Strip HTML from strings in Python

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from mechanize import Browser
br = Browser()
br.open(\'http://somewebpage\')
html = br.response().readlines()
for line in html:
  print line

When p

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26条回答

北海茫月

2020-11-22 02:55

I needed a way to strip tags and decode HTML entities to plain text. The following solution is based on Eloff's answer (which I couldn't use because it strips entities).

from HTMLParser import HTMLParser
import htmlentitydefs

class HTMLTextExtractor(HTMLParser):
    def __init__(self):
        HTMLParser.__init__(self)
        self.result = [ ]

    def handle_data(self, d):
        self.result.append(d)

    def handle_charref(self, number):
        codepoint = int(number[1:], 16) if number[0] in (u'x', u'X') else int(number)
        self.result.append(unichr(codepoint))

    def handle_entityref(self, name):
        codepoint = htmlentitydefs.name2codepoint[name]
        self.result.append(unichr(codepoint))

    def get_text(self):
        return u''.join(self.result)

def html_to_text(html):
    s = HTMLTextExtractor()
    s.feed(html)
    return s.get_text()

A quick test:

html = u'<a href="#">Demo <em>(&not; \u0394&#x03b7;&#956;&#x03CE;)</em></a>'
print repr(html_to_text(html))

Result:

u'Demo (\xac \u0394\u03b7\u03bc\u03ce)'

Error handling:

Invalid HTML structure may cause an HTMLParseError.
Invalid named HTML entities (such as &#apos;, which is valid in XML and XHTML, but not plain HTML) will cause a ValueError exception.
Numeric HTML entities specifying code points outside the Unicode range acceptable by Python (such as, on some systems, characters outside the Basic Multilingual Plane) will cause a ValueError exception.

Security note: Do not confuse HTML stripping (converting HTML into plain text) with HTML sanitizing (converting plain text into HTML). This answer will remove HTML and decode entities into plain text – that does not make the result safe to use in a HTML context.

Example: <script>alert("Hello");</script> will be converted to <script>alert("Hello");</script>, which is 100% correct behavior, but obviously not sufficient if the resulting plain text is inserted as-is into a HTML page.

The rule is not hard: Any time you insert a plain-text string into HTML output, you should always HTML escape it (using cgi.escape(s, True)), even if you "know" that it doesn't contain HTML (e.g. because you stripped HTML content).

(However, the OP asked about printing the result to the console, in which case no HTML escaping is needed.)

Python 3.4+ version: (with doctest!)

import html.parser

class HTMLTextExtractor(html.parser.HTMLParser):
    def __init__(self):
        super(HTMLTextExtractor, self).__init__()
        self.result = [ ]

    def handle_data(self, d):
        self.result.append(d)

    def get_text(self):
        return ''.join(self.result)

def html_to_text(html):
    """Converts HTML to plain text (stripping tags and converting entities).
    >>> html_to_text('<a href="#">Demo<!--...--> <em>(&not; \u0394&#x03b7;&#956;&#x03CE;)</em></a>')
    'Demo (\xac \u0394\u03b7\u03bc\u03ce)'

    "Plain text" doesn't mean result can safely be used as-is in HTML.
    >>> html_to_text('&lt;script&gt;alert("Hello");&lt;/script&gt;')
    '<script>alert("Hello");</script>'

    Always use html.escape to sanitize text before using in an HTML context!

    HTMLParser will do its best to make sense of invalid HTML.
    >>> html_to_text('x < y &lt z <!--b')
    'x < y < z '

    Unrecognized named entities are included as-is. '&apos;' is recognized,
    despite being XML only.
    >>> html_to_text('&nosuchentity; &apos; ')
    "&nosuchentity; ' "
    """
    s = HTMLTextExtractor()
    s.feed(html)
    return s.get_text()

Note that HTMLParser has improved in Python 3 (meaning less code and better error handling).

