API improvements

guacamole-common/src/main/java/net/sourceforge/guacamole/net/Configuration.java

@@ -1,6 +1,8 @@
 
 package net.sourceforge.guacamole.net;
 
+import java.util.HashMap;
+
 /*
  *  Guacamole - Clientless Remote Desktop
  *  Copyright (C) 2010  Michael Jumper
@@ -19,111 +21,25 @@ package net.sourceforge.guacamole.net;
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import javax.servlet.ServletContext;
+public class Configuration {
-import net.sourceforge.guacamole.GuacamoleException;
 
-public abstract class Configuration {
+    private String protocol;
-
+    private HashMap<String, String> parameters = new HashMap<String, String>();
-    protected String humanReadableList(Object... values) {
-
-        String list = "";
-        for (int i=0; i<values.length; i++) {
-
-            if (i >= 1)
-                list += ", ";
-
-            if (i == values.length -1)
-                list += " or ";
-
-            list += "\"" + values[i] + "\"";
-        }
-
-        return list;
 
+    public String getProtocol() {
+        return protocol;
     }
 
-    protected String readParameter(String name) throws GuacamoleException {
+    public void setProtocol(String protocol) {
-        String value = GuacamoleProperties.getProperty(name);
+        this.protocol = protocol;
-        return value;
     }
 
-    protected String readParameter(String name, String defaultValue, String... allowedValues) throws GuacamoleException {
+    public String getParameter(String name) {
-
+        return parameters.get(name);
-        String value = GuacamoleProperties.getProperty(name);
-
-        // Use default if not specified
-        if (value == null) {
-            if (defaultValue == null)
-                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
-
-            return defaultValue;
-        }
-
-        // If not restricted to certain values, just return whatever is given.
-        if (allowedValues.length == 0)
-            return value;
-
-        // If restricted, only return value within given list
-        for (String allowedValue : allowedValues)
-            if (value.equals(allowedValue))
-                return value;
-
-        throw new GuacamoleException("Parameter \"" + name + "\" must be " + humanReadableList((Object) allowedValues));
     }
 
-    protected boolean readBooleanParameter(String name, Boolean defaultValue) throws GuacamoleException {
+    public void setParameter(String name, String value) {
-
+        parameters.put(name, value);
-        String value = GuacamoleProperties.getProperty(name);
-
-        // Use default if not specified
-        if (value == null) {
-            if (defaultValue == null)
-                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
-
-            return defaultValue;
-        }
-
-        value = value.trim();
-        if (value.equals("true"))
-            return true;
-
-        if (value.equals("false"))
-            return false;
-
-        throw new GuacamoleException("Parameter \"" + name + "\" must be \"true\" or \"false\".");
-
-    }
-
-    protected int readIntParameter(String name, Integer defaultValue, Integer... allowedValues) throws GuacamoleException {
-
-        String parmString = GuacamoleProperties.getProperty(name);
-
-        // Use default if not specified
-        if (parmString== null) {
-            if (defaultValue == null)
-                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
-
-            return defaultValue;
-        }
-
-        try {
-            int value = Integer.parseInt(parmString);
-
-            // If not restricted to certain values, just return whatever is given.
-            if (allowedValues.length == 0)
-                return value;
-
-            // If restricted, only return value within given list
-            for (int allowedValue : allowedValues)
-                if (value == allowedValue)
-                    return value;
-
-            throw new GuacamoleException("Parameter \"" + name + "\" must be " + humanReadableList((Object) allowedValues));
-        }
-        catch (NumberFormatException e) {
-            throw new GuacamoleException("Parameter \"" + name + "\" must be an integer.", e);
-        }
-
     }
 
 }

guacamole-common/src/main/java/net/sourceforge/guacamole/net/GuacamoleConfiguration.java

