"""HTML utilities suitable for global use.""" from __future__ import unicode_literals import re import string try: from urllib.parse import quote, urlsplit, urlunsplit except ImportError: # Python 2 from urllib import quote from urlparse import urlsplit, urlunsplit from django.utils.safestring import SafeData, mark_safe from django.utils.encoding import smart_bytes, force_text from django.utils.functional import allow_lazy from django.utils import six from django.utils.text import normalize_newlines # Configuration for urlize() function. TRAILING_PUNCTUATION = ['.', ',', ':', ';', '.)'] WRAPPING_PUNCTUATION = [('(', ')'), ('<', '>'), ('<', '>')] # List of possible strings used for bullets in bulleted lists. DOTS = ['·', '*', '\u2022', '•', '•', '•'] unencoded_ampersands_re = re.compile(r'&(?!(\w+|#\d+);)') unquoted_percents_re = re.compile(r'%(?![0-9A-Fa-f]{2})') word_split_re = re.compile(r'(\s+)') simple_url_re = re.compile(r'^https?://\w', re.IGNORECASE) simple_url_2_re = re.compile(r'^www\.|^(?!http)\w[^@]+\.(com|edu|gov|int|mil|net|org)$', re.IGNORECASE) simple_email_re = re.compile(r'^\S+@\S+\.\S+$') link_target_attribute_re = re.compile(r'(]*?)target=[^\s>]+') html_gunk_re = re.compile(r'(?:
|<\/i>|<\/b>|<\/em>|<\/strong>|<\/?smallcaps>|<\/?uppercase>)', re.IGNORECASE) hard_coded_bullets_re = re.compile(r'((?:

(?:%s).*?[a-zA-Z].*?

\s*)+)' % '|'.join([re.escape(x) for x in DOTS]), re.DOTALL) trailing_empty_content_re = re.compile(r'(?:

(?: |\s|
)*?

\s*)+\Z') def escape(text): """ Returns the given text with ampersands, quotes and angle brackets encoded for use in HTML. """ return mark_safe(force_text(text).replace('&', '&').replace('<', '<').replace('>', '>').replace('"', '"').replace("'", ''')) escape = allow_lazy(escape, six.text_type) _base_js_escapes = ( ('\\', '\\u005C'), ('\'', '\\u0027'), ('"', '\\u0022'), ('>', '\\u003E'), ('<', '\\u003C'), ('&', '\\u0026'), ('=', '\\u003D'), ('-', '\\u002D'), (';', '\\u003B'), ('\u2028', '\\u2028'), ('\u2029', '\\u2029') ) # Escape every ASCII character with a value less than 32. _js_escapes = (_base_js_escapes + tuple([('%c' % z, '\\u%04X' % z) for z in range(32)])) def escapejs(value): """Hex encodes characters for use in JavaScript strings.""" for bad, good in _js_escapes: value = mark_safe(force_text(value).replace(bad, good)) return value escapejs = allow_lazy(escapejs, six.text_type) def conditional_escape(text): """ Similar to escape(), except that it doesn't operate on pre-escaped strings. """ if isinstance(text, SafeData): return text else: return escape(text) def format_html(format_string, *args, **kwargs): """ Similar to str.format, but passes all arguments through conditional_escape, and calls 'mark_safe' on the result. This function should be used instead of str.format or % interpolation to build up small HTML fragments. """ args_safe = map(conditional_escape, args) kwargs_safe = dict([(k, conditional_escape(v)) for (k, v) in six.iteritems(kwargs)]) return mark_safe(format_string.format(*args_safe, **kwargs_safe)) def format_html_join(sep, format_string, args_generator): """ A wrapper format_html, for the common case of a group of arguments that need to be formatted using the same format string, and then joined using 'sep'. 'sep' is also passed through conditional_escape. 'args_generator' should be an iterator that returns the sequence of 'args' that will be passed to format_html. Example: format_html_join('\n', "
  • {0} {1}
  • ", ((u.first_name, u.last_name) for u in users)) """ return mark_safe(conditional_escape(sep).join( format_html(format_string, *tuple(args)) for args in args_generator)) def linebreaks(value, autoescape=False): """Converts newlines into

    and
    s.""" value = normalize_newlines(value) paras = re.split('\n{2,}', value) if autoescape: paras = ['

    %s

    ' % escape(p).replace('\n', '
    ') for p in paras] else: paras = ['

