140 lines
4.5 KiB
Python
140 lines
4.5 KiB
Python
from bs4 import BeautifulSoup, NavigableString
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import re
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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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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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class MarkdownConverter(object):
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def __init__(self, tags_to_strip=None, tags_to_convert=None):
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if tags_to_strip is not None and tags_to_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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self.tags_to_strip = tags_to_strip
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self.tags_to_convert = tags_to_convert
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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)
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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(unicode(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 heading levels > 2
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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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if self.tags_to_strip is not None:
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return tag not in self.tags_to_strip
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elif self.tags_to_convert is not None:
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return tag in self.tags_to_convert
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else:
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return True
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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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href = el.get('href')
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title = el.get('title')
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if 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)' % (text or '', href, title_part) if href else text or ''
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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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return '*%s*' % text if text else ''
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def convert_h1(self, el, text):
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return self.underline(text, '=')
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def convert_h2(self, el, text):
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return self.underline(text, '-')
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def convert_hn(self, n, el, text):
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return '%s %s\n\n' % ('#' * n, text.rstrip()) if text else ''
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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_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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bullet = '*'
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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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return '**%s**' % text if text else ''
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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, strip=None, convert=None):
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converter = MarkdownConverter(strip, convert)
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return converter.convert(html)
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