@@ -1,80 +0,0 @@
-
-package net.sourceforge.guacamole.net;
-
-/*
- *  Guacamole - Clientless Remote Desktop
- *  Copyright (C) 2010  Michael Jumper
- *
- *  This program is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU Affero General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU Affero General Public License for more details.
- *
- *  You should have received a copy of the GNU Affero General Public License
- *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-import net.sourceforge.guacamole.net.authentication.GuacamoleSessionProvider;
-import java.lang.reflect.InvocationTargetException;
-import javax.servlet.http.HttpSession;
-import net.sourceforge.guacamole.GuacamoleException;
-
-public class GuacamoleConfiguration extends Configuration {
-
-    private String guacd_hostname;
-    private int guacd_port;
-    private GuacamoleSessionProvider sessionProvider;
-
-    public GuacamoleConfiguration() throws GuacamoleException {
-
-        guacd_hostname       = readParameter("guacd-hostname");
-        guacd_port           = readIntParameter("guacd-port", null);
-
-        // Get session provider instance
-        try {
-            String sessionProviderClassName = readParameter("session-provider");
-            Object obj = Class.forName(sessionProviderClassName).getConstructor().newInstance();
-            if (!(obj instanceof GuacamoleSessionProvider))
-                throw new GuacamoleException("Specified session provider class is not a GuacamoleSessionProvider");
-
-            sessionProvider = (GuacamoleSessionProvider) obj;
-        }
-        catch (ClassNotFoundException e) {
-            throw new GuacamoleException("Session provider class not found", e);
-        }
-        catch (NoSuchMethodException e) {
-            throw new GuacamoleException("Default constructor for session provider not present", e);
-        }
-        catch (SecurityException e) {
-            throw new GuacamoleException("Creation of session provider disallowed; check your security settings", e);
-        }
-        catch (InstantiationException e) {
-            throw new GuacamoleException("Unable to instantiate session provider", e);
-        }
-        catch (IllegalAccessException e) {
-            throw new GuacamoleException("Unable to access default constructor of session provider", e);
-        }
-        catch (InvocationTargetException e) {
-            throw new GuacamoleException("Internal error in constructor of session provider", e.getTargetException());
-        }
-
-    }
-
-    public int getProxyPort() {
-        return guacd_port;
-    }
-
-    public String getProxyHostname() {
-        return guacd_hostname;
-    }
-
-    public GuacamoleSession createSession(HttpSession session) throws GuacamoleException {
-        return sessionProvider.createSession(session);
-    }
-
-}

guacamole-common/src/main/java/net/sourceforge/guacamole/net/GuacamoleProperties.java

@@ -21,8 +21,10 @@ package net.sourceforge.guacamole.net;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.lang.reflect.InvocationTargetException;
 import java.util.Properties;
 import net.sourceforge.guacamole.GuacamoleException;
+import net.sourceforge.guacamole.net.authentication.GuacamoleClientProvider;
 
 public class GuacamoleProperties {
 
@@ -47,9 +49,146 @@ public class GuacamoleProperties {
 
     }
 
+    public static String getProxyHostname() throws GuacamoleException {
+        return GuacamoleProperties.getProperty("guacd-hostname");
+    }
+
+    public static int getProxyPort() throws GuacamoleException {
+        return GuacamoleProperties.getIntProperty("guacd-port", null);
+    }
+
+    public static GuacamoleClientProvider getClientProvider() throws GuacamoleException {
+
+        // Get client provider instance
+        try {
+            String sessionProviderClassName = GuacamoleProperties.getProperty("client-provider");
+            Object obj = Class.forName(sessionProviderClassName).getConstructor().newInstance();
+            if (!(obj instanceof GuacamoleClientProvider))
+                throw new GuacamoleException("Specified client provider class is not a GuacamoleClientProvider");
+
+            return (GuacamoleClientProvider) obj;
+        }
+        catch (ClassNotFoundException e) {
+            throw new GuacamoleException("Session provider class not found", e);
+        }
+        catch (NoSuchMethodException e) {
+            throw new GuacamoleException("Default constructor for client provider not present", e);
+        }
+        catch (SecurityException e) {
+            throw new GuacamoleException("Creation of client provider disallowed; check your security settings", e);
+        }
+        catch (InstantiationException e) {
+            throw new GuacamoleException("Unable to instantiate client provider", e);
+        }
+        catch (IllegalAccessException e) {
+            throw new GuacamoleException("Unable to access default constructor of client provider", e);
+        }
+        catch (InvocationTargetException e) {
+            throw new GuacamoleException("Internal error in constructor of client provider", e.getTargetException());
+        }
+
+    }
+
     public static String getProperty(String name) throws GuacamoleException {
         if (exception != null) throw exception;
         return properties.getProperty(name);
     }
 
