Deploying Qt WebEngine Applications

The way to package and deploy applications varies between operating systems. For Windows and macOS, windeployqt and macdeployqt automate the steps to generate a stand-alone application package.

When manually deploying applications that depend on Qt WebEngine, all the files that are required to run the application have to be included: libraries, QML imports, plugins, and translations.

For more information, see Deploying Qt Applications.

Target Platforms

Qt WebEngine does try to support all Supported Platforms of Qt. However, due to different requirements of Chromium this is not always possible. Known limitations are:

  • Qt WebEngine currently supports only Windows, Linux, and macOS.
  • On Windows, Qt WebEngine only supports Windows Vista or newer as target platform. Due to use of newer API in Chromium, Windows XP is not supported. WinRT is not supported, either.

Deploying Applications Manually

When manually deploying applications that depend on Qt WebEngine, the following files might have to be deployed:

  • Libraries
  • QML imports
  • Qt WebEngine process
  • Resources
  • Translations
  • Audio and video codecs

Deploying Libraries

The following libraries must be deployed with applications that depend on Qt WebEngine:

Deploying QML Imports

If Qt Quick integration is used in the application, the QtWebEngine import directory needs to be deployed.

Deploying Qt WebEngine Processes

Qt WebEngine takes advantage of the multi-process model that the Chromium project offers. The multi-process model requires that the Qt WebEngine Process executable be deployed alongside your application.

The WebEngine process is executed for each QWebEngineView or WebEngineView instance. For example, a browser application with two tabs open should have two separate instances of the process running. This is a common approach used by most modern web engines to provide a stable browsing experience.

At runtime, Qt WebEngine looks for the QtWebEngineProcess executable in the directory that QLibraryInfo::location(QLibraryInfo::LibraryExecutablesPath) returns. For Qt installations, this is QTDIR/libexec (Linux) or QTDIR\bin (Windows). The path can be changed by defining a qt.conf file, for example. Alternatively, an executable path can be set as a value of the QTWEBENGINEPROCESS_PATH environment variable. On macOS, Qt WebEngine looks for the executable in .app/Helpers/QtWebEngineProcess.

Deploying Resources

Qt WebEngine requires the following resource files:

  • qtwebengine_resources.pak contains the resources needed by Chromium.
  • qtwebengine_devtools_resources.pak contains tools for remote debugging.
  • qtwebengine_resources_100p.pak contains images suitable for low resolution displays.
  • qtwebengine_resources_200p.pak contains images suitable for high DPI displays.
  • icudtl.dat provides support for International Components for Unicode (ICU). It is the Chromium version of ICU, which is not needed if Qt WebEngine was configured to use the system ICU.

Resources are searched from the following locations:

  • On Linux and Windows: the resources directory in the directory specified by QLibraryInfo::location(QLibraryInfo::DataPath)
  • On macOS: .app/Content/Resources

Translations

Locale data (such as en-US.pak) is searched form the following locations:

  • On macOS: .app/Content/Resources
  • On Linux and Windows: qtwebengine_locales directory in the directory specified by QLibraryInfo::location(QLibraryInfo::TranslationsPath)

JavaScript Files in Qt Resource Files

If your WebEngine application is built using the Qt Quick Compiler, and the application ships JavaScript files inside .qrc resources, and these files are supposed to be loaded from inside HTML pages, make sure to specify the resource files in a QTQUICK_COMPILER_SKIPPED_RESOURCES qmake variable inside your project. This prevents the Qt Quick Compiler from trying to generate C++ code for the corresponding JavaScript code, as well as removing the original JavaScript code from the Qt resources file, which would lead to broken HTML pages. For example:

QTQUICK_COMPILER_SKIPPED_RESOURCES += resources/my_resource.qrc

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