Motivation:
https in xmlns URIs does not work and will let the maven release plugin fail:
```
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 1.779 s
[INFO] Finished at: 2020-11-10T07:45:21Z
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-release-plugin:2.5.3:prepare (default-cli) on project netty-parent: Execution default-cli of goal org.apache.maven.plugins:maven-release-plugin:2.5.3:prepare failed: The namespace xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" could not be added as a namespace to "project": The namespace prefix "xsi" collides with an additional namespace declared by the element -> [Help 1]
[ERROR]
```
See also https://issues.apache.org/jira/browse/HBASE-24014.
Modifications:
Use http for xmlns
Result:
Be able to use maven release plugin
Motivation:
Heart-beat is a functionality of STOMP enabling clients and servers to know the healthiness of the connection. The current decoder didn't allow for heart-beat messages to be forwarded to the decoder and were simply swallowed as part of the frame decoding.
Modifications:
Adding support for heartbeat message parsing by introducing a new HEARTBEAT command (not a real STOMP command).
Heartbeat received on the channel will trigger a StompFrame with the command set to HEARTBEAT.
Sending heartbeat on the channel is achieved by creating a StompFrame with the command set to HEARTBEAT.
Result:
Heartbeat can now be received/sent and acted upon to determine the healthiness of the connection and terminate it if needed.
Motivation:
HTTP is a plaintext protocol which means that someone may be able
to eavesdrop the data. To prevent this, HTTPS should be used whenever
possible. However, maintaining using https:// in all URLs may be
difficult. The nohttp tool can help here. The tool scans all the files
in a repository and reports where http:// is used.
Modifications:
- Added nohttp (via checkstyle) into the build process.
- Suppressed findings for the websites
that don't support HTTPS or that are not reachable
Result:
- Prevent using HTTP in the future.
- Encourage users to use HTTPS when they follow the links they found in
the code.
Motivation:
Not always STOMP frames contain any payload some times it just headers. So we wan't allocate additional buffer with NULL content for this situation.
Modification:
Modify StompSubframeEncoder to check if content is readable or not. If content is not readable just add NULL byte to encoded header buffer.
Result:
Less allocations
Motivation:
We can replace some "hand-rolled" integer checks with our own static utility method to simplify the code.
Modifications:
Use methods provided by `ObjectUtil`.
Result:
Cleaner code and less duplication
