WebSocket Implementation

WebSocket Implementation - c#

I want to Create WebSocket Example in which i do not want to refresh the page for getting latest data.
I Create one Html page in which create one object of websocket.
E.g
ClientSide Implementation
var ws = new WebSocket(hostURL);
ws.onopen = function ()
{
// When Connection Open
};
ws.onmessage = function (evt)
{
// When Any Response come from WebSocket
}
ws.onclose = function (e)
{
// OnClose of WebSocket Conection
}
Server Side Implementation
public class WebSocketManager : WebSocketHandler
{
private static WebSocketCollection WebSocketObj4AddMessage = new WebSocketCollection();
public override void OnOpen()
{
// Do when Connection Is Open
}
public override void OnClose()
{
// Close Connection
}
public override void OnMessage(string message)
{
// When Any Message Sent to Client
}
}
Is I am doing right way to use WebSocket ?
Please help me to clear out in this section.

Here a sample.
First you have to install Asp.net SignalR package along with its dependenies.
You have call the SignalR when the app starts
namespace ABC
{
public partial class Startup
{
public void Configuration(IAppBuilder app)
{
ConfigureAuth(app);
app.MapSignalR(); <--{Add this line}
}
}
}
You have start the SqlDependency when app start and stop when app stops in the Global.asax file.
string ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionStringsName"].ConnectionString;
protected void Application_Start()
{
SqlDependency.Start(ConnectionString);
}
protected void Application_End()
{
SqlDependency.Stop(ConnectionString);
}
You have to create custom Hubclass extending Hub Base class
public class MessagesHub : Hub
{
[HubMethodName("sendMessages")]
public void SendMessages()
{
IHubContext context = GlobalHost.ConnectionManager.GetHubContext<MessagesHub>();
context.Clients.All.updateMessages();
}
}
Then in the client page, you have add these code in the javascript section
$(function () {
// Declare a proxy to reference the hub.
var notifications = $.connection.messagesHub;
//debugger;
// Create a function that the hub can call to broadcast messages.
notifications.client.updateMessages = function () {
getAllMessages()
};
// Start the connection.
$.connection.hub.start().done(function () {
getAllMessages();
}).fail(function (e) {
alert(e);
});
});
function getAllMessages() {
$.ajax({
url: '../../Notifications/GetNotificationMessages',
.
.
}
The server call this function when there there is any change in the database table using sqlDependency
The getAllMessages() is the controller for your code to handle, that should be shown in the view page and it will be call when the app starts and any change in db
public ActionResult GetNotificationMessages()
{
NotificationRepository notification = new NotificationRepository();
return PartialView("_NotificationMessage");
}
The in model class
public class NotificationRepository
{
readonly string connectionString = ConfigurationManager.ConnectionStrings["InexDbContext"].ConnectionString;
public IEnumerable<Notification> GetAllMessages(string userId)
{
var messages = new List<Notification>();
using(var connection = new SqlConnection(connectionString))
{
connection.Open();
using (var command = new SqlCommand(#"SELECT [NotificationID], [Message], [NotificationDate], [Active], [Url], [userId] FROM [dbo].[Notifications] WHERE [Active] = 1 AND [userId] ='" + userId + "'", connection))
{
command.Notification = null;
var dependency = new SqlDependency(command);
dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);
if (connection.State == ConnectionState.Closed)
{
connection.Open();
}
var reader = command.ExecuteReader();
while (reader.Read())
{
messages.Add(item: new Notification { NotificationID = (int)reader["NotificationID"], Message = (string)reader["Message"], Url = (string)reader["Url"] });
}
}
}
return messages;
}
private void dependency_OnChange(object sender, SqlNotificationEventArgs e)
{
if (e.Type == SqlNotificationType.Change)
{
MessagesHub message = new MessagesHub();
message.SendMessages();
}
}
}
This well show latest data when the database table is updated. the message will shown at runtime.
Hope this helps

You are on the right path
You can refer this if I am not late ...This is working example
CLIENT SIDE
var ws;
var username = "JOHN";
function startchat() {
var log= $('log');
var url = 'ws://<server path>/WebSocketsServer.ashx?username=' + username;
ws = new WebSocket(url);
ws.onerror = function (e) {
log.appendChild(createSpan('Problem with connection: ' + e.message));
};
ws.onopen = function () {
ws.send("I am Active-" +username);
};
ws.onmessage = function (e) {
if (e.data.toString() == "Active?") {
ws.send("I am Active-" + username);
}
else {
}
};
ws.onclose = function () {
log.innerHTML = 'Closed connection!';
};
}
</script>
<div id="log">
</div>
Server Side in Websocketserver.ashx page
public class WebSocketsServer : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
if (context.IsWebSocketRequest)
{
context.AcceptWebSocketRequest(new MicrosoftWebSockets());
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
Add below class in the server side
public class MicrosoftWebSockets : WebSocketHandler
{
private static WebSocketCollection clients = new WebSocketCollection();
private string msg;
public override void OnOpen()
{
this.msg = this.WebSocketContext.QueryString["username"];
clients.Add(this);
clients.Broadcast(msg);
}
public override void OnMessage(string message)
{
clients.Broadcast(string.Format(message));
}
public override void OnClose()
{
clients.Remove(this);
clients.Broadcast(string.Format(msg));
}
add this dll to the above class
using Microsoft.Web.WebSockets;
I donot remeber where I got the reference ...but above code is derived from my current working application

