Send Stream in WCF Callback

Question

Hi All,

I wanted to implement a Stream data transfer over wcf callback.Is there any way is to achieve this?

My contract is something looks below.

Thanks in advance.

   [ServiceContract(CallbackContract = typeof(IDataTansferCallback), SessionMode = SessionMode.Required)]
    public interface IDataTransfer
    {
        [OperationContract]
        Stream Download();

        [OperationContract]
        bool Upload(Stream stream);

        [OperationContract]
        bool DownLoadAsync(string id);
    }

    [ServiceContract]
    public interface IDataTansferCallback
    {

        [OperationContract]
        void Send(Stream data);
    }

Answer 1

Hi @la07k-4914

First of all, I will give you the code：

Server port service class:

namespace Test
{
   [ServiceContract(CallbackContract=typeof(ICallback))] 
      public interface ICalculator
      {
          [OperationContract]
        void ReceiveStream(Stream a);
    }
     public interface ICallback
     {
    [OperationContract(IsOneWay = true)]
        
        void Display(string Str);
    }
     public class CalculatorService : ICalculator
     {
        public void ReceiveStream(Stream a)
         {
            StreamReader s = new StreamReader(a);
            string str = s.ReadLine();          
            s.Close();
            ICallback callback = OperationContext.Current.GetCallbackChannel<ICallback>();
             callback.Display(str);            
         }
}
}

Since my client doesn't need to get anything from the server, I set "Isoneway=true".

This is the callback method

ICallback callback = OperationContext.Current.GetCallbackChannel<ICallback>()

callback.Display(str);

This is my server startup class "Nettcpbinding":

class main
    {
        static void Main(string[] args)
        {
            using (ServiceHost host = new ServiceHost(typeof(CalculatorService)))
            {
                TcpTransportBindingElement transport = new TcpTransportBindingElement();
                host.Open();
                    Console.WriteLine("work");
                
                Console.ReadKey();
            }
        }
    }

This is my app.config(Basic ABC protocol):

<configuration>
	<system.serviceModel>
		<behaviors>
			<serviceBehaviors>
				<behavior>
					<serviceMetadata httpGetEnabled="true" httpGetUrl="http://localhost:8080/Metadata"/>
				</behavior>
			</serviceBehaviors>
		</behaviors>
		<services>
			<service name="Test.CalculatorService">
				<endpoint address="net.tcp://localhost:9003/CalculatorService" binding="netTcpBinding" contract="Test.ICalculator"/>
			</service>
		</services>
	</system.serviceModel>
</configuration>

This is my client callback class:

[ServiceContract( CallbackContract=typeof(ICallback))] 
      public interface ICalculator
      {
          [OperationContract]
        void ReceiveStream(Stream a);
    }
     public interface ICallback
     {
    [OperationContract(IsOneWay = true)]
        
        void Display(string Str);
    }
     public class CalculatorService : ICalculator
     {
        public void ReceiveStream(Stream a)
         {
            StreamReader s = new StreamReader(a);
            string str = s.ReadLine();          
            s.Close();
            ICallback callback = OperationContext.Current.GetCallbackChannel<ICallback>();
             callback.Display(str);            
         }
}

This is my client startup class

class Program
      {
         static void Main(string[] args)
          {
              InstanceContext instanceContex = new InstanceContext(new CallbackWCFService());
            CalculatorClient proxy = new CalculatorClient(instanceContex);
            FileStream f = new FileStream("C:\\Users\\Administrator\\Desktop\\a.txt", FileMode.OpenOrCreate);
            proxy.ReceiveStream(f);
            f.Close();
            Console.Read();
         }
     }

These are the basic WCF client invocation patterns above:

Here are my test results:

I've implemented callback streaming for both the server and the client. Since you didn't give me your method, I wrote the method myself.If you have any questions, you can leave a message below.

Best Regards

Qi You

---

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Answer 2

Hi @One07k-4914

I'll build you an example from scratch to demonstrate:

1.I set up a txt file myself and saved the content as an mp4 file.

2.Create a server.Most of my code is the same as you gave, and I modified your web.config file.

<serviceBehaviors>
<behavior>
<serviceMetadata httpGetEnabled="true" httpGetUrl="http://localhost:8080/Metadata"/>
<serviceDebug includeExceptionDetailInFaults="true" />
</behavior>

3.Build the client. I modified your main function code and callback code for testing.

 public void SendStream(Stream stream)
        {
            byte[] buffer = new byte[16 * 1024];
            using (MemoryStream ms = new MemoryStream())
            {
                int read;
                while ((read = stream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    ms.Write(buffer, 0, read);
                }
                byte[] result = ms.ToArray();
                string str= System.Text.Encoding.Default.GetString(result);
                File.WriteAllBytes("C:\\Users\\Administrator\\Desktop\\WriteDocument.txt", result);
                Console.WriteLine(str);
            }
        }

static void Main(string[] args)
        {
            var inst = new InstanceContext(new StreamServiceCallback());
            StreamServiceClient proxy= new StreamServiceClient(inst);
            var sss = proxy.Execute();
            Console.WriteLine(sss);
            Console.ReadLine();
        }

Here are my test results:

Best Regards

Qi You

---

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