This migration guide will get you through to make your code work with latest CEF Python. This document includes notable changes that were introduced to cefpython and each topic is prefixed with version number in which a change was introduced. This migration guide doesn't cover all changes required for your software to run smoothly. Some changes depend on the GUI framework you are using and this guide doesn't cover these. You will have to go to the examples/ root directory and see the example for your GUI framework. The new examples are very straightforward and include many useful comments explaining whys. You will have to get through its code and see if anything changed that also requires changes in your application.
Table of contents:
- v50+ Distribution packages
- v50+ Importing the cefpython3 package on Linux
- v50+ Install X11 error handlers on Linux
- v50+ Set window bounds on Linux
- v50+ Notify CEF on move or resize events
- v50+ Keyboard focus issues on Linux
- v50+ Windows XP and Vista are no more supported
- v50+ Mac 32-bit is no more supported
- v50+ cefbuilds.com is deprected, use Spotify Automated CEF Builds
- v50+ Build instructions and build tools
- v51+ Off-screen-rendering: new option "windowless_rendering_enabled"
- v51+ Remove LifespanHandler.RunModal
- v51+ BrowserSettings options removed
- v51+ cef.Request.Flags changed
- v51+ Request.GetHeaderMap and SetHeaderMap change
- v54+ GTK 3 example doesn't work anymore on Linux
- v54+ libcef.so library is stripped from symbols on Linux
- v55+ HTTPS cache problems on pages with certificate errors
- v55.3+ Handlers' callbacks and other interfaces
- v56+ MacOS 10.9+ required to run
- v57.1+ High DPI support on Windows
In latest CEF Python there is only one distribution package available: a wheel package. Wheel packages are distributed on PyPI and you can install it using the pip tool (8.1+ required on Linux). You can also download wheel packages from GitHub Releases.
Windows
On Windows many of the distribution packages such as MSI, EXE, ZIP and InnoSetup files, are no more available. It is too much hassle to support these.
Linux debian package
On Linux the debian package is not supported anymore. Since pip 8.1+ added support for manylinux1 wheel packages, you can now easily install cefpython on Linux using the pip tool. Installing cefpython on Ubuntu using pip should work out of the box, all OS dependencies on Ubuntu should be satisfied by default. However since upstream CEF has OS dependencies that might not be installed by default on other OSes like e.g. Fedora, and since debian packages allow to list these and install in an automated manner, it might be reconsidered in the future to provide debian packages again.
In the past on Linux it was required for the cefpython3 package to be imported before any other packages due to tcmalloc global hook being loaded. This is not required anymore, tcmalloc is disabled by default.
It is required to install X11 error handlers on Linux, otherwise you will see 'BadWindow' errors happening - sometimes randomly - which will cause application to terminate. Since v56+ x11 error handlers are installed automatically by default during the call to cef.Initialize(). However sometimes that is not enough like for example in the wxpython.py example which requires the x11 error handlers to be installed manually after wx was initialized, and that is because wx initialization had reset x11 error handlers that were installed earlier during cef initialization (Issue #334).
You can install X11 error handlers by calling:
WindowUtils = cef.WindowUtils()
WindowUtils.InstallX11ErrorHandlers()
API ref: WindowUtils.InstallX11ErrorHandlers()
It is now required to set window bounds during window "resize", "move" and "configure" events on Linux. You can do so by calling:
browser.SetBounds(x, y, width, height)
API ref: Browser.SetBounds()
It is required to notify the browser on move or resize events so that popup widgets (e.g. <select>) are displayed in the correct location and dismissed when the window moves. Also so that drag & drop areas are updated accordingly.
browser.NotifyMoveOrResizeStarted()
API ref: Browser.NotifyMoveOrResizeStarted()
There several keyboard focus issues on Linux since CEF library replaced GTK library with X11 library. Most of these issues are fixed in examples by calling SetFocus in LoadHandler.OnLoadStart during initial app loading and/or by calling SetFocus in FocusHandler.OnGotFocus. This keyboard focus issues need to be fixed in usptream CEF. For more details see Issue #284.