Related

How to use signalr in Android

I am trying to integrate signalR in android app but no luck. I've been looking at various links but none of them provide proper information about implementation.
I've the following questions.
SignalR integration has to be done inside Service/Intent Service?
If we want to receive response via same calling method then how to get?
I've added three libraries i.e signalr android,signalr client and gson but unable to understand how code works, no proper documentation is available to understand the code.
Some of the questions asked but not much information
SignalR in Android Studio
Unable to implement p2p chat using SignalR in Android
If anyone experienced in signal for native apps, it would be very helpful for me.
Update
public class SignalRService extends Service {
private static final String TAG = "Service";
private HubConnection mHubConnection;
private HubProxy mHubProxy;
private Handler mHandler; // to display Toast message
private final IBinder mBinder = new LocalBinder();
private SharedPreferences sp;
#Override
public void onCreate() {
super.onCreate();
Utility.showLog(TAG, "Service Created");
sp = getSharedPreferences(Utility.SHARED_PREFS, MODE_PRIVATE);
mHandler = new Handler(Looper.myLooper());
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
int result = super.onStartCommand(intent, flags, startId);
startSignalR();
return result;
}
#Override
public IBinder onBind(Intent intent) {
startSignalR();
return mBinder;
}
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
public SignalRService getService() {
// Return this instance of SignalRService so clients can call public methods
return SignalRService.this;
}
}
/**
* method for clients (activities)
*/
public void sendMessage() {
String SERVER_METHOD_SEND = "iAmAvailable";
final String string = new String();
mHubProxy.invoke(new String(), SERVER_METHOD_SEND, sp.getString("user_id", null), sp.getString("pass", null), "TransMedic").done(new Action() {
#Override
public void run(Object o) throws Exception {
Utility.showLog(TAG, o.toString());
}
}).onError(new ErrorCallback() {
#Override
public void onError(Throwable throwable) {
}
});
}
private void startSignalR() {
Platform.loadPlatformComponent(new AndroidPlatformComponent());
String serverUrl = "http://transit.alwaysaware.org/signalr";
mHubConnection = new HubConnection(serverUrl);
String SERVER_HUB_CHAT = "ChatHub";
mHubProxy = mHubConnection.createHubProxy(SERVER_HUB_CHAT);
ClientTransport clientTransport = new ServerSentEventsTransport(mHubConnection.getLogger());
SignalRFuture<Void> signalRFuture = mHubConnection.start(clientTransport);
try {
signalRFuture.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
return;
}
sendMessage();
}
#Override
public void onDestroy() {
mHubConnection.stop();
super.onDestroy();
}
}

