wx.html2.WebView fails with longer load times in 4.2.1 (regression from 4.1.1)

[mmmmichael]

Operating system: Windows 11. wxPython version & source: 4.2.1 via pip. Python version & source: Official Python 3.9.1 installer for Windows.

Description of the problem:

1. Modify https://github.com/wxWidgets/Phoenix/blob/wxPython-4.2.1/samples/html2/webview_sample.py by adding an import time at the beginning and a time.sleep(120) directly before the app.MainLoop(), see code below.
2. Run the modified version. At first the buttons are not rendered yet, because the application is hanging in the sleep as expected, see fist screenshot
3. Wait for 120 seconds until the buttons a shown.
4. The web view does not show the sample text "html2.WebView Sample ...", see second screenshot.
5. For comparison: It is shown correctly with 4.1.1, see third screenshot.

Code Example (click to expand)

```python import sys import os from six import BytesIO import wx import wx.html2 as webview import time HERE = os.path.abspath(os.path.dirname(__file__)) BASE = 'file://{}/'.format(HERE.replace('\\', '/')) URL = BASE + 'webview_sample.html' LOGO = os.path.join(HERE, 'logo.png') # We need to be in the HERE folder for the archive link to work since the sample # page does not use a full path os.chdir(HERE) #-------------------------------------------------------------------------- class SampleFrame(wx.Frame): def __init__(self, parent, url=URL): wx.Frame.__init__(self, parent, title="html2.WebView Sample", size=(800,900)) # add a statusbar self.CreateStatusBar() # Add a menubar with just a quit item mb = wx.MenuBar() menu = wx.Menu() menu.Append(wx.ID_EXIT, '&Quit') mb.Append(menu, "File") self.SetMenuBar(mb) self.Bind(wx.EVT_MENU, self.OnQuit, id=wx.ID_EXIT) # Create the main panel pnl = WebViewPanel(self, url) # Menu event handler to close the frame def OnQuit(self, evt): self.Close(force=True) #-------------------------------------------------------------------------- class WebViewPanel(wx.Panel): def __init__(self, parent, url): wx.Panel.__init__(self, parent) self.current = url self.frame = self.GetTopLevelParent() self.titleBase = self.frame.GetTitle() sizer = wx.BoxSizer(wx.VERTICAL) btnSizer = wx.BoxSizer(wx.HORIZONTAL) # Ensure that a newer version of the IE/Edge control will be used # on Windows webview.WebView.MSWSetEmulationLevel() # Create the webView control self.wv = webview.WebView.New(self) # Register a handler for the memory: file system self.wv.RegisterHandler(webview.WebViewFSHandler("memory")) # This handler takes care of links that are in zip files self.wv.RegisterHandler(webview.WebViewArchiveHandler("wxzip")) # And this one is for the custom: file system implemented by the # CustomWebViewHandler class below self.wv.RegisterHandler(CustomWebViewHandler()) self.Bind(webview.EVT_WEBVIEW_NAVIGATING, self.OnWebViewNavigating, self.wv) self.Bind(webview.EVT_WEBVIEW_NAVIGATED, self.OnWebViewNavigated, self.wv) self.Bind(webview.EVT_WEBVIEW_LOADED, self.OnWebViewLoaded, self.wv) self.Bind(webview.EVT_WEBVIEW_TITLE_CHANGED, self.OnWebViewTitleChanged, self.wv) btn = wx.Button(self, -1, "Open", style=wx.BU_EXACTFIT) self.Bind(wx.EVT_BUTTON, self.OnOpenButton, btn) btnSizer.Add(btn, 0, wx.EXPAND|wx.ALL, 2) btn = wx.Button(self, -1, "◀︎", style=wx.BU_EXACTFIT) self.Bind(wx.EVT_BUTTON, self.OnPrevPageButton, btn) btnSizer.Add(btn, 0, wx.EXPAND|wx.ALL, 2) self.Bind(wx.EVT_UPDATE_UI, self.OnCheckCanGoBack, btn) btn = wx.Button(self, -1, "▶︎", style=wx.BU_EXACTFIT) self.Bind(wx.EVT_BUTTON, self.OnNextPageButton, btn) btnSizer.Add(btn, 0, wx.EXPAND|wx.ALL, 2) self.Bind(wx.EVT_UPDATE_UI, self.OnCheckCanGoForward, btn) btn = wx.Button(self, -1, "Stop", style=wx.BU_EXACTFIT) self.Bind(wx.EVT_BUTTON, self.OnStopButton, btn) btnSizer.Add(btn, 0, wx.EXPAND|wx.ALL, 2) btn = wx.Button(self, -1, "Refresh", style=wx.BU_EXACTFIT) self.Bind(wx.EVT_BUTTON, self.OnRefreshPageButton, btn) btnSizer.Add(btn, 0, wx.EXPAND|wx.ALL, 2) txt = wx.StaticText(self, -1, "Location:") btnSizer.Add(txt, 0, wx.CENTER|wx.ALL, 2) self.location = wx.ComboBox( self, -1, "", style=wx.CB_DROPDOWN|wx.TE_PROCESS_ENTER) self.location.AppendItems(['http://wxPython.org', 'http://wxwidgets.org', 'http://google.com']) self.Bind(wx.EVT_COMBOBOX, self.OnLocationSelect, self.location) self.location.Bind(wx.EVT_TEXT_ENTER, self.OnLocationEnter) btnSizer.Add(self.location, 1, wx.EXPAND|wx.ALL, 2) sizer.Add(btnSizer, 0, wx.EXPAND) sizer.Add(self.wv, 1, wx.EXPAND) self.SetSizer(sizer) self.wv.LoadURL(self.current) # WebView events def OnWebViewNavigating(self, evt): # this event happens prior to trying to get a resource if evt.GetURL() == 'https://www.microsoft.com/': if wx.MessageBox("Are