Earth calling maya.standalone!

Sat 05 April 2014

Somebody over on Tech-artists.org was asking about how to control a maya.standalone instance remotely. In ordinary Maya you could use the commandPort, but the commandPort doesn’t exist when running under standalone - apparently it’s part of the GUI layer which is not present in batch mode.

So, I whipped up an uber-simple JSON-RPC-like server to run in a maya standalone and accept remote commands. In response to some queries I’ve polished it up and put it onto GitHub.

It’s an ultra-simple setup. Running the module as a script form mayapy.exe starts a server:

    mayapy.exe   path/to/standaloneRPC.py

To connect to it from another environment, you import the module, format the command you want to send, and shoot it across to the server. Commands return a JSON-encoded dictionary. When you make a successful command, the return object will include a field called ‘results’ containg a json-encoded version of the results:

cmd = CMD('cmds.ls', type='transform')  
print send_command(cmd)  
>>> {success:True, result:[u'persp', u'top', u'side', u'front'}

For failed queries, the result includes the exception and a traceback string:

cmd = CMD('cmds.fred')  # nonexistent command  
print send_command(cmd)  
>>> {"exception": "",   
     "traceback": "Traceback (most recent call last)... #SNIP#",  
     "success": false,   
     "args": "[]",   
     "kwargs": "{}",   
     "cmd_name": "cmds.fred"}

It’s a single file for easy drop. Please, please read the notes - the module includes no effort at authentication or security, so it exposes any machine running it to anyone who knows its there. Don’t let a machine running this be visible to the internet!