GUACAMOLE-1048: Leverage exception conversion provided by GuacamoleStatus for "error" instruction handling.

guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java

@@ -21,12 +21,13 @@ package org.apache.guacamole.protocol;
 
 import java.util.List;
 import org.apache.guacamole.GuacamoleException;
-import org.apache.guacamole.GuacamoleServerErrorInstructionException;
 import org.apache.guacamole.GuacamoleServerException;
 import org.apache.guacamole.io.GuacamoleReader;
 import org.apache.guacamole.io.GuacamoleWriter;
 import org.apache.guacamole.net.DelegatingGuacamoleSocket;
 import org.apache.guacamole.net.GuacamoleSocket;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * A GuacamoleSocket which pre-configures the connection based on a given
@@ -40,6 +41,12 @@ import org.apache.guacamole.net.GuacamoleSocket;
  */
 public class ConfiguredGuacamoleSocket extends DelegatingGuacamoleSocket {
 
+    /**
+     * Logger for this class.
+     */
+    private static final Logger logger =
+            LoggerFactory.getLogger(ConfiguredGuacamoleSocket.class);
+
     /**
      * The configuration to use when performing the Guacamole protocol
      * handshake.
@@ -62,23 +69,59 @@ public class ConfiguredGuacamoleSocket extends DelegatingGuacamoleSocket {
             GuacamoleProtocolVersion.VERSION_1_0_0;
 
     /**
-     * Parses the arguments for the Guacamole "error" server instruction and returns
-     * the corresponding exception.
-     * @param args The arguments as provided by the server instruction.
-     * @return An instance of {@link GuacamoleServerErrorInstructionException} configured
-     *         with the server-provided arguments, or a generic {@link GuacamoleServerException} if
-     *         the specified arguments are invalid.
+     * Parses the given "error" instruction, throwing a GuacamoleException that
+     * corresponds to its status code and message.
+     *
+     * @param instruction
+     *     The "error" instruction to parse.
+     *
+     * @throws GuacamoleException
+     *     A GuacamoleException that corresponds to the status code and message
+     *     present within the given "error" instruction.
      */
-    private static GuacamoleServerException parseServerErrorInstructionArgs(List<String> args) {
-        try {
-            if (args.size() >= 2) {
-                int code = Integer.parseInt(args.get(1));
-                GuacamoleStatus status = GuacamoleStatus.fromGuacamoleStatusCode(code);
-                return new GuacamoleServerErrorInstructionException(args.get(0), status);
-            }
-        } catch (NumberFormatException ignored) {}
+    private static void handleReceivedError(GuacamoleInstruction instruction)
+            throws GuacamoleException {
+
+        // Provide reasonable default error message for invalid "error"
+        // instructions that fail to provide one
+        String message = "Internal error within guacd / protocol handling.";
+
+        // Consider all error instructions without a corresponding status code
+        // to be server errors
+        GuacamoleStatus status = GuacamoleStatus.SERVER_ERROR;
+
+        // Parse human-readable message from "error" instruction, warning if no
+        // message was given
+        List<String> args = instruction.getArgs();
+        if (args.size() >= 1)
+            message = args.get(0);
+        else
+            logger.debug("Received \"error\" instruction with no corresponding message.");
+
+        // Parse the status code from the received error instruction, warning
+        // if the status code is missing or invalid
+        if (args.size() >= 2) {
+            try {
+                
+                // Translate numeric status code into a GuacamoleStatus
+                int statusCode = Integer.parseInt(args.get(1));
+                GuacamoleStatus parsedStatus = GuacamoleStatus.fromGuacamoleStatusCode(statusCode);
+                if (parsedStatus != null)
+                    status = parsedStatus;
+                else
+                    logger.debug("Received \"error\" instruction with unknown/invalid status code: {}", statusCode);
+
+            }
+            catch (NumberFormatException e) {
+                logger.debug("Received \"error\" instruction with non-numeric status code.", e);
+            }
+        }
+        else
+            logger.debug("Received \"error\" instruction without status code.");
+
+        // Convert parsed status code and message to a GuacamoleException
+        throw status.toException(message);
 
-        return new GuacamoleServerException("Invalid error instruction arguments received: " + args);
     }
 
     /**
@@ -107,7 +150,7 @@ public class ConfiguredGuacamoleSocket extends DelegatingGuacamoleSocket {
         if ("disconnect".equals(instruction.getOpcode()))
             throw new GuacamoleServerException("Server disconnected while waiting for \"" + opcode + "\".");
         if ("error".equals(instruction.getOpcode()))
-            throw parseServerErrorInstructionArgs(instruction.getArgs());
+            handleReceivedError(instruction);
 
         // Ensure instruction has expected opcode
         if (!instruction.getOpcode().equals(opcode))