Remove HTML tags not on an allowed list from a Python string

Solution 1:

Use lxml.html.clean! It's VERY easy!

from lxml.html.clean import clean_html
print clean_html(html)

Suppose the following html:

html = '''\
<html>
 <head>
   <script type="text/javascript" src="evil-site"></script>
   <link rel="alternate" type="text/rss" src="evil-rss">
   <style>
     body {background-image: url(javascript:do_evil)};
     div {color: expression(evil)};
   </style>
 </head>
 <body onload="evil_function()">
    <!-- I am interpreted for EVIL! -->
   <a href="javascript:evil_function()">a link</a>
   <a href="#" onclick="evil_function()">another link</a>
   <p onclick="evil_function()">a paragraph</p>
   <div style="display: none">secret EVIL!</div>
   <object> of EVIL! </object>
   <iframe src="evil-site"></iframe>
   <form action="evil-site">
     Password: <input type="password" name="password">
   </form>
   <blink>annoying EVIL!</blink>
   <a href="evil-site">spam spam SPAM!</a>
   <image src="evil!">
 </body>
</html>'''

The results...

<html>
  <body>
    <div>
      <style>/* deleted */</style>
      <a href="">a link</a>
      <a href="#">another link</a>
      <p>a paragraph</p>
      <div>secret EVIL!</div>
      of EVIL!
      Password:
      annoying EVIL!
      <a href="evil-site">spam spam SPAM!</a>
      <img src="evil!">
    </div>
  </body>
</html>

You can customize the elements you want to clean and whatnot.

Solution 2:

Here's a simple solution using BeautifulSoup:

from bs4 import BeautifulSoup

VALID_TAGS = ['strong', 'em', 'p', 'ul', 'li', 'br']

def sanitize_html(value):

    soup = BeautifulSoup(value)

    for tag in soup.findAll(True):
        if tag.name not in VALID_TAGS:
            tag.hidden = True

    return soup.renderContents()

If you want to remove the contents of the invalid tags as well, substitute tag.extract() for tag.hidden.

You might also look into using lxml and Tidy.

Remove HTML tags not on an allowed list from a Python string

Solution 1:

Solution 2:

Related

Recent Posts