Async support: downloading, json parsing, and add-on install

Downloading, parsing index.json, and installing add-ons all now are handled asynchronously using the asyncio module. These operations will no longer block Blender, allowing them to run in the background.

package_manager/__init__.py

@@ -69,7 +69,18 @@ class PackageManagerPreferences(AddonPreferences):
     
     def draw(self, context):
         layout = self.layout
-        layout.operator("wm.update_index", text="Update List",  icon='FILE_REFRESH')
+        
+        split = layout.split(percentage=1.0/3)
+        if (len(self.pm_addons) == 0 or networking.download_install_status in
+            ("Processing response", "Downloading update",
+            "Processing failed", "Update failed")):
+            split.label(text=networking.download_install_status or
+                        "Update add-on list.")
+        else:
+            split.label(text="Available add-ons:")
+        split.separator()
+        split.operator("wm.update_index", text="Update List",  icon='FILE_REFRESH')
+        
         rows = 1 if len(self.pm_addons) == 0 else 4
         layout.template_list("UI_UL_list", "addons_list", self, "pm_addons",
             self, "pm_addons_index", rows=rows)
@@ -93,7 +104,14 @@ class PackageManagerPreferences(AddonPreferences):
         else:
             split.label(text="Installed: No")
         split.separator()
+        
+        if (networking.download_install_status not in
+            ("Processing response", "Downloading update",
+            "Processing failed", "Update failed")):
+            split.label(text=networking.download_install_status)
+        else:
             split.separator()
+        
         split.operator("wm.addon_download_install",
                         text="Install from Web",
                         icon='URL').addon = addon.module_name

package_manager/networking.py

@@ -21,10 +21,12 @@ import json
 import logging
 import os
 import shutil
+import asyncio
 import urllib.request
 import zipfile
 from bpy.props import StringProperty
 
+download_install_status = ""
 log = logging.getLogger('networking')
 
 INDEX_DOWNLOAD_URL = ("https://git.blender.org/gitweb/gitweb.cgi/"
@@ -35,23 +37,106 @@ class WM_OT_update_index(bpy.types.Operator):
     bl_idname = "wm.update_index"
     bl_label = "Check for updated list of add-ons"
     
+    _timer = None
+    _redraw = False
+    
+    @classmethod
+    def poll(self, context):
+        global download_install_status
+        return (not download_install_status
+                or download_install_status == "Install successful"
+                or "failed" in download_install_status)
+    
+    def __init__ (self):
+        global download_install_status
+        download_install_status = ""
+        
+        self._redraw = False
+        
+        self.loop = asyncio.get_event_loop()
+        self.loop.stop()
+
     def execute(self, context):
+        # Update add-on index
+        self.loop.stop()
+        
+        self.status("Starting")
+        
+        self.loop.run_in_executor(None, self.update_index)
+        
+        wm = context.window_manager
+        wm.modal_handler_add(self)
+        self._timer = wm.event_timer_add(0.0001, context.window)
+        
+        return {'RUNNING_MODAL'}
+    
+    def modal(self, context, event):
+        global download_install_status
+        
+        if self._redraw:
+            context.area.tag_redraw()
+            self._redraw = False
+        
+        if "failed" in download_install_status:
+            self.cancel(context)
+            return {'CANCELLED'}
+        
+        if download_install_status == "":
+            self.cancel(context)
+            return {'FINISHED'}
+        
+        return {'PASS_THROUGH'}
+
+    def cancel(self, context):
+        self.loop.stop()
+        
+        wm = context.window_manager
+        wm.event_timer_remove(self._timer)
+    
+    def status(self, text):
+        global download_install_status
+        
+        download_install_status = text
+        self._redraw = True
+    
+    def update_index(self):
+        self.status("Downloading update")
+        index_file = self.download_index()
+        
+        if index_file:
+            self.status("Processing response")
+            
+            if self.parse_json(index_file):
+                self.status("")
+                return
+            
+            self.status("Processing failed")
+            return
+        
+        self.status("Update failed")
+    
+    def download_index(self):
         # Download the index.json file
         try:
             req = urllib.request.urlopen(INDEX_DOWNLOAD_URL)
             index_file = req.read().decode('utf-8')
             req.close()
         except urllib.error.HTTPError as err:
-            self.report({'ERROR'}, "Error requesting update: %s %s" % (str(err.code), err.reason))
-            return {'CANCELLED'}
+            log.warning("Error requesting update: %s %s", err.code, err.reason)
+            return False
+        except urllib.error.URLError as err:
+            log.warning("Download failed with URLError: %s", err)
+            return False
         
