceExecutor serviceExecutor;
            
        public TradeFacade()  { this.serviceExecutor = new ServiceExecutor(); }

        public void UpdateTradesDatabase(System.String userId, Action<CallCompleteEventArgs<System.Int32>> callback)
        {
            serviceExecutor.Put<System.Int32>("/Trades", JsonConvert.SerializeObject(userId), callback);
        }
    }    
}

Core REST service execution code

namespace ClientProxy
{
    public interface IServiceExecutor
    {
        void Get<TResponse>(string uriTemplate, Action<CallCompleteEventArgs<TResponse>> callback);
        void Put<TResponse>(string uriTemplate, string request, Action<CallCompleteEventArgs<TResponse>> callback);
    }

    public class ServiceExecutor : IServiceExecutor
    {
        ServiceEnvironment serviceEnvironment = new ServiceEnvironment() { UseHttpS = false, BaseAddress = "localhost", Port = 52802 };

        public void Get<TResponse>(string uriTemplate, Action<CallCompleteEventArgs<TResponse>> callback)
        {
            var client = new WebClient();
            var address = GetUri(uriTemplate);
            client.DownloadStringCompleted += (sender, eventArgs) => 
                {
                    if (callback == null) return;
                    var response = JsonConvert.DeserializeObject<TResponse>(eventArgs.Result);
                    callback(new CallCompleteEventArgs<TResponse>(response, eventArgs)); 
                };
            client.DownloadStringAsync(address);
        }

        public void Put<TResponse>(string uriTemplate, string request, Action<CallCompleteEventArgs<TResponse>> callback)
        {
            var client = new WebClient();
            var address = GetUri(uriTemplate);
            client.UploadStringCompleted += (sender, eventArgs) => 
                {
                    if (callback == null) return;
                    var response = JsonConvert.DeserializeObject<TResponse>(eventArgs.Result);
                    callback(new CallCompleteEventArgs<TResponse>(response, eventArgs)); 
                };
            client.Headers[HttpRequestHeader.ContentType] = "application/json";
            client.UploadStringAsync(address, "PUT", request);
        }

        private Uri GetUri(string uriTemplate)
        {
            var uriString = string.Format("http{0}://{1}:{2}/Facades{3}", 
                                        serviceEnvironment.UseHttpS ? "s" : "",
                                        serviceEnvironment.BaseAddress,
                                        serviceEnvironment.Port,
                                        uriTemplate);
            return new Uri(uriString);
        }
    }
}

Source code

The solution features:

• DTOS:  A portable class library project containing DTOs
  
• Interfaces:  A class library containing the WCF interfaces.  This project also contains the T4 template scripts
  
• WCF ServiceDirectory:  A Silverlight project which calls the rest services , contains REST service calling code.
  
• A website project with Web API (WCF) REST Services

https://github.com/stevenh77/AsyncServiceInterfaces