Source code for openlp.plugins.custom.lib.customxmlhandler

# -*- coding: utf-8 -*-
# vim: autoindent shiftwidth=4 expandtab textwidth=120 tabstop=4 softtabstop=4

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# OpenLP - Open Source Lyrics Projection                                      #
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# Copyright (c) 2008-2017 OpenLP Developers                                   #
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"""
The :mod:`customxmlhandler` module provides the XML functionality for custom
slides

The basic XML is of the format::

    <?xml version="1.0" encoding="UTF-8"?>
    <song version="1.0">
        <lyrics language="en">
            <verse type="chorus" label="1">
                <![CDATA[ ... ]]>
            </verse>
        </lyrics>
    </song>
"""

import logging

from xml.dom.minidom import Document
from xml.etree.ElementTree import dump
from lxml import etree, objectify

log = logging.getLogger(__name__)


# TODO: These classes need to be refactored into a single class.
class CustomXMLBuilder(object):
    """
    This class builds the XML used to describe songs.
    """
    log.info('CustomXMLBuilder Loaded')

    def __init__(self):
        """
        Set up the custom builder.
        """
        # Create the minidom document
        self.custom_xml = Document()
        self.new_document()
        self.add_lyrics_to_song()

    def new_document(self):
        """
        Create a new custom XML document.
        """
        # Create the <song> base element
        self.song = self.custom_xml.createElement('song')
        self.custom_xml.appendChild(self.song)
        self.song.setAttribute('version', '1.0')

    def add_lyrics_to_song(self):
        """
        Set up and add a ``<lyrics>`` tag which contains the lyrics of the
        custom item.
        """
        # Create the main <lyrics> element
        self.lyrics = self.custom_xml.createElement('lyrics')
        self.lyrics.setAttribute('language', 'en')
        self.song.appendChild(self.lyrics)

    def add_verse_to_lyrics(self, verse_type, number, content):
        """
        Add a verse to the ``<lyrics>`` tag.

        :param verse_type: A string denoting the type of verse. Possible values are "Chorus", "Verse", "Bridge",
            and "Custom".
        :param number:  An integer denoting the number of the item, for example: verse 1.
        :param content: The actual text of the verse to be stored.

        """
        verse = self.custom_xml.createElement('verse')
        verse.setAttribute('type', verse_type)
        verse.setAttribute('label', number)
        self.lyrics.appendChild(verse)
        # add data as a CDATA section to protect the XML from special chars
        cds = self.custom_xml.createCDATASection(content)
        verse.appendChild(cds)

    def _dump_xml(self):
        """
        Debugging aid to dump XML so that we can see what we have.
        """
        return self.custom_xml.toprettyxml(indent='  ')

    def extract_xml(self):
        """
        Extract our newly created XML custom.
        """
        return self.custom_xml.toxml('utf-8')


class CustomXMLParser(object):
    """
    A class to read in and parse a custom's XML.
    """
    log.info('CustomXMLParser Loaded')

    def __init__(self, xml):
        """
        Set up our custom XML parser.

        :param xml: The XML of the custom to be parsed.
        """
        self.custom_xml = None
        if xml[:5] == '<?xml':
            xml = xml[38:]
        try:
            self.custom_xml = objectify.fromstring(xml)
        except etree.XMLSyntaxError:
            log.exception('Invalid xml {xml}'.format(xml=xml))

    def get_verses(self):
        """
        Iterates through the verses in the XML and returns a list of verses and their attributes.
        """
        xml_iter = self.custom_xml.getiterator()
        verse_list = []
        for element in xml_iter:
            if element.tag == 'verse':
                if element.text is None:
                    element.text = ''
                verse_list.append([element.attrib, str(element.text)])
        return verse_list

    def _dump_xml(self):
        """
        Debugging aid to dump XML so that we can see what we have.
        """
        return dump(self.custom_xml)