+        return index_file
+    
+    def parse_json(self, index_file):
         # Parse downloaded file
         try:
             addon_list = json.loads(index_file)
         except ValueError as err:
-            self.report({'ERROR'}, "Error: JSON file could not parse.")
-            log.warning("ValueError: %s", err)
-            return {'CANCELLED'}
+            log.warning("JSON file could not parse. ValueError: %s", err)
+            return False
         
         # Get the add-on preferences
         prefs = bpy.context.user_preferences.addons.get("package_manager").preferences
@@ -78,7 +163,7 @@ class WM_OT_update_index(bpy.types.Operator):
 
                 self.load_addon_data(addon, name, content)
         
-        return {'FINISHED'}
+        return True
     
     def load_addon_data(self, addon, module_name, content):
         addon.name = content["name"]
@@ -125,6 +210,25 @@ class WM_OT_addon_download_install(bpy.types.Operator):
     
     addon = bpy.props.StringProperty()
     
+    _timer = None
+    _redraw = False
+    
+    @classmethod
+    def poll(self, context):
+        global download_install_status
+        return (not download_install_status
+                or download_install_status == "Install successful"
+                or "failed" in download_install_status)
+    
+    def __init__ (self):
+        global download_install_status
+        download_install_status = ""
+        
+        self._redraw = False
+        
+        self.loop = asyncio.get_event_loop()
+        self.loop.stop()
+
     def execute(self, context):
         if self.addon is None:
             return {'CANCELLED'}
@@ -144,11 +248,61 @@ class WM_OT_addon_download_install(bpy.types.Operator):
         ext = os.path.splitext(download_url)[1]
         
         # Download and install the selected add-on
-        if self.download(self.addon, download_url):
-            if self.install(self.addon, ext):
+        self.loop.stop()
+        
+        self.status("Starting")
+        
+        self.loop.run_in_executor(None, self.download_and_install,
+                                    self.addon, download_url, ext)
+        
+        wm = context.window_manager
+        wm.modal_handler_add(self)
+        self._timer = wm.event_timer_add(0.0001, context.window)
+        
+        return {'RUNNING_MODAL'}
+    
+    def modal(self, context, event):
+        global download_install_status
+        
+        if self._redraw:
+            context.area.tag_redraw()
+            self._redraw = False
+        
+        if "failed" in download_install_status:
+            self.cancel(context)
+            return {'CANCELLED'}
+        
+        if download_install_status == "Install successful":
+            self.cancel(context)
             return {'FINISHED'}
         
-        return {'CANCELLED'}
+        return {'PASS_THROUGH'}
+
+    def cancel(self, context):
+        self.loop.stop()
+        
+        wm = context.window_manager
+        wm.event_timer_remove(self._timer)
+    
+    def status(self, text):
+        global download_install_status
+        
+        download_install_status = text
+        self._redraw = True
+    
+    def download_and_install (self, addon, download_url, filetype):
+        # Perform download; if successful, install
+        self.status("Downloading")
+        if self.download(addon, download_url):
+            self.status("Installing")
+            if self.install(addon, filetype):
+                self.status("Install successful")
+                return
+            self.status("Install failed")
+            return
+        
+        self.status("Download failed")
+        self._redraw = True
     
     def download(self, addon, download_url):
         filetype = os.path.splitext(download_url)[1]
@@ -165,6 +319,9 @@ class WM_OT_addon_download_install(bpy.types.Operator):
         except urllib.error.HTTPError as err:
             log.warning("Download failed with HTTPError: %s %s", str(err.code), err.reason)
             return False
+        except urllib.error.URLError as err:
+            log.warning("Download failed with URLError: %s", err)
+            return False
         
         return True
 
@@ -184,7 +341,8 @@ class WM_OT_addon_download_install(bpy.types.Operator):
                 shutil.rmtree(addon_path)
             with zipfile.ZipFile(download_path,"r") as zipped_addon:
                 zipped_addon.extractall(bpy.utils.user_resource('SCRIPTS', path="addons"))
-            
+        else:
+            return False
         
         return True