UPDATE 2018:
If you are using SignalR.net Core use this library otherwise you will get error on connection.
SERVER SIDE:
The following is my sample server-side code, you can pay attention to public void Send(string message) and public void SendChatMessage(string to, string message).
Server-side app: public void SendChatMessage(string to, string message)
Android client app: mHubProxy.invoke("SendChatMessage", receiverName, message);
Server-side app: public void Send(string message)
Android client app: mHubProxy.invoke("Send", message);
namespace SignalRDemo
{
public class ChatHub : Hub
{
private static ConcurrentDictionary<string, string> FromUsers = new ConcurrentDictionary<string, string>(); // <connectionId, userName>
private static ConcurrentDictionary<string, string> ToUsers = new ConcurrentDictionary<string, string>(); // <userName, connectionId>
private string userName = "";
public override Task OnConnected()
{
DoConnect();
Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Online" });
return base.OnConnected();
}
public override Task OnDisconnected(bool stopCalled)
{
if (stopCalled) // Client explicitly closed the connection
{
string id = Context.ConnectionId;
FromUsers.TryRemove(id, out userName);
ToUsers.TryRemove(userName, out id);
Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Offline" });
}
else // Client timed out
{
// Do nothing here...
// FromUsers.TryGetValue(Context.ConnectionId, out userName);
// Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Offline By TimeOut"});
}
return base.OnDisconnected(stopCalled);
}
public override Task OnReconnected()
{
DoConnect();
Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = "I'm Online Again" });
return base.OnReconnected();
}
private void DoConnect()
{
userName = Context.Request.Headers["User-Name"];
if (userName == null || userName.Length == 0)
{
userName = Context.QueryString["User-Name"]; // for javascript clients
}
FromUsers.TryAdd(Context.ConnectionId, userName);
String oldId; // for case: disconnected from Client
ToUsers.TryRemove(userName, out oldId);
ToUsers.TryAdd(userName, Context.ConnectionId);
}
public void Send(string message)
{
// Call the broadcastMessage method to update clients.
string fromUser;
FromUsers.TryGetValue(Context.ConnectionId, out fromUser);
Clients.AllExcept(Context.ConnectionId).broadcastMessage(new ChatMessage() { UserName = fromUser, Message = message });
}
public void SendChatMessage(string to, string message)
{
FromUsers.TryGetValue(Context.ConnectionId, out userName);
string receiver_ConnectionId;
ToUsers.TryGetValue(to, out receiver_ConnectionId);
if (receiver_ConnectionId != null && receiver_ConnectionId.Length > 0)
{
Clients.Client(receiver_ConnectionId).broadcastMessage(new ChatMessage() { UserName = userName, Message = message });
}
}
}
public class ChatMessage
{
public string UserName { get; set; }
public string Message { get; set; }
}
}
CLIENT SIDE:
If you have not read my answer at the following question:
SignalR integration in android studio
Then, here is my working basic code:
public class SignalRService extends Service {
private HubConnection mHubConnection;
private HubProxy mHubProxy;
private Handler mHandler; // to display Toast message
private final IBinder mBinder = new LocalBinder(); // Binder given to clients
public SignalRService() {
}
#Override
public void onCreate() {
super.onCreate();
mHandler = new Handler(Looper.getMainLooper());
}
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
int result = super.onStartCommand(intent, flags, startId);
startSignalR();
return result;
}
#Override
public void onDestroy() {
mHubConnection.stop();
super.onDestroy();
}
#Override
public IBinder onBind(Intent intent) {
// Return the communication channel to the service.
startSignalR();
return mBinder;
}
/**
* Class used for the client Binder. Because we know this service always
* runs in the same process as its clients, we don't need to deal with IPC.
*/
public class LocalBinder extends Binder {
public SignalRService getService() {
// Return this instance of SignalRService so clients can call public methods
return SignalRService.this;
}
}
/**
* method for clients (activities)
*/
public void sendMessage(String message) {
String SERVER_METHOD_SEND = "Send";
mHubProxy.invoke(SERVER_METHOD_SEND, message);
}
private void startSignalR() {
Platform.loadPlatformComponent(new AndroidPlatformComponent());
Credentials credentials = new Credentials() {
#Override
public void prepareRequest(Request request) {
request.addHeader("User-Name", "BNK");
}
};
String serverUrl = "http://192.168.1.100";
mHubConnection = new HubConnection(serverUrl);
mHubConnection.setCredentials(credentials);
String SERVER_HUB_CHAT = "ChatHub";
mHubProxy = mHubConnection.createHubProxy(SERVER_HUB_CHAT);
ClientTransport clientTransport = new ServerSentEventsTransport(mHubConnection.getLogger());
SignalRFuture<Void> signalRFuture = mHubConnection.start(clientTransport);
try {
signalRFuture.get();
} catch (InterruptedException | ExecutionException e) {
e.printStackTrace();
return;
}
String HELLO_MSG = "Hello from Android!";
sendMessage(HELLO_MSG);
String CLIENT_METHOD_BROADAST_MESSAGE = "broadcastMessage";
mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE,
new SubscriptionHandler1<CustomMessage>() {
#Override
public void run(final CustomMessage msg) {
final String finalMsg = msg.UserName + " says " + msg.Message;
// display Toast message
mHandler.post(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(), finalMsg, Toast.LENGTH_SHORT).show();
}
});
}
}
, CustomMessage.class);
}
}
Activity:
public class MainActivity extends AppCompatActivity {
private final Context mContext = this;
private SignalRService mService;
private boolean mBound = false;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = new Intent();
intent.setClass(mContext, SignalRService.class);
bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}
#Override
protected void onStop() {
// Unbind from the service
if (mBound) {
unbindService(mConnection);
mBound = false;
}
super.onStop();
}
public void sendMessage(View view) {
if (mBound) {
// Call a method from the SignalRService.
// However, if this call were something that might hang, then this request should
// occur in a separate thread to avoid slowing down the activity performance.
EditText editText = (EditText) findViewById(R.id.edit_message);
if (editText != null && editText.getText().length() > 0) {
String message = editText.getText().toString();
mService.sendMessage(message);
}
}
}
/**
* Defines callbacks for service binding, passed to bindService()
*/
private final ServiceConnection mConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName className,
IBinder service) {
// We've bound to SignalRService, cast the IBinder and get SignalRService instance
SignalRService.LocalBinder binder = (SignalRService.LocalBinder) service;
mService = binder.getService();
mBound = true;
}
#Override
public void onServiceDisconnected(ComponentName arg0) {
mBound = false;
}
};
}
CustomMessage Class:
public class CustomMessage {
public String UserName;
public String Message;
}
You can also see my sample client project at this GitHub link
UPDATE FOR RESPONSE FROM INVOKE:
I have just added new sample methods:
Server side:
public string iAmAvailable(string username, string password, string message)
{
return "BNK Response for testing Android INVOKE";
}
Client side:
mHubProxy.invoke(String.class, "iAmAvailable", "username", "password", "TransMedic").done(new Action<String>() {
#Override
public void run(String s) throws Exception {
Log.w("SimpleSignalR", s);
}
}).onError(new ErrorCallback() {
#Override
public void onError(Throwable throwable) {
Log.e("SimpleSignalR", throwable.toString());
}
});
And here is the screenshot:

