Я попытался реализовать протокол WebSocket и подключить JavaScript WebSocket к серверу Java WebSocket.
Часть JavaScript довольно прямолинейна и работает, как и ожидалось. Я сам написал сервер Java и прочитал rfc 6455 page 7 для правильного ответ на рукопожатие. Таким образом, сервер формирует правильный ответ и отправляет его. Я написал манекен клиента Java, чтобы убедиться, что он будет отправлен.
Но проблема в том, что JavaScript/браузер, кажется, не получает ответ на рукопожатие и убивает запрос через несколько секунд (но не закрывает сокет tcp).
Вот рукопожатие:
Клиент
GET / HTTP/1.1
Host: 127.0.0.1:4455
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: de,en-US;q=0.7,en;q=0.3
Accept-Encoding: gzip, deflate
Sec-WebSocket-Version: 13
Origin: http://localhost
Sec-WebSocket-Extensions: permessage-deflate
Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==
Connection: keep-alive, Upgrade
Pragma: no-cache
Cache-Control: no-cache
Upgrade: websocket
Сервер
HTTP/1.1 101 Switching Protocols
Upgrade: websocket
Connection: Upgrade
Sec-WebSocket-Accept: s3pPLMBiTxaQ9kYGzzhZRbK+xOo=
Sec-WebSocket-Protocol: chat
HTML JavaScript
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Socket testing - Client</title>
</head>
<body>
<div id="container"></div>
<script type="text/javascript">
var socket = new WebSocket('ws://127.0.0.1:4455');
socket.addEventListener("error",function(e){
console.log("an error ocurred: ",e)
})
socket.addEventListener("close",function(e){
console.log("the connection was closed: ",e)
})
socket.addEventListener("open",function(e){
console.log("the connection was opened: ",e)
})
socket.addEventListener("message",function(e){
console.log("recieved a message: ",e)
})
</script>
</body>
</html>
Ява (отрывок)
public class SocketHandlerWebSocketLevel extends SocketHandler {
private HashMap<String, String> connectionHeaders;
private InputStreamReader stringReader;
private OutputStreamWriter stringWriter;
public SocketHandlerWebSocketLevel(Socket socket) {
super(socket);
connectionHeaders = new HashMap<String, String>();
try {
stringReader = new InputStreamReader(s.getInputStream());
} catch (IOException e) {
e.printStackTrace();
close();
print("could not get the input stream");
return;
}
try {
stringWriter = new OutputStreamWriter(s.getOutputStream());
} catch (IOException e) {
e.printStackTrace();
close();
print("could not get the output stream");
return;
}
}
@Override
public void run() {
print("Started handler");
char b;
String buffer = "";
try {
mainLoop: while (true) {
while (stringReader.ready() || buffer.length() == 0) {
if ((b = (char) stringReader.read()) != -1) {
buffer += b;
} else {
break mainLoop;
}
}
gotMessage(buffer);
buffer = "";
}
} catch (IOException e) {
close();
print("connection was killed remotly, could not read the next byte");
return;
}
close();
print("connection was closed remotely, stopped Handler, closed socked");
}
private void gotMessage(String message) {
if (connectionHeaders.size() == 0) {
connectionHeaders = parseHttpHeader(message);
handshakeResponse();
} else {
print(message);
}
}
private void handshakeResponse() {
/*
taken from: https://tools.ietf.org/html/rfc6455#page-7
For this header field, the server has to take the value (as present
in the header field, e.g., the base64-encoded [RFC4648] version minus
any leading and trailing whitespace) and concatenate this with the
Globally Unique Identifier (GUID, [RFC4122]) "258EAFA5-E914-47DA-
95CA-C5AB0DC85B11" in string form, which is unlikely to be used by
network endpoints that do not understand the WebSocket Protocol. A
SHA-1 hash (160 bits) [FIPS.180-3], base64-encoded (see Section 4 of
[RFC4648]), of this concatenation is then returned in the server's
handshake.
Concretely, if as in the example above, the |Sec-WebSocket-Key|
header field had the value "dGhlIHNhbXBsZSBub25jZQ==", the server
would concatenate the string "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
to form the string "dGhlIHNhbXBsZSBub25jZQ==258EAFA5-E914-47DA-95CA-
C5AB0DC85B11". The server would then take the SHA-1 hash of this,
giving the value 0xb3 0x7a 0x4f 0x2c 0xc0 0x62 0x4f 0x16 0x90 0xf6
0x46 0x06 0xcf 0x38 0x59 0x45 0xb2 0xbe 0xc4 0xea. This value is
then base64-encoded (see Section 4 of [RFC4648]), to give the value
"s3pPLMBiTxaQ9kYGzzhZRbK+xOo=". This value would then be echoed in
the |Sec-WebSocket-Accept| header field.
*/
String secWebSocketKey, secWebSocketAccept, GUID, template, merged, toSend;
secWebSocketKey = connectionHeaders.get("Sec-WebSocket-Key");
GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
template = "HTTP/1.1 101 Switching Protocols\nUpgrade: websocket\nConnection: Upgrade\nSec-WebSocket-Accept: %s\nSec-WebSocket-Protocol: chat\n";
// combine secWebSocketKey and the GUID
merged = secWebSocketKey + GUID;
print("merged: " + merged);
// convert to byte[]
byte[] asBytes = merged.getBytes();
print("asBytes: " + Arrays.toString(asBytes));
// SHA-1 hash
byte[] sha1 = SHA1Hash(asBytes);
print("sha1: " + Arrays.toString(sha1));
// base64 encode
byte[] base64 = base64Encode(sha1);
print("base64: " + Arrays.toString(base64));
// reconvert to string to put it into the template
secWebSocketAccept = new String(base64);
toSend = String.format(template, secWebSocketAccept);
print(toSend);
try {
stringWriter.write(toSend, 0, toSend.length());
stringWriter.flush();
} catch (IOException e) {
print("hanshake sending failed!");
}
}
private HashMap<String, String> parseHttpHeader(String h) {
HashMap<String, String> fields = new HashMap<String, String>();
String[] rows = h.split("\n");
if (rows.length > 1) {
fields.put("Prototcol", rows[0]);
Pattern pattern = Pattern.compile("^([^:]+): (.+)$");
for (int i = 1; i < rows.length; i++) {
Matcher matcher = pattern.matcher(rows[i]);
while (matcher.find()) {
if (matcher.groupCount() == 2) {
fields.put(matcher.group(1), matcher.group(2));
}
}
}
}
return fields;
}
private byte[] SHA1Hash(byte[] bytes) {
MessageDigest md;
try {
md = MessageDigest.getInstance("SHA-1");
} catch (NoSuchAlgorithmException e) {
return null;
}
md.update(bytes);
return md.digest();
}
private byte[] base64Encode(byte[] bytes) {
byte[] encodedBytes = Base64.getEncoder().encode(bytes);
return encodedBytes;
}
Где может быть моя ошибка? Что может отсутствовать, может символ "конец сообщения"?
Обратите внимание, что я не хочу использовать фреймворк.
