Sending commands to printer from plugin

Development
1

I'm writing a pretty useful OctoPrint plugin. The way it works is by intercepting an unused Gcode - G910 - and then performing a calibration step based on a computer vision analysis.

So far I've been able to intercept the G910 calls using the octoprint.comm.protocol.gcode hooks. I can perform my analysis, and prepare the ~10 Gcode commands that I'd like to send.

In my code, after receiving the G910 command, I'd like to:

  1. Pause further gcodes from sending until my script finishes
  2. Send my own ~ 10 gcodes commands to the printer
  3. Resume the remainder of the .gcode script

Is it possible to do this in OctoPrint? I can't find info on plugins sending commands to the printer and I'm not sure the .gcode file will wait for G910 to finish before sending more commands right now.

2

In the hook documentation you linked there's an example of how to replace a gcode command by returning a different one in the hook callback.

https://docs.octoprint.org/en/master/plugins/hooks.html#id11

3

Thanks. G910 takes about 5 seconds to run and process. I will comment back here if it doesnt work but thank you

4

Unless it's already there, you might want to then add G910 to the list of long-running gcode commands in the Settings.

5

Wouldn't an atcommand be better than a non-standard gcode in this case?

An example from the docs:

“queuing” phase only: A list of any of the above to allow for expanding one command into many. The following example shows how any queued command could be turned into a sequence of a temperature query, line number reset, display of the gcode on the printer’s display and finally the actual command (this example does not make a lot of sense to be quite honest):

def rewrite_foo(self, comm_instance, phase, cmd, cmd_type, gcode, subcode=None, tags=None *args, **kwargs):
    if gcode or not cmd.startswith("@foo"):
        return

    return [("M105", "temperature_poll"),    # 2-tuple, command & command type
            ("M110",),                       # 1-tuple, just the command
            "M117 echo foo: {}".format(cmd)] # string, just the command

__plugin_hooks__ = {
    "octoprint.comm.protocol.gcode.queuing": rewrite_foo
}
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