This work for me : Full source Android (Client) & Server GitHub
Server Slide If one argument must use this interface SubscriptionHandler1 if two argument must use this interfaceSubscriptionHandler2 ,...
Sample for two argument like :
Server slide :
using Microsoft.AspNet.SignalR;
namespace SignalRChat
{
public class ChatHub : Hub
{
public void Send(string name, string message)
{
// Two argument must use this interfaceSubscriptionHandler2 .
Clients.All.broadcastMessage(name, message);
}
}
}
Client slide :
mHubProxy.on(CLIENT_METHOD_BROADAST_MESSAGE,
new SubscriptionHandler2<String, String>() {
#Override
public void run(final String name,final String msg) {
final String finalMsg = msg.toString();
// display Toast message
mHandler.post(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(), finalMsg, Toast.LENGTH_SHORT).show();
}
});
}
}
, String.class,String.class);
For catch all message can use this :
mHubConnection.received(new MessageReceivedHandler() {
#Override
public void onMessageReceived(final JsonElement json) {
Log.e("onMessageReceived ", json.toString());
mHandler.post(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(), json.toString(), Toast.LENGTH_SHORT).show();
}
});
}
});

The SignalR team recently released a Java client for ASP.NET Core SignalR. Here is a link to getting started docs https://learn.microsoft.com/en-us/aspnet/core/signalr/java-client?view=aspnetcore-2.2

do this tutorial step by step :
https://learn.microsoft.com/en-us/aspnet/core/tutorials/signalr?tabs=visual-studio-mac&view=aspnetcore-5.0
1.According above tutorial publish your chat server to favorite host
2.add this dependency to your android sample:
implementation 'com.microsoft.signalr:signalr:3.0.0'
3.add these permission to manifest.xml
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
4.below code is MainActivity.class:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
HubConnection hubConnection =
HubConnectionBuilder.create("https://your_chat_server_url/chatHub").build();
TextView textView = (TextView)findViewById(R.id.tvMain);
ListView listView = (ListView)findViewById(R.id.lvMessages);
Button sendButton = (Button)findViewById(R.id.bSend);
EditText editText = (EditText)findViewById(R.id.etMessageText);
List<String> messageList = new ArrayList<String>();
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(MainActivity.this,
android.R.layout.simple_list_item_1, messageList);
listView.setAdapter(arrayAdapter);
hubConnection.on("ReceiveMessage", (user, message)-> {
runOnUiThread(new Runnable() {
#Override
public void run() {
arrayAdapter.add( user + " : " + message);
arrayAdapter.notifyDataSetChanged();
}
});
}, String.class,String.class);
sendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String message = editText.getText().toString();
String user = "SAEID";
editText.setText("");
try {
hubConnection.send("SendMessage", user,message);
} catch (Exception e) {
e.printStackTrace();
}
}
});
new HubConnectionTask().execute(hubConnection);
}
static class HubConnectionTask extends AsyncTask<HubConnection, Void, Void>{
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected Void doInBackground(HubConnection... hubConnections) {
HubConnection hubConnection = hubConnections[0];
hubConnection.start().blockingAwait();
return null;
}
}
}
5.below code is activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical" >
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/tvMain" />
<ListView
android:layout_height="0dp"
android:layout_weight="1"
android:layout_width="fill_parent"
android:id="#+id/lvMessages"
android:transcriptMode="alwaysScroll">
</ListView>
<EditText
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:id="#+id/etMessageText"
android:hint="Enter Message" />
<Button
android:text="Send"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/bSend" />
</LinearLayout>

For those who are implementing signalR client in android and the given answer here doesn't help in receiving the messages can check out this answer by rejnev.
The answer implements a different method connection.received() which is able to receive message callbacks from the server in my case.

Connecting Silverlight client to SignalR server

I've been driving myself nuts trying to resolve this issue so really hoping someone has some insight.
I have a console application which runs/hosts my signalR server.
I have already successfully connected to it using a web(javascript) client and a windows forms client with no trouble at all.
BUT for the life of me I cannot get a silverlight client to connect to it. Initially I was getting a
'System.Security.SecurityException' occurred in Microsoft.Threading.Tasks error
on
await Connection.Start();
I managed to fix that by force sending the clientaccesspolicy file using code i found on a random thread.
THREAD
However the connection still never establishes. The status goes thru connecting, disconnected, connection closed.
I am at my wits end as to why this won't work. Any input is appreciated. Code below.
MainPage.xaml.cs
public partial class MainPage : UserControl
{
private SignalRClient client;
public MainPage()
{
InitializeComponent();
dataGrid1.ItemsSource = new ItemsCollection();
client = new SignalRClient();
client.RunAsync();
Debug.WriteLine("Init Done");
}
}
-
SignalRClient.cs
public class SignalRClient
{
private HubConnection Connection { get; set; }
private IHubProxy HubProxy { get; set; }
const string url = "http://localhost:8080/";
public SignalRClient()
{
}
public async void RunAsync()
{
Connection = new HubConnection(url, useDefaultUrl: true);
Connection.Closed += Connection_Closed;
Connection.StateChanged += ConnectionDidSomething;
HubProxy = Connection.CreateHubProxy("TickerHub");
HubProxy.On<string>("receiveAllData", data => Debug.WriteLine("RECDATA={0}", data));
try
{
await Connection.Start();
}
catch (HttpClientException e)
{
Debug.WriteLine("Unable to connect to server.1 {0}", e.Message);
return;
}
catch (HttpRequestException e)
{
Debug.WriteLine("Unable to connect to server.2 {0}", e.Message);
return;
}
}
-
Server
class Program
{
static void Main(string[] args)
{
string url = "http://localhost:8080/";
using (WebApp.Start(url))
{
Console.WriteLine("SignalR server running on {0}", url);
Console.ReadLine();
}
Console.ReadLine();
}
}
class Startup
{
public void Configuration(IAppBuilder app)
{
Console.WriteLine("Configuration");
//Tried this approach too
/*app.Map("/signalr", map =>
{
map.UseCors(CorsOptions.AllowAll);
var hubConfiguration = new HubConfiguration
{
EnableJSONP = true
};
map.RunSignalR(hubConfiguration);
});*/
app.UseCors(CorsOptions.AllowAll);
app.MapSignalR<ClientAccessPolicyConnection>("/clientaccesspolicy.xml");
}
}
-
TickerHub.cs
public class TickerHub : Hub
{
public override Task OnConnected()
{
string connectionID = Context.ConnectionId;
Console.WriteLine("New Connection:" + connectionID);
InitNewClient(connectionID);
return base.OnConnected();
}
//send all data to newly connected client
public void InitNewClient(string connectionID)
{
}
//client requested all data
public void GetAllData()
{
Console.WriteLine("Get Data Triggered");
Clients.All.receiveAllData("TESTING123");
}
}

