JavaScript executed inside Qt WebEngine can use the
Chrome console API
to log information to a console. The logging messages are forwarded to Qt's logging facilities inside a
js
日志类别
. However, only warning and fatal messages are printed by default. To change this, you either have to set custom rules for the
js
category, or provide custom message handlers by reimplementing
QWebEnginePage::javaScriptConsoleMessage
(), or connecting to
WebEngineView::javaScriptConsoleMessage
().
也可通过 Qt WebEngine 开发者工具，访问所有消息。
The Qt WebEngine module provides web developer tools that make it easy to inspect and debug layout and performance issues of any web content.
The developer tools are accessed as a local web page using a Chromium or Qt WebEngine based browser, such as the Chrome browser.
To activate the developer tools, start an application that uses Qt WebEngine with the command-line argument
--remote-debugging-port=<portnumber>
.
注意：
任何
WebEngine
command line options should be specified after the
--webEngineArgs
option, which is used to separate the user's application specific options from the
WebEngine
's ones.
--webEngineArgs --remote-debugging-port=<portnumber>
Where
<port_number>
refers to a local network port. The web developer tools can then be accessed by launching a browser at the address
http://localhost:<port_number>
.
Alternatively, the environment variable QTWEBENGINE_REMOTE_DEBUGGING can be set. It can be set as either just a port working similarly to
--remote-debugging-port
or given both a host address and a port. The latter can be used to control which network interface to export the interface on, so that you can access the developer tools from a remote device.
For a detailed explanation of the capabilities of developer tools, see the Chrome DevTools 页面。
You can use the following command-line arguments while debugging to provide input for bug reports:
--disable-gpu
disables GPU hardware acceleration. This is useful when diagnosing OpenGL problems.
--disable-logging
disables console logging, which might be useful for debug builds.
--enable-logging --log-level=0
enables console logging and sets the logging level to 0, which means that messages of the severity
info
and above are recorded in the log. This is the default for debug builds. Other possible log levels are
1
for warnings,
2
for errors, and
3
for fatal errors.
--v=1
Increases the logging level beyond what
--log-level
can, and enables logging debug messages up to verbosity level
1
. A higher number further increases verbosity, but may result in a large number of logged messages. Default is
0
(no debug messages).
--no-sandbox
disables the sandbox for the renderer and plugin processes. Keep in mind that disabling the sandbox might present a security risk.
--single-process
runs the renderer and plugins in the same process as the browser. This is useful for getting stack traces for renderer crashes.
--enable-features=NetworkServiceInProcess
runs networking in the main process. This may help firewall management, since only the application executable will need to be whitelisted and not QtWebEngineProcess. It means losing the security of sandboxing of the network service though.
Alternatively, the environment variable QTWEBENGINE_CHROMIUM_FLAGS can be set. For example, the following value could be set to disable logging while debugging an application called mybrowser :
QTWEBENGINE_CHROMIUM_FLAGS="--disable-logging" mybrowser
QTWEBENGINE_CHROMIUM_FLAGS can also be set using
qputenv
from within the application if called before QtWebEngineQuick::initialize().
For dumping the WebEngineContext information, you can set the
QT_LOGGING_RULES
环境变量到
"qt.webenginecontext.debug=true"
.
The output contains information about the graphical backend, and the way how Qt WebEngine is initialized for the application. This is particularly useful for reproducing issues.