CEF Python v31.2 was the last version to support Windows XP. This is due to Chromium/CEF dropping XP support, last version that supported XP was CEF v49.
CEF Python v31.2 was the last version to support Mac 32-bit. This is due to CEF/Chromium dropping 32-bit support, last version that supported 32-bit was CEF v38.
The cefbuilds.com site with CEF prebuilt binaries is now deprecated. From now on download prebuilt CEF binaries from the Spotify Automated CEF Builds:
http://opensource.spotify.com/cefbuilds/index.html
There were many changes in regards to building CEF and CEF Python. There are now new tools in the tools/ root directory that fully automate building CEF and CEF Python. CEF Python now provides upstream CEF prebuilt binaries and libraries on GitHub Releases tagged eg. "v56-upstream". With these binaries you can build CEF Python from sources in less than 10 minutes. See the new Build instructions document.
When using off-screen-rendering you must set the ApplicationSettings "windowless_rendering_enabled" option to True. This applies to examples such as: Kivy, Panda3D and screenshot example.
API ref: ApplicationSettings.windowless_rendering_enabled
LifespanHandler.RunModal callback is no more available.
The following options were removed from BrowserSettings:
- user_style_sheet_location
- java_disabled
- accelerated_compositing
- author_and_user_styles_disabled
The following flags were removed from cef.Request.Flags:
- AllowCookies
- ReportLoadTiming
- ReportRawHeaders
API ref: Request.GetFlags
GetHeaderMap() will not include the Referer value if any and SetHeaderMap() will ignore the Referer value.
API ref: Request.GetHeaderMap
Currently GTK 3 example is broken on Linux. You can either downgrade to an old cefpython v53 (available on GitHub release page) or use GTK 2 example. For more details on the problem see Issue #261.
Symbols useful for debugging are no more available in libcef.so shipped with distribution packages on Linux. This is explained in details in Issue #262.
The fix for HTTPS cache problems on pages with certificate errors is no more applied on Windows.
Soon this will fix also won't be applied on Linux anymore when cefpython starts using CEF prebuilt binaries from Spotify.
See Issue #125 for more details.
Since v55.3 all handlers' callbacks and other interfaces such as CookieVisitor, StringVisitor and WebRequestClient, are now called using keyword arguments (Issue #291). This will cause many of existing code to break. This is how you should declare callbacks using the new style:
def OnLoadStart(self, browser, **_):
pass
def OnLoadStart(self, **kwargs):
browser = kwargs["browser"]
In the first declaration you see that only one argument is declared, the browser, the others unused will be in the "_" variable (the name of the variable is so that PyCharm doesn't warn about unused variable).
Even if you specify and use all arguments, always add the
unused kwargs (**_) at the end:
def OnLoadStart(self, browser, frame, **_):
pass
This will be handy in the future, in a case when upstream CEF adds a new argument to the API, your code won't break. When an argument is removed in upstream CEF API, if it's possible CEF Python will try to keep backward compatibility by emulating behavior of the old argument.
In case of OnLoadStart, when you've used "browser" and "frame"
names for the arguments, your code won't break. However in
many other callbacks, where you've used argument names that
differed from how they were named in API docs, your code will
break. Also argument names were changed from camelCase
to underscores. For example the OnLoadEnd callback has renamed
the httpStatusCode argument to http_code. So in this case
your code will definitely break, unless you've also used
"http_code" for argument name.
CEF v55 was the last version to support MacOS 10.7.
The cef.DpiAware.SetProcessDpiAware function is now deprecated.
Use cef.DpiAware.EnableHighDpiSupport
function instead.
The ApplicationSettings.auto_zooming option should have its value set to an empty string (a default now) for High DPI support. In previous versions the default value was "system_dpi" and if you have set it explicitilly in your application, then you should change it to an empty string now.