Fixed deadlocks in page event handling

Author: FeodorFitsner

examples/autoscroll.py

@@ -1,5 +1,9 @@
+import logging
+
 import pglet
-from pglet import Text, Stack, Button, Image
+from pglet import Button, Image, Stack, Text
+
+logging.basicConfig(level=logging.DEBUG)
 
 page = pglet.page("autoscroll", update=False, no_window=True, permissions="")
 # page.theme_primary_color = "green"

examples/chat.py

@@ -1,6 +1,7 @@
 import logging
+
 import pglet
-from pglet import Stack, Button, Textbox, Text, Dialog
+from pglet import Button, Dialog, Stack, Text, Textbox
 
 logging.basicConfig(level=logging.DEBUG)
 

examples/stack.py

@@ -0,0 +1,53 @@
+import logging
+
+import pglet
+from pglet import Slider, Stack, Text
+
+logging.basicConfig(level=logging.DEBUG)
+
+with pglet.page("horizontal-stack-wrapping") as page:
+
+    bg_color = "#ddddee"
+    page.horizontal_align = "stretch"
+
+    def items(count):
+        items = []
+        for i in range(1, count + 1):
+            items.append(
+                Text(
+                    value=i,
+                    align="center",
+                    vertical_align="center",
+                    width=30,
+                    height=30,
+                    bgcolor="BlueMagenta10",
+                    color="white",
+                    padding=5,
+                )
+            )
+        return items
+
+    def wrap_slider_change(e):
+        print("wrap_slider_change", e)
+        width = int(e.control.value)
+        wrap_stack.width = f"{width}%"
+        wrap_stack.update()
+
+    wrap_slider = Slider(
+        "Change the stack width to see how child items wrap onto multiple rows:",
+        min=0,
+        max=100,
+        step=1,
+        value=100,
+        show_value=True,
+        value_format="{value}%",
+        on_change=wrap_slider_change,
+    )
+
+    wrap_stack = Stack(
+        horizontal=True, wrap=True, bgcolor=bg_color, gap=20, controls=items(10)
+    )
+
+    page.add(wrap_slider, wrap_stack)
+
+    input()

pglet/connection.py

@@ -4,9 +4,8 @@
 import uuid
 
 from pglet.event import Event
-
-from pglet.reconnecting_websocket import ReconnectingWebSocket
 from pglet.protocol import *
+from pglet.reconnecting_websocket import ReconnectingWebSocket
 
 
 class Connection:
@@ -49,7 +48,16 @@ def _on_message(self, data):
             evt.set()
         elif msg.action == Actions.PAGE_EVENT_TO_HOST:
             if self._on_event != None:
-                self._on_event(self, PageEventPayload(**msg.payload))
+                th = threading.Thread(
+                    target=self._on_event,
+                    args=(
+                        self,
+                        PageEventPayload(**msg.payload),
+                    ),
+                    daemon=True,
+                )
+                th.start()
+                # self._on_event(self, PageEventPayload(**msg.payload))
         elif msg.action == Actions.SESSION_CREATED:
             if self._on_session_created != None:
                 th = threading.Thread(

pglet/page.py

@@ -2,6 +2,7 @@
 import logging
 import threading
 from typing import List, Literal, Optional
+
 from beartype import beartype
 
 from pglet import constants
@@ -149,8 +150,8 @@ def error(self, message=""):
     def on_event(self, e):
         logging.info(f"page.on_event: {e.target} {e.name} {e.data}")
 
-        if e.target == "page" and e.name == "change":
-            with self._lock:
+        with self._lock:
+            if e.target == "page" and e.name == "change":
                 for props in json.loads(e.data):
                     id = props["i"]
                     if id in self._index:
@@ -160,17 +161,17 @@ def on_event(self, e):
                                     name, props[name], dirty=False
                                 )
 
-        elif e.target in self._index:
-            self._last_event = ControlEvent(
-                e.target, e.name, e.data, self._index[e.target], self
-            )
-            handler = self._index[e.target].event_handlers.get(e.name)
-            if handler:
-                t = threading.Thread(
-                    target=handler, args=(self._last_event,), daemon=True
+            elif e.target in self._index:
+                self._last_event = ControlEvent(
+                    e.target, e.name, e.data, self._index[e.target], self
                 )
-                t.start()
-            self._event_available.set()
+                handler = self._index[e.target].event_handlers.get(e.name)
+                if handler:
+                    t = threading.Thread(
+                        target=handler, args=(self._last_event,), daemon=True
+                    )
+                    t.start()
+                self._event_available.set()
 
     def wait_event(self):
         self._event_available.clear()

pglet/reconnecting_websocket.py

@@ -1,5 +1,6 @@
 import logging
-import random, threading
+import random
+import threading
 
 import websocket
 
@@ -80,6 +81,7 @@ def _connect_loop(self):
         while not self.exit.is_set():
             logging.info(f"Connecting Pglet Server at {self._url}...")
             r = self.wsapp.run_forever()
+            logging.debug(f"Exited run_forever()")
             self.connected.clear()
             if r != True:
                 return