Python node operator for combined node collapsing and hiding unused sockets. Socket hide flag is added to RNA as well, but can only be set when the socket is not connected, to avoid dangling links in editor drawing. Currently this operator has no default hotkey, but can be called from the Node menu.

release/scripts/startup/bl_operators/node.py

@@ -134,3 +134,34 @@ class NODE_OT_add_search(Operator):
 
         context.window_manager.invoke_search_popup(self)
         return {'CANCELLED'}
+
+
+class NODE_OT_collapse_hide_unused_toggle(Operator):
+    '''Toggle collapsed nodes and hide unused sockets'''
+    bl_idname = "node.collapse_hide_unused_toggle"
+    bl_label = "Collapse and Hide Unused Sockets"
+    bl_options = {'REGISTER', 'UNDO'}
+
+    @classmethod
+    def poll(cls, context):
+        space = context.space_data
+        # needs active node editor and a tree
+        return space.type == 'NODE_EDITOR' and space.edit_tree
+
+    def execute(self, context):
+        space = context.space_data
+        tree = space.edit_tree
+
+        for node in tree.nodes:
+            if node.select:
+                hide = not node.hide
+                
+                node.hide = hide
+                # Note: connected sockets are ignored internally
+                for socket in node.inputs:
+                    socket.hide = hide
+                for socket in node.outputs:
+                    socket.hide = hide
+                    
+        return {'FINISHED'}
+

release/scripts/startup/bl_ui/space_node.py

@@ -182,6 +182,7 @@ class NODE_MT_node(Menu):
         layout.operator("node.preview_toggle")
         layout.operator("node.hide_socket_toggle")
         layout.operator("node.options_toggle")
+        layout.operator("node.collapse_hide_unused_toggle")
 
         layout.separator()
 

source/blender/makesdna/DNA_node_types.h

@@ -127,7 +127,7 @@ typedef struct bNodeSocket {
 /* sock->flag, first bit is select */
 	/* hidden is user defined, to hide unused */
 #define SOCK_HIDDEN				2
-	/* only used now for groups... */
+	/* for quick check if socket is linked */
 #define SOCK_IN_USE				4	/* XXX deprecated */
 	/* unavailable is for dynamic sockets */
 #define SOCK_UNAVAIL			8

source/blender/makesrna/intern/rna_nodetree.c

@@ -324,6 +324,20 @@ static char *rna_NodeSocket_path(PointerRNA *ptr)
 	return NULL;
 }
 
+static void rna_NodeSocket_hide_set(PointerRNA *ptr, int value)
+{
+	bNodeSocket *sock = (bNodeSocket *)ptr->data;
+	
+	/* don't hide linked sockets */
+	if (sock->flag & SOCK_IN_USE)
+		return;
+	
+	if (value)
+		sock->flag |= SOCK_HIDDEN;
+	else
+		sock->flag &= ~SOCK_HIDDEN;
+}
+
 /* Button Set Funcs for Matte Nodes */
 static void rna_Matte_t1_set(PointerRNA *ptr, float value)
 {
@@ -4106,6 +4120,17 @@ static void rna_def_node_socket(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Group Socket",
 	                         "For group nodes, the group input or output socket this corresponds to");
 
+	prop = RNA_def_property(srna, "hide", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", SOCK_HIDDEN);
+	RNA_def_property_boolean_funcs(prop, NULL, "rna_NodeSocket_hide_set");
+	RNA_def_property_ui_text(prop, "Hide", "Hide the socket");
+	RNA_def_property_update(prop, NC_NODE | NA_EDITED, NULL);
+
+	prop = RNA_def_property(srna, "is_linked", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flag", SOCK_IN_USE);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_ui_text(prop, "Linked", "True if the socket is connected");
+
 	prop = RNA_def_property(srna, "show_expanded", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_negative_sdna(prop, NULL, "flag", SOCK_COLLAPSED);
 	RNA_def_property_ui_text(prop, "Expanded", "Socket links are expanded in the user interface");