Dynamic serial port configuration

Core Development Feature Requests
1

Hi everyone!

I have a serial in node from node-red-node-serialport (2.0.3) that works as expected. Unfortunately, the serial port, which is in my case "/dev/ttymxc3", needs to be configured also in other parts of my Node-RED flows. In order to achieve a better cohesion I tried to utilize an environment variable for the setting "Serial Port" within the serial port configuration node. However, it seems that environment variables are not supported for this purpose.
In order to set the serial port with an environment variable, I tried utilizing the "serial control" node from node-red-node-serialport (2.0.3).

This is a part of the docs for the serial control node:

In order to control the communication, just send msg.payload containing.

{
"serialport": "/dev/ttyUSB0",
"serialbaud": 115200,
"databits": 8,
"parity": "none",
"stopbits": 1,
"enabled": true
}

After Node-RED starts, my serial control node gets the following incoming message:

{
     "payload": {
          "serialport": "/dev/ttymxc3",
          "serialbaud": 9600,
           "databits": 8,
          "parity": "none",
          "stopbits": 1,
          "enabled": true
    }
}

After the serial control node gets this message, the status of the node seems ok, but it does not output any messages as I would expect. Is the serial control node really able to mimic the functionality of a serial in node? If yes, has anybody an idea what I got wrong?

2

The serial control mode only controls the operation of the other nodes so you still need to use them for the actual in and out

3

@dceejay Thanks for the hint. It seems like the serial control node is manipulating other "serial port config" nodes, but not other "serial port in" nodes. One thing that is not consistent is that the string for "Serial Port" in a "serial port config" node must not be empty. However, a single white space character is enough to make it work.