Fix #1764. Bug where OpenLCA UI would freeze if it couldn't connect to OpenLCA.

src/blenderbim/blenderbim/bim/module/lca/__init__.py

@@ -21,6 +21,7 @@ from . import ui, prop, operator
 
 classes = (
     operator.CalculateLCA,
+    operator.ConnectOpenLCA,
     prop.BIMLCAProperties,
     ui.BIM_PT_lca,
 )

src/blenderbim/blenderbim/bim/module/lca/data.py

@@ -0,0 +1,49 @@
+# BlenderBIM Add-on - OpenBIM Blender Add-on
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of BlenderBIM Add-on.
+#
+# BlenderBIM Add-on is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# BlenderBIM Add-on is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
+
+import bpy
+import olca
+import blenderbim.tool as tool
+
+
+def refresh():
+    LcaData.is_loaded = False
+
+
+class LcaData:
+    data = {}
+    is_loaded = False
+
+    @classmethod
+    def load(cls):
+        cls.data = {
+            "product_systems": cls.product_systems(),
+        }
+        cls.is_loaded = True
+
+    @classmethod
+    def product_systems(cls):
+        if not bpy.context.scene.BIMLCAProperties.is_connected:
+            return []
+        results = []
+        client = olca.Client(context.preferences.addons["blenderbim"].preferences.openlca_port)
+        try:
+            results = [(ps.name, ps.name, "") for ps in client.get_all(olca.ProductSystem)]
+        except:
+            pass
+        return results

src/blenderbim/blenderbim/bim/module/lca/operator.py

@@ -43,3 +43,13 @@ class CalculateLCA(bpy.types.Operator):
     def invoke(self, context, event):
         context.window_manager.fileselect_add(self)
         return {"RUNNING_MODAL"}
+
+
+class ConnectOpenLCA(bpy.types.Operator):
+    bl_idname = "bim.connect_openlca"
+    bl_label = "Connect OpenLCA"
+    bl_options = {"REGISTER", "UNDO"}
+
+    def execute(self, context):
+        bpy.context.scene.BIMLCAProperties.is_connected = True
+        return {"FINISHED"}

src/blenderbim/blenderbim/bim/module/lca/prop.py

@@ -17,7 +17,7 @@
 # along with BlenderBIM Add-on.  If not, see <http://www.gnu.org/licenses/>.
 
 import bpy
-import olca
+from blenderbim.bim.module.lca.data import LcaData
 from blenderbim.bim.prop import StrProperty, Attribute
 from bpy.types import PropertyGroup
 from bpy.props import (
@@ -31,25 +31,14 @@ from bpy.props import (
     CollectionProperty,
 )
 
-productsystems_enum = []
-
-
-def purge():
-    global productsystems_enum
-    productsystems_enum = []
-
 
 def get_product_systems(self, context):
-    global productsystems_enum
-    if not len(productsystems_enum):
-        client = olca.Client(context.preferences.addons["blenderbim"].preferences.openlca_port)
-        try:
-            productsystems_enum = [(ps.name, ps.name, "") for ps in client.get_all(olca.ProductSystem)]
-        except:
-            pass
-    return productsystems_enum
+    if not LcaData.is_loaded:
+        LcaData.load()
+    return LcaData.data["product_systems"]
 
 
 class BIMLCAProperties(PropertyGroup):
+    is_connected: BoolProperty(name="Is Connected")
     amount: FloatProperty(name="Amount")
     product_systems: EnumProperty(items=get_product_systems, name="Product Systems")

src/blenderbim/blenderbim/bim/module/lca/ui.py

@@ -30,9 +30,13 @@ class BIM_PT_lca(Panel):
 
     def draw(self, context):
         props = context.scene.BIMLCAProperties
-        row = self.layout.row()
-        row.prop(props, "product_systems", text="")
-        row = self.layout.row()
-        row.prop(props, "amount", text="")
-        row = self.layout.row()
-        row.operator("bim.calculate_lca")
+        if props.is_connected:
+            row = self.layout.row()
+            row.prop(props, "product_systems", text="")
+            row = self.layout.row()
+            row.prop(props, "amount", text="")
+            row = self.layout.row()
+            row.operator("bim.calculate_lca")
+        else:
+            row = self.layout.row()
+            row.operator("bim.connect_openlca")