+    protected static String humanReadableList(Object... values) {
+
+        String list = "";
+        for (int i=0; i<values.length; i++) {
+
+            if (i >= 1)
+                list += ", ";
+
+            if (i == values.length -1)
+                list += " or ";
+
+            list += "\"" + values[i] + "\"";
+        }
+
+        return list;
+
+    }
+
+    public static String getProperty(String name, String defaultValue, String... allowedValues) throws GuacamoleException {
+
+        String value = getProperty(name);
+
+        // Use default if not specified
+        if (value == null) {
+            if (defaultValue == null)
+                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
+
+            return defaultValue;
+        }
+
+        // If not restricted to certain values, just return whatever is given.
+        if (allowedValues.length == 0)
+            return value;
+
+        // If restricted, only return value within given list
+        for (String allowedValue : allowedValues)
+            if (value.equals(allowedValue))
+                return value;
+
+        throw new GuacamoleException("Parameter \"" + name + "\" must be " + humanReadableList((Object) allowedValues));
+    }
+
+    public static boolean getBooleanProperty(String name, Boolean defaultValue) throws GuacamoleException {
+
+        String value = getProperty(name);
+
+        // Use default if not specified
+        if (value == null) {
+            if (defaultValue == null)
+                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
+
+            return defaultValue;
+        }
+
+        value = value.trim();
+        if (value.equals("true"))
+            return true;
+
+        if (value.equals("false"))
+            return false;
+
+        throw new GuacamoleException("Parameter \"" + name + "\" must be \"true\" or \"false\".");
+
+    }
+
+    public static int getIntProperty(String name, Integer defaultValue, Integer... allowedValues) throws GuacamoleException {
+
+        String parmString = getProperty(name);
+
+        // Use default if not specified
+        if (parmString== null) {
+            if (defaultValue == null)
+                throw new GuacamoleException("Parameter \"" + name + "\" is required.");
+
+            return defaultValue;
+        }
+
+        try {
+            int value = Integer.parseInt(parmString);
+
+            // If not restricted to certain values, just return whatever is given.
+            if (allowedValues.length == 0)
+                return value;
+
+            // If restricted, only return value within given list
+            for (int allowedValue : allowedValues)
+                if (value == allowedValue)
+                    return value;
+
+            throw new GuacamoleException("Parameter \"" + name + "\" must be " + humanReadableList((Object) allowedValues));
+        }
+        catch (NumberFormatException e) {
+            throw new GuacamoleException("Parameter \"" + name + "\" must be an integer.", e);
+        }
+
+    }
+
 }

guacamole-common/src/main/java/net/sourceforge/guacamole/net/GuacamoleServlet.java

@@ -1,83 +0,0 @@
-
-package net.sourceforge.guacamole.net;
-
-/*
- *  Guacamole - Clientless Remote Desktop
- *  Copyright (C) 2010  Michael Jumper
- *
- *  This program is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU Affero General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU Affero General Public License for more details.
- *
- *  You should have received a copy of the GNU Affero General Public License
- *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-
-import java.io.IOException;
-import javax.servlet.ServletConfig;
-import javax.servlet.ServletException;
-import javax.servlet.http.HttpServlet;
-import javax.servlet.http.HttpServletRequest;
-import javax.servlet.http.HttpServletResponse;
-import javax.servlet.http.HttpSession;
-import net.sourceforge.guacamole.GuacamoleException;
-
-public abstract class GuacamoleServlet extends HttpServlet  {
-
-    private GuacamoleConfiguration config;
-
-    @Override
-    public void init() throws ServletException {
-        try {
-            this.config = new GuacamoleConfiguration();
-        }
-        catch (GuacamoleException e) {
-            throw new ServletException(e);
-        }
-    }
-
-    @Override
-    protected final void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
-        try {
-            handleRequest(req, resp);
-        }
-        catch (GuacamoleException e) {
-            throw new ServletException(e);
-        }
-    }
-
-    @Override
-    protected final void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
-        try {
-            handleRequest(req, resp);
-        }
-        catch (GuacamoleException e) {
-            throw new ServletException(e);
-        }
-    }
-
-    private final void handleRequest(HttpServletRequest request, HttpServletResponse response) throws GuacamoleException {
-
-        HttpSession httpSession = request.getSession(shouldCreateSession());
-
-        if (httpSession != null) {
-            GuacamoleSession session = config.createSession(httpSession);
-            handleRequest(session, request, response);
-        }
-        else
-            throw new GuacamoleException("No session");
-    }
-
-    protected abstract void handleRequest(GuacamoleSession session, HttpServletRequest request, HttpServletResponse response) throws GuacamoleException;
-
-    protected boolean shouldCreateSession() {
-        return false;
-    }
-
-}

