Web backend: run ManaTools AUI apps in a web browser

manatools/aui/backends/__init__.py

@@ -12,7 +12,7 @@
 _logger = logging.getLogger("manatools.aui.backends")
 
 # advertised subpackages (may be absent if not installed)
-__all__ = ["gtk", "qt", "ncurses"]
+__all__ = ["gtk", "qt", "ncurses", "web"]
 
 def __getattr__(name: str) -> ModuleType:
     """

manatools/aui/backends/qt/replacepointqt.py

@@ -210,13 +210,13 @@ def _attach_child_backend(self):
                     except Exception:
                         pass
                 except Exception:
-                    # fallback: try remove any previous parent then add
+                    # fallback: widget may already be in the layout; check indexOf
+                    # before re-adding.  Never call setParent(None) on a visible
+                    # widget — that promotes it to a top-level window (popup).
                     try:
-                        try:
-                            cw.setParent(None)
-                        except Exception:
-                            pass
-                        self._layout.addWidget(cw)
+                        if self._layout.indexOf(cw) < 0:
+                            cw.setParent(self._backend_widget)
+                            self._layout.addWidget(cw)
                     except Exception:
                         self._logger.exception("_attach_child_backend: addWidget fallback failed")
                 # Encourage the child to expand so content becomes visible

manatools/aui/backends/qt/tableqt.py

@@ -383,20 +383,23 @@ class YTableQt(YSelectionWidget):
     """
 
     def __init__(self, parent, header: YTableHeader, multiSelection=False):
-        super().__init__(parent)
+        # All instance attributes must be set BEFORE super().__init__(parent).
+        # YWidget.__init__ calls parent.addChild(self), which causes
+        # YDumbTabQt.addChild → get_backend_widget() → _create_backend_widget()
+        # while this constructor is still executing.  _create_backend_widget()
+        # must find every attribute it reads already in place.
+        if header is None:
+            raise ValueError("YTableQt requires a YTableHeader")
         self._header = header
         self._multi = bool(multiSelection)
         # Force single-selection when any checkbox column is present.
-        if self._header is not None:
-            try:
-                for c_idx in range(self._header.columns()):
-                    if self._header.isCheckboxColumn(c_idx):
-                        self._multi = False
-                        break
-            except Exception:
-                pass
-        else:
-            raise ValueError("YTableQt requires a YTableHeader")
+        try:
+            for c_idx in range(self._header.columns()):
+                if self._header.isCheckboxColumn(c_idx):
+                    self._multi = False
+                    break
+        except Exception:
+            pass
 
         self._view = None    # QTableView
         self._model = None   # _YTableModel
@@ -407,6 +410,8 @@ def __init__(self, parent, header: YTableHeader, multiSelection=False):
         self._logger = logging.getLogger(f"manatools.aui.qt.{self.__class__.__name__}")
         self._changed_item = None
 
+        super().__init__(parent)  # may trigger _create_backend_widget via addChild
+
     def widgetClass(self):
         return "YTable"
 
@@ -512,8 +517,8 @@ def rebuildTable(self):
         beginResetModel/endResetModel does not create any widgets — the view
         repaints only the visible viewport (O(visible×cols)).
         """
-        self._logger.debug("rebuildTable: %d items",
-                           len(self._items) if self._items else 0)
+        _items = getattr(self, '_items', None) or []
+        self._logger.debug("rebuildTable: %d items", len(_items))
         if self._model is None:
             self._create_backend_widget()
             return  # _create_backend_widget calls rebuildTable recursively