    %s

    ' % p.replace('\n', '
    ') for p in paras] return '\n\n'.join(paras) linebreaks = allow_lazy(linebreaks, six.text_type) def strip_tags(value): """Returns the given HTML with all tags stripped.""" return re.sub(r'<[^>]*?>', '', force_text(value)) strip_tags = allow_lazy(strip_tags) def strip_spaces_between_tags(value): """Returns the given HTML with spaces between tags removed.""" return re.sub(r'>\s+<', '><', force_text(value)) strip_spaces_between_tags = allow_lazy(strip_spaces_between_tags, six.text_type) def strip_entities(value): """Returns the given HTML with all entities (&something;) stripped.""" return re.sub(r'&(?:\w+|#\d+);', '', force_text(value)) strip_entities = allow_lazy(strip_entities, six.text_type) def fix_ampersands(value): """Returns the given HTML with all unencoded ampersands encoded correctly.""" return unencoded_ampersands_re.sub('&', force_text(value)) fix_ampersands = allow_lazy(fix_ampersands, six.text_type) def smart_urlquote(url): "Quotes a URL if it isn't already quoted." # Handle IDN before quoting. scheme, netloc, path, query, fragment = urlsplit(url) try: netloc = netloc.encode('idna') # IDN -> ACE except UnicodeError: # invalid domain part pass else: url = urlunsplit((scheme, netloc, path, query, fragment)) # An URL is considered unquoted if it contains no % characters or # contains a % not followed by two hexadecimal digits. See #9655. if '%' not in url or unquoted_percents_re.search(url): # See http://bugs.python.org/issue2637 url = quote(smart_bytes(url), safe=b'!*\'();:@&=+$,/?#[]~') return force_text(url) def urlize(text, trim_url_limit=None, nofollow=False, autoescape=False): """ Converts any URLs in text into clickable links. Works on http://, https://, www. links, and also on links ending in one of the original seven gTLDs (.com, .edu, .gov, .int, .mil, .net, and .org). Links can have trailing punctuation (periods, commas, close-parens) and leading punctuation (opening parens) and it'll still do the right thing. If trim_url_limit is not None, the URLs in link text longer than this limit will truncated to trim_url_limit-3 characters and appended with an elipsis. If nofollow is True, the URLs in link text will get a rel="nofollow" attribute. If autoescape is True, the link text and URLs will get autoescaped. """ 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 safe_input = isinstance(text, SafeData) words = word_split_re.split(force_text(text)) for i, word in enumerate(words): match = None if '.' in word or '@' in word or ':' in word: # Deal with punctuation. lead, middle, trail = '', word, '' for punctuation in TRAILING_PUNCTUATION: if middle.endswith(punctuation): middle = middle[:-len(punctuation)] trail = punctuation + trail for opening, closing in WRAPPING_PUNCTUATION: if middle.startswith(opening): middle = middle[len(opening):] lead = lead + opening # Keep parentheses at the end only if they're balanced. if (middle.endswith(closing) and middle.count(closing) == middle.count(opening) + 1): middle = middle[:-len(closing)] trail = closing + trail # Make URL we want to point to. url = None nofollow_attr = ' rel="nofollow"' if nofollow else '' if simple_url_re.match(middle): url = smart_urlquote(middle) elif simple_url_2_re.match(middle): url = smart_urlquote('http://%s' % middle) elif not ':' in middle and simple_email_re.match(middle): local, domain = middle.rsplit('@', 1) try: domain = domain.encode('idna') except UnicodeError: continue url = 'mailto:%s@%s' % (local, domain) nofollow_attr = '' # Make link. if url: trimmed = trim_url(middle) if autoescape and not safe_input: lead, trail = escape(lead), escape(trail) url, trimmed = escape(url), escape(trimmed) middle = '
    %s' % (url, nofollow_attr, trimmed) words[i] = mark_safe('%s%s%s' % (lead, middle, trail)) else: if safe_input: words[i] = mark_safe(word) elif autoescape: words[i] = escape(word) elif safe_input: words[i] = mark_safe(word) elif autoescape: words[i] = escape(word) return ''.join(words) urlize = allow_lazy(urlize, six.text_type) def clean_html(text): """ Clean the given HTML. Specifically, do the following: * Convert and to and . * Encode all ampersands correctly. * Remove all "target" attributes from tags. * Remove extraneous HTML, such as presentational tags that open and immediately close and
    . * Convert hard-coded bullets into HTML unordered lists. * Remove stuff like "

      

    ", but only if it's at the bottom of the text. """ from django.utils.text import normalize_newlines text = normalize_newlines(force_text(text)) text = re.sub(r'<(/?)\s*b\s*>', '<\\1strong>', text) text = re.sub(r'<(/?)\s*i\s*>', '<\\1em>', text) text = fix_ampersands(text) # Remove all target="" attributes from
    tags. text = link_target_attribute_re.sub('\\1', text) # Trim stupid HTML such as
    . text = html_gunk_re.sub('', text) # Convert hard-coded bullets into HTML unordered lists. def replace_p_tags(match): s = match.group().replace('

    ', '') for d in DOTS: s = s.replace('

    %s' % d, '

  • ') return '
      \n%s\n
    ' % s text = hard_coded_bullets_re.sub(replace_p_tags, text) # Remove stuff like "

      

    ", but only if it's at the bottom # of the text. text = trailing_empty_content_re.sub('', text) return text clean_html = allow_lazy(clean_html, six.text_type)