當麻許的超技八

sudo apt-get update
sudo apt-get install nodejs
sudo apt-get install npm

//require our websocket library 
var WebSocketServer = require('ws').Server;

//creating a websocket server at port 9090 
var wss = new WebSocketServer({ port: 9090 });

//all connected to the server users 
var users = {};

//when a user connects to our sever 
wss.on('connection', function (connection) {

    console.log("User connected");

    //when server gets a message from a connected user 
    connection.on('message', function (message) {

        var data;
        //accepting only JSON messages 
        try {
            data = JSON.parse(message);
        } catch (e) {
            console.log("Invalid JSON");
            data = {};
        }

        //switching type of the user message 
        switch (data.type) {
            //when a user tries to login 
            case "login":
                console.log("User logged", data.name);
                //if anyone is logged in with this username then refuse 
                if (users[data.name]) {
                    sendTo(connection, {
                        type: "login",
                        success: false,
			message: '重複登入'
                    });
                } else {
                    //save user connection on the server 
                    users[data.name] = connection;
                    connection.name = data.name;

                    sendTo(connection, {
                        type: "login",
                        success: true
                    });
                }
		console.log("users data: ", users);
                break;

            case "offer":
                //for ex. UserA wants to call UserB 
                console.log("Sending offer to: ", data.name);
		
                //if UserB exists then send him offer details 
                var conn = users[data.name];

                if (conn != null) {
                    //setting that UserA connected with UserB 
                    connection.otherName = data.name;

                    sendTo(conn, {
                        type: "offer",
                        offer: data.offer,
                        name: connection.name
                    });
                }
		

                break;

            case "answer":
                console.log("Sending answer to: ", data.name);
                //for ex. UserB answers UserA 
                var conn = users[data.name];

                if (conn != null) {
                    connection.otherName = data.name;
                    sendTo(conn, {
                        type: "answer",
                        answer: data.answer
                    });
                }

                break;
 	
	     

            case "candidate":
                console.log("Sending candidate to:", data.name);
                var conn = users[data.name];

                if (conn != null) {
                    sendTo(conn, {
                        type: "candidate",
                        candidate: data.candidate
                    });
                }

                break;

            case "leave":
                
                var conn = users[data.name];
		
		users[data.name]=undefined;
               
		//conn.otherName = null;

                //notify the other user so he can disconnect his peer connection 
                if (conn != null) {
                    sendTo(conn, {
                        type: "leave"
                    });
                }
		
		console.log("[leave] users data : ", users);

                break;

            default:
                sendTo(connection, {
                    type: "error",
                    message: "Command not found: " + data.type
                });

                break;

        }
    });

    //when user exits, for example closes a browser window 
    //this may help if we are still in "offer","answer" or "candidate" state 
    connection.on("close", function () {

        if (connection.name) {
            delete users[connection.name];

            if (connection.otherName) {
                console.log("Disconnecting from ", connection.otherName);
                var conn = users[connection.otherName];
		
                if (conn != null) {
		    conn.otherName = null;
                    sendTo(conn, {
                        type: "leave"
                    });
                }
            }
        }
    });

    connection.send(JSON.stringify({
                        type: "hello",
                        message: 'Welcome to connect Signaling Server'
                    }));

});

function sendTo(connection, message) {
    connection.send(JSON.stringify(message));
}

npm install ws