guacamole-common/src/main/java/net/sourceforge/guacamole/net/GuacamoleSession.java

@@ -19,7 +19,6 @@ package net.sourceforge.guacamole.net;
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import java.util.HashMap;
 import java.util.concurrent.locks.ReentrantLock;
 import javax.servlet.http.HttpSession;
 import javax.servlet.http.HttpSessionBindingEvent;
@@ -30,31 +29,10 @@ import net.sourceforge.guacamole.GuacamoleException;
 
 public class GuacamoleSession {
 
-    private GuacamoleConfiguration config;
-
     private final HttpSession session;
     private SessionClient client;
     private ReentrantLock instructionStreamLock;
 
-    private String protocol;
-    private HashMap<String, String> parameters = new HashMap<String, String>();
-
-    public String getProtocol() {
-        return protocol;
-    }
-
-    public void setProtocol(String protocol) {
-        this.protocol = protocol;
-    }
-
-    public String getParameter(String name) {
-        return parameters.get(name);
-    }
-
-    public void setParameter(String name, String value) {
-        parameters.put(name, value);
-    }
-
     public class SessionClient extends Client implements HttpSessionBindingListener {
 
         private Client client;
@@ -96,34 +74,22 @@ public class GuacamoleSession {
             throw new GuacamoleException("User has no session.");
 
         this.session = session;
-        synchronized (session) {
 
-            // Read configuration parameters
+        synchronized (session) {
-            config = new GuacamoleConfiguration();
 
             client = (SessionClient) session.getAttribute("CLIENT");
             instructionStreamLock = (ReentrantLock) session.getAttribute("INSTRUCTION_STREAM_LOCK");
+
         }
 
     }
 
-    public void connect() throws GuacamoleException {
+    public void attachClient(GuacamoleClient client) throws GuacamoleException {
 
         synchronized (session) {
 
-            if (client != null)
+            this.client = new SessionClient(client);
-                client.disconnect();
+            session.setAttribute("CLIENT", this.client);
-
-            client = new SessionClient(
-                    new GuacamoleClient (
-                        config.getProxyHostname(),
-                        config.getProxyPort()
-                    )
-            );
-
-            // TODO: Send "select" and "connect" messages here.
-
-            session.setAttribute("CLIENT", client);
 
             instructionStreamLock = new ReentrantLock();
             session.setAttribute("INSTRUCTION_STREAM_LOCK", instructionStreamLock);
@@ -132,21 +98,11 @@ public class GuacamoleSession {
 
     }
 
-    public boolean isConnected() {
-        synchronized (session) {
-            return client != null;
-        }
-    }
-
-    public GuacamoleConfiguration getConfiguration() {
-        return config;
-    }
-
     public SessionClient getClient() throws GuacamoleException {
         synchronized (session) {
 
             if (client == null)
-                throw new GuacamoleException("Client not yet connected.");
+                throw new GuacamoleException("Client not yet attached.");
 
             return client;
         }
@@ -156,7 +112,7 @@ public class GuacamoleSession {
         session.invalidate();
     }
 
-    public void disconnect() throws GuacamoleException {
+    public void detachClient() throws GuacamoleException {
 
         synchronized (session) {
 

guacamole-common/src/main/java/net/sourceforge/guacamole/net/authentication/GuacamoleClientProvider.java

@@ -2,8 +2,8 @@
 package net.sourceforge.guacamole.net.authentication;
 
 import javax.servlet.http.HttpSession;
+import net.sourceforge.guacamole.GuacamoleClient;
 import net.sourceforge.guacamole.GuacamoleException;
-import net.sourceforge.guacamole.net.GuacamoleSession;
 
