A minimalist Gtk3 web browser that looks like Epiphany

browser.py

#!/usr/bin/python3

import gi, sys

gi.require_version('Gtk', '3.0')
gi.require_version('WebKit2', '4.0')

from gi.repository import Gtk, WebKit2 as WebKit, Pango

class Tab(Gtk.VBox):
    def __init__(self):
        super().__init__()

        self.webview = WebKit.WebView()
        self.webview.parent_tab = self
        scrolled_window = Gtk.ScrolledWindow()
        scrolled_window.add(self.webview)
        self.add(scrolled_window)
        
        settings = self.webview.get_settings()
        # Disable javascript
        # settings.props.enable_javascript = False


class Browser(Gtk.Window):

    def __init__(self):
        super().__init__(title="Browser")

        self.set_default_size(800, 600)
        self.set_position(Gtk.WindowPosition.CENTER)

        self.address_bar = Gtk.Entry(expand=True)
        self.address_bar.connect('activate', lambda entry: self.currentTab().webview.load_uri(entry.get_text()))

        btnPrevious = Gtk.Button().new_from_icon_name(
            'go-previous', Gtk.IconSize.BUTTON)
        btnPrevious.set_tooltip_text("Go back")
        btnPrevious.connect('clicked', lambda btn: self.currentTab().webview.go_back())

        btnNext = Gtk.Button().new_from_icon_name('go-next', Gtk.IconSize.BUTTON)
        btnNext.set_tooltip_text("Go forward")
        btnNext.connect('clicked', lambda btn: self.currentTab().webview.go_forward())

        btnRefresh = Gtk.Button().new_from_icon_name('view-refresh', Gtk.IconSize.BUTTON)
        btnRefresh.set_tooltip_text("Reload page")
        btnRefresh.connect('clicked', lambda btn: self.currentTab().webview.reload())

        btnNewTab = Gtk.Button().new_from_icon_name('tab-new', Gtk.IconSize.BUTTON)
        btnNewTab.set_tooltip_text("New tab")
        btnNewTab.connect('clicked', lambda btn: self.addTab())

        headerBtns = Gtk.HBox(expand=True)
        headerBtns.pack_start(btnPrevious, False, False, 0)
        headerBtns.pack_start(btnNext, False, False, 0)
        headerBtns.pack_start(btnRefresh, False, False, 10)
        headerBtns.pack_start(btnNewTab, False, False, 0)

        self.headerbar = Gtk.HeaderBar(show_close_button=True)
        self.headerbar.set_custom_title(self.address_bar)
        self.headerbar.pack_start(headerBtns)

        self.set_titlebar(self.headerbar)
        self.notebook = Gtk.Notebook(scrollable=True)
        self.notebook.connect('switch-page', self._ontabSwitched)
        self.add(self.notebook)
        self.show_all()

    def addTab(self):
        tab = Tab()
        tab.webview.connect('load-changed', self._onLoadChanged)

        btnClose = Gtk.Button(margin_start=3).new_from_icon_name('application-exit', Gtk.IconSize.BUTTON)
        btnClose.get_style_context().add_class("flat")
        btnClose.connect('clicked', lambda btn: self.notebook.remove_page(self.notebook.page_num(tab)))
        tabLabel = Gtk.HBox()
        label = Gtk.Label(label="New page",
                          width_chars=20,
                          ellipsize=Pango.EllipsizeMode.END,
                          halign=Gtk.Align.CENTER)
        tabLabel.pack_start(label, False, False, 0)
        tabLabel.pack_end(btnClose, False, False, 0)

        page_num = self.notebook.append_page(tab, tabLabel)
        self.notebook.set_tab_reorderable(tab, True)

        tabLabel.show_all()
        tab.show_all()

        if page_num > 0:
            self.address_bar.set_text("")
            self.notebook.set_current_page(page_num)

        return page_num

    def currentTab(self):
        page_num = self.notebook.get_current_page()

        if page_num == -1:
            page_num = self.addTab()

        return self.notebook.get_nth_page(page_num)

    def _ontabSwitched(self, notebook, page, page_num):

        if notebook.get_n_pages() > 1:
            uri = page.webview.get_uri()
            self.address_bar.set_text(uri or "")

    def _onLoadChanged(self, webview, loadEvent):

        if loadEvent == WebKit.LoadEvent.COMMITTED:
            uri = webview.get_uri()

            if uri:
                page_num = self.notebook.page_num(webview.parent_tab)

                if self.notebook.get_current_page() == page_num:
                    self.address_bar.set_text(uri)

        elif loadEvent == WebKit.LoadEvent.FINISHED:
            title = webview.get_title()

            if title:
                tabLabel = self.notebook.get_tab_label(self.currentTab())
                label = tabLabel.get_children()[0]
                label.set_text(title)


if __name__ == "__main__":
    Gtk.init(sys.argv)
    win = Browser()
    win.connect("delete-event", Gtk.main_quit)
    Gtk.main()