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.

As hekevintran answer suggests, you may use cgi.escape(s) for encoding stings, but notice that encoding of quote is false by default in that function and it may be a good idea to pass the quote=True keyword argument alongside your string. But even by passing quote=True, the function won’t escape single quotes ("'") (Because of these issues the function has been deprecated since version 3.2)

It’s been suggested to use html.escape(s) instead of cgi.escape(s). (New in version 3.2)

Also html.unescape(s) has been introduced in version 3.4.

So in python 3.4 you can:

• Use html.escape(text).encode('ascii', 'xmlcharrefreplace').decode() to convert special characters to HTML entities.
• And html.unescape(text) for converting HTML entities back to plain-text representations.

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 Curxe9 of the xabNotre-Dame-de-Grxe2cexbb 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 Curxe9 of the xabNotre-Dame-de-Grxe2cexbb 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'

I used the following function to convert unicode ripped from an xls file into a an html file while conserving the special characters found in the xls file:

def html_wr(f, dat):
    ''' write dat to file f as html
        . file is assumed to be opened in binary format
        . if dat is nul it is replaced with non breakable space
        . non-ascii characters are translated to xml       
    '''
    if not dat:
        dat = ' '
    try:
        f.write(dat.encode('ascii'))
    except:
        f.write(html.escape(dat).encode('ascii', 'xmlcharrefreplace'))

hope this is useful to somebody

If someone like me is out there wondering why some entity numbers (codes) like ™ (for trademark symbol), € (for euro symbol) are not encoded properly, the reason is in ISO-8859-1 (aka Windows-1252) those characters are not defined.

Also note that, the default character set as of html5 is utf-8 it was ISO-8859-1 for html4

So, we will have to workaround somehow (find & replace those at first)

Reference (starting point) from Mozilla’s documentation

https://developer.mozilla.org/en-US/docs/Web/Guide/Localizations_and_character_encodings

$ python3 -c "
> import html
> print(
>     html.unescape('&©—')
> )"
&©—

$ python3 -c "
> import html
> print(
>     html.escape('&©—')
> )"
&©—

$ python2 -c "
> from HTMLParser import HTMLParser
> print(
>     HTMLParser().unescape('&©—')
> )"
&©—

$ python2 -c "
> import cgi
> print(
>     cgi.escape('&©—')
> )"
&©—

HTML only strictly requires & (ampersand) and < (left angle bracket / less-than sign) to be escaped. https://html.spec.whatwg.org/multipage/parsing.html#data-state

#!/usr/bin/env python3
import fileinput
import html

for line in fileinput.input():
    print(html.unescape(line.rstrip('n')))

For python3 use html.unescape():

import html
s = "&"
decoded = html.unescape(s)
# &