DOM Bookmarks Example#

Provides a reader for XML Bookmark Exchange Language files.

The DOM Bookmarks example provides a reader for XML Bookmark Exchange Language (XBEL) files that uses Qt’s DOM-based XML API to read and parse the files. The SAX Bookmarks example provides an alternative way to read this type of file.

DOM Bookmark Screenshot

Download this example

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE xbel>
<xbel version="1.0">
    <folder folded="no">
        <title>Qt Resources</title>
        <bookmark href="https://www.qt.io/">
            <title>Qt home page</title>
        </bookmark>
        <bookmark href="https://www.qt.io/contact-us/partners">
            <title>Qt Partners</title>
        </bookmark>
        <bookmark href="https://www.qt.io/qt-professional-services">
            <title>Professional Services</title>
        </bookmark>
        <bookmark href="https://doc.qt.io/">
            <title>Qt Documentation</title>
        </bookmark>
        <folder folded="yes">
            <title>Community Resources</title>
            <bookmark href="https://contribute.qt-project.org">
                <title>The Qt Project</title>
            </bookmark>
            <bookmark href="https://www.qtcentre.org/content/">
                <title>Qt Centre</title>
            </bookmark>
            <bookmark href="https://forum.qt.io/">
                <title>Forum.Qt.org</title>
            </bookmark>
            <bookmark href="https://digitalfanatics.org/projects/qt_tutorial/">
                <title>The Independent Qt Tutorial</title>
            </bookmark>
            <bookmark href="https://www.qtforum.de/">
                <title>German Qt Forum</title>
            </bookmark>
            <bookmark href="https://www.qt-dev.com/">
                <title>Korean Qt Community Site</title>
            </bookmark>
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                <title>Russian Qt Forum</title>
            </bookmark>
        </folder>
    </folder>
    <folder folded="no">
        <title>Online Dictionaries</title>
        <bookmark href="https://www.dictionary.com/">
            <title>Dictionary.com</title>
        </bookmark>
        <bookmark href="https://www.merriam-webster.com/">
            <title>Merriam-Webster Online</title>
        </bookmark>
        <bookmark href="https://dictionary.cambridge.org/">
            <title>Cambridge Dictionaries Online</title>
        </bookmark>
        <bookmark href="https://www.onelook.com/">
            <title>OneLook Dictionary Search</title>
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        <separator/>
        <bookmark href="https://dict.tu-chemnitz.de/">
            <title>BEOLINGUS, a service of TU Chemnitz</title>
        </bookmark>
        <separator/>
        <bookmark href="http://atilf.atilf.fr/tlf.htm">
            <title>Trésor de la Langue Française informatisé</title>
        </bookmark>
        <bookmark href="https://www.dictionnaire-academie.fr/">
            <title>Dictionnaire de l'Académie Française</title>
        </bookmark>
    </folder>
</xbel>
# Copyright (C) 2013 Riverbank Computing Limited.
# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

"""PySide6 port of the xml/dombookmarks example from Qt v5.x"""

import sys

from PySide6.QtCore import QDir, QFile, Qt, QTextStream
from PySide6.QtGui import QAction, QIcon, QKeySequence
from PySide6.QtWidgets import (QApplication, QFileDialog, QHeaderView,
                               QMainWindow, QMessageBox, QStyle, QTreeWidget,
                               QTreeWidgetItem)
from PySide6.QtXml import QDomDocument


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)

        self._xbel_tree = XbelTree()
        self.setCentralWidget(self._xbel_tree)

        self.create_menus()

        self.statusBar().showMessage("Ready")

        self.setWindowTitle("DOM Bookmarks")
        self.resize(480, 320)

    def open(self):
        file_name = QFileDialog.getOpenFileName(self,
                                                "Open Bookmark File", QDir.currentPath(),
                                                "XBEL Files (*.xbel *.xml)")[0]

        if not file_name:
            return

        in_file = QFile(file_name)
        if not in_file.open(QFile.ReadOnly | QFile.Text):
            reason = in_file.errorString()
            QMessageBox.warning(self, "DOM Bookmarks",
                                f"Cannot read file {file_name}:\n{reason}.")
            return

        if self._xbel_tree.read(in_file):
            self.statusBar().showMessage("File loaded", 2000)

    def save_as(self):
        file_name = QFileDialog.getSaveFileName(self,
                                                "Save Bookmark File", QDir.currentPath(),
                                                "XBEL Files (*.xbel *.xml)")[0]

        if not file_name:
            return

        out_file = QFile(file_name)
        if not out_file.open(QFile.WriteOnly | QFile.Text):
            reason = out_file.errorString()
            QMessageBox.warning(self, "DOM Bookmarks",
                                f"Cannot write file {file_name}:\n{reason}.")
            return

        if self._xbel_tree.write(out_file):
            self.statusBar().showMessage("File saved", 2000)

    def about(self):
        QMessageBox.about(self, "About DOM Bookmarks",
                          "The <b>DOM Bookmarks</b> example demonstrates how to use Qt's "
                          "DOM classes to read and write XML documents.")