 /*
  *  Guacamole - Clientless Remote Desktop
@@ -23,8 +23,8 @@ import net.sourceforge.guacamole.net.GuacamoleSession;
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-public interface GuacamoleSessionProvider {
+public interface GuacamoleClientProvider {
 
-    public GuacamoleSession createSession(HttpSession session) throws GuacamoleException;
+    public GuacamoleClient createClient(HttpSession session) throws GuacamoleException;
 
 }

guacamole-common/src/main/java/net/sourceforge/guacamole/net/authentication/NullGuacamoleClientProvider.java

@@ -2,8 +2,8 @@
 package net.sourceforge.guacamole.net.authentication;
 
 import javax.servlet.http.HttpSession;
+import net.sourceforge.guacamole.GuacamoleClient;
 import net.sourceforge.guacamole.GuacamoleException;
-import net.sourceforge.guacamole.net.GuacamoleSession;
 
 /*
  *  Guacamole - Clientless Remote Desktop
@@ -23,10 +23,10 @@ import net.sourceforge.guacamole.net.GuacamoleSession;
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-public class NullGuacamoleSessionProvider implements GuacamoleSessionProvider {
+public class NullGuacamoleClientProvider implements GuacamoleClientProvider {
 
-    public GuacamoleSession createSession(HttpSession session) throws GuacamoleException {
+    public GuacamoleClient createClient(HttpSession session) throws GuacamoleException {
-        throw new GuacamoleException("Null provider will not create sessions");
+        throw new GuacamoleException("Null provider will not create clients.");
     }
 
 }

guacamole-common/src/main/java/net/sourceforge/guacamole/net/tunnel/Connect.java

@@ -18,30 +18,35 @@ package net.sourceforge.guacamole.net.tunnel;
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-import net.sourceforge.guacamole.GuacamoleException;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-import net.sourceforge.guacamole.net.GuacamoleServlet;
+import javax.servlet.http.HttpSession;
-
+import net.sourceforge.guacamole.GuacamoleException;
+import net.sourceforge.guacamole.net.GuacamoleProperties;
 import net.sourceforge.guacamole.net.GuacamoleSession;
 
-public class Connect extends GuacamoleServlet {
+
+public class Connect extends HttpServlet {
 
     @Override
-    protected boolean shouldCreateSession() {
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException {
-        return true;
-    }
 
-    @Override
+        HttpSession httpSession = request.getSession(false);
-    protected void handleRequest(GuacamoleSession session, HttpServletRequest request, HttpServletResponse response) throws GuacamoleException {
 
-        // Disconnect if already connected
+        try {
-        if (session.isConnected())
-            session.disconnect();
 
-        // Obtain new connection
+            GuacamoleSession session = new GuacamoleSession(httpSession);
-        session.connect();
+            session.attachClient(
+                GuacamoleProperties.getClientProvider().createClient(httpSession)
+            );
+
+        }
+        catch (GuacamoleException e) {
+            throw new ServletException(e);
+        }
 
     }
 

guacamole-common/src/main/java/net/sourceforge/guacamole/net/tunnel/Inbound.java

@@ -22,33 +22,43 @@ import net.sourceforge.guacamole.GuacamoleException;
 
 import java.io.Reader;
 import java.io.IOException;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-import net.sourceforge.guacamole.net.GuacamoleServlet;
+import javax.servlet.http.HttpSession;
-
 import net.sourceforge.guacamole.net.GuacamoleSession;
 
-public class Inbound extends GuacamoleServlet {
+
+public class Inbound extends HttpServlet {
 
     @Override
-    protected void handleRequest(GuacamoleSession session, HttpServletRequest request, HttpServletResponse response) throws GuacamoleException {
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException {
-        
+
-        // Send data
+        HttpSession httpSession = request.getSession(false);
+
         try {
 
-            Reader input = request.getReader();
+            GuacamoleSession session = new GuacamoleSession(httpSession);
-            char[] buffer = new char[8192];
 
-            int length;
+            // Send data
-            while ((length = input.read(buffer, 0, buffer.length)) != -1)
+            try {
-                session.getClient().write(buffer, 0, length);
+
+                Reader input = request.getReader();
+                char[] buffer = new char[8192];
+
+                int length;
+                while ((length = input.read(buffer, 0, buffer.length)) != -1)
+                    session.getClient().write(buffer, 0, length);
+
+            }
+            catch (IOException e) {
+                throw new GuacamoleException("I/O Error sending data to server: " + e.getMessage(), e);
+            }
 
