Create Debugging Terminal for Session

[francois-normandin]

Debugging why a connection is refused is painful with the current library. Having access to a generic, low-level, debug terminal would allow inspection of reasons of failures more efficiently.

An example use case is when connecting to a new service or client library. I've been using the Paho MQTT client over Websockets with a local LabVIEW-based MQTT server and the browser's javascript code was not subscribing after a connection attempt.

Debugging at the byte stream layer gives a lot of insights. For example, this is a quick attempt at monitoring and highlighting streams at the session layer, for a client connected to the server.

[francois-normandin]

Ideally, the debugging panel would be configurable (max buffer size, input/output) and provide insight into packet-specific information to extract. For example, the CONNACK packet listed below represents a rejected connection. It would be useful to be able to select a packet from the stream, and list its properties in a human readable way.

[francois-normandin]

• MQTT Base should include an injected Session Debuging Terminal class.
• MQTT Base should provide a default Session Debugging Terminal class
• MQTT Base should expose methods to start/stop debugging session (default = OFF)
• MQTT Base should expose methods to open/close debugging terminal

[francois-normandin]

package release 4.1.2 includes an Implementation of a Terminal Class distributed with this MQTT Connection package, which can be injected into the Connection of a MQTT server or a client class.

The process (and View) is not exhaustive and is meant to be overwritable as an injectable VI reference into the "Launch Terminal" method. If unwired, the default (simple) panel is used. This will allow extensions to be developed and distributed (or not) by developer based on the example process provided. The provided terminal process (example code) limits the incoming and outgoing buffers to 5000 packets. Developers can use it as an example and develop their own UX + configurability.

To be used as this example:

[francois-normandin]

I will be adding more flexibility to this feature in MQTT-Connection 4.2.0

• Overwritable Process allows developer to create their own packet renderer
• Multiple processes can be launched
• Processes can be subpanelable
• Formatter class can be injected to change the parsing of the incoming stream. Default implementation shown below.