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独厮守ぢ

2020-11-22 02:55

I'm parsing Github readmes and I find that the following really works well:

import re
import lxml.html

def strip_markdown(x):
    links_sub = re.sub(r'\[(.+)\]\([^\)]+\)', r'\1', x)
    bold_sub = re.sub(r'\*\*([^*]+)\*\*', r'\1', links_sub)
    emph_sub = re.sub(r'\*([^*]+)\*', r'\1', bold_sub)
    return emph_sub

def strip_html(x):
    return lxml.html.fromstring(x).text_content() if x else ''

And then

readme = """<img src="https://raw.githubusercontent.com/kootenpv/sky/master/resources/skylogo.png" />

            sky is a web scraping framework, implemented with the latest python versions in mind (3.4+). 
            It uses the asynchronous `asyncio` framework, as well as many popular modules 
            and extensions.

            Most importantly, it aims for **next generation** web crawling where machine intelligence 
            is used to speed up the development/maintainance/reliability of crawling.

            It mainly does this by considering the user to be interested in content 
            from *domains*, not just a collection of *single pages*
            ([templating approach](#templating-approach))."""

strip_markdown(strip_html(readme))

Removes all markdown and html correctly.

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盖世英雄少女心

2020-11-22 02:57

For one project, I needed so strip HTML, but also css and js. Thus, I made a variation of Eloffs answer:

class MLStripper(HTMLParser):
    def __init__(self):
        self.reset()
        self.strict = False
        self.convert_charrefs= True
        self.fed = []
        self.css = False
    def handle_starttag(self, tag, attrs):
        if tag == "style" or tag=="script":
            self.css = True
    def handle_endtag(self, tag):
        if tag=="style" or tag=="script":
            self.css=False
    def handle_data(self, d):
        if not self.css:
            self.fed.append(d)
    def get_data(self):
        return ''.join(self.fed)

def strip_tags(html):
    s = MLStripper()
    s.feed(html)
    return s.get_data()

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小鲜肉

2020-11-22 02:57

2020 Update

Use the Mozilla Bleach library, it really lets you customize which tags to keep and which attributes to keep and also filter out attributes based on values

Here are 2 cases to illustrate

1) Do not allow any HTML tags or attributes

Take sample raw text

raw_text = """
<p><img width="696" height="392" src="https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-768x432.jpg" class="attachment-medium_large size-medium_large wp-post-image" alt="Ethereum Classic 51% Attack: Okex Crypto Exchange Suffers $5.6 Million Loss, Contemplates Delisting ETC" style="float:left; margin:0 15px 15px 0;" srcset="https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-768x432.jpg 768w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-300x169.jpg 300w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-1024x576.jpg 1024w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-696x392.jpg 696w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-1068x601.jpg 1068w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-747x420.jpg 747w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-190x107.jpg 190w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-380x214.jpg 380w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-760x428.jpg 760w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc.jpg 1280w" sizes="(max-width: 696px) 100vw, 696px" />Cryptocurrency exchange Okex reveals it suffered the $5.6 million loss as a result of the double-spend carried out by the attacker(s) in Ethereum Classic 51% attack. Okex says it fully absorbed the loss as per its user-protection policy while insisting that the attack did not cause any loss to the platform&#8217;s users. Also as part [&#8230;]</p>
<p>The post <a rel="nofollow" href="https://news.bitcoin.com/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc/">Ethereum Classic 51% Attack: Okex Crypto Exchange Suffers $5.6 Million Loss, Contemplates Delisting ETC</a> appeared first on <a rel="nofollow" href="https://news.bitcoin.com">Bitcoin News</a>.</p> 
"""

2) Remove all HTML tags and attributes from raw text

# DO NOT ALLOW any tags or any attributes
from bleach.sanitizer import Cleaner
cleaner = Cleaner(tags=[], attributes={}, styles=[], protocols=[], strip=True, strip_comments=True, filters=None)
print(cleaner.clean(raw_text))

Output

Cryptocurrency exchange Okex reveals it suffered the $5.6 million loss as a result of the double-spend carried out by the attacker(s) in Ethereum Classic 51% attack. Okex says it fully absorbed the loss as per its user-protection policy while insisting that the attack did not cause any loss to the platform&#8217;s users. Also as part [&#8230;]
The post Ethereum Classic 51% Attack: Okex Crypto Exchange Suffers $5.6 Million Loss, Contemplates Delisting ETC appeared first on Bitcoin News.

