Question

I am trying to create my own WebSocket Server with Java.

When my client connects, I get following request:

(14): GET / HTTP/1.1
(18): Upgrade: WebSocket
(19): Connection: Upgrade
(20): Host: localhost:8483
(24): Origin: http://localhost
(45): Sec-WebSocket-Key1: P3$04 H85Zf# 9 9d a0 x10[
(34): Sec-WebSocket-Key2: 416393 2  560Y
(0): 

(The numbers in brackets, the brackets, the colons and the spaces thereafter only being something I add for the System.out.println() command). The numbers in brackets are the length of the line in bytes.

I first process the request using this function:

public boolean processHandshake(int lineNumber, String line){

    if(handshakeProcessed || lineNumber > 9 || lineNumber < 1){

        return false;

    }

    switch(lineNumber){

        case 1:{ handshakeGetLocation = line.replace("GET ", "").replace(" HTTP/1.1", ""); break; }
        case 2:{ handshakeUpgrade = line.replace("Upgrade: ", ""); break; }
        case 3:{ handshakeConnection = line.replace("Connection: ", ""); break; }
        case 4:{ handshakeHost = line.replace("Host: : ", ""); break; }
        case 5:{ handshakeOrigin = line.replace("Origin: ", ""); break; }
        case 6:{ handshakeSecWebSocketKey1 = line.replace("Sec-WebSocket-Key1: ", ""); break; }
        case 7:{ handshakeSecWebSocketKey2 = line.replace("Sec-WebSocket-Key2: ", ""); handshakeProcessed = false; break; }
        case 8:{ handshakeProcessed = true; }
        case 9:{ handshakeProcessed = true; }

    }

    return true;

}

Now, according to this article and assuming it’s the first version of the protocol I need to process, I’ve been wondering how to deal with the quotients:

The thing is, for each key, I need to divide the number of digits by that of the spaces. I’ve been doing it like that:

private double calculateKeyReply(String key){

    double numCount = key.replaceAll("[^0-9]", "").length();
    double spaceCount = key.replaceAll("[^\\ ]", "").length();

    System.out.println(numCount+"/"+spaceCount+"="+numCount/spaceCount);

    return numCount/spaceCount;

}

And calling following function (replyHandshake()):

String handshake;

handshake = "HTTP/1.1 101 WebSocket Protocol Handshake\n";
handshake += "Upgrade: "+handshakeUpgrade+"\n"; // handshakeUpgrade and the following variables are instance variables I set when I process the request
handshake += "Connection: "+handshakeConnection+"\n";
handshake += "Sec-WebSocket-Origin: "+handshakeOrigin+"\n";
handshake += "Sec-WebSocket-Location: "+handshakeOrigin.replace("http", "ws")+handshakeGetLocation+"\n";
handshake += "Sec-WebSocket-Protocol: sample\n";
// handshake += "\n";

String nums = calculateKeyReply(handshakeSecWebSocketKey1)+""+calculateKeyReply(handshakeSecWebSocketKey2);

MessageDigest md5Digestor = MessageDigest.getInstance("MD5");
String md5 = new String(md5Digestor.digest(nums.getBytes()));

handshake += md5;

return handshake;

And then, somewhere else:

out.println(replyHandshake());

Am I doing something wrong? I’m testing it with the latest version of Google Chrome.

Thanks in advance!

Answer 1

If you go the extra mile and implement a server for yourself from scratch today, I would target the latest version of the protocol (version 8, draft 10).

The above handshake is from an outdated version.

Chrome 14 and Firefox 7/8 support the latest. Firefox 6 has a (disabled by default) old version. Chrome might very well drop support for any version <8.