A few days ago I was reading up on some WCF technology called Peer Channel. It looked pretty cool so I decided to try it out. I was pretty shocked to find out how easy it was to build a chat messaging service using this this stuff. I was able to run a chat client on my computer, a chat client on my friends computer, and the WCF Chat service on a server. We were able to send messages back and forth to each other (all on the same network of course). It worked pretty fast without using a lot of resouces on either computer or over the network. I threw a WPF interface on it to look nice, which was really easy to do as well. I just wanted to post up some of the code here on my blog in case anyone wanted to see how it works.
Client 1 and Client 2:
Service that runs on the server:
Only needed a few files to make it work:
Here's the code to the important files:
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PeerChannel – Client – App.config
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.serviceModel>
<client>
<!-- chat instance participating in the mesh -->
<endpoint name="ChatEndpoint" address="net.p2p://chatMesh/MyChatServer/Chat" binding="netPeerTcpBinding" bindingConfiguration="BindingCustomResolver" contract="MyChat.IChat">
</endpoint>
</client>
<bindings>
<netPeerTcpBinding>
<!-- Refer to Peer channel security samples on how to configure netPeerTcpBinding for security -->
<binding name="BindingCustomResolver" port="0">
<security mode="None"/>
<resolver mode="Custom">
<custom address="net.tcp://SERVERNAMEGOESHERE/MyChatServer/peerResolverService" binding="netTcpBinding" bindingConfiguration="Binding3"/>
</resolver>
</binding>
</netPeerTcpBinding>
<netTcpBinding>
<!-- You can change security mode to enable security -->
<binding name="Binding3">
<security mode="None"/>
</binding>
</netTcpBinding>
</bindings>
</system.serviceModel>
</configuration>
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PeerChannel – Client – ChatClient.xaml.cs
using System;
using System.DirectoryServices;
using System.Security.Principal;
using System.Windows;
using System.Windows.Input;
namespace MyChat
{
public partial class ChatClient : Window
{
PeerChat chat;
public ChatClient()
{
InitializeComponent();
}
private void btnJoin_Click(object sender, RoutedEventArgs e)
{
if (!String.IsNullOrEmpty(txtName.Text))
{
chat = new PeerChat(txtName.Text);
chat.OnChatOnline += new PeerChat.ChatOnline(chat_OnChatOnline);
chat.OnChatOffline += new PeerChat.ChatOffline(chat_OnChatOffline);
chat.OnJoin += new PeerChat.JoinChat(chat_OnJoin);
chat.OnLeave += new PeerChat.LeaveChat(chat_OnLeave);
chat.OnChat += new PeerChat.ChatSendReceive(chat_OnChat);
string result = chat.Start();
txtChat.Text += result;
}
}
void chat_OnChat(string member, string msg)
{
txtChat.Text += String.Format("[{0}] {1}" + Environment.NewLine, member, msg);
txtChat.ScrollToEnd();
}
void chat_OnLeave(string member)
{
txtChat.Text += String.Format("[{0} left]" + Environment.NewLine, member);
}
void chat_OnJoin(string member)
{
txtChat.Text += String.Format("[{0} joined]" + Environment.NewLine, member);
btnSend.IsEnabled = true;
}
void chat_OnChatOffline(object sender, EventArgs e)
{
txtChat.Text += String.Format("** Offline" + Environment.NewLine);
}
void chat_OnChatOnline(object sender, EventArgs e)
{
txtChat.Text += String.Format("** Online" + Environment.NewLine);
}
private void btnSend_Click(object sender, RoutedEventArgs e)
{
chat.SendMessage(txtMessage.Text);
txtMessage.Text = String.Empty;
}
private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
{
if (chat != null)
chat.End();
}
private void txtMessage_KeyDown(object sender, KeyEventArgs e)
{
if (e.Key == Key.Enter)
{
chat.SendMessage(txtMessage.Text);
txtMessage.Text = String.Empty;
}
}
}
}
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PeerChannel – Client – PeerChat.cs
using System;
using System.ServiceModel;
namespace MyChat
{
[ServiceContract(Namespace = "MyChat", CallbackContract = typeof(IChat))]
public interface IChat
{
[OperationContract(IsOneWay = true)]
void Join(string member);
