app/django/utils/html.py
changeset 54 03e267d67478
child 323 ff1a9aa48cfd
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/utils/html.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,163 @@
+"""HTML utilities suitable for global use."""
+
+import re
+import string
+
+from django.utils.safestring import SafeData, mark_safe
+from django.utils.encoding import force_unicode
+from django.utils.functional import allow_lazy
+from django.utils.http import urlquote
+
+# Configuration for urlize() function.
+LEADING_PUNCTUATION  = ['(', '<', '&lt;']
+TRAILING_PUNCTUATION = ['.', ',', ')', '>', '\n', '&gt;']
+
+# List of possible strings used for bullets in bulleted lists.
+DOTS = ['&middot;', '*', '\xe2\x80\xa2', '&#149;', '&bull;', '&#8226;']
+
+unencoded_ampersands_re = re.compile(r'&(?!(\w+|#\d+);)')
+word_split_re = re.compile(r'(\s+)')
+punctuation_re = re.compile('^(?P<lead>(?:%s)*)(?P<middle>.*?)(?P<trail>(?:%s)*)$' % \
+    ('|'.join([re.escape(x) for x in LEADING_PUNCTUATION]),
+    '|'.join([re.escape(x) for x in TRAILING_PUNCTUATION])))
+simple_email_re = re.compile(r'^\S+@[a-zA-Z0-9._-]+\.[a-zA-Z0-9._-]+$')
+link_target_attribute_re = re.compile(r'(<a [^>]*?)target=[^\s>]+')
+html_gunk_re = re.compile(r'(?:<br clear="all">|<i><\/i>|<b><\/b>|<em><\/em>|<strong><\/strong>|<\/?smallcaps>|<\/?uppercase>)', re.IGNORECASE)
+hard_coded_bullets_re = re.compile(r'((?:<p>(?:%s).*?[a-zA-Z].*?</p>\s*)+)' % '|'.join([re.escape(x) for x in DOTS]), re.DOTALL)
+trailing_empty_content_re = re.compile(r'(?:<p>(?:&nbsp;|\s|<br \/>)*?</p>\s*)+\Z')
+del x # Temporary variable
+
+def escape(html):
+    """Returns the given HTML with ampersands, quotes and carets encoded."""
+    return mark_safe(force_unicode(html).replace('&', '&amp;').replace('<', '&lt;').replace('>', '&gt;').replace('"', '&quot;').replace("'", '&#39;'))
+escape = allow_lazy(escape, unicode)
+
+def conditional_escape(html):
+    """
+    Similar to escape(), except that it doesn't operate on pre-escaped strings.
+    """
+    if isinstance(html, SafeData):
+        return html
+    else:
+        return escape(html)
+
+def linebreaks(value, autoescape=False):
+    """Converts newlines into <p> and <br />s."""
+    value = re.sub(r'\r\n|\r|\n', '\n', force_unicode(value)) # normalize newlines
+    paras = re.split('\n{2,}', value)
+    if autoescape:
+        paras = [u'<p>%s</p>' % escape(p.strip()).replace('\n', '<br />') for p in paras]
+    else:
+        paras = [u'<p>%s</p>' % p.strip().replace('\n', '<br />') for p in paras]
+    return u'\n\n'.join(paras)
+linebreaks = allow_lazy(linebreaks, unicode)
+
+def strip_tags(value):
+    """Returns the given HTML with all tags stripped."""
+    return re.sub(r'<[^>]*?>', '', force_unicode(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_unicode(value))
+strip_spaces_between_tags = allow_lazy(strip_spaces_between_tags, unicode)
+
+def strip_entities(value):
+    """Returns the given HTML with all entities (&something;) stripped."""
+    return re.sub(r'&(?:\w+|#\d+);', '', force_unicode(value))
+strip_entities = allow_lazy(strip_entities, unicode)
+
+def fix_ampersands(value):
+    """Returns the given HTML with all unencoded ampersands encoded correctly."""
+    return unencoded_ampersands_re.sub('&amp;', force_unicode(value))
+fix_ampersands = allow_lazy(fix_ampersands, unicode)
+
+def urlize(text, trim_url_limit=None, nofollow=False, autoescape=False):
+    """
+    Converts any URLs in text into clickable links.
+
+    Works on http://, https://, and www. links.  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:
+        trim_url = lambda x, limit=trim_url_limit: conditional_escape(limit is not None and (len(x) > limit and ('%s...' % x[:max(0, limit - 3)])) or x)
+    else:
+        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_unicode(text))
+    nofollow_attr = nofollow and ' rel="nofollow"' or ''
+    for i, word in enumerate(words):
+        match = punctuation_re.match(word)
+        if match:
+            lead, middle, trail = match.groups()
+            if safe_input:
+                middle = mark_safe(middle)
+            if middle.startswith('www.') or ('@' not in middle and not middle.startswith('http://') and \
+                    len(middle) > 0 and middle[0] in string.ascii_letters + string.digits and \
+                    (middle.endswith('.org') or middle.endswith('.net') or middle.endswith('.com'))):
+                middle = 'http://%s' % middle
+            if middle.startswith('http://') or middle.startswith('https://'):
+                url = urlquote(middle, safe='/&=:;#?+*')
+                if autoescape and not safe_input:
+                    url = escape(url)
+                trimmed_url = trim_url(middle)
+                middle = '<a href="%s"%s>%s</a>' % (url, nofollow_attr,
+                        trimmed_url)
+            elif '@' in middle and not middle.startswith('www.') and \
+                      not ':' in middle and simple_email_re.match(middle):
+                if autoescape:
+                    middle = conditional_escape(middle)
+                middle = '<a href="mailto:%s">%s</a>' % (middle, middle)
+            if lead + middle + trail != word:
+                if autoescape and not safe_input:
+                    lead, trail = escape(lead), escape(trail)
+                words[i] = mark_safe('%s%s%s' % (lead, middle, trail))
+            elif autoescape and not safe_input:
+                words[i] = escape(word)
+        elif safe_input:
+            words[i] = mark_safe(word)
+        elif autoescape:
+            words[i] = escape(word)
+    return u''.join(words)
+urlize = allow_lazy(urlize, unicode)
+
+def clean_html(text):
+    """
+    Clean the given HTML.  Specifically, do the following:
+        * Convert <b> and <i> to <strong> and <em>.
+        * Encode all ampersands correctly.
+        * Remove all "target" attributes from <a> tags.
+        * Remove extraneous HTML, such as presentational tags that open and
+          immediately close and <br clear="all">.
+        * Convert hard-coded bullets into HTML unordered lists.
+        * Remove stuff like "<p>&nbsp;&nbsp;</p>", but only if it's at the
+          bottom of the text.
+    """
+    from django.utils.text import normalize_newlines
+    text = normalize_newlines(force_unicode(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 <a> tags.
+    text = link_target_attribute_re.sub('\\1', text)
+    # Trim stupid HTML such as <br clear="all">.
+    text = html_gunk_re.sub('', text)
+    # Convert hard-coded bullets into HTML unordered lists.
+    def replace_p_tags(match):
+        s = match.group().replace('</p>', '</li>')
+        for d in DOTS:
+            s = s.replace('<p>%s' % d, '<li>')
+        return u'<ul>\n%s\n</ul>' % s
+    text = hard_coded_bullets_re.sub(replace_p_tags, text)
+    # Remove stuff like "<p>&nbsp;&nbsp;</p>", 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, unicode)