CODEWITHSUNDEEP
pythonhtml-parsing
ensnare
ensnare

Reputation: 42033

What's the fastest way to strip certain html tags in a Python string?

I'd like to strip all html / javascript except for:

<b></b>
<ul></ul>
<li></li>
<a></a>

Thanks.

Upvotes: 1

Views: 462

Answers (3)

s29
s29

Reputation: 2057

While I agree with Laurence, there are occasions where a quick and dirty 99% approach gets the job done without creating other problems.

Here's an example that demonstrates a regex based approach --

import re

CLEANBODY_RE = re.compile(r'<(/?)(.+?)>', re.M)

def _repl(match):
    tag = match.group(2).split(' ')[0]
    if tag == 'p':
        return '<%sp>' % match.group(1)
    elif tag in ('a', 'br', 'ul', 'li', 'b', 'strong', 'em', 'i'):
        return match.group(0)
    return u''

def cleanbody(html):
    return CLEANBODY_RE.sub(_repl, html)

Upvotes: 2

Laurence Gonsalves
Laurence Gonsalves

Reputation: 143154

Do you want a way that's fast or a way that's correct? A regex-based approach is unlikely to be correct and may open you up to XSS attacks.

You should use an HTML parser like Beautiful Soup or even htmllib.

Also, <a> can contain javascript: hrefs and there are also the various on* attributes which are javascript. You probably want to strip all of those out. In general, a whitelist approach is best: only keep attributes (and attribute values) you know are safe.

Upvotes: 4

Daniel
Daniel

Reputation: 126

Replace the elements you want to keep with a place holder value, then regex out any remaining <.*>, finally replace the placeholders with the corresponding html elements.

Upvotes: 0

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