3 Allow Only img tag with srcset attribute

from bleach.sanitizer import Cleaner
# ALLOW ONLY img tags with src attribute
cleaner = Cleaner(tags=['img'], attributes={'img': ['srcset']}, styles=[], protocols=[], strip=True, strip_comments=True, filters=None)
print(cleaner.clean(raw_text))

Output

<img srcset="https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-768x432.jpg 768w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-300x169.jpg 300w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-1024x576.jpg 1024w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-696x392.jpg 696w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-1068x601.jpg 1068w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-747x420.jpg 747w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-190x107.jpg 190w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-380x214.jpg 380w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc-760x428.jpg 760w, https://news.bitcoin.com/wp-content/uploads/2020/08/ethereum-classic-51-attack-okex-crypto-exchange-suffers-5-6-million-loss-contemplates-delisting-etc.jpg 1280w">Cryptocurrency exchange Okex reveals it suffered the $5.6 million loss as a result of the double-spend carried out by the attacker(s) in Ethereum Classic 51% attack. Okex says it fully absorbed the loss as per its user-protection policy while insisting that the attack did not cause any loss to the platform&#8217;s users. Also as part [&#8230;]
The post Ethereum Classic 51% Attack: Okex Crypto Exchange Suffers $5.6 Million Loss, Contemplates Delisting ETC appeared first on Bitcoin News.

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隐瞒了意图╮

2020-11-22 03:02

The solutions with HTML-Parser are all breakable, if they run only once:

html_to_text('<<b>script>alert("hacked")<</b>/script>

results in:

<script>alert("hacked")</script>

what you intend to prevent. if you use a HTML-Parser, count the Tags until zero are replaced:

from HTMLParser import HTMLParser

class MLStripper(HTMLParser):
    def __init__(self):
        self.reset()
        self.fed = []
        self.containstags = False

    def handle_starttag(self, tag, attrs):
       self.containstags = True

    def handle_data(self, d):
        self.fed.append(d)

    def has_tags(self):
        return self.containstags

    def get_data(self):
        return ''.join(self.fed)

def strip_tags(html):
    must_filtered = True
    while ( must_filtered ):
        s = MLStripper()
        s.feed(html)
        html = s.get_data()
        must_filtered = s.has_tags()
    return html

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再見小時候

2020-11-22 03:02

Using BeautifulSoup, html2text or the code from @Eloff, most of the time, it remains some html elements, javascript code...

So you can use a combination of these libraries and delete markdown formatting (Python 3):

import re
import html2text
from bs4 import BeautifulSoup
def html2Text(html):
    def removeMarkdown(text):
        for current in ["^[ #*]{2,30}", "^[ ]{0,30}\d\\\.", "^[ ]{0,30}\d\."]:
            markdown = re.compile(current, flags=re.MULTILINE)
            text = markdown.sub(" ", text)
        return text
    def removeAngular(text):
        angular = re.compile("[{][|].{2,40}[|][}]|[{][*].{2,40}[*][}]|[{][{].{2,40}[}][}]|\[\[.{2,40}\]\]")
        text = angular.sub(" ", text)
        return text
    h = html2text.HTML2Text()
    h.images_to_alt = True
    h.ignore_links = True
    h.ignore_emphasis = False
    h.skip_internal_links = True
    text = h.handle(html)
    soup = BeautifulSoup(text, "html.parser")
    text = soup.text
    text = removeAngular(text)
    text = removeMarkdown(text)
    return text

It works well for me but it can be enhanced, of course...

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