LocalStorage in QWebEngineView not saved after running.

Daic

Hello everyone,

I’m currently working on a PySide6 application that uses QWebEngineView to display a simple HTML page. The simple example page uses JavaScript to store the "last open time" in localStorage. However, no matter how I set it up, the value for the last_open_time always shows as null each time I run the application, even though I’m saving it to localStorage. But when I run the html file in browser, it can work correctly.

import sys
from pathlib import Path
from PySide6.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget
from PySide6.QtWebEngineWidgets import QWebEngineView
from PySide6.QtWebEngineCore import QWebEngineProfile, QWebEnginePage

CACHE_PATH = Path(__file__).parent / "cache"
CACHE_PATH.mkdir(exist_ok=True)


class MyWebEngineView(QWebEngineView):
    def __init__(self, profile, parent=None):
        super().__init__(parent)

        # Use the passed profile for this WebEngineView to ensure persistent localStorage
        self.setPage(QWebEnginePage(profile, self))

        # Load the HTML content
        self.setHtml(self.create_html())

    def create_html(self):
        """Create simple HTML content with JavaScript to manage localStorage."""
        html_content = """
        <!DOCTYPE html>
        <html>
        <head><title>Web Page</title></head>
        <body>
            <h1>Welcome to the Web Page</h1>
            <p>Last open time: <span id="last_open_time">null</span></p>

            <script>
                // Get the last open time from localStorage
                var lastOpenTime = localStorage.getItem('last_open_time');

                // If lastOpenTime exists, display it; otherwise, show null
                if (lastOpenTime) {
                    document.getElementById('last_open_time').textContent = lastOpenTime;
                } else {
                    document.getElementById('last_open_time').textContent = 'null';
                }

                // Save the current open time to localStorage
                var currentTime = new Date().toISOString();
                localStorage.setItem('last_open_time', currentTime);
            </script>
        </body>
        </html>
        """
        return html_content


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        # Create a shared QWebEngineProfile with persistent storage
        profile = QWebEngineProfile.defaultProfile()

        # # Tried these, also didn't work
        # profile.setCachePath(CACHE_PATH.as_posix())
        # profile.setPersistentStoragePath(CACHE_PATH.as_posix())
        # profile.setHttpCacheType(QWebEngineProfile.HttpCacheType.DiskHttpCache)

        # Create QWebEngineView instance using the shared profile
        view = MyWebEngineView(profile)

        # Set up layout and main window
        layout = QVBoxLayout()
        layout.addWidget(view)
        central_widget = QWidget()
        central_widget.setLayout(layout)
        self.setCentralWidget(central_widget)

        self.setWindowTitle("Last Open Time Example")


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    sys.exit(app.exec())

JonB

@Daic
I don't know, but start by verifying

Setting attribute QWebEngineSettings::LocalStorageEnabled is true.
QWebEngineProfile::persistentStoragePath() is set to where you expect, does it get updated?