GUAC-442: Move base JSR implementation of WebSocket tunnel to guacamole-common.

guacamole-common/pom.xml

@@ -104,6 +104,14 @@
             <scope>provided</scope>
         </dependency>
 
+        <!-- JSR 356 WebSocket API -->
+        <dependency>
+            <groupId>javax.websocket</groupId>
+            <artifactId>javax.websocket-api</artifactId>
+            <version>1.0</version>
+            <scope>provided</scope>
+        </dependency>
+
         <!-- SLF4J - logging -->
         <dependency>
             <groupId>org.slf4j</groupId>

guacamole-common/src/main/java/org/glyptodon/guacamole/websocket/GuacamoleWebSocketTunnelEndpoint.java

@@ -0,0 +1,231 @@
+/*
+ * Copyright (C) 2014 Glyptodon LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package org.glyptodon.guacamole.websocket;
+
+import java.io.IOException;
+import javax.websocket.CloseReason;
+import javax.websocket.CloseReason.CloseCode;
+import javax.websocket.Endpoint;
+import javax.websocket.EndpointConfig;
+import javax.websocket.MessageHandler;
+import javax.websocket.OnClose;
+import javax.websocket.OnMessage;
+import javax.websocket.OnOpen;
+import javax.websocket.RemoteEndpoint;
+import javax.websocket.Session;
+import org.glyptodon.guacamole.GuacamoleException;
+import org.glyptodon.guacamole.io.GuacamoleReader;
+import org.glyptodon.guacamole.io.GuacamoleWriter;
+import org.glyptodon.guacamole.net.GuacamoleTunnel;
+import org.glyptodon.guacamole.GuacamoleClientException;
+import org.glyptodon.guacamole.protocol.GuacamoleStatus;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A WebSocket implementation of GuacamoleTunnel functionality, compatible with
+ * the Guacamole.WebSocketTunnel object included with the JavaScript API.
+ * Messages sent/received are simply chunks of the Guacamole protocol
+ * instruction stream.
+ *
+ * @author Michael Jumper
+ */
+public abstract class GuacamoleWebSocketTunnelEndpoint extends Endpoint {
+
+    /**
+     * The default, minimum buffer size for instructions.
+     */
+    private static final int BUFFER_SIZE = 8192;
+
+    /**
+     * Logger for this class.
+     */
+    private final Logger logger = LoggerFactory.getLogger(GuacamoleWebSocketTunnelEndpoint.class);
+
+    /**
+     * The underlying GuacamoleTunnel. WebSocket reads/writes will be handled
+     * as reads/writes to this tunnel.
+     */
+    private GuacamoleTunnel tunnel;
+    
+    /**
+     * Sends the given status on the given WebSocket connection and closes the
+     * connection.
+     *
+     * @param session The outbound WebSocket connection to close.
+     * @param guac_status The status to send.
+     */
+    private void closeConnection(Session session, GuacamoleStatus guac_status) {
+
+        try {
+            CloseCode code = CloseReason.CloseCodes.getCloseCode(guac_status.getWebSocketCode());
+            String message = Integer.toString(guac_status.getGuacamoleStatusCode());
+            session.close(new CloseReason(code, message));
+        }
+        catch (IOException e) {
+            logger.error("Unable to close WebSocket connection.", e);
+        }
+
+    }
+
+    /**
+     * Returns a new tunnel for the given session. How this tunnel is created
+     * or retrieved is implementation-dependent.
+     *
+     * @param session The session associated with the active WebSocket
+     *                connection.
+     * @param config Configuration information associated with the instance of
+     *               the endpoint created for handling this single connection.
+     * @return A connected tunnel, or null if no such tunnel exists.
+     * @throws GuacamoleException If an error occurs while retrieving the
+     *                            tunnel, or if access to the tunnel is denied.
+     */
+    protected abstract GuacamoleTunnel createTunnel(Session session, EndpointConfig config)
+            throws GuacamoleException;
+
+    @Override
+    @OnOpen
+    public void onOpen(final Session session, EndpointConfig config) {
+
+        try {
+
+            // Get tunnel
+            tunnel = createTunnel(session, config);
+            if (tunnel == null) {
+                closeConnection(session, GuacamoleStatus.RESOURCE_NOT_FOUND);
+                return;
+            }
+
+        }
+        catch (GuacamoleException e) {
+            logger.error("Error connecting WebSocket tunnel.", e);
+            closeConnection(session, e.getStatus());
+            return;
+        }
+
+        // Manually register message handler
+        session.addMessageHandler(new MessageHandler.Whole<String>() {
+
+            @Override
+            public void onMessage(String message) {
+                GuacamoleWebSocketTunnelEndpoint.this.onMessage(message);
+            }
+
+        });
+
+        // Prepare read transfer thread
+        Thread readThread = new Thread() {
+
+            /**
+             * Remote (client) side of this connection
+             */
+            private final RemoteEndpoint.Basic remote = session.getBasicRemote();
+                
+            @Override
+            public void run() {
+
+                StringBuilder buffer = new StringBuilder(BUFFER_SIZE);
+                GuacamoleReader reader = tunnel.acquireReader();
+                char[] readMessage;
+
+                try {
+
+                    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) {
+                                remote.sendText(buffer.toString());
+                                buffer.setLength(0);
+                            }
+
+                        }
+
+                        // No more data
+                        closeConnection(session, GuacamoleStatus.SUCCESS);
+
+                    }
+
+                    // Catch any thrown guacamole exception and attempt
+                    // to pass within the WebSocket connection, logging
+                    // each error appropriately.
+                    catch (GuacamoleClientException e) {
+                        logger.warn("Client request rejected: {}", e.getMessage());
+                        closeConnection(session, e.getStatus());
+                    }
+                    catch (GuacamoleException e) {
+                        logger.error("Internal server error.", e);
+                        closeConnection(session, e.getStatus());
+                    }
+
+                }
+                catch (IOException e) {
+                    logger.debug("I/O error prevents further reads.", e);
+                }
+
+            }
+
+        };
+
+        readThread.start();
+
+    }
+
+    @OnMessage
+    public void onMessage(String message) {
+
+        GuacamoleWriter writer = tunnel.acquireWriter();
+
+        try {
+            // Write received message
+            writer.write(message.toCharArray());
+        }
+        catch (GuacamoleException e) {
+            logger.debug("Tunnel write failed.", e);
+        }
+
+        tunnel.releaseWriter();
+
+    }
+    
+    @Override
+    @OnClose
+    public void onClose(Session session, CloseReason closeReason) {
+
+        try {
+            if (tunnel != null)
+                tunnel.close();
+        }
+        catch (GuacamoleException e) {
+            logger.debug("Unable to close WebSocket tunnel.", e);
+        }
+        
+    }
+
+}
+