python check html valid

Question

How can I check the validity of HTML code with Python?

I need closed tags check, and braces in tags params. Such as |a href="xxx'| and other possible validations, which libs I can use for this?

score 3 · Accepted Answer · answered Sep 05 '10 at 16:33

Well, this isn't exactly what you're looking for, but to validate the HTML for a web site I work on, I ask the W3C Validator to check it for me, and I just screen scrape the output to get the basic yes/no result. Note there are several validation services on the web as alternatives, but W3C works well enough for me.

#!/usr/bin/python2.6
import re
import urllib
import urllib2

def validate(URL):
    validatorURL = "http://validator.w3.org/check?uri=" + \
        urllib.quote_plus(URL)
    opener = urllib2.urlopen(validatorURL)
    output = opener.read()
    opener.close()
    if re.search("This document was successfully checked as".replace(
            " ", r"\s+"), output):
        print "    VALID: ", URL
    else:
        print "INVALID: ", URL

https://stackoverflow.com/a/10519634/2729778 is a similar but cleaner answer. — Changaco, Mar 27 '20 at 08:41

score 2 · Answer 2 · answered Mar 27 '20 at 12:46

The html5lib module can be used to perform basic HTML validation:

>>> import html5lib
>>> html5parser = html5lib.HTMLParser(strict=True)
>>> html5parser.parse('<html></html>')
Traceback (most recent call last):
  ...
html5lib.html5parser.ParseError: Unexpected start tag (html). Expected DOCTYPE.
>>> html5parser.parseFragment('<p>Lorem <a href="/foobar">ipsum</a>')
<Element 'DOCUMENT_FRAGMENT' at 0x7f1d4a58fd60>
>>> html5parser.parseFragment('<p>Lorem </a>ipsum<a href="/foobar">')
Traceback (most recent call last):
  ...
html5lib.html5parser.ParseError: Unexpected end tag (a). Ignored.
>>> html5parser.parseFragment('<p><form></form></p>')
Traceback (most recent call last):
  ...
html5lib.html5parser.ParseError: Unexpected end tag (p). Ignored.
>>> html5parser.parseFragment('<option value="example" />')
Traceback (most recent call last):
  ...
html5lib.html5parser.ParseError: Trailing solidus not allowed on element option

This seems not to catch the following invalid HTML: `html5parser.parseFragment('
')`. — Garrett, Aug 18 '20 at 16:02

python check html valid

2 Answers2

Linked