Websockets
The websocket handler integrates Fleck to upgrade client connections so that you can use websocket functionality in your application.
The following example hosts a simple console application that provides a websocket server that will echo received messages back to connected clients:
using GenHTTP.Engine.Internal;
using GenHTTP.Modules.Practices;
using GenHTTP.Modules.Websockets;
var allSockets = new List<IWebsocketConnection>();
var websocket = Websocket.Create()
.OnOpen((socket) =>
{
Console.WriteLine("Open!");
allSockets.Add(socket);
})
.OnClose((socket) =>
{
Console.WriteLine("Close!");
allSockets.Remove(socket);
})
.OnMessage((socket, message) =>
{
Console.WriteLine(message);
allSockets.ToList().ForEach(s => s.Send("Echo: " + message));
});
var host = Host.Create()
.Handler(websocket)
.Defaults()
.Development()
.Console();
await host.StartAsync();
var input = Console.ReadLine();
while (input != "exit")
{
if (input != null)
{
foreach (var socket in allSockets.ToList())
{
await socket.Send(input);
}
}
input = Console.ReadLine();
}
await host.StopAsync();After starting the server, you can open the following HTML page (provided by the Fleck project as a sample) in your browser to connect to the server:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title>websocket client</title>
<script type="text/javascript">
var start = function () {
var inc = document.getElementById('incomming');
var wsImpl = window.WebSocket || window.MozWebSocket;
var form = document.getElementById('sendForm');
var input = document.getElementById('sendText');
inc.innerHTML += "connecting to server ..<br/>";
// create a new websocket and connect
window.ws = new wsImpl('ws://localhost:8080/');
// when data is comming from the server, this metod is called
ws.onmessage = function (evt) {
inc.innerHTML += evt.data + '<br/>';
};
// when the connection is established, this method is called
ws.onopen = function () {
inc.innerHTML += '.. connection open<br/>';
};
// when the connection is closed, this method is called
ws.onclose = function () {
inc.innerHTML += '.. connection closed<br/>';
}
form.addEventListener('submit', function(e){
e.preventDefault();
var val = input.value;
ws.send(val);
input.value = "";
});
}
window.onload = start;
</script>
</head>
<body>
<form id="sendForm">
<input id="sendText" placeholder="Text to send" />
</form>
<pre id="incomming"></pre>
</body>
</html>Every browser instance of this page will connect to the server and show messages entered in the server app or any other browser window.