I figured it out! Hopefully this helps someone in the future.
Its quite simple. This is what you need to have in your startup class configuration method.
Below that is the code required to send the clientaccesspolicy.xml.
class Startup
{
public void Configuration(IAppBuilder app)
{
// Branch the pipeline here for requests that start with "/signalr"
app.Map("/signalr", map =>
{
// Setup the CORS middleware to run before SignalR.
// By default this will allow all origins. You can
// configure the set of origins and/or http verbs by
// providing a cors options with a different policy.
map.UseCors(CorsOptions.AllowAll);
var hubConfiguration = new HubConfiguration
{
// You can enable JSONP by uncommenting line below.
// JSONP requests are insecure but some older browsers (and some
// versions of IE) require JSONP to work cross domain
EnableJSONP = true
};
// Run the SignalR pipeline. We're not using MapSignalR
// since this branch already runs under the "/signalr"
// path.
map.RunSignalR(hubConfiguration);
});
app.UseCors(CorsOptions.AllowAll);
app.MapSignalR<ClientAccessPolicyConnection>("/clientaccesspolicy.xml");
}
}
-
public class ClientAccessPolicyConnection : PersistentConnection
{
public override Task ProcessRequest(Microsoft.AspNet.SignalR.Hosting.HostContext context)
{
string[] urlArray = context.Request.Url.ToString().Split('/');
string path = urlArray[urlArray.Length - 1];
if (path.Equals("clientaccesspolicy.xml", StringComparison.InvariantCultureIgnoreCase))
{
//Convert policy to byteArray
var array = Encoding.UTF8.GetBytes(ClientAccessPolicy);
var segment = new ArraySegment<byte>(array);
//Write response
context.Response.ContentType = "text/xml";
context.Response.Write(segment);
//Return empty task to escape from SignalR's default Connection/Transport checks.
return EmptyTask;
}
return EmptyTask;
}
private static readonly Task EmptyTask = MakeTask<object>(null);
public static Task<T> MakeTask<T>(T value)
{
var tcs = new TaskCompletionSource<T>();
tcs.SetResult(value);
return tcs.Task;
}
public static readonly string ClientAccessPolicy =
"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
+ "<access-policy>"
+ "<cross-domain-access>"
+ "<policy>"
+ "<allow-from http-request-headers=\"*\">"
+ "<domain uri=\"*\"/>"
+ "</allow-from>"
+ "<grant-to>"
+ "<resource path=\"/\" include-subpaths=\"true\"/>"
+ "</grant-to>"
+ "</policy>"
+ "</cross-domain-access>"
+ "</access-policy>";
}

