WebEngine Quick Nano Browser

A web browser implemented using the WebEngineView QML type.

Quick Nano Browser demonstrates how to use the Qt WebEngine QML types to develop a small web browser application that consists of a browser window with a title bar, toolbar, tab view, and status bar. The web content is loaded in a web engine view within the tab view. If certificate errors occur, users are prompted for action in a message dialog. The status bar pops up to display the URL of a hovered link.

A web page can issue a request for being displayed in fullscreen mode. Users can allow full screen mode by using a toolbar button. They can leave fullscreen mode by using a keyboard shortcut. Additional toolbar buttons enable moving backwards and forwards in the browser history, reloading tab content, and opening a settings menu for enabling the following features: JavaScript, plugins, fullscreen mode, off the record, HTTP disk cache, autoloading images, and ignoring certificate errors.

Running the Example

To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.

Creating the Main Browser Window

When the browser main window is loaded, it creates an empty tab using the default profile. Each tab is a web engine view that fills the main window.

We create the main window in the BrowserWindow.qml file using the ApplicationWindow type:

ApplicationWindow {
    id: browserWindow
    property QtObject applicationRoot
    property Item currentWebView: tabBar.currentIndex < tabBar.count ? tabLayout.children[tabBar.currentIndex] : null
    ...
    width: 1300
    height: 900
    visible: true
    title: currentWebView && currentWebView.title

We use the TabBar Qt Quick control to create a tab bar anchored to the top of the window, and create a new, empty tab:

    TabBar {
        id: tabBar
        anchors.top: parent.top
        anchors.left: parent.left
        anchors.right: parent.right
        Component.onCompleted: createTab(defaultProfile)

        function createTab(profile, focusOnNewTab = true, url = undefined) {
            var webview = tabComponent.createObject(tabLayout, {profile: profile});
            var newTabButton = tabButtonComponent.createObject(tabBar, {tabTitle: Qt.binding(function () { return webview.title; })});
            tabBar.addItem(newTabButton);
            if (focusOnNewTab) {
                tabBar.setCurrentIndex(tabBar.count - 1);
            }

The tab contains a web engine view that loads web content:

        Component {
            id: tabComponent
            WebEngineView {
                id: webEngineView
                focus: true

                onLinkHovered: function(hoveredUrl) {
                    if (hoveredUrl == "")
                        hideStatusText.start();
                    else {
                        statusText.text = hoveredUrl;
                        statusBubble.visible = true;
                        hideStatusText.stop();
                    }
                }

                states: [
                    State {
                        name: "FullScreen"
                        PropertyChanges {
                            target: tabBar
                            visible: false
                            height: 0
                        }
                        PropertyChanges {
                            target: navigationBar
                            visible: false
                        }
                    }
                ]
                settings.autoLoadImages: appSettings.autoLoadImages
                settings.javascriptEnabled: appSettings.javaScriptEnabled
                settings.errorPageEnabled: appSettings.errorPageEnabled
                settings.pluginsEnabled: appSettings.pluginsEnabled
                settings.fullScreenSupportEnabled: appSettings.fullScreenSupportEnabled
                settings.autoLoadIconsForPage: appSettings.autoLoadIconsForPage
                settings.touchIconsEnabled: appSettings.touchIconsEnabled
                settings.webRTCPublicInterfacesOnly: appSettings.webRTCPublicInterfacesOnly
                settings.pdfViewerEnabled: appSettings.pdfViewerEnabled

                onCertificateError: function(error) {
                    error.defer();
                    sslDialog.enqueue(error);
                }

                onNewWindowRequested: function(request) {
                    if (!request.userInitiated)
                        console.warn("Blocked a popup window.");
                    else if (request.destination === WebEngineNewWindowRequest.InNewTab) {
                        var tab = tabBar.createTab(currentWebView.profile, true, request.requestedUrl);
                        tab.acceptAsNewWindow(request);
                    } else if (request.destination === WebEngineNewWindowRequest.InNewBackgroundTab) {
                        var backgroundTab = tabBar.createTab(currentWebView.profile, false);
                        backgroundTab.acceptAsNewWindow(request);
                    } else if (request.destination === WebEngineNewWindowRequest.InNewDialog) {
                        var dialog = applicationRoot.createDialog(currentWebView.profile);
                        dialog.currentWebView.acceptAsNewWindow(request);
                    } else {
                        var window = applicationRoot.createWindow(currentWebView.profile);
                        window.currentWebView.acceptAsNewWindow(request);
                    }
                }

                onFullScreenRequested: function(request) {
                    if (request.toggleOn) {
                        webEngineView.state = "FullScreen";
                        browserWindow.previousVisibility = browserWindow.visibility;
                        browserWindow.showFullScreen();
                        fullScreenNotification.show();
                    } else {
                        webEngineView.state = "";
                        browserWindow.visibility = browserWindow.previousVisibility;
                        fullScreenNotification.hide();
                    }
                    request.accept();
                }

                onQuotaRequested: function(request) {
                    if (request.requestedSize <= 5 * 1024 * 1024)
                        request.accept();
                    else
                        request.reject();
                }

                onRegisterProtocolHandlerRequested: function(request) {
                    console.log("accepting registerProtocolHandler request for "
                                + request.scheme + " from " + request.origin);
                    request.accept();
                }