you sure you want to visit Microsoft?", style=wx.YES_NO|wx.ICON_QUESTION) == wx.NO: # This is how you can cancel loading a page. evt.Veto() def OnWebViewNavigated(self, evt): self.frame.SetStatusText("Loading %s..." % evt.GetURL()) def OnWebViewLoaded(self, evt): # The full document has loaded self.current = evt.GetURL() self.location.SetValue(self.current) self.frame.SetStatusText("Loaded") def OnWebViewTitleChanged(self, evt): # Set the frame's title to include the document's title self.frame.SetTitle("%s -- %s" % (self.titleBase, evt.GetString())) # Control bar events def OnLocationSelect(self, evt): url = self.location.GetStringSelection() self.wv.LoadURL(url) def OnLocationEnter(self, evt): url = self.location.GetValue() self.location.Append(url) self.wv.LoadURL(url) def OnOpenButton(self, event): dlg = wx.TextEntryDialog(self, "Open Location", "Enter a full URL or local path", self.current, wx.OK|wx.CANCEL) dlg.CentreOnParent() if dlg.ShowModal() == wx.ID_OK: self.current = dlg.GetValue() self.wv.LoadURL(self.current) dlg.Destroy() def OnPrevPageButton(self, event): #for i in self.wv.GetBackwardHistory(): # print("%s %s" % (i.Url, i.Title)) self.wv.GoBack() def OnNextPageButton(self, event): #for i in self.wv.GetForwardHistory(): # print("%s %s" % (i.Url, i.Title)) self.wv.GoForward() def OnCheckCanGoBack(self, event): event.Enable(self.wv.CanGoBack()) def OnCheckCanGoForward(self, event): event.Enable(self.wv.CanGoForward()) def OnStopButton(self, evt): self.wv.Stop() def OnRefreshPageButton(self, evt): self.wv.Reload() #-------------------------------------------------------------------------- def SetupMemoryFiles(): # Set up an in-memory file system with virtual "files" that can be # loaded into the webview just like network or local file sources. # These "files" can be access using a protocol specifier of "memory:" wx.FileSystem.AddHandler(wx.MemoryFSHandler()) wx.FileSystem.AddHandler(wx.ArchiveFSHandler()) wx.MemoryFSHandler.AddFile( "page1.html", "" "" "

Page 1

" "

" "

This file was loaded directly from a virtual in-memory filesystem.

" "

Here's another page: Page 2.

") wx.MemoryFSHandler.AddFile( "page2.html", "" "" "

Page 2

" "

Page 1 was better.

") wx.MemoryFSHandler.AddFile( "test.css", "h1 {color: red;}") wx.MemoryFSHandler.AddFile('logo.png', wx.Bitmap(LOGO), wx.BITMAP_TYPE_PNG) #-------------------------------------------------------------------------- class CustomWebViewHandler(webview.WebViewHandler): # This shows how to make a custom handler for providing content to the # WebView for a specific scheme ("custom:" in this case). This handler # class simply needs to implement the GetFile method, which will be called # whenever a resource with a matching scheme is to be loaded, and it needs # to respond by returning a wx.FSFile object. This means that, unlike the # wx.MemoryFSHandler, content can be generated on the fly rather than # needing to be preloaded into a filesystem. # def __init__(self): wx.html2.WebViewHandler.__init__(self, 'custom') self.count = 0 def GetFile(self, uri): # We'll just provide the same content for every URI in this example, but # normally you would generate or fetch appropriate content that is # referenced by the given URI. self.count += 1 content = """\

Custom Handler Example

This page is provided dynamically from the CustomWebViewHandler class.

It has been loaded {} times.

""".format(self.count) stream = BytesIO(content.encode('utf-8')) fsfile = wx.FSFile(stream, uri, 'page1.html', 'text/html', wx.DateTime.Now()) return fsfile #-------------------------------------------------------------------------- def main(): app = wx.App() SetupMemoryFiles() frm = SampleFrame(None) frm.Show() time.sleep(120) app.MainLoop() #-------------------------------------------------------------------------- if __name__ == '__main__': main() ```

[swt2c]

I presume in point 5 that you mean 4.1.1?

I wonder if this is a drawing issue - does resizing the window cause it to work?

[mmmmichael]

Yes, in point 5 I mean 4.1.1, not 4.2.1. I fixed it in the description.

No, resizing the window doesn't help, also minimizing and maximizing again doesn't help, see following screenshot. Also pressing Open and entering a complete different URL like https://google.com, selecting a URL in the dropdown or pressing refresh doesn't work. It always remains the same.

Adding prints shows that the only event called from the webview is EVT_UPDATE_UI. But no EVT_WEBVIEW_NAVIGATING, EVT_WEBVIEW_NAVIGATED, EVT_WEBVIEW_LOADED or EVT_WEBVIEW_TITLE_CHANGED.

[Metallicow]

If a button has not shown up in 42 seconds then disreguard all the awesomeness, of Al Gore not winning the Internectcy.