Websocket帮助！

Question

I'm working on a websocket application. I have a server that is written in C#. I have tested it using another C# application for sending and receiving data. The problem occurs when I use a JavaScript on the chrome developer tool (console) and use Websockets to connect to my server.

1. I receive the header string from the websocket script, with two keys and the last 8 characters for hashing.

2. I used the header string keys to generate a hash code and crate a header to send back to chrome(j script on the developer tool).

Issues:-

1. the onopen event is never triggered and the websocket does not receive the header(I assume). I use the onerror to capture any errors. Which never occur.

2. The readystate on the websocket is 0 or 2(always).

   • But when I send a disconnect response from the server, the websocket triggers the onclose method. (So I assume that he was open but not ready to communicate)

Any suggestions??????? Here's the JavaScript if it helps.

websocket = new WebSocket('ws://My server IP here:8080'); 

try {
    websocket.onopen = function(evt) { 
        open(evt)
        //websocket.send("Message to send");
        alert("Message is sent...");
    }
}
catch(err) { 
    debug(err,'error')
} 

websocket.onerror = function(evt) {
    error(evt)
} 

websocket.onclose = function(evt) { 
    close(evt) 
}

websocket.onmessage = function(evt) {
    message(evt) 
}

function open(evt) { 
    alert("CONNECTED"); 
    doSend("WebSocket rocks"); 
} 

function error(evt) {
    alert (evt.data)
}

function close(evt) { 
    alert("DISCONNECTED"); 
} 

function message(evt) { 
    alert(evt.data); 
} 

function doSend(message) {
    alert(message); 
    websocket.send(message); 
}

And the header I sent back

HTTP/1.1 101 WebSocket Protocol Handshake

Upgrade: WebSocket

Connection: Upgrade

Sec-WebSocket-Origin: chrome://newtab

Sec-WebSocket-Location: ws://My server IP:8080 ??i???m?!??9?

Thanks everyone.

Answer 1

It looks like you're trying to respond to the handshake request without the appropriate challenge response. Like Robin mentioned, the handshake is now more complex and involves a challenge for newer versions of the WebSocket protocol. This is a good article that explains the version 76 handshake in more detail.

Here's a code sample that detects the WebSocket protocol version and replies with the appropriate response. (It's in Java, so YMMV, but it should point you in the right direction.)

// Create the WebSocket handshake response.
HttpResponse res = new DefaultHttpResponse(HTTP_1_1,
    new HttpResponseStatus(101, "Web Socket Protocol Handshake"));
res.addHeader(Names.UPGRADE, WEBSOCKET);
res.addHeader(CONNECTION, Values.UPGRADE);

// Fill in the headers and contents depending on handshake method.
// New handshake specification has a challenge.
if (req.containsHeader(SEC_WEBSOCKET_KEY1)
        && req.containsHeader(SEC_WEBSOCKET_KEY2)) {

    // New handshake method with challenge
    res.addHeader(SEC_WEBSOCKET_ORIGIN, req.getHeader(ORIGIN));
    res.addHeader(SEC_WEBSOCKET_LOCATION, getWebSocketLocation(req));

    String protocol = req.getHeader(SEC_WEBSOCKET_PROTOCOL);

    if (protocol != null) {
        res.addHeader(SEC_WEBSOCKET_PROTOCOL, protocol);
    }

    // Calculate the answer of the challenge.
    String key1 = req.getHeader(SEC_WEBSOCKET_KEY1);
    String key2 = req.getHeader(SEC_WEBSOCKET_KEY2);
    int a = (int) (Long.parseLong(key1.replaceAll("[^0-9]", "")) / key1
            .replaceAll("[^ ]", "").length());
    int b = (int) (Long.parseLong(key2.replaceAll("[^0-9]", "")) / key2
            .replaceAll("[^ ]", "").length());
    long c = req.getContent().readLong();
    ChannelBuffer input = ChannelBuffers.buffer(16);
    input.writeInt(a);
    input.writeInt(b);
    input.writeLong(c);
    ChannelBuffer output = ChannelBuffers
            .wrappedBuffer(MessageDigest.getInstance("MD5").digest(
                    input.array()));
    res.setContent(output);
} else {
    // Old handshake method with no challenge:
    res.addHeader(WEBSOCKET_ORIGIN, req.getHeader(ORIGIN));
    res.addHeader(WEBSOCKET_LOCATION, getWebSocketLocation(req));
    String protocol = req.getHeader(WEBSOCKET_PROTOCOL);
    if (protocol != null) {
        res.addHeader(WEBSOCKET_PROTOCOL, protocol);
    }
}

// Send the response...

Answer 2

Are you implementing the correct Websockets Protocol version? Chrome has moved to version 76 , which means the handshake is more complex than it was. If your Javascript client is failing to connect properly this is possibly the cause.