manatools/aui/backends/qt/treeqt.py

@@ -24,13 +24,15 @@ class YTreeQt(YSelectionWidget):
     - recursiveSelection if it should select children recursively
     """
     def __init__(self, parent=None, label="", multiSelection=False, recursiveSelection=False):
-        super().__init__(parent)
+        # All instance attributes must be set BEFORE super().__init__(parent).
+        # YDumbTabQt.addChild calls get_backend_widget() synchronously when
+        # its content area already exists, which triggers _create_backend_widget()
+        # before the subclass constructor has had a chance to set its own attrs.
         self._label = label
         self._multi = bool(multiSelection)
         self._recursive = bool(recursiveSelection)
         if self._recursive:
             self._multi = True  # recursive selection implies multi-selection
-        self._immediate = self.notify()
         self._backend_widget = None
         self._tree_widget = None
         # mappings between QTreeWidgetItem and logical YTreeItem (python objects in self._items)
@@ -42,7 +44,10 @@ def __init__(self, parent=None, label="", multiSelection=False, recursiveSelecti
         self._last_selected_qitems = set()
         # track logical selected item ids to preserve across rebuilds/swaps
         self._last_selected_ids = set()
-        self._logger = logging.getLogger(f"manatools.aui.qt.{self.__class__.__name__}")            
+        self._logger = logging.getLogger(f"manatools.aui.qt.{self.__class__.__name__}")
+
+        super().__init__(parent)  # may trigger _create_backend_widget via YDumbTabQt.addChild
+        self._immediate = self.notify()
 
     def widgetClass(self):
         return "YTree"
@@ -83,7 +88,8 @@ def rebuildTree(self):
 
     def _rebuildTree(self):
         """Rebuild the QTreeWidget from self._items (calls helper recursively)."""
-        self._logger.debug("rebuildTree: rebuilding tree with %d items", len(self._items) if self._items else 0)
+        _items = getattr(self, '_items', None) or []
+        self._logger.debug("rebuildTree: rebuilding tree with %d items", len(_items))
         self._suppress_selection_handler = True
         if self._tree_widget is None:
             # ensure backend exists

