How to insert node between two connected nodes using python.

Hello Paul,

In simple terms, inserting a new node a between two connected nodes A and B involves the following steps:

1. Acquiring the connected properties of nodes A and B
2. Deleting the existing connection between A and B
3. Creating the new node
4. Creating new connections:
   • Node A output --> New node input
   • New node output --> Node B input

Here is a sample script which does just that. Bear in mind the script applies to the specific setup illustrated below. It also assumes a single connection exists for nodes A and B and that the new node has a single connectable input and output.

import sd
from sd.api import sdapplication, sdproperty
import os

app = sd.getContext().getSDApplication()
pkg_mgr = app.getPackageMgr()
ui_mgr = app.getQtForPythonUIMgr()

rsc_dir = app.getPath(sdapplication.SDApplicationPath.DefaultResourcesDir)

graph = ui_mgr.getCurrentGraph()
graph_nodes = graph.getNodes()
node_a = None
node_b = None

# Define nodes A and B
for node in graph_nodes:
	label = node.getDefinition().getLabel()
	if label == "Base Material":
		node_a = node
	elif label == "Levels":
		node_b = node

# Get connected output of node A
node_a_output_props = node_a.getProperties(sdproperty.SDPropertyCategory.Output)
node_a_connected_output_prop = None
for prop in node_a_output_props:
	if node_a.getPropertyConnections(prop):
		node_a_connected_output_prop = prop

# Get connected input of node B
node_b_input_props = node_b.getProperties(sdproperty.SDPropertyCategory.Input)
node_b_connected_input_prop = None
for prop in node_b_input_props:
	if node_b.getPropertyConnections(prop):
		node_b_connected_input_prop = prop		

# Create new node
target_pkg = pkg_mgr.loadUserPackage(os.path.join(
	rsc_dir,
	"packages",
	"color_space_conversion.sbs"
	))
target_rsc = target_pkg.findResourceFromUrl("pkg:///srgb_to_acescg")
new_node = graph.newInstanceNode(target_rsc)
pkg_mgr.unloadUserPackage(target_pkg)

# Get connectable input of new node
new_node_input_props = new_node.getProperties(sdproperty.SDPropertyCategory.Input)
for prop in new_node_input_props:
	if prop.isConnectable():
		new_node_input_prop = prop

# Get connectable output of new node
new_node_output_props = new_node.getProperties(sdproperty.SDPropertyCategory.Output)
for prop in new_node_output_props:
	if prop.isConnectable():
		new_node_output_prop = prop

# Replace existing connection
node_a.deletePropertyConnections(node_a_connected_output_prop)
node_a.newPropertyConnection(
	node_a_connected_output_prop,
	new_node,
	new_node_input_prop
	)
new_node.newPropertyConnection(
	new_node_output_prop,
	node_b,
	node_b_connected_input_prop
	)

You can see the script in action in the attached video. Have fun!