Added very basic WebSocket support to json server

Author: Gamadril

libsrc/jsonserver/JsonClientConnection.cpp

@@ -10,6 +10,8 @@
 // Qt includes
 #include <QResource>
 #include <QDateTime>
+#include <QCryptographicHash>
+#include <QHostInfo>
 
 // hyperion util includes
 #include <hyperion/ImageProcessorFactory.h>
@@ -27,6 +29,7 @@ JsonClientConnection::JsonClientConnection(QTcpSocket *socket, Hyperion * hyperi
 	_hyperion(hyperion),
 	_receiveBuffer()
 {
+	_webSocketHandshakeDone = false;
 	// connect internal signals and slots
 	connect(_socket, SIGNAL(disconnected()), this, SLOT(socketClosed()));
 	connect(_socket, SIGNAL(readyRead()), this, SLOT(readData()));
@@ -41,7 +44,126 @@ JsonClientConnection::~JsonClientConnection()
 void JsonClientConnection::readData()
 {
 	_receiveBuffer += _socket->readAll();
-
+	
+	if (_webSocketHandshakeDone) { // websocket mode, data frame
+		quint8 opCode = 0;
+		quint64 payloadLength = 0;
+		bool isMasked = false;
+		quint32 index = 0;
+		quint8 maskKey[4];
+				
+		if ((_receiveBuffer.at(0) & 0x80) == 0x80) { // final bit
+			opCode = _receiveBuffer.at(0) & 0x0F;
+			isMasked = (_receiveBuffer.at(1) & 0x80) == 0x80;
+			payloadLength = _receiveBuffer.at(1) & 0x7F;
+			index = 2;
+			
+			switch (payloadLength) {
+				case 126:
+					payloadLength = ((_receiveBuffer.at(2) << 8) & 0xFF00) | (_receiveBuffer.at(3) & 0xFF);
+					index += 2;
+					break;
+				case 127: {
+						payloadLength = 0;
+						for (int i=0; i < 8; i++) {
+							payloadLength |= ((quint64)(_receiveBuffer.at(index+i) & 0xFF)) << (8*(7-i));
+						}
+						index += 8;
+					}
+					break;
+				default:
+					break;
+			}
+			
+			if (isMasked) { // if the data is masked we need to get the key for unmasking
+				for (int i=0; i < 4; i++) {
+					maskKey[i] = _receiveBuffer.at(index + i);	
+				}
+				index += 4;
+			}
+			
+			// check the type of data frame
+			switch (opCode) {
+				case 0x01: { // text
+					QByteArray result = _receiveBuffer.mid(index, payloadLength);
+					_receiveBuffer.clear();
+					
+					// unmask data if necessary
+					if (isMasked) {
+						for (uint i=0 ; i < payloadLength; i++) {
+							result[i] = (result[i] ^ maskKey[i % 4]);
+						}
+					}
+										
+					handleMessage(QString(result).toStdString());
+				}
+				break;
+				case 0x08: { // close
+					quint8 close[]={0x88, 0};				
+					_socket->write((const char*)close, 2);
+					_socket->flush();
+					_socket->close();
+				}
+				break;
+				case 0x09: { // ping, send pong
+					quint8 close[]={0x0A, 0};				
+					_socket->write((const char*)close, 2);
+					_socket->flush();
+				}
+				break;
+			}
+		} else {
+			std::cout << "Someone is sending very big messages over several frames... it's not supported yet" << std::endl;
+			quint8 close[]={0x88, 0};				
+			_socket->write((const char*)close, 2);
+			_socket->flush();
+			_socket->close();
+		}
+	} else { // might be a handshake request or raw socket data
+		if(_receiveBuffer.contains("Upgrade: websocket")){ // http header, might not be a very reliable check...
+			std::cout << "Websocket handshake" << std::endl;
+		
+			// get the key to tprepare an answer
+			int start = _receiveBuffer.indexOf("Sec-WebSocket-Key") + 19;
+			std::string value(_receiveBuffer.mid(start, _receiveBuffer.indexOf("\r\n", start) - start).data());
+			_receiveBuffer.clear();
+
+			// must be always appended
+			value += "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
+		
+			// generate sha1 hash
+			QByteArray hash = QCryptographicHash::hash(value.c_str(), QCryptographicHash::Sha1);
+		
+			// prepare an answer
+			std::ostringstream h;
+			h << "HTTP/1.1 101 Switching Protocols\r\n" <<
+			"Upgrade: websocket\r\n" <<
+			"Connection: Upgrade\r\n" << 
+			"Sec-WebSocket-Accept: " << QString(hash.toBase64()).toStdString() << "\r\n\r\n";
+
+			_socket->write(h.str().c_str());
+			_socket->flush();
+			_webSocketHandshakeDone = true; // we are in WebSocket mode, data frames should follow next
+		} else { // raw socket data, handling as usual
+			int bytes = _receiveBuffer.indexOf('\n') + 1;
+			while(bytes > 0)
+			{
+				// create message string
+				std::string message(_receiveBuffer.data(), bytes);
+
+				// remove message data from buffer
+				_receiveBuffer = _receiveBuffer.mid(bytes);
+
+				// handle message
+				handleMessage(message);
+
+				// try too look up '\n' again
+				bytes = _receiveBuffer.indexOf('\n') + 1;
+			}		
+		}
+	}
+	
+	/*
 	int bytes = _receiveBuffer.indexOf('\n') + 1;
 	while(bytes > 0)
 	{
@@ -57,10 +179,12 @@ void JsonClientConnection::readData()
 		// try too look up '\n' again
 		bytes = _receiveBuffer.indexOf('\n') + 1;
 	}
+	*/
 }
 
 void JsonClientConnection::socketClosed()
 {
+	_webSocketHandshakeDone = false;
 	emit connectionClosed(this);
 }
 
@@ -205,6 +329,9 @@ void JsonClientConnection::handleServerInfoCommand(const Json::Value &)
 	Json::Value result;
 	result["success"] = true;
 	Json::Value & info = result["info"];
+	
+	// add host name for remote clients
+	info["hostname"] = QHostInfo::localHostName().toStdString();
 
 	// collect priority information
 	Json::Value & priorities = info["priorities"] = Json::Value(Json::arrayValue);
@@ -362,7 +489,28 @@ void JsonClientConnection::sendMessage(const Json::Value &message)
 {
 	Json::FastWriter writer;
 	std::string serializedReply = writer.write(message);
-	_socket->write(serializedReply.data(), serializedReply.length());
+	
+	if (!_webSocketHandshakeDone) { // raw tcp socket mode
+		_socket->write(serializedReply.data(), serializedReply.length());
+	} else { // websocket mode
+		quint32 size = serializedReply.length();
+	
+		// prepare data frame
+		QByteArray response;
+		response.append(0x81);
+		if (size > 125) {
+			response.append(0x7E);
+			response.append((size >> 8) & 0xFF);
+			response.append(size & 0xFF);
+		} else {
+			response.append(size);
+		}
+	
+		QByteArray data(serializedReply.c_str(), serializedReply.length());
+		response.append(data);
+	
+		_socket->write(response.data(), response.length());		
+	}
 }
 
 void JsonClientConnection::sendSuccessReply()

libsrc/jsonserver/JsonClientConnection.h

@@ -161,4 +161,7 @@ private slots:
 
 	/// The buffer used for reading data from the socket
 	QByteArray _receiveBuffer;
+	
+	/// used for WebSocket detection and connection handling
+	bool _webSocketHandshakeDone;
 };