WCF self-hosted WebSocket Service with Javascript client

I have this WCF self-hosted WebSocket service code:
Main:
//Create a URI to serve as the base address
Uri httpUrl = new Uri("http://192.168.1.95:8080/service");
//Create ServiceHost
ServiceHost host = new ServiceHost(typeof(WebSocketService), httpUrl);
//Add a service endpoint
host.AddServiceEndpoint(typeof(IWebSocket), new NetHttpBinding(), "");
//Enable metadata exchange
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
host.Description.Behaviors.Add(smb);
//Start the Service
host.Open();
Console.WriteLine("Service is host at " + DateTime.Now.ToString());
Console.WriteLine("Host is running... Press <Enter> key to stop");
Console.ReadLine();
Interface:
namespace IWebSocketHostTest
{
[ServiceContract]
interface IWebSocketCallBack
{
[OperationContract(IsOneWay = true)]
void Send(int num);
}
[ServiceContract(CallbackContract = typeof(IWebSocketCallBack))]
public interface IWebSocket
{
[OperationContract]
void StartSend();
}
}
Service:
namespace IWebSocketHostTest
{
class WebSocketService : IWebSocket
{
Timer timer = null;
List<IWebSocketCallBack> callbackClientList = null;
public WebSocketService()
{
callbackClientList = new List<IWebSocketCallBack>();
timer = new Timer(3000);
timer.Elapsed += new ElapsedEventHandler(sendNumber);
timer.Start();
}
public void StartSend()
{
sender.addClient(OperationContext.Current.GetCallbackChannel<IWebSocketCallBack>());
}
private void sendNumber(Object o, ElapsedEventArgs eea)
{
timer.Stop();
var random = new Random();
int randomNum = random.Next(100);
foreach (IWebSocketCallBack callback in callbackClientList)
{
callback.Send(randomNum);
}
timer.Interval = random.Next(1000, 10000);
timer.Start();
}
}
}
This works perfect if i add a reference of this service in another .NET application.
But, what i need is to consume this service from an HTML+Javascript application, and i´m realy lost in how to do that. I couldn´t find a good example or tutorial with a Javascript client consuming a self-hosted WCF WebSocket service.
All the Javascript WebSocket code that i could find seems to be very simple, but i couldn´t make it work.
Here is my short JavaScript client test:
var ws = new WebSocket("ws://192.168.1.95:8080/service");
ws.onopen = function () {
console.log("WEBSOCKET CONNECTED");
};
it returns "WebSocket Error: Incorrect HTTP response. Status code 400, Bad Request" testing it with Fiddler.
What am i missing? Could you please give me some doc links to get more information or a code example?
Thank you!
EDIT:
Now i´ve tried using the "Microsoft.ServiceModel.WebSocket" library to try to make it work.
But, first, i don´t know if it´s still maintained by Microsoft or if it is deprecated, because i couldn´t find any information at MSDN and there is few info at internet.
And second, the "Open()" method of the "WebSocketHost" class is not found, so i don´t know how to make the server run...
Here is my code, i´ve taken it from a question at the ASP.NET forum.
using System;
using Microsoft.ServiceModel.WebSockets;
namespace WebSocketTest
{
class Program
{
static void Main(string[] args)
{
var host = new WebSocketHost<EchoService>(new Uri("ws://localhost:8080/echo"));
host.AddWebSocketEndpoint();
host.Open();
Console.Read();
host.Close();
}
}
class EchoService : WebSocketService
{
public override void OnOpen()
{
base.OnOpen();
Console.WriteLine("WebSocket opened.");
}
public override void OnMessage(string message)
{
Console.WriteLine("Echoing to client:");
Console.WriteLine(message);
this.Send(message);
}
protected override void OnClose()
{
base.OnClose();
Console.WriteLine("WebSocket closed.");
}
protected override void OnError()
{
base.OnError();
Console.WriteLine("WebSocket error occured.");
}
}
}
But, like i said before, the "host.Open()" method is not found, so i don´t know if i´m missing some reference or what, because i couldn´t find info about the WebSocketHost class... Any help?

