Convert HTML entities to Unicode and vice versa

As to the "vice versa" (which I needed myself, leading me to find this question, which didn't help, and subsequently another site which had the answer):

u'some string'.encode('ascii', 'xmlcharrefreplace')

will return a plain string with any non-ascii characters turned into XML (HTML) entities.

You need to have BeautifulSoup.

from BeautifulSoup import BeautifulStoneSoup
import cgi

def HTMLEntitiesToUnicode(text):
    """Converts HTML entities to unicode.  For example '&' becomes '&'."""
    text = unicode(BeautifulStoneSoup(text, convertEntities=BeautifulStoneSoup.ALL_ENTITIES))
    return text

def unicodeToHTMLEntities(text):
    """Converts unicode to HTML entities.  For example '&' becomes '&'."""
    text = cgi.escape(text).encode('ascii', 'xmlcharrefreplace')
    return text

text = "&, ®, <, >, ¢, £, ¥, €, §, ©"

uni = HTMLEntitiesToUnicode(text)
htmlent = unicodeToHTMLEntities(uni)

print uni
print htmlent
# &, ®, <, >, ¢, £, ¥, €, §, ©
# &amp;, &#174;, &lt;, &gt;, &#162;, &#163;, &#165;, &#8364;, &#167;, &#169;

Update for Python 2.7 and BeautifulSoup4

Unescape -- Unicode HTML to unicode with htmlparser (Python 2.7 standard lib):

>>> escaped = u'Monsieur le Curé of the «Notre-Dame-de-Grâce» neighborhood'
>>> from HTMLParser import HTMLParser
>>> htmlparser = HTMLParser()
>>> unescaped = htmlparser.unescape(escaped)
>>> unescaped
u'Monsieur le Cur\xe9 of the \xabNotre-Dame-de-Gr\xe2ce\xbb neighborhood'
>>> print unescaped
Monsieur le Curé of the «Notre-Dame-de-Grâce» neighborhood

Unescape -- Unicode HTML to unicode with bs4 (BeautifulSoup4):

>>> html = '''<p>Monsieur le Cur&eacute; of the &laquo;Notre-Dame-de-Gr&acirc;ce&raquo; neighborhood</p>'''
>>> from bs4 import BeautifulSoup
>>> soup = BeautifulSoup(html)
>>> soup.text
u'Monsieur le Cur\xe9 of the \xabNotre-Dame-de-Gr\xe2ce\xbb neighborhood'
>>> print soup.text
Monsieur le Curé of the «Notre-Dame-de-Grâce» neighborhood

Escape -- Unicode to unicode HTML with bs4 (BeautifulSoup4):

>>> unescaped = u'Monsieur le Curé of the «Notre-Dame-de-Grâce» neighborhood'
>>> from bs4.dammit import EntitySubstitution
>>> escaper = EntitySubstitution()
>>> escaped = escaper.substitute_html(unescaped)
>>> escaped
u'Monsieur le Curé of the «Notre-Dame-de-Grâce» neighborhood'