[OperationContract(IsOneWay = true)]
void Chat(string member, string msg);
[OperationContract(IsOneWay = true)]
void Leave(string member);
}
public interface IChatChannel : IChat, IClientChannel
{
}
public class PeerChat : IChat
{
private bool IsConnected { get; set; }
string member;
IChatChannel participant;
DuplexChannelFactory<IChatChannel> factory;
public delegate void JoinChat(string member);
public delegate void ChatSendReceive(string member, string msg);
public delegate void LeaveChat(string member);
public delegate void ChatOnline(object sender, EventArgs e);
public delegate void ChatOffline(object sender, EventArgs e);
public event JoinChat OnJoin;
public event ChatSendReceive OnChat;
public event LeaveChat OnLeave;
public event ChatOnline OnChatOnline;
public event ChatOffline OnChatOffline;
public PeerChat(string member)
{
this.member = member;
}
public string Start()
{
string result = String.Empty;
InstanceContext instanceContext = new InstanceContext(this);
factory = new DuplexChannelFactory<IChatChannel>(instanceContext, "ChatEndpoint");
participant = factory.CreateChannel();
IOnlineStatus ostat = participant.GetProperty<IOnlineStatus>();
ostat.Online += new EventHandler(OnOnline);
ostat.Offline += new EventHandler(OnOffline);
try
{
participant.Open();
IsConnected = true;
}
catch (CommunicationException)
{
result += "Could not find resolver." + Environment.NewLine +
"Please make sure the Chat Server is running before using this chat client." + Environment.NewLine +
"Refer to the readme for more details." + Environment.NewLine;
IsConnected = false;
return result;
}
participant.Join(member);
return result;
}
public void SendMessage(string message)
{
participant.Chat(member, message);
}
public void End()
{
try
{
if (IsConnected)
{
if (participant != null)
{
participant.Leave(member);
participant.Close();
participant.Dispose();
}
if (factory != null)
{
factory.Close();
}
}
IsConnected = false;
}
catch (Exception)
{
}
}
public void Join(string member)
{
if (OnJoin != null)
OnJoin(member);
}
public void Chat(string member, string msg)
{
if (OnChat != null)
OnChat(member, msg);
}
public void Leave(string member)
{
if (OnLeave != null)
OnLeave(member);
}
public void OnOnline(object sender, EventArgs e)
{
if (OnChatOnline != null)
OnChatOnline(member, e);
}
public void OnOffline(object sender, EventArgs e)
{
if (OnChatOffline != null)
OnChatOffline(member, e);
}
}
}
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PeerChannel – WCF Service Console – App.config
<?xml version="1.0"?>
<configuration>
<system.serviceModel>
<services>
<service name="System.ServiceModel.PeerResolvers.CustomPeerResolverService">
<host>
<baseAddresses>
<add baseAddress="net.tcp://SERVERNAMEGOESHERE/MyChatServer/peerResolverService"/>
</baseAddresses>
</host>
<!-- use base address provided by the host -->
<endpoint address="net.tcp://SERVERNAMEGOESHERE/MyChatServer/peerResolverService" binding="netTcpBinding" bindingConfiguration="Binding1" contract="System.ServiceModel.PeerResolvers.IPeerResolverContract"/>
</service>
</services>
<bindings>
<netTcpBinding>
<!-- You can change security mode to enable security -->
<binding name="Binding1">
<security mode="None"/>
</binding>
</netTcpBinding>
</bindings>
</system.serviceModel>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>
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PeerChannel – WCF Service Console – DefaultCustomResolver.cs
using System;
using System.ServiceModel;
using System.ServiceModel.PeerResolvers;
namespace MyChatServer
{
class DefaultCustomResolver
{
public static void Main()
{
// Create a new resolver service
CustomPeerResolverService crs = new CustomPeerResolverService();
crs.ControlShape = false;
// Create a new service host
ServiceHost customResolver = new ServiceHost(crs);
// Open the resolver service
crs.Open();
customResolver.Open();
Console.WriteLine("Custom resolver service is started");
Console.WriteLine("Press <ENTER> to terminate service");
Console.ReadLine();
}
}
}
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