-        }
-        catch (IOException e) {
-            throw new GuacamoleException("I/O Error sending data to server: " + e.getMessage(), e);
         }
         catch (GuacamoleException e) {
-            throw new GuacamoleException("Error sending data to server: " + e.getMessage(), e);
+            throw new ServletException(e);
         }
 
     }

guacamole-common/src/main/java/net/sourceforge/guacamole/net/tunnel/Outbound.java

@@ -22,73 +22,86 @@ import java.io.Writer;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.util.concurrent.locks.ReentrantLock;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
 import net.sourceforge.guacamole.Client;
-import net.sourceforge.guacamole.net.GuacamoleServlet;
 import net.sourceforge.guacamole.GuacamoleException;
 import net.sourceforge.guacamole.net.GuacamoleSession;
 
 
-public class Outbound extends GuacamoleServlet {
+public class Outbound extends HttpServlet {
 
     @Override
-    protected void handleRequest(GuacamoleSession session, HttpServletRequest request, HttpServletResponse response) throws GuacamoleException {
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException {
 
-        ReentrantLock instructionStreamLock = session.getInstructionStreamLock();
+        HttpSession httpSession = request.getSession(false);
-        instructionStreamLock.lock();
 
         try {
 
-            response.setContentType("text/plain");
+            GuacamoleSession session = new GuacamoleSession(httpSession);
-            Writer out = response.getWriter();
+
+            ReentrantLock instructionStreamLock = session.getInstructionStreamLock();
+            instructionStreamLock.lock();
 
             try {
 
-                // Query new update from server
+                response.setContentType("text/plain");
-                Client client = session.getClient();
+                Writer out = response.getWriter();
 
-                // For all messages, until another stream is ready (we send at least one message)
+                try {
-                char[] message;
-                while ((message = client.read()) != null) {
 
-                    // Get message output bytes
+                    // Query new update from server
-                    out.write(message, 0, message.length);
+                    Client client = session.getClient();
+
+                    // For all messages, until another stream is ready (we send at least one message)
+                    char[] message;
+                    while ((message = client.read()) != null) {
+
+                        // Get message output bytes
+                        out.write(message, 0, message.length);
+                        out.flush();
+                        response.flushBuffer();
+
+                        // No more messages another stream can take over
+                        if (instructionStreamLock.hasQueuedThreads())
+                            break;
+
+                    }
+
+                    if (message == null) {
+                        session.detachClient();
+                        throw new GuacamoleException("Disconnected.");
+                    }
+
+                }
+                catch (GuacamoleException e) {
+                    out.write("error:" + e.getMessage() + ";");
                     out.flush();
                     response.flushBuffer();
-
-                    // No more messages another stream can take over
-                    if (instructionStreamLock.hasQueuedThreads())
-                        break;
-
                 }
 
-                if (message == null) {
+                // End-of-instructions marker
-                    session.disconnect();
+                out.write(';');
-                    throw new GuacamoleException("Disconnected.");
-                }
-
-            }
-            catch (GuacamoleException e) {
-                out.write("error:" + e.getMessage() + ";");
                 out.flush();
                 response.flushBuffer();
+
+            }
+            catch (UnsupportedEncodingException e) {
+                throw new ServletException("UTF-8 not supported by Java.", e);
+            }
+            catch (IOException e) {
+                throw new ServletException("I/O error writing to servlet output stream.", e);
+            }
+            finally {
+                instructionStreamLock.unlock();
             }
 
-            // End-of-instructions marker
-            out.write(';');
-            out.flush();
-            response.flushBuffer();
-
         }
-        catch (UnsupportedEncodingException e) {
+        catch (GuacamoleException e) {
-            throw new GuacamoleException("UTF-8 not supported by Java.", e);
+            throw new ServletException(e);
-        }
-        catch (IOException e) {
-            throw new GuacamoleException("I/O error writing to servlet output stream.", e);
-        }
-        finally {
-            instructionStreamLock.unlock();
         }
 
     }