After spending a day with the same task I finally got working solution. Hope it will help someone in the future.
Client JS script:
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>WebSocket Chat</title>
<script src="http://ajax.aspnetcdn.com/ajax/jquery/jquery-2.1.1.js"></script>
<script type="text/javascript">
var ws;
$().ready(function ()
{
$("#btnConnect").click(function ()
{
$("#spanStatus").text("connecting");
ws = new WebSocket("ws://localhost:8080/hello");
ws.onopen = function ()
{
$("#spanStatus").text("connected");
};
ws.onmessage = function (evt)
{
$("#spanStatus").text(evt.data);
};
ws.onerror = function (evt)
{
$("#spanStatus").text(evt.message);
};
ws.onclose = function ()
{
$("#spanStatus").text("disconnected");
};
});
$("#btnSend").click(function ()
{
if (ws.readyState == WebSocket.OPEN)
{
var res = ws.send($("#textInput").val());
}
else
{
$("#spanStatus").text("Connection is closed");
}
});
$("#btnDisconnect").click(function ()
{
ws.close();
});
});
</script>
</head>
<body>
<input type="button" value="Connect" id="btnConnect" />
<input type="button" value="Disconnect" id="btnDisconnect" /><br />
<input type="text" id="textInput" />
<input type="button" value="Send" id="btnSend" /><br />
<span id="spanStatus">(display)</span>
</body>
</html>
Self hosted server:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.WebSockets;
using System.ServiceModel;
using System.ServiceModel.Activation;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.Text;
using System.Threading.Tasks;
namespace WebSocketsServer
{
class Program
{
static void Main(string[] args)
{
Uri baseAddress = new Uri("http://localhost:8080/hello");
// Create the ServiceHost.
using(ServiceHost host = new ServiceHost(typeof(WebSocketsServer), baseAddress))
{
// Enable metadata publishing.
ServiceMetadataBehavior smb = new ServiceMetadataBehavior();
smb.HttpGetEnabled = true;
smb.MetadataExporter.PolicyVersion = PolicyVersion.Policy15;
host.Description.Behaviors.Add(smb);
CustomBinding binding = new CustomBinding();
binding.Elements.Add(new ByteStreamMessageEncodingBindingElement());
HttpTransportBindingElement transport = new HttpTransportBindingElement();
//transport.WebSocketSettings = new WebSocketTransportSettings();
transport.WebSocketSettings.TransportUsage = WebSocketTransportUsage.Always;
transport.WebSocketSettings.CreateNotificationOnConnection = true;
binding.Elements.Add(transport);
host.AddServiceEndpoint(typeof(IWebSocketsServer), binding, "");
host.Open();
Console.WriteLine("The service is ready at {0}", baseAddress);
Console.WriteLine("Press <Enter> to stop the service.");
Console.ReadLine();
// Close the ServiceHost.
host.Close();
}
}
}
[ServiceContract(CallbackContract = typeof(IProgressContext))]
public interface IWebSocketsServer
{
[OperationContract(IsOneWay = true, Action = "*")]
void SendMessageToServer(Message msg);
}
[ServiceContract]
interface IProgressContext
{
[OperationContract(IsOneWay = true, Action = "*")]
void ReportProgress(Message msg);
}
public class WebSocketsServer: IWebSocketsServer
{
public void SendMessageToServer(Message msg)
{
var callback = OperationContext.Current.GetCallbackChannel<IProgressContext>();
if(msg.IsEmpty || ((IChannel)callback).State != CommunicationState.Opened)
{
return;
}
byte[] body = msg.GetBody<byte[]>();
string msgTextFromClient = Encoding.UTF8.GetString(body);
string msgTextToClient = string.Format(
"Got message {0} at {1}",
msgTextFromClient,
DateTime.Now.ToLongTimeString());
callback.ReportProgress(CreateMessage(msgTextToClient));
}
private Message CreateMessage(string msgText)
{
Message msg = ByteStreamMessage.CreateMessage(
new ArraySegment<byte>(Encoding.UTF8.GetBytes(msgText)));
msg.Properties["WebSocketMessageProperty"] =
new WebSocketMessageProperty
{
MessageType = WebSocketMessageType.Text
};
return msg;
}
}
}
UPDATE
As of .net 4.5 new way of writing server side have emerged. The benefits are cleaner code and possibility to support secure web sockets (WSS) over https.
public class WebSocketsServer
{
#region Fields
private static CancellationTokenSource m_cancellation;
private static HttpListener m_listener;
#endregion
#region Private Methods
private static async Task AcceptWebSocketClientsAsync(HttpListener server, CancellationToken token)
{
while (!token.IsCancellationRequested)
{
var hc = await server.GetContextAsync();
if (!hc.Request.IsWebSocketRequest)
{
hc.Response.StatusCode = 400;
hc.Response.Close();
return;
}
try
{
var ws = await hc.AcceptWebSocketAsync(null).ConfigureAwait(false);
if (ws != null)
{
Task.Run(() => HandleConnectionAsync(ws.WebSocket, token));
}
}
catch (Exception aex)
{
// Log error here
}
}
}
private static async Task HandleConnectionAsync(WebSocket ws, CancellationToken cancellation)
{
try
{
while (ws.State == WebSocketState.Open && !cancellation.IsCancellationRequested)
{
String messageString = await ReadString(ws).ConfigureAwait(false);
var strReply = "OK"; // Process messageString and get your reply here;
var buffer = Encoding.UTF8.GetBytes(strReply);
var segment = new ArraySegment<byte>(buffer);
await ws.SendAsync(segment, WebSocketMessageType.Text, true, CancellationToken.None).ConfigureAwait(false);
}
await ws.CloseAsync(WebSocketCloseStatus.NormalClosure, "Done", CancellationToken.None);
}
catch (Exception aex)
{
// Log error
try
{
await ws.CloseAsync(WebSocketCloseStatus.InternalServerError, "Done", CancellationToken.None).ConfigureAwait(false);
}
catch
{
// Do nothing
}
}
finally
{
ws.Dispose();
}
}
private static async Task<String> ReadString(WebSocket ws)
{
ArraySegment<Byte> buffer = new ArraySegment<byte>(new Byte[8192]);
WebSocketReceiveResult result = null;
using (var ms = new MemoryStream())
{
do
{
result = await ws.ReceiveAsync(buffer, CancellationToken.None);
ms.Write(buffer.Array, buffer.Offset, result.Count);
}
while (!result.EndOfMessage);
ms.Seek(0, SeekOrigin.Begin);
using (var reader = new StreamReader(ms, Encoding.UTF8))
{
return reader.ReadToEnd();
}
}
}
#endregion
#region Public Methods
public static void Start(string uri)
{
m_listener = new HttpListener();
m_listener.Prefixes.Add(uri);
m_listener.Start();
m_cancellation = new CancellationTokenSource();
Task.Run(() => AcceptWebSocketClientsAsync(m_listener, m_cancellation.Token));
}
public static void Stop()
{
if(m_listener != null && m_cancellation != null)
{
try
{
m_cancellation.Cancel();
m_listener.Stop();
m_listener = null;
m_cancellation = null;
}
catch
{
// Log error
}
}
}
#endregion
}

