I've faced the following problem:

Loading file: file:///home/somobu/[some-path]/index.html
js: Access to XMLHttpRequest at 'https://[some-domain]/[some-endpoint]' from origin 'file://' has been blocked by CORS policy: Cross origin requests are only supported for protocol schemes: http, data, chrome, chrome-extension, chrome-untrusted, https.

It can be solved by adding to the core/include/webview/detail/backends/qt5_qwebengine.hh, function void window_settings(bool debug) the following line:

m_webview->settings()->setAttribute(QWebEngineSettings::LocalContentCanAccessRemoteUrls, true);

Not sure if it is 100% safe to do, but at least it works for me.

Also, to prevent gcc from complaining that _deps/webview-src/core/include/webview/detail/backends/../platform/linux/gtk/compat.hh:35:10: fatal error: gtk/gtk.h: No such file or directory, I had to set both set(WEBVIEW_QT true) and add_definitions(-DWEBVIEW_QT) in my project's CMakeLists.txt (setting only one of them isn't enough). Not sure if this was intended.

It looks like you cannot make window resizeable. The following line makes window resizable on GTK webview, but not on Qt5 one:

w.set_size(1280, 800, WEBVIEW_HINT_NONE);

Qt5 has reached its EOL, and therefore qt5-webengine has been removed from Arch repos one month ago.

Also, to prevent gcc from complaining that _deps/webview-src/core/include/webview/detail/backends/../platform/linux/gtk/compat.hh:35:10: fatal error: gtk/gtk.h: No such file or directory, I had to set both set(WEBVIEW_QT true) and add_definitions(-DWEBVIEW_QT) in my project's CMakeLists.txt (setting only one of them isn't enough). Not sure if this was intended.

Did some research and found https://discourse.cmake.org/t/cmake-command-line-d-and-using-defined/2264/6 :

The command line interface explicitly considers -DVAR an error.

I use -DWEBVIEW_QT=1 when making test builds from command line, as -DWEBVIEW_QT makes me the same troubles.

Qt5 has reached its EOL

Ugh. Will need some time to upgrade...

Ugh. Will need some time to upgrade...

File cmake/webview.cmake:

• replace all Qt5 -> Qt6;
• remove Qt5WebEngine (it seems that this pkg doen't exist anymore);

File core/CMakeLists.txt:

• replace Qt5 -> Qt6;

File core/include/webview/detail/backends/qt5_qwebengine.hh:

• m_webview->page()->scripts().findScripts(script_name); -> ...->script().find(script_name);;
• in m_app = new QApplication(m_argc, m_argv); constructor call you now have to provide non-zero argc -- first argument is an app name (in practice it can be any non-zero string, looks like Qt does nothing with it);

Transition to Qt6 introduces regression: webview data is now lost on app restart.

To make webview storage persistent, you have to make the following changes in core/include/webview/detail/backends/qt5_qwebengine.hh:

1. Add QWebEngineProfile* prof field on a qt_web_engine;

2. In qt_web_engine::window_init, initialize the profile:

// Initialize webview widget
prof = new QWebEngineProfile(QString("Default"), nullptr);
m_webview = new QWebEngineView(prof, nullptr);

3. In qt_web_engine::~qt_web_engine, destroy the profile (data won't be saved if you not call profile destructor);

Took a while for personal reasons. Qt version is being switched by WEBVIEW_QT value, 5 stands for 5, everything else is for 6.

I love you so much. That was my fault. I', really sorry)