    def create_menus(self):
        self._file_menu = self.menuBar().addMenu("&File")
        self._file_menu.addAction(QAction("&Open...", self,
                                          shortcut=QKeySequence(
                                              Qt.CTRL | Qt.Key_O), triggered=self.open))
        self._file_menu.addAction(QAction("&Save As...", self,
                                          shortcut=QKeySequence(
                                              Qt.CTRL | Qt.Key_S), triggered=self.save_as))
        self._file_menu.addAction(QAction("E&xit", self,
                                          shortcut=QKeySequence(
                                              Qt.CTRL | Qt.Key_Q), triggered=self.close))

        self.menuBar().addSeparator()

        self._help_menu = self.menuBar().addMenu("&Help")
        self._help_menu.addAction(QAction("&About", self, triggered=self.about))
        self._help_menu.addAction(QAction("About &Qt", self, triggered=qApp.aboutQt))


class XbelTree(QTreeWidget):
    def __init__(self, parent=None):
        super().__init__(parent)

        self.header().setSectionResizeMode(QHeaderView.Stretch)
        self.setHeaderLabels(("Title", "Location"))

        self._dom_document = QDomDocument()

        self._dom_element_for_item = {}

        self._folder_icon = QIcon()
        self._bookmark_icon = QIcon()

        self._folder_icon.addPixmap(self.style().standardPixmap(QStyle.SP_DirClosedIcon),
                                    QIcon.Normal, QIcon.Off)
        self._folder_icon.addPixmap(self.style().standardPixmap(QStyle.SP_DirOpenIcon),
                                    QIcon.Normal, QIcon.On)
        self._bookmark_icon.addPixmap(self.style().standardPixmap(QStyle.SP_FileIcon))

    def read(self, device):
        ok, errorStr, errorLine, errorColumn = self._dom_document.setContent(device, True)
        if not ok:
            QMessageBox.information(self.window(), "DOM Bookmarks",
                                    f"Parse error at line {errorLine}, "
                                    f"column {errorColumn}:\n{errorStr}")
            return False

        root = self._dom_document.documentElement()
        if root.tagName() != 'xbel':
            QMessageBox.information(self.window(), "DOM Bookmarks",
                                    "The file is not an XBEL file.")
            return False
        elif root.hasAttribute('version') and root.attribute('version') != '1.0':
            QMessageBox.information(self.window(), "DOM Bookmarks",
                                    "The file is not an XBEL version 1.0 file.")
            return False

        self.clear()

        # It might not be connected.
        try:
            self.itemChanged.disconnect(self.update_dom_element)
        except RuntimeError:
            pass

        child = root.firstChildElement('folder')
        while not child.isNull():
            self.parse_folder_element(child)
            child = child.nextSiblingElement('folder')

        self.itemChanged.connect(self.update_dom_element)

        return True

    def write(self, device):
        INDENT_SIZE = 4

        out = QTextStream(device)
        self._dom_document.save(out, INDENT_SIZE)
        return True

    def update_dom_element(self, item, column):
        element = self._dom_element_for_item.get(id(item))
        if not element.isNull():
            if column == 0:
                old_title_element = element.firstChildElement('title')
                new_title_element = self._dom_document.createElement('title')

                new_title_text = self._dom_document.createTextNode(item.text(0))
                new_title_element.appendChild(new_title_text)

                element.replaceChild(new_title_element, old_title_element)
            else:
                if element.tagName() == 'bookmark':
                    element.setAttribute('href', item.text(1))

    def parse_folder_element(self, element, parentItem=None):
        item = self.create_item(element, parentItem)

        title = element.firstChildElement('title').text()
        if not title:
            title = "Folder"

        item.setFlags(item.flags() | Qt.ItemIsEditable)
        item.setIcon(0, self._folder_icon)
        item.setText(0, title)

        folded = (element.attribute('folded') != 'no')
        item.setExpanded(not folded)

        child = element.firstChildElement()
        while not child.isNull():
            if child.tagName() == 'folder':
                self.parse_folder_element(child, item)
            elif child.tagName() == 'bookmark':
                child_item = self.create_item(child, item)

                title = child.firstChildElement('title').text()
                if not title:
                    title = "Folder"

                child_item.setFlags(item.flags() | Qt.ItemIsEditable)
                child_item.setIcon(0, self._bookmark_icon)
                child_item.setText(0, title)
                child_item.setText(1, child.attribute('href'))
            elif child.tagName() == 'separator':
                child_item = self.create_item(child, item)
                child_item.setFlags(item.flags() & ~(Qt.ItemIsSelectable | Qt.ItemIsEditable))
                child_item.setText(0, 30 * "\xb7")

            child = child.nextSiblingElement()

    def create_item(self, element, parentItem=None):
        item = QTreeWidgetItem()

        if parentItem is not None:
            item = QTreeWidgetItem(parentItem)
        else:
            item = QTreeWidgetItem(self)

        self._dom_element_for_item[id(item)] = element
        return item


if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_win = MainWindow()
    main_win.show()
    main_win.open()
    sys.exit(app.exec())