211 lines
6.6 KiB
Python
211 lines
6.6 KiB
Python
from bs4 import BeautifulSoup, NavigableString
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import re
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import six
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convert_heading_re = re.compile(r'convert_h(\d+)')
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line_beginning_re = re.compile(r'^', re.MULTILINE)
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whitespace_re = re.compile(r'[\r\n\s\t ]+')
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FRAGMENT_ID = '__MARKDOWNIFY_WRAPPER__'
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wrapped = '<div id="%s">%%s</div>' % FRAGMENT_ID
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# Heading styles
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ATX = 'atx'
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ATX_CLOSED = 'atx_closed'
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UNDERLINED = 'underlined'
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SETEXT = UNDERLINED
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def escape(text):
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if not text:
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return ''
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return text.replace('_', r'\_')
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def chomp(text):
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"""
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If the text in an inline tag like b, a, or em contains a leading or trailing
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space, strip the string and return a space as suffix of prefix, if needed.
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This function is used to prevent conversions like
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<b> foo</b> => ** foo**
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"""
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prefix = ' ' if text and text[0] == ' ' else ''
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suffix = ' ' if text and text[-1] == ' ' else ''
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text = text.strip()
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return (prefix, suffix, text)
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def _todict(obj):
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return dict((k, getattr(obj, k)) for k in dir(obj) if not k.startswith('_'))
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class MarkdownConverter(object):
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class DefaultOptions:
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strip = None
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convert = None
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autolinks = True
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heading_style = UNDERLINED
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bullets = '*+-' # An iterable of bullet types.
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class Options(DefaultOptions):
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pass
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def __init__(self, **options):
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# Create an options dictionary. Use DefaultOptions as a base so that
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# it doesn't have to be extended.
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self.options = _todict(self.DefaultOptions)
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self.options.update(_todict(self.Options))
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self.options.update(options)
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if self.options['strip'] is not None and self.options['convert'] is not None:
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raise ValueError('You may specify either tags to strip or tags to'
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' convert, but not both.')
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def convert(self, html):
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# We want to take advantage of the html5 parsing, but we don't actually
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# want a full document. Therefore, we'll mark our fragment with an id,
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# create the document, and extract the element with the id.
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html = wrapped % html
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soup = BeautifulSoup(html, 'html.parser')
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return self.process_tag(soup.find(id=FRAGMENT_ID), children_only=True)
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def process_tag(self, node, children_only=False):
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text = ''
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# Convert the children first
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for el in node.children:
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if isinstance(el, NavigableString):
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text += self.process_text(six.text_type(el))
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else:
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text += self.process_tag(el)
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if not children_only:
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convert_fn = getattr(self, 'convert_%s' % node.name, None)
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if convert_fn and self.should_convert_tag(node.name):
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text = convert_fn(node, text)
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return text
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def process_text(self, text):
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return escape(whitespace_re.sub(' ', text or ''))
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def __getattr__(self, attr):
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# Handle headings
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m = convert_heading_re.match(attr)
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if m:
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n = int(m.group(1))
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def convert_tag(el, text):
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return self.convert_hn(n, el, text)
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convert_tag.__name__ = 'convert_h%s' % n
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setattr(self, convert_tag.__name__, convert_tag)
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return convert_tag
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raise AttributeError(attr)
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def should_convert_tag(self, tag):
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tag = tag.lower()
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strip = self.options['strip']
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convert = self.options['convert']
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if strip is not None:
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return tag not in strip
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elif convert is not None:
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return tag in convert
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else:
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return True
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def indent(self, text, level):
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return line_beginning_re.sub('\t' * level, text) if text else ''
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def underline(self, text, pad_char):
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text = (text or '').rstrip()
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return '%s\n%s\n\n' % (text, pad_char * len(text)) if text else ''
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def convert_a(self, el, text):
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prefix, suffix, text = chomp(text)
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if not text:
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return ''
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href = el.get('href')
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title = el.get('title')
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if self.options['autolinks'] and text == href and not title:
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# Shortcut syntax
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return '<%s>' % href
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title_part = ' "%s"' % title.replace('"', r'\"') if title else ''
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return '%s[%s](%s%s)%s' % (prefix, text, href, title_part, suffix) if href else text
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def convert_b(self, el, text):
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return self.convert_strong(el, text)
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def convert_blockquote(self, el, text):
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return '\n' + line_beginning_re.sub('> ', text) if text else ''
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def convert_br(self, el, text):
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return ' \n'
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def convert_em(self, el, text):
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prefix, suffix, text = chomp(text)
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if not text:
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return ''
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return '%s*%s*%s' % (prefix, text, suffix)
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def convert_hn(self, n, el, text):
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style = self.options['heading_style']
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text = text.rstrip()
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if style == UNDERLINED and n <= 2:
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line = '=' if n == 1 else '-'
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return self.underline(text, line)
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hashes = '#' * n
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if style == ATX_CLOSED:
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return '%s %s %s\n\n' % (hashes, text, hashes)
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return '%s %s\n\n' % (hashes, text)
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def convert_i(self, el, text):
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return self.convert_em(el, text)
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def convert_list(self, el, text):
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nested = False
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while el:
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if el.name == 'li':
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nested = True
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break
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el = el.parent
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if nested:
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text = '\n' + self.indent(text, 1)
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return '\n' + text + '\n'
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convert_ul = convert_list
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convert_ol = convert_list
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def convert_li(self, el, text):
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parent = el.parent
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if parent is not None and parent.name == 'ol':
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bullet = '%s.' % (parent.index(el) + 1)
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else:
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depth = -1
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while el:
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if el.name == 'ul':
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depth += 1
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el = el.parent
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bullets = self.options['bullets']
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bullet = bullets[depth % len(bullets)]
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return '%s %s\n' % (bullet, text or '')
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def convert_p(self, el, text):
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return '%s\n\n' % text if text else ''
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def convert_strong(self, el, text):
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prefix, suffix, text = chomp(text)
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if not text:
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return ''
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return '%s**%s**%s' % (prefix, text, suffix)
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def convert_img(self, el, text):
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alt = el.attrs.get('alt', None) or ''
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src = el.attrs.get('src', None) or ''
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title = el.attrs.get('title', None) or ''
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title_part = ' "%s"' % title.replace('"', r'\"') if title else ''
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return '' % (alt, src, title_part)
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def markdownify(html, **options):
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return MarkdownConverter(**options).convert(html)
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