/**************************************************************************** ** ** Copyright (C) 2017 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the documentation of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:FDL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Free Documentation License Usage ** Alternatively, this file may be used under the terms of the GNU Free ** Documentation License version 1.3 as published by the Free Software ** Foundation and appearing in the file included in the packaging of ** this file. Please review the following information to ensure ** the GNU Free Documentation License version 1.3 requirements ** will be met: https://www.gnu.org/licenses/fdl-1.3.html. ** $QT_END_LICENSE$ ** ****************************************************************************/ /*! \page qtwebengine-debugging.html \title Qt WebEngine Debugging and Profiling \section1 Console Logging JavaScript executed inside \QWE can use the \l{Chrome console API} to log information to a console. The logging messages are forwarded to Qt's logging facilities inside a \c js \l{QLoggingCategory}{logging category}. However, only warning and fatal messages are printed by default. To change this, you either have to set custom rules for the \c js category, or provide custom message handlers by reimplementing \l{QWebEnginePage::javaScriptConsoleMessage()}, or connecting to \l{WebEngineView::javaScriptConsoleMessage()}. All messages can also be accessed through the \QWE developer tools. \section1 Qt WebEngine Developer Tools The \QWE 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 \QWE based browser, such as the Chrome browser. To activate the developer tools, start an application that uses \QWE with the command-line arguments: \badcode --remote-debugging-port= \endcode Where \c refers to a local network port. The web developer tools can then be accessed by launching a browser at the address \c http://localhost:. Alternatively, the environment variable QTWEBENGINE_REMOTE_DEBUGGING can be set. It can be set as either just a port working similarly to \c --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 \l {Chrome DevTools} page. \section1 Using Command-Line Arguments You can use the following command-line arguments while debugging to provide input for bug reports: \list \li \c {--disable-gpu} disables GPU hardware acceleration. This is useful when diagnosing OpenGL problems. \li \c {--disable-logging} disables console logging, which might be useful for debug builds. \li \c {--enable-logging --log-level=0} enables console logging and sets the logging level to 0, which means that messages of the severity \c info and above are recorded in the log. This is the default for debug builds. Other possible log levels are \c 1 for warnings, \c 2 for errors, and \c 3 for fatal errors. \li \c {--v=1} Increases the logging level beyond what \c {--log-level} can, and enables logging debug messages up to verbosity level \c 1. A higher number further increases verbosity, but may result in a large number of logged messages. Default is \c 0 (no debug messages). \li \c {--no-sandbox} disables the sandbox for the renderer and plugin processes. Keep in mind that disabling the sandbox might present a security risk. \li \c {--single-process} runs the renderer and plugins in the same process as the browser. This is useful for getting stack traces for renderer crashes. \endlist 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 \e mybrowser: \code QTWEBENGINE_CHROMIUM_FLAGS="--disable-logging" mybrowser \endcode */