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Posted to dev@guacamole.apache.org by GitBox <gi...@apache.org> on 2021/02/14 00:24:27 UTC
[GitHub] [guacamole-client] mike-jumper commented on a change in pull request #500: GUACAMOLE-1048: Support server control commands during handshake
mike-jumper commented on a change in pull request #500:
URL: https://github.com/apache/guacamole-client/pull/500#discussion_r575728206
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/GuacamoleServerErrorCommandException.java
##########
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole;
+
+import org.apache.guacamole.protocol.GuacamoleStatus;
+
+/**
+ * The exception thrown when the Guacamole server explicitly sends an error
+ * command to the client. The error message and status code reflect the arguments
+ * of the error command as determined by the server.
+ */
+public class GuacamoleServerErrorCommandException extends GuacamoleServerException {
Review comment:
Regarding `GuacamoleServerErrorCommandException` and its description, "error command" isn't terminology used within the Guacamole protocol. In this case, the correct term would be "error instruction", but I don't think simply renaming things to `GuacamoleServerErrorInstructionException` would be a good choice, as that too closely ties the error to the vehicle carrying it. The naming of the exception and the documentation describing the exception should capture the context, rather than the means.
I suggest something like `GuacamoleHandshakeException`, for an error that prevents the Guacamole protocol handshake from continuing. I'm sure there are other possibilities.
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java
##########
@@ -83,14 +111,24 @@ private GuacamoleInstruction expect(GuacamoleReader reader, String opcode)
if (instruction == null)
throw new GuacamoleServerException("End of stream while waiting for \"" + opcode + "\".");
+ // Handle server control commands
Review comment:
instructions*
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java
##########
@@ -63,12 +64,39 @@
*/
private GuacamoleProtocolVersion protocolVersion =
GuacamoleProtocolVersion.VERSION_1_0_0;
-
+
+ /**
+ * Parses the arguments for the Guacamole "error" server command and returns
+ * the corresponding exception.
+ * @param args The arguments as provided by the server command.
+ * @return An instance of {@link GuacamoleServerErrorCommandException} configured
+ * with the server-provided arguments, or {@literal null} if the specified
+ * arguments are invalid.
+ */
+ private static GuacamoleServerErrorCommandException parseServerErrorCommandArgs(List<String> args) {
+ if (args == null || args.size() != 2)
+ return null;
Review comment:
1. It's pretty common for instructions to be extended down the line by adding new arguments, relying on older implementations to ignore any additional arguments. I think it would be better here to test `args.size() < 2`.
2. Under what circumstance would `args` be `null`?
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java
##########
@@ -83,14 +111,24 @@ private GuacamoleInstruction expect(GuacamoleReader reader, String opcode)
if (instruction == null)
throw new GuacamoleServerException("End of stream while waiting for \"" + opcode + "\".");
+ // Handle server control commands
+ if ("disconnect".equals(instruction.getOpcode()))
+ throw new GuacamoleServerException("Server disconnected while waiting for \"" + opcode + "\".");
+ if ("error".equals(instruction.getOpcode())) {
+ GuacamoleServerErrorCommandException e = parseServerErrorCommandArgs(instruction.getArgs());
+ if (e == null)
+ throw new GuacamoleServerException("Invalid command received from server: " + instruction);
Review comment:
These are referred to as instructions, not commands.
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/GuacamoleServerErrorCommandException.java
##########
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole;
+
+import org.apache.guacamole.protocol.GuacamoleStatus;
+
+/**
+ * The exception thrown when the Guacamole server explicitly sends an error
+ * command to the client. The error message and status code reflect the arguments
+ * of the error command as determined by the server.
+ */
+public class GuacamoleServerErrorCommandException extends GuacamoleServerException {
+ /**
+ * The Guacamole protocol status code, as determined by the server;
+ */
+ private final GuacamoleStatus status;
+
+ /**
+ * Creates a new GuacamoleServerException with the given message and status.
+ *
+ * @param message The error message, as determined by the server where the error
+ * originated.
+ * @param status The status code, as determined by the server where the error originated.
Review comment:
Please follow the style used for documentation elsewhere in the code. For example:
https://github.com/apache/guacamole-client/blob/0091bb1aea14c567c8166f0ed8eadf7c31b6bd6e/guacamole-common/src/main/java/org/apache/guacamole/GuacamoleUpstreamUnavailableException.java#L30-L42
The style you've used here is similar to what we used to do, but we migrated away from that since it can be difficult to read, particularly for long variable names. New code should use the new style.
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/GuacamoleServerErrorCommandException.java
##########
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.guacamole;
+
+import org.apache.guacamole.protocol.GuacamoleStatus;
+
+/**
+ * The exception thrown when the Guacamole server explicitly sends an error
+ * command to the client. The error message and status code reflect the arguments
+ * of the error command as determined by the server.
+ */
+public class GuacamoleServerErrorCommandException extends GuacamoleServerException {
+ /**
+ * The Guacamole protocol status code, as determined by the server;
+ */
+ private final GuacamoleStatus status;
+
+ /**
+ * Creates a new GuacamoleServerException with the given message and status.
Review comment:
This should note the name of the exception in question, not `GuacamoleServerException`.
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java
##########
@@ -63,12 +64,39 @@
*/
private GuacamoleProtocolVersion protocolVersion =
GuacamoleProtocolVersion.VERSION_1_0_0;
-
+
+ /**
+ * Parses the arguments for the Guacamole "error" server command and returns
+ * the corresponding exception.
+ * @param args The arguments as provided by the server command.
+ * @return An instance of {@link GuacamoleServerErrorCommandException} configured
+ * with the server-provided arguments, or {@literal null} if the specified
+ * arguments are invalid.
+ */
+ private static GuacamoleServerErrorCommandException parseServerErrorCommandArgs(List<String> args) {
+ if (args == null || args.size() != 2)
+ return null;
+
+ int code;
+ try {
+ code = Integer.parseInt(args.get(1));
+ } catch (NumberFormatException e) {
+ return null;
+ }
+ GuacamoleStatus status = GuacamoleStatus.fromGuacamoleStatusCode(code);
+ return (status == null)
+ ? null
+ : new GuacamoleServerErrorCommandException(args.get(0), status);
+ }
+
/**
* Waits for the instruction having the given opcode, returning that
* instruction once it has been read. If the instruction is never read,
* an exception is thrown.
- *
+ *
+ * Respects server control commands that are allowed during the handshake
Review comment:
instructions*
##########
File path: guacamole-common/src/main/java/org/apache/guacamole/protocol/ConfiguredGuacamoleSocket.java
##########
@@ -83,14 +111,24 @@ private GuacamoleInstruction expect(GuacamoleReader reader, String opcode)
if (instruction == null)
throw new GuacamoleServerException("End of stream while waiting for \"" + opcode + "\".");
+ // Handle server control commands
+ if ("disconnect".equals(instruction.getOpcode()))
+ throw new GuacamoleServerException("Server disconnected while waiting for \"" + opcode + "\".");
+ if ("error".equals(instruction.getOpcode())) {
+ GuacamoleServerErrorCommandException e = parseServerErrorCommandArgs(instruction.getArgs());
+ if (e == null)
+ throw new GuacamoleServerException("Invalid command received from server: " + instruction);
Review comment:
Might be better to let it be the responsibility of the function parsing the `error` instruction to decide whether the instruction is valid and throw an appropriate exception if it isn't. This would simplify the logic here and more cleanly separate concerns.
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