Blender XML RPC Server

Blender XML RPC Server runs an xml_rpc server in blender. It runs in a separate thread within blender in order not to breach scene graph evaluation performance. Thanks to Kristen Skogholt Haave who helped me figuring this out.

XML RPC allows to send string commands from outside of blender. One of its purpose is to allow python2.7 based pipelines to talk to blender sending string commands. It can be also usefull to have two blender sessions talking to each other.

RELEASE NOTES

By default it the server will run on first available port as of 8000. So, given the fact that port 8000 is available on your computer, if you start a new blender session, it will take the next available port as of 8001, etc. You can find the status of the xml rpc server in the world tab of the Properties panel > Server Panel. The addon is compatible with both 2.7* and 2.8* versions of blender. Even if it will complain that it's been written with 2.8* it will still properly run in 2.7*

KNOWN ISSUES

It can happen that exiting a blender session leaves a zombie process. You can check this after exiting all blender sessions if the port is not the first supposignly available as of 8000 in a session you just started.

INSTALL

If you want the xml_rpc to launch at blender startup you should clone wihin a folder like:

[PATH_YOU_SET_IN_BLENDER_SCRIPTS_FILEPATH_PREFERENCE]
	├── addons
	├── modules
	├── presets
	└── startup
	    └── xmlrpc_server
	        ├── .git
	        ├── .gitignore
	        ├── __init__.py
	        ├── LICENSE
	        └── README.md

USE CASES

within a python2.7* enviromnent you should proceed this way:

import xmlrpclib, socket

# get server data function
def server_data(host='localhost', port=8000, app='', debug=False):
    if debug:
        print 'Scanning port:', port
    try:
        proxy = xmlrpclib.ServerProxy(
            'http://'+host+':'+str(port)+'/', allow_none=True)
        data = proxy.server_data()
        if debug:
            print('   ', port, data)
        if app in data['exe']:
            return data
    except(socket.error):
        if debug:
            print('Couldnt connect with the socket-server: %s\n' % port)

# send a command to the server
def xmlrpc_command(string_cmd, host='localhost', port=8000, debug=False):
    proxy = xmlrpclib.ServerProxy(
        'http://'+host+':'+str(port)+'/',
        allow_none=True)
    com = proxy.command(string_cmd)
    if debug:
        print(
            'on port',
            port,
            'and host',
            host,
            'Your command is: ' + com
            )
    return com

# get blender data as scene contents
port=8000
data = server_data(port=port)
scene_objects = data['scene_objects']
print scene_objects, type(scene_objects)

# send a string command
string_cmd=''
string_cmd+='print()\n'
string_cmd+='print("Blender data is: '+str(data)+'")\n'
string_cmd+='print("Scene Objects are: '+str(scene_objects)+'")\n'
string_cmd+='print()\n'
xmlrpc_command(string_cmd, port=port)

within a python3.* environment. In this example we assume a blender session talking to another one on localhost.

import xmlrpc.client as xmlrpclib
import socket


# get server data function
def server_data(host='localhost', port=8000, app='', debug=False):
    if debug:
        print('Scanning port:', port)
    try:
        proxy = xmlrpclib.ServerProxy(
            'http://'+host+':'+str(port)+'/', allow_none=True)
        data = proxy.server_data()
        if debug:
            print('   ', port, data)
        if app in data['exe']:
            return data
    except(socket.error):
        if debug:
            print('Couldnt connect with the socket-server: %s\n' % port)

# send a command to the server
def xmlrpc_command(string_cmd, host='localhost', port=8000, debug=False):
    proxy = xmlrpclib.ServerProxy(
        'http://'+host+':'+str(port)+'/',
        allow_none=True)
    com = proxy.command(string_cmd)
    if debug:
        print(
            'on port',
            port,
            'and host',
            host,
            'Your command is: ' + com
            )
    return com

# since in this example, we assume you are running this script
# from a blender session which already runs an xml-rpc server on port 8000
# in order to talk to another on which is running xml-rpc server on port 8001
port=8001

# print data from remote blender session within the current blender session
data = server_data(port=port)
scene_objects = str(data['scene_objects'])
print('Scene Objects are:', scene_objects)

# send print data cmd from current blender session in the remote blender session
string_cmd=''
string_cmd+='print()\n'
string_cmd+='print("Blender data is: '+str(data)+'")\n'
string_cmd+='print("Scene Objects are: '+str(scene_objects)+'")\n'
string_cmd+='print()\n'
xmlrpc_command(string_cmd, port=port)

IMPORTANT LINKS:

https://docs.python.org/3/library/xmlrpc.server.html

https://docs.python.org/3/library/threading.html