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# -*- coding: utf-8 -*-
from html.parser import HTMLParser
try:
from html.parser import HTMLParseError
except ImportError:
# HTMLParseError was removed in Python 3.5. It could never be
# thrown, so we define a placeholder instead.
class HTMLParseError(Exception):
pass
from html.entities import name2codepoint
import sys
import re
import cgi
# Normalization code, adapted from
# https://github.com/karlcow/markdown-testsuite/
significant_attrs = ["alt", "href", "src", "title"]
whitespace_re = re.compile('\s+')
class MyHTMLParser(HTMLParser):
def __init__(self):
HTMLParser.__init__(self)
self.last = "starttag"
self.in_pre = False
self.output = ""
self.last_tag = ""
def handle_data(self, data):
after_tag = self.last == "endtag" or self.last == "starttag"
after_block_tag = after_tag and self.is_block_tag(self.last_tag)
if after_tag and self.last_tag == "br":
data = data.lstrip('\n')
if not self.in_pre:
data = whitespace_re.sub(' ', data)
if after_block_tag and not self.in_pre:
if self.last == "starttag":
data = data.lstrip()
elif self.last == "endtag":
data = data.strip()
self.output += data
self.last = "data"
def handle_endtag(self, tag):
if tag == "pre":
self.in_pre = False
elif self.is_block_tag(tag):
self.output = self.output.rstrip()
self.output += "</" + tag + ">"
self.last_tag = tag
self.last = "endtag"
def handle_starttag(self, tag, attrs):
if tag == "pre":
self.in_pre = True
if self.is_block_tag(tag):
self.output = self.output.rstrip()
self.output += "<" + tag
# For now we don't strip out 'extra' attributes, because of
# raw HTML test cases.
# attrs = filter(lambda attr: attr[0] in significant_attrs, attrs)
if attrs:
attrs.sort()
for (k,v) in attrs:
self.output += " " + k
if v != None:
self.output += ("=" + '"' + cgi.escape(v,quote=True) + '"')
self.output += ">"
self.last_tag = tag
self.last = "starttag"
def handle_startendtag(self, tag, attrs):
"""Ignore closing tag for self-closing """
self.handle_starttag(tag, attrs)
self.last_tag = tag
self.last = "endtag"
def handle_comment(self, data):
self.output += '<!--' + data + '-->'
self.last = "comment"
def handle_decl(self, data):
self.output += '<!' + data + '>'
self.last = "decl"
def unknown_decl(self, data):
self.output += '<!' + data + '>'
self.last = "decl"
def handle_pi(self,data):
self.output += '<?' + data + '>'
self.last = "pi"
def handle_entityref(self, name):
try:
c = chr(name2codepoint[name])
except KeyError:
c = None
self.output_char(c, '&' + name + ';')
self.last = "ref"
def handle_charref(self, name):
try:
if name.startswith("x"):
c = chr(int(name[1:], 16))
else:
c = chr(int(name))
except ValueError:
c = None
self.output_char(c, '&' + name + ';')
self.last = "ref"
# Helpers.
def output_char(self, c, fallback):
if c == '<':
self.output += "<"
elif c == '>':
self.output += ">"
elif c == '&':
self.output += "&"
elif c == '"':
self.output += """
elif c == None:
self.output += fallback
else:
self.output += c
def is_block_tag(self,tag):
return (tag in ['article', 'header', 'aside', 'hgroup', 'blockquote',
'hr', 'iframe', 'body', 'li', 'map', 'button', 'object', 'canvas',
'ol', 'caption', 'output', 'col', 'p', 'colgroup', 'pre', 'dd',
'progress', 'div', 'section', 'dl', 'table', 'td', 'dt',
'tbody', 'embed', 'textarea', 'fieldset', 'tfoot', 'figcaption',
'th', 'figure', 'thead', 'footer', 'tr', 'form', 'ul',
'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'video', 'script', 'style'])
def normalize_html(html):
r"""
Return normalized form of HTML which ignores insignificant output
differences:
Multiple inner whitespaces are collapsed to a single space (except
in pre tags):
>>> normalize_html("<p>a \t b</p>")
'<p>a b</p>'
>>> normalize_html("<p>a \t\nb</p>")
'<p>a b</p>'
* Whitespace surrounding block-level tags is removed.
>>> normalize_html("<p>a b</p>")
'<p>a b</p>'
>>> normalize_html(" <p>a b</p>")
'<p>a b</p>'
>>> normalize_html("<p>a b</p> ")
'<p>a b</p>'
>>> normalize_html("\n\t<p>\n\t\ta b\t\t</p>\n\t")
'<p>a b</p>'
>>> normalize_html("<i>a b</i> ")
'<i>a b</i> '
* Self-closing tags are converted to open tags.
>>> normalize_html("<br />")
'<br>'
* Attributes are sorted and lowercased.
>>> normalize_html('<a title="bar" HREF="foo">x</a>')
'<a href="foo" title="bar">x</a>'
* References are converted to unicode, except that '<', '>', '&', and
'"' are rendered using entities.
>>> normalize_html("∀&><"")
'\u2200&><"'
"""
html_chunk_re = re.compile("(\<!\[CDATA\[.*?\]\]\>|\<[^>]*\>|[^<]+)")
try:
parser = MyHTMLParser()
# We work around HTMLParser's limitations parsing CDATA
# by breaking the input into chunks and passing CDATA chunks
# through verbatim.
for chunk in re.finditer(html_chunk_re, html):
if chunk.group(0)[:8] == "<