                onRenderProcessTerminated: function(terminationStatus, exitCode) {
                    var status = "";
                    switch (terminationStatus) {
                    case WebEngineView.NormalTerminationStatus:
                        status = "(normal exit)";
                        break;
                    case WebEngineView.AbnormalTerminationStatus:
                        status = "(abnormal exit)";
                        break;
                    case WebEngineView.CrashedTerminationStatus:
                        status = "(crashed)";
                        break;
                    case WebEngineView.KilledTerminationStatus:
                        status = "(killed)";
                        break;
                    }

                    print("Render process exited with code " + exitCode + " " + status);
                    reloadTimer.running = true;
                }

                onSelectClientCertificate: function(selection) {
                    selection.certificates[0].select();
                }

                onFindTextFinished: function(result) {
                    if (!findBar.visible)
                        findBar.visible = true;

                    findBar.numberOfMatches = result.numberOfMatches;
                    findBar.activeMatch = result.activeMatch;
                }

                onLoadingChanged: function(loadRequest) {
                    if (loadRequest.status == WebEngineView.LoadStartedStatus)
                        findBar.reset();
                }

                Timer {
                    id: reloadTimer
                    interval: 0
                    running: false
                    repeat: false
                    onTriggered: currentWebView.reload()
                }
            }
        }

We use the Action type to create new tabs:

    Action {
        shortcut: StandardKey.AddTab
        onTriggered: {
            tabBar.createTab(tabBar.count != 0 ? currentWebView.profile : defaultProfile);
            addressBar.forceActiveFocus();
            addressBar.selectAll();
        }

We use the TextField Qt Quick Control within a ToolBar to create an address bar that shows the current URL and where users can enter another URL:

    menuBar: ToolBar {
        id: navigationBar
        RowLayout {
            anchors.fill: parent
    ...
            TextField {
                id: addressBar
    ...
                focus: true
                Layout.fillWidth: true
                Binding on text {
                    when: currentWebView
                    value: currentWebView.url
                }
                onAccepted: currentWebView.url = utils.fromUserInput(text)
                selectByMouse: true
            }

Handling Certificate Errors

If the certificate of the site being loaded triggers a certificate error, we call the defer() QML method to pause the URL request and wait for user input:

                onCertificateError: function(error) {
                    error.defer();
                    sslDialog.enqueue(error);
                }

We use the Dialog type to prompt users to continue or cancel the loading of the web page. If users select Yes, we call the acceptCertificate() method to continue loading content from the URL. If users select No, we call the rejectCertificate() method to reject the request and stop loading content from the URL:

    Dialog {
        id: sslDialog
        anchors.centerIn: parent
        contentWidth: Math.max(mainText.width, detailedText.width)
        contentHeight: mainText.height + detailedText.height
        property var certErrors: []
        // fixme: icon!
        // icon: StandardIcon.Warning
        standardButtons: Dialog.No | Dialog.Yes
        title: "Server's certificate not trusted"
        contentItem: Item {
            id: textContentItem
            Label {
                id: mainText
                text: "Do you wish to continue?"
            }
            Text {
                id: detailedText
                anchors.top: mainText.bottom
                text: "If you wish so, you may continue with an unverified certificate.\n" +
                      "Accepting an unverified certificate means\n" +
                      "you may not be connected with the host you tried to connect to.\n" +
                      "Do you wish to override the security check and continue?"
            }
        }

        onAccepted: {
            certErrors.shift().acceptCertificate();
            presentError();
        }
        onRejected: reject()

        function reject(){
            certErrors.shift().rejectCertificate();
            presentError();
        }
        function enqueue(error){
            certErrors.push(error);
            presentError();
        }
        function presentError(){
            visible = certErrors.length > 0
        }
    }

Entering and Leaving Fullscreen Mode

We create a menu item for allowing fullscreen mode in a settings menu that we place on the tool bar. Also, we create an action for leaving fullscreen mode by using a keyboard shortcut. We call the accept() method to accept the fullscreen request. The methdod sets the isFullScreen property to be equal to the toggleOn property.

                onFullScreenRequested: function(request) {
                    if (request.toggleOn) {
                        webEngineView.state = "FullScreen";
                        browserWindow.previousVisibility = browserWindow.visibility;
                        browserWindow.showFullScreen();
                        fullScreenNotification.show();
                    } else {
                        webEngineView.state = "";
                        browserWindow.visibility = browserWindow.previousVisibility;
                        fullScreenNotification.hide();
                    }
                    request.accept();
                }

When entering fullscreen mode, we display a notification using the FullScreenNotification custom type that we create in FullScreenNotification.qml.

We use the Action type in the settings menu to create a shortcut for leaving fullscreen mode by pressing the escape key:

    Settings {
        id : appSettings
        property alias fullScreenSupportEnabled: fullScreenSupportEnabled.checked
        property alias autoLoadIconsForPage: autoLoadIconsForPage.checked
        property alias touchIconsEnabled: touchIconsEnabled.checked
        property alias webRTCPublicInterfacesOnly : webRTCPublicInterfacesOnly.checked
        property alias devToolsEnabled: devToolsEnabled.checked
        property alias pdfViewerEnabled: pdfViewerEnabled.checked
    }

    Action {
        shortcut: "Escape"
        onTriggered: {
            if (currentWebView.state == "FullScreen") {
                browserWindow.visibility = browserWindow.previousVisibility;
                fullScreenNotification.hide();
                currentWebView.triggerWebAction(WebEngineView.ExitFullScreen);
            }

            if (findBar.visible)
                findBar.visible = false;
        }
    }

Files and Attributions

The example uses icons from the Tango Icon Library:

Tango Icon LibraryPublic Domain

Example project @ code.qt.io

© 2021 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.