topic Re: How do I use commandPort? in Maya Forum

How do I use commandPort?

Henrik_Cederblad — Sat, 15 Jan 2022 03:11:59 GMT

I wish to get started using Maya's commandPort on Windows in order to trigger external (MEL) commands from my Elgato Stream Deck. My only issue is, I'm really not a programmer and I don't know how to set it up.

I'm primarily looking for the MEL method, but a Python version would also be relevant. Here's my Python info:

>>> sys.version
'3.9.5 (tags/v3.9.5:0a7dcbd, May 3 2021, 17:27:52) [MSC v.1928 64 bit (AMD64)]'
>>> sys.executable
'C:\\Python39\\python.exe'

How do I do this? 🙂

Re: How do I use commandPort?

Henrik_Cederblad — Sun, 30 Jan 2022 20:35:36 GMT

Since there's been no reply, I'll fill in the details I've gathered so far. Still haven't got it to work as I'm getting a TypeError when executing a command, but maybe someone can help me understand if this is a bug in Maya or something I can work around?

1. Create a userSetup.mel if you haven't got one already (could be py also, but we'll stick with .mel here) in

C:\Users\<user>\Documents\maya\<mayaversion>\scripts

2. Add the following inside that file (you may change the port numbers to anything you like):

commandPort -name "localhost:7001" -sourceType "mel" -echoOutput; commandPort -name "localhost:7002" -sourceType "python" -echoOutput;

3. Then create a Python file (in this example I'll call it commandPort_Template.py). Note: As I wish to send MEL commands, I'll use the MEL port (7001) as assigned in Step 2):

import socket HOST = '127.0.0.1' PORT = 7001 ADDR=(HOST,PORT) def SendCommand(): client = socket.socket (socket.AF_INET, socket.SOCK_STREAM) client.connect(ADDR) command = 'polyCube' client.send(command) client.close() if __name__=='__main__': SendCommand()

4. Run the Python file. In my case, I run it like so:

"C:\Python39\python.exe" "D:\3D\Maya\SCRIPTS\commandPort_Template.py"

That should work, but it doesn't. As said, I'm getting a TypeError when sending the command to Maya:

# # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\socketserver.py", line 720, in __init__ self.handle() # TypeError: a bytes-like object is required, not 'str' # ---------------------------------------- # ---------------------------------------- # Exception happened during processing of request from ('127.0.0.1', 54756) # Traceback (most recent call last): # # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\socketserver.py", line 316, in _handle_request_noblock self.process_request(request, client_address) # # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\socketserver.py", line 347, in process_request self.finish_request(request, client_address) # # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\socketserver.py", line 360, in finish_request self.RequestHandlerClass(request, client_address, self) # # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\site-packages\maya\app\general\CommandPort.py", line 134, in handle self.wfile.write(self.server.commandMessageQueue.get() + self.resp_term) # # File "C:\Program Files\Autodesk\Maya2022\Python37\lib\socketserver.py", line 799, in write self._sock.sendall(b)

Re: How do I use commandPort?

Henrik_Cederblad — Sun, 30 Jan 2022 20:34:57 GMT

Someone, please! I'm so close being able to use my Stream Deck to send commands to Maya, removing the necessity to use hotkeys, which I've ran out of since long ago ... How do I get past this error?! (Sorry for the bold text.)

Re: How do I use commandPort?

Henrik_Cederblad — Fri, 04 Feb 2022 21:45:42 GMT

For anyone looking how to use commandPort, I'm happy to report that I've got a working solution that won't give any TypeErrors (which my previous attempts gave) and now I can use my Stream Deck XL rather than running out of hotkeys for all my commands and scripts. This more or less makes Maya's shelves redundant also.

1. I've created a userSetup.py file here: <drive>:\<yourusername>\Documents\maya\<20XX>\scripts\userSetup.py

2. In userSetup.py, I'ved added these lines:

import maya.cmds as cmds cmds.commandPort(name=":54321", sourceType="mel") cmds.commandPort(name=":54322", sourceType="python")

Note: Someone told me it can be a good idea to open the commandPorts using evalDeferred, like so:

cmds.evalDeferred('cmds.commandPort(name=":54321", sourceType="mel")') cmds.evalDeferred('cmds.commandPort(name=":54322", sourceType="python")')

Which, according to the person I talked to, was to make sure it's executed at the correct time.

3. Then I've created a first template_command.py file with the following (creating a cube):

import socket HOST = '127.0.0.1' # the local host PORT = 54322 # The same port as used by the server ADDR = (HOST, PORT) def send_command(): client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) client.connect(ADDR) command = 'cmds.polyCube()' message = command client.send(str.encode(message)) data = client.recv(1024) # receive the result info client.close() print(data) if __name__ == '__main__': # Run this within Maya to open the ports. The port can be any 5 digits """ import maya.cmds as cmds cmds.commandPort(name=":54322", sourceType="python") """ send_command()

4. (N.B. Windows only). To prevent a momentary console window popping up when execiting scripts, I've renamed the script so that it has the .pyw suffix rather than .py, e.g. changed template_command.py to template_command.pyw. There are other ways to accomplish this in UNIX OSes like macOS and Linux by instead keeping the .py extension and first chmod +x template_command.py ot make it executable without invoking it via a Python interpreter and then adding a shebang like #!/usr/bin/python (there are variations to this shebang line that allows better control over which Python executable you're running, etc. but I won't go into that here) at the very first line in the script.

That's it!

Note: the above pertains to >Maya 2022.3 which uses Python3. If you're on older Maya versions, they use Python2 and the code might have to be tweaked to worked for that Python version first.

Re: How do I use commandPort?

fedepuopolo — Mon, 09 May 2022 21:26:29 GMT

Hi, thanks for sharing this. I'm trying to implement it but following these steps Maya opens a new scene and I'm getting an error "Unrecognized file type" when doing double click on template_command.pyw (same if I drag that file to my viewport).

For my userSetup.py I tried both version, with and without evalDeferred. And I also set the security to off in Maya's preferences.

Any advice on how to make this work?

Thanks!