in guacamole/src/main/java/org/apache/guacamole/tunnel/websocket/tomcat/GuacamoleWebSocketTunnelServlet.java [130:374]
public StreamInbound createWebSocketInbound(String protocol,
HttpServletRequest request) {
final TunnelRequest tunnelRequest = new HTTPTunnelRequest(request);
// Return new WebSocket which communicates through tunnel
return new StreamInbound() {
/**
* The GuacamoleTunnel associated with the connected WebSocket. If
* the WebSocket has not yet been connected, this will be null.
*/
private GuacamoleTunnel tunnel = null;
/**
* The outbound half of the WebSocket connection. This value will
* always be non-null if tunnel is non-null.
*/
private WsOutbound outbound = null;
/**
* Sends a Guacamole instruction along the outbound WebSocket
* connection to the connected Guacamole client. If an instruction
* is already in the process of being sent by another thread, this
* function will block until in-progress instructions are complete.
*
* @param instruction
* The instruction to send.
*
* @throws IOException
* If an I/O error occurs preventing the given instruction from
* being sent.
*/
private void sendInstruction(CharSequence instruction)
throws IOException {
// NOTE: Synchronization on the non-final remote field here is
// intentional. The outbound websocket connection is only
// sensitive to simultaneous attempts to send messages with
// respect to itself. If the connection changes, then
// synchronization need only be performed in context of the new
// connection
synchronized (outbound) {
outbound.writeTextMessage(CharBuffer.wrap(instruction));
}
}
/**
* Sends a Guacamole instruction along the outbound WebSocket
* connection to the connected Guacamole client. If an instruction
* is already in the process of being sent by another thread, this
* function will block until in-progress instructions are complete.
*
* @param instruction
* The instruction to send.
*
* @throws IOException
* If an I/O error occurs preventing the given instruction from being
* sent.
*/
private void sendInstruction(GuacamoleInstruction instruction)
throws IOException {
sendInstruction(instruction.toString());
}
@Override
protected void onTextData(Reader reader) throws IOException {
// Ignore inbound messages if there is no associated tunnel
if (tunnel == null)
return;
// Filter received instructions, handling tunnel-internal
// instructions without passing through to guacd
GuacamoleWriter writer = new FilteredGuacamoleWriter(tunnel.acquireWriter(), new GuacamoleFilter() {
@Override
public GuacamoleInstruction filter(GuacamoleInstruction instruction)
throws GuacamoleException {
// Filter out all tunnel-internal instructions
if (instruction.getOpcode().equals(GuacamoleTunnel.INTERNAL_DATA_OPCODE)) {
// Respond to ping requests
List<String> args = instruction.getArgs();
if (args.size() >= 2 && args.get(0).equals(PING_OPCODE)) {
try {
sendInstruction(new GuacamoleInstruction(
GuacamoleTunnel.INTERNAL_DATA_OPCODE,
PING_OPCODE, args.get(1)
));
}
catch (IOException e) {
logger.debug("Unable to send \"ping\" response for WebSocket tunnel.", e);
}
}
return null;
}
// Pass through all non-internal instructions untouched
return instruction;
}
});
// Write all available data
try {
char[] buffer = new char[BUFFER_SIZE];
int num_read;
while ((num_read = reader.read(buffer)) > 0)
writer.write(buffer, 0, num_read);
}
catch (GuacamoleConnectionClosedException e) {
logger.debug("Connection to guacd closed.", e);
}
catch (GuacamoleException e) {
logger.debug("WebSocket tunnel write failed.", e);
}
tunnel.releaseWriter();
}
@Override
public void onOpen(final WsOutbound outbound) {
// Store outbound connection for future use via sendInstruction()
this.outbound = outbound;
try {
tunnel = doConnect(tunnelRequest);
}
catch (GuacamoleException e) {
logger.error("Creation of WebSocket tunnel to guacd failed: {}", e.getMessage());
logger.debug("Error connecting WebSocket tunnel.", e);
closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(),
e.getWebSocketCode());
return;
}
// Do not start connection if tunnel does not exist
if (tunnel == null) {
closeConnection(outbound, GuacamoleStatus.RESOURCE_NOT_FOUND);
return;
}
Thread readThread = new Thread() {
@Override
public void run() {
StringBuilder buffer = new StringBuilder(BUFFER_SIZE);
GuacamoleReader reader = tunnel.acquireReader();
char[] readMessage;
try {
// Send tunnel UUID
sendInstruction(new GuacamoleInstruction(
GuacamoleTunnel.INTERNAL_DATA_OPCODE,
tunnel.getUUID().toString()
));
try {
// Attempt to read
while ((readMessage = reader.read()) != null) {
// Buffer message
buffer.append(readMessage);
// Flush if we expect to wait or buffer is getting full
if (!reader.available() || buffer.length() >= BUFFER_SIZE) {
sendInstruction(CharBuffer.wrap(buffer));
buffer.setLength(0);
}
}
// No more data
closeConnection(outbound, GuacamoleStatus.SUCCESS);
}
// Catch any thrown guacamole exception and attempt
// to pass within the WebSocket connection, logging
// each error appropriately.
catch (GuacamoleClientException e) {
logger.info("WebSocket connection terminated: {}", e.getMessage());
logger.debug("WebSocket connection terminated due to client error.", e);
closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(),
e.getWebSocketCode());
}
catch (GuacamoleConnectionClosedException e) {
logger.debug("Connection to guacd closed.", e);
closeConnection(outbound, GuacamoleStatus.SUCCESS);
}
catch (GuacamoleException e) {
logger.error("Connection to guacd terminated abnormally: {}", e.getMessage());
logger.debug("Internal error during connection to guacd.", e);
closeConnection(outbound, e.getStatus().getGuacamoleStatusCode(),
e.getWebSocketCode());
}
}
catch (IOException e) {
logger.debug("I/O error prevents further reads.", e);
closeConnection(outbound, GuacamoleStatus.SERVER_ERROR);
}
}
};
readThread.start();
}
@Override
public void onClose(int i) {
try {
if (tunnel != null)
tunnel.close();
}
catch (GuacamoleException e) {
logger.debug("Unable to close connection to guacd.", e);
}
}
@Override
protected void onBinaryData(InputStream in) throws IOException {
throw new UnsupportedOperationException("Not supported yet.");
}
};
}