SignalR + passing custom object from server to client not working

I am trying to pass a custom object from self hosted signalr hub server to all the clients, the method in client side not getting invoked .But if the same custom class object is passed from client to server works fine, meaning it invokes the server method.
below is the sample code :
public class ChatHub : Hub
{
public void Send(DataContract message)
{
//below call not reaching to client while passing custom obj
Clients.All.SendMessage(message);
//below string passing works - means invokes client method
Clients.All.SendMsg("test");
}
}
custom class defined in both client and server project via dll:
public class DataContract
{
public string Name
{
get;set;
}
public int Id
{
get;set;
}
}
client side method:
public class SignalRClient
{
HubConnection hubConnection = null;
IHubProxy chat;
public SignalRClient()
{
hubConnection = new HubConnection("https://localhost/");
chat = hubConnection.CreateHubProxy("ChatHub");
}
public void StartConnection()
{
if (hubConnection != null)
{
hubConnection.Start().Wait();
}
chat.On<DataContract>("SendMessage", (stock) =>
{
Console.WriteLine("name {0} id {1}", stock.Name, stock.Id.ToString());
});
chat.On<string>("SendMsg", (message) =>
{
Console.WriteLine(message);
});
}
public void SendMessage(DataContract dd)
{
dd.Name = "test";
chat.Invoke("Send", dd).Wait();
}
public void SendMessage(string msg)
{
chat.Invoke("SendMsg", "Console app", msg).Wait();
}
}
//program.cs
main()
{
SignalRClient client = new SignalRClient();
client.StartConnection();
string msg = null;
while ((msg = Console.ReadLine()) != null)
{
DataContract dd = new DataContract { Name = "arun", Id = 9 };
//below calls reaches to server both string type and custome obj
client.SendMessage(dd);
client.SendMessage("client");
}
}
Any clue on why when calling from server (i.e Clients.All.SendMessage(message); ) not invoking client method when param is custom object.
Thanks in advance.

SignalR 2 Not working on azurewebsites

I have a simple SignalR based timer on the server which updates my dashboard panel. Everything works fine on VS2012, however when I deploy to azure or IIS7.5 it can't stablish a connection. Here are the errors from console.
This is my hub:
public class BroadCastHub : Hub
{
// Is set via the constructor on each creation
//private readonly Broadcaster _broadcaster;
private readonly TimeSpan BroadcastInterval = TimeSpan.FromMilliseconds(AppConfig.Instance.Tracing.RefreshRate * 1000);
public BroadCastHub() {
if (AppConfig.Instance.Tracing.EnableServerAutoUpdates)
{
// Start the broadcast loop
var _broadcastLoop = new Timer(
UpdatePanel,
null,
BroadcastInterval,
BroadcastInterval);
}
}
public void UpdatePanel()
{
UpdatePanel(null);
}
public void UpdatePanel(object o)
{
var appService = DependencyResolver.Current.GetService<IApplicationService>();
var applications = appService.GetSummaryCollection();
var model = applications.Select(c => new ApplicationState
{
id = c.id,
lastRunTime = c.lastRunTime.GetValueOrDefault(),
totalTraces = c.totalTraces,
status = appService.GetStatus(c.lastRunTime, c.lastTraceType, c.traceInterval)
}.InjectFrom(c)).Cast<ApplicationState>().AsQueryable();
Clients.All.updatePanel(model);
}
}
This is my JS code (Angular):
function init() {
var broadCastHub = $.connection.broadCastHub;
broadCastHub.client.updatePanel = function(apps) {
console.log('Broadcasting');
};
$.connection.hub.start()
.done(function () {
console.log('Now connected, connection ID=' + $.connection.hub.id);
})
.fail(function () { console.log('Could not Connect!'); });
//listenBroadcast();
}
EDIT:
Curiously, I saw a similar article and implemented like this:
public class Broadcaster
{
private readonly IApplicationService _applicationService;
private readonly static Lazy<Broadcaster> _instance = new Lazy<Broadcaster>(() => new Broadcaster());
// We're going to broadcast to all clients a maximum of 25 times per second
private readonly TimeSpan BroadcastInterval = TimeSpan.FromMilliseconds(AppConfig.Instance.Tracing.RefreshRate * 1000);
private readonly IHubContext _hubContext;
private Timer _broadcastLoop;
public Broadcaster()
{
_applicationService = DependencyResolver.Current.GetService<IApplicationService>();
// Save our hub context so we can easily use it
// to send to its connected clients
_hubContext = GlobalHost.ConnectionManager.GetHubContext<BroadCastHub>();
if (AppConfig.Instance.Tracing.EnableServerAutoUpdates) {
// Start the broadcast loop
_broadcastLoop = new Timer(
UpdatePanel,
null,
BroadcastInterval,
BroadcastInterval);
}
}
public void UpdatePanel(object state)
{
var applications = _applicationService.GetSummaryCollection();
var model = applications.Select(c => new ApplicationState
{
id = c.id,
lastRunTime = c.lastRunTime.GetValueOrDefault(),
totalTraces = c.totalTraces,
status = _applicationService.GetStatus(c.lastRunTime, c.lastTraceType, c.traceInterval)
}.InjectFrom(c)).Cast<ApplicationState>().AsQueryable();
_hubContext.Clients.All.updatePanel(model);
}
public static Broadcaster Instance
{
get
{
return _instance.Value;
}
}
}
My hub:
public class BroadCastHub : Hub
{
// Is set via the constructor on each creation
private readonly Broadcaster _broadcaster;
public BroadCastHub()
: this(Broadcaster.Instance)
{
}
public BroadCastHub(Broadcaster broadcaster)
{
_broadcaster = broadcaster;
}
public void UpdatePanel()
{
_broadcaster.UpdatePanel(null);
}
}
Thanks for the article, I'll take a deeper look.

We Keep Coding

C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

WebSocket Implementation - c#

Related

How to use signalr in Android

Connecting Silverlight client to SignalR server

WCF self-hosted WebSocket Service with Javascript client

SignalR + passing custom object from server to client not working

SignalR 2 Not working on azurewebsites

Categories

Resources