manatools/aui/backends/web/README.md

@@ -0,0 +1,212 @@
+# ManaTools Web Backend
+
+A web-based backend for python-manatools AUI that renders applications in a web browser via HTTP/WebSocket.
+
+## Overview
+
+This package adds a new `web` backend to python-manatools, allowing any ManaTools application to be accessed through a web browser without any code changes.
+
+## Usage
+
+### Running with Web Backend
+
+Set the `MUI_BACKEND` environment variable to `web`:
+
+```bash
+# Linux/macOS
+export MUI_BACKEND=web
+python your_app.py
+
+# Windows (Command Prompt)
+set MUI_BACKEND=web
+python your_app.py
+
+# Windows (PowerShell)
+$env:MUI_BACKEND="web"
+python your_app.py
+```
+
+When the application starts, it will display a URL:
+
+```
+==================================================
+  Dialog available at: http://127.0.0.1:8080/
+  Open this URL in your web browser
+==================================================
+```
+
+Open this URL in any modern web browser to interact with the application.
+
+### Application Code
+
+No changes are needed to your application code! The same code works with Qt, GTK, curses, or web backend:
+
+```python
+from manatools.aui.yui import YUI
+
+factory = YUI.widgetFactory()
+dialog = factory.createMainDialog()
+vbox = factory.createVBox(dialog)
+
+factory.createLabel(vbox, "Hello, World!")
+button = factory.createPushButton(vbox, "&OK")
+
+dialog.open()
+
+while True:
+    event = dialog.waitForEvent()
+    if event.widget() == button:
+        break
+
+dialog.destroy()
+```
+
+## Architecture
+
+```
+Browser (HTML/CSS/JS)
+        │
+        │ WebSocket / HTTP
+        ▼
+┌─────────────────────────────┐
+│      WebServer (Python)      │
+│   - HTTP: Serve HTML/CSS/JS  │
+│   - WebSocket: Real-time     │
+└─────────────┬───────────────┘
+              │
+              ▼
+┌─────────────────────────────┐
+│      YDialogWeb              │
+│   - Event queue              │
+│   - Widget tree → HTML       │
+│   - waitForEvent() blocks    │
+└─────────────────────────────┘
+```
+
+## Widget Support
+
+All standard ManaTools widgets are supported:
+
+| Widget | Status | Notes |
+|--------|--------|-------|
+| YDialog | ✅ | Main and popup dialogs |
+| YVBox, YHBox | ✅ | Layout containers |
+| YLabel | ✅ | Text and headings |
+| YPushButton | ✅ | With icons and shortcuts |
+| YInputField | ✅ | Text and password mode |
+| YCheckBox | ✅ | |
+| YRadioButton | ✅ | |
+| YComboBox | ✅ | Dropdown selection |
+| YSelectionBox | ✅ | List selection |
+| YFrame | ✅ | Grouped content |
+| YCheckBoxFrame | ✅ | Toggleable frame |
+| YProgressBar | ✅ | |
+| YSlider | ✅ | |
+| YTable | ✅ | |
+| YTree | ✅ | |
+| YRichText | ✅ | HTML content |
+| YMenuBar | ✅ | |
+| YImage | ✅ | |
+| YIntField | ✅ | Number input |
+| YDateField | ✅ | Date picker |
+| YTimeField | ✅ | Time picker |
+| YMultiLineEdit | ✅ | Textarea |
+| YLogView | ✅ | Log display |
+| YDumbTab | ✅ | Tab bar |
+| YPaned | ✅ | Split panes |
+| YSpacing | ✅ | Layout spacing |
+| YAlignment | ✅ | Content alignment |
+| YReplacePoint | ✅ | Dynamic content |
+
+## File Structure
+
+```
+manatools/aui/
+├── yui.py              # Modified: Added Backend.WEB
+├── yui_web.py          # NEW: YUIWeb, YWidgetFactoryWeb, YApplicationWeb
+└── backends/
+    ├── __init__.py     # Modified: Added "web" to __all__
+    └── web/            # NEW: All web backend files
+        ├── __init__.py
+        ├── commonweb.py
+        ├── server.py
+        ├── dialogweb.py
+        ├── vboxweb.py
+        ├── hboxweb.py
+        ├── labelweb.py
+        ├── pushbuttonweb.py
+        ├── inputfieldweb.py
+        ├── checkboxweb.py
+        ├── comboboxweb.py
+        ├── selectionboxweb.py
+        ├── frameweb.py
+        ├── progressbarweb.py
+        ├── alignmentweb.py
+        ├── spacingweb.py
+        ├── treeweb.py
+        ├── tableweb.py
+        ├── richtextweb.py
+        ├── menubarweb.py
+        ├── replacepointweb.py
+        ├── checkboxframeweb.py
+        ├── radiobuttonweb.py
+        ├── intfieldweb.py
+        ├── multilineditweb.py
+        ├── imageweb.py
+        ├── dumbtabweb.py
+        ├── sliderweb.py
+        ├── datefieldweb.py
+        ├── timefieldweb.py
+        ├── logviewweb.py
+        ├── panedweb.py
+        └── static/
+            ├── css/
+            │   └── manatools.css
+            └── js/
+                └── manatools.js
+```
+
+## Browser Support
+
+- Chrome/Chromium (recommended)
+- Firefox
+- Safari
+- Edge
+
+WebSocket is required for real-time updates. Falls back to HTTP POST for older browsers.
+
+## Configuration
+
+The web server binds to `127.0.0.1` (localhost only) by default. To allow remote access, modify `server.py`:
+
+```python
+self._server = WebServer(self, host="0.0.0.0", port=8080)
+```
+
+⚠️ **Security Warning**: Allowing remote access exposes your application to the network. Consider adding authentication for production use.
+
+## Dependencies
+
+**None!** The web backend uses only Python standard library:
+- `http.server` - HTTP serving
+- `threading` - Background server
+- `queue` - Event queue
+- `json` - WebSocket messages
+- `hashlib`, `base64`, `struct` - WebSocket protocol
+
+## Limitations
+
+- File dialogs (`askForExistingFile`, etc.) are not supported in the browser
+- Window positioning/sizing is handled by the browser
+- System tray integration is not available
+- Native menus use HTML menus instead
+
+## License
+
+LGPLv2+ (same as python-manatools)
+
+## Author
+
+Matteo Pasotti <xquiet@coriolite.com>
+
+Based on python-manatools by Angelo Naselli <anaselli@linux.it>