Implemented AuthenticatingHttpServlet which automatically authenticates the requesting user (if possible), only allowing the request through if authentication succeeded.

guacamole/src/main/java/net/sourceforge/guacamole/net/basic/AuthenticatingHttpServlet.java

@@ -0,0 +1,116 @@
+
+package net.sourceforge.guacamole.net.basic;
+
+import java.io.IOException;
+import java.util.Map;
+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;
+import net.sourceforge.guacamole.net.auth.AuthenticationProvider;
+import net.sourceforge.guacamole.net.auth.Credentials;
+import net.sourceforge.guacamole.net.basic.properties.BasicGuacamoleProperties;
+import net.sourceforge.guacamole.properties.GuacamoleProperties;
+import net.sourceforge.guacamole.protocol.GuacamoleConfiguration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Abstract servlet which provides an authenticatedService() function that
+ * is only called if the HTTP request is authenticated, or the current
+ * HTTP session has already been authenticated.
+ * 
+ * Authorized configurations are retrieved using the authentication provider
+ * defined in guacamole.properties. The authentication provider has access
+ * to the request and session, in addition to any submitted username and
+ * password, in order to authenticate the user.
+ * 
+ * All authorized configurations will be stored in the current HttpSession.
+ * 
+ * Success and failure are logged.
+ * 
+ * @author Michael Jumper
+ */
+public abstract class AuthenticatingHttpServlet extends HttpServlet {
+
+    private Logger logger = LoggerFactory.getLogger(AuthenticatingHttpServlet.class);
+    
+    private AuthenticationProvider authProvider;
+
+    @Override
+    public void init() throws ServletException {
+
+        // Get auth provider instance
+        try {
+            authProvider = GuacamoleProperties.getRequiredProperty(BasicGuacamoleProperties.AUTH_PROVIDER);
+        }
+        catch (GuacamoleException e) {
+            logger.error("Error getting authentication provider from properties.", e);
+            throw new ServletException(e);
+        }
+
+    }
+
+    @Override
+    protected void service(HttpServletRequest request, HttpServletResponse response)
+    throws IOException, ServletException {
+
+        HttpSession httpSession = request.getSession(true);
+
+        // Try to get configs from session
+        Map<String, GuacamoleConfiguration> configs =
+                (Map<String, GuacamoleConfiguration>) httpSession.getAttribute("GUAC_CONFIGS");
+
+        // If no configs, try to authenticate the user to get the configs using
+        // this request.
+        if (configs == null) {
+
+            // Retrieve username and password from parms
+            String username = request.getParameter("username");
+            String password = request.getParameter("password");
+
+            // Build credentials object
+            Credentials credentials = new Credentials ();
+            credentials.setSession(httpSession);
+            credentials.setRequest(request);
+            credentials.setUsername(username);
+            credentials.setPassword(password);
+            
+            // Get authorized configs
+            try {
+                configs = authProvider.getAuthorizedConfigurations(credentials);
+            }
+            catch (GuacamoleException e) {
+                logger.error("Error retrieving configuration(s) for user {}.", username);
+                response.sendError(HttpServletResponse.SC_FORBIDDEN);
+                return;
+            }
+            
+            if (configs == null) {
+                logger.warn("Authentication attempt from {} for user \"{}\".",
+                        request.getRemoteAddr(), username);
+                response.sendError(HttpServletResponse.SC_FORBIDDEN);
+                return;
+            }
+
+            logger.info("User \"{}\" successfully authenticated from {}.",
+                    username, request.getRemoteAddr());
+
+            // Associate configs with session
+            httpSession.setAttribute("GUAC_CONFIGS", configs);
+
+        }
+
+        // Allow servlet to run now that authentication has been validated
+        authenticatedService(configs, request, response);
+
+    }
+
+    protected abstract void authenticatedService(
+            Map<String, GuacamoleConfiguration> configs,
+            HttpServletRequest request, HttpServletResponse response)
+            throws ServletException, IOException;
+
+}