129 lines
6.0 KiB
Python
129 lines
6.0 KiB
Python
"HTML utilities suitable for global use."
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import re
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import string
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from django.utils.encoding import force_unicode
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from django.utils.functional import allow_lazy
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# Configuration for urlize() function
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LEADING_PUNCTUATION = ['(', '<', '<']
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TRAILING_PUNCTUATION = ['.', ',', ')', '>', '\n', '>']
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# list of possible strings used for bullets in bulleted lists
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DOTS = ['·', '*', '\xe2\x80\xa2', '•', '•', '•']
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unencoded_ampersands_re = re.compile(r'&(?!(\w+|#\d+);)')
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word_split_re = re.compile(r'(\s+)')
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punctuation_re = re.compile('^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % \
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('|'.join([re.escape(x) for x in LEADING_PUNCTUATION]),
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'|'.join([re.escape(x) for x in TRAILING_PUNCTUATION])))
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simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$')
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link_target_attribute_re = re.compile(r'(<a [^>]*?)target=[^\s>]+')
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html_gunk_re = re.compile(r'(?:<br clear="all">|<i><\/i>|<b><\/b>|<em><\/em>|<strong><\/strong>|<\/?smallcaps>|<\/?uppercase>)', re.IGNORECASE)
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hard_coded_bullets_re = re.compile(r'((?:<p>(?:%s).*?[a-zA-Z].*?</p>\s*)+)' % '|'.join([re.escape(x) for x in DOTS]), re.DOTALL)
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trailing_empty_content_re = re.compile(r'(?:<p>(?: |\s|<br \/>)*?</p>\s*)+\Z')
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del x # Temporary variable
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def escape(html):
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"Return the given HTML with ampersands, quotes and carets encoded."
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return force_unicode(html).replace('&', '&').replace('<', '<').replace('>', '>').replace('"', '"').replace("'", ''')
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escape = allow_lazy(escape, unicode)
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def linebreaks(value):
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"Convert newlines into <p> and <br />s."
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value = re.sub(r'\r\n|\r|\n', '\n', force_unicode(value)) # normalize newlines
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paras = re.split('\n{2,}', value)
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paras = [u'<p>%s</p>' % p.strip().replace('\n', '<br />') for p in paras]
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return u'\n\n'.join(paras)
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linebreaks = allow_lazy(linebreaks, unicode)
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def strip_tags(value):
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"Return the given HTML with all tags stripped."
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return re.sub(r'<[^>]*?>', '', force_unicode(value))
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strip_tags = allow_lazy(strip_tags)
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def strip_spaces_between_tags(value):
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"Return the given HTML with spaces between tags removed."
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return re.sub(r'>\s+<', '><', force_unicode(value))
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strip_spaces_between_tags = allow_lazy(strip_spaces_between_tags, unicode)
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def strip_entities(value):
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"Return the given HTML with all entities (&something;) stripped."
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return re.sub(r'&(?:\w+|#\d+);', '', force_unicode(value))
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strip_entities = allow_lazy(strip_entities, unicode)
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def fix_ampersands(value):
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"Return the given HTML with all unencoded ampersands encoded correctly."
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return unencoded_ampersands_re.sub('&', force_unicode(value))
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fix_ampersands = allow_lazy(fix_ampersands, unicode)
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def urlize(text, trim_url_limit=None, nofollow=False):
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"""
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Convert any URLs in text into clickable links.
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Works on http://, https://, and www. links. Links can have trailing
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punctuation (periods, commas, close-parens) and leading punctuation
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(opening parens) and it'll still do the right thing.
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If trim_url_limit is not None, the URLs in link text longer than this limit
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will truncated to trim_url_limit-3 characters and appended with an elipsis.
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If nofollow is True, the URLs in link text will get a rel="nofollow"
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attribute.
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"""
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trim_url = lambda x, limit=trim_url_limit: limit is not None and (len(x) > limit and ('%s...' % x[:max(0, limit - 3)])) or x
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words = word_split_re.split(force_unicode(text))
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nofollow_attr = nofollow and ' rel="nofollow"' or ''
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for i, word in enumerate(words):
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match = punctuation_re.match(word)
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if match:
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lead, middle, trail = match.groups()
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if middle.startswith('www.') or ('@' not in middle and not middle.startswith('http://') and \
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len(middle) > 0 and middle[0] in string.letters + string.digits and \
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(middle.endswith('.org') or middle.endswith('.net') or middle.endswith('.com'))):
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middle = '<a href="http://%s"%s>%s</a>' % (middle, nofollow_attr, trim_url(middle))
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if middle.startswith('http://') or middle.startswith('https://'):
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middle = '<a href="%s"%s>%s</a>' % (middle, nofollow_attr, trim_url(middle))
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if '@' in middle and not middle.startswith('www.') and not ':' in middle \
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and simple_email_re.match(middle):
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middle = '<a href="mailto:%s">%s</a>' % (middle, middle)
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if lead + middle + trail != word:
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words[i] = lead + middle + trail
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return u''.join(words)
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urlize = allow_lazy(urlize, unicode)
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def clean_html(text):
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"""
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Clean the given HTML. Specifically, do the following:
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* Convert <b> and <i> to <strong> and <em>.
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* Encode all ampersands correctly.
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* Remove all "target" attributes from <a> tags.
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* Remove extraneous HTML, such as presentational tags that open and
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immediately close and <br clear="all">.
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* Convert hard-coded bullets into HTML unordered lists.
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* Remove stuff like "<p> </p>", but only if it's at the
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bottom of the text.
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"""
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from django.utils.text import normalize_newlines
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text = normalize_newlines(force_unicode(text))
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text = re.sub(r'<(/?)\s*b\s*>', '<\\1strong>', text)
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text = re.sub(r'<(/?)\s*i\s*>', '<\\1em>', text)
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text = fix_ampersands(text)
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# Remove all target="" attributes from <a> tags.
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text = link_target_attribute_re.sub('\\1', text)
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# Trim stupid HTML such as <br clear="all">.
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text = html_gunk_re.sub('', text)
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# Convert hard-coded bullets into HTML unordered lists.
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def replace_p_tags(match):
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s = match.group().replace('</p>', '</li>')
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for d in DOTS:
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s = s.replace('<p>%s' % d, '<li>')
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return u'<ul>\n%s\n</ul>' % s
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text = hard_coded_bullets_re.sub(replace_p_tags, text)
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# Remove stuff like "<p> </p>", but only if it's at the bottom
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# of the text.
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text = trailing_empty_content_re.sub('', text)
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return text
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clean_html = allow_lazy(clean_html, unicode)
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