You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
440 lines
16 KiB
Python
440 lines
16 KiB
Python
5 years ago
|
# encoding: utf-8
|
||
|
|
"""Use the HTMLParser library to parse HTML files that aren't too bad."""
|
||
|
|
|
||
|
|
# Use of this source code is governed by the MIT license.
|
||
|
|
__license__ = "MIT"
|
||
|
|
|
||
|
|
__all__ = [
|
||
|
|
'HTMLParserTreeBuilder',
|
||
|
|
]
|
||
|
|
|
||
|
|
from html.parser import HTMLParser
|
||
|
|
|
||
|
|
try:
|
||
|
|
from html.parser import HTMLParseError
|
||
|
|
except ImportError as e:
|
||
|
|
# HTMLParseError is removed in Python 3.5. Since it can never be
|
||
|
|
# thrown in 3.5, we can just define our own class as a placeholder.
|
||
|
|
class HTMLParseError(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
import sys
|
||
|
|
import warnings
|
||
|
|
|
||
|
|
# Starting in Python 3.2, the HTMLParser constructor takes a 'strict'
|
||
|
|
# argument, which we'd like to set to False. Unfortunately,
|
||
|
|
# http://bugs.python.org/issue13273 makes strict=True a better bet
|
||
|
|
# before Python 3.2.3.
|
||
|
|
#
|
||
|
|
# At the end of this file, we monkeypatch HTMLParser so that
|
||
|
|
# strict=True works well on Python 3.2.2.
|
||
|
|
major, minor, release = sys.version_info[:3]
|
||
|
|
CONSTRUCTOR_TAKES_STRICT = major == 3 and minor == 2 and release >= 3
|
||
|
|
CONSTRUCTOR_STRICT_IS_DEPRECATED = major == 3 and minor == 3
|
||
|
|
CONSTRUCTOR_TAKES_CONVERT_CHARREFS = major == 3 and minor >= 4
|
||
|
|
|
||
|
|
|
||
|
|
from bs4.element import (
|
||
|
|
CData,
|
||
|
|
Comment,
|
||
|
|
Declaration,
|
||
|
|
Doctype,
|
||
|
|
ProcessingInstruction,
|
||
|
|
)
|
||
|
|
from bs4.dammit import EntitySubstitution, UnicodeDammit
|
||
|
|
|
||
|
|
from bs4.builder import (
|
||
|
|
HTML,
|
||
|
|
HTMLTreeBuilder,
|
||
|
|
STRICT,
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
HTMLPARSER = 'html.parser'
|
||
|
|
|
||
|
|
class BeautifulSoupHTMLParser(HTMLParser):
|
||
|
|
"""A subclass of the Python standard library's HTMLParser class, which
|
||
|
|
listens for HTMLParser events and translates them into calls
|
||
|
|
to Beautiful Soup's tree construction API.
|
||
|
|
"""
|
||
|
|
|
||
|
|
def __init__(self, *args, **kwargs):
|
||
|
|
HTMLParser.__init__(self, *args, **kwargs)
|
||
|
|
|
||
|
|
# Keep a list of empty-element tags that were encountered
|
||
|
|
# without an explicit closing tag. If we encounter a closing tag
|
||
|
|
# of this type, we'll associate it with one of those entries.
|
||
|
|
#
|
||
|
|
# This isn't a stack because we don't care about the
|
||
|
|
# order. It's a list of closing tags we've already handled and
|
||
|
|
# will ignore, assuming they ever show up.
|
||
|
|
self.already_closed_empty_element = []
|
||
|
|
|
||
|
|
def error(self, msg):
|
||
|
|
"""In Python 3, HTMLParser subclasses must implement error(), although
|
||
|
|
this requirement doesn't appear to be documented.
|
||
|
|
|
||
|
|
In Python 2, HTMLParser implements error() by raising an exception,
|
||
|
|
which we don't want to do.
|
||
|
|
|
||
|
|
In any event, this method is called only on very strange
|
||
|
|
markup and our best strategy is to pretend it didn't happen
|
||
|
|
and keep going.
|
||
|
|
"""
|
||
|
|
warnings.warn(msg)
|
||
|
|
|
||
|
|
def handle_startendtag(self, name, attrs):
|
||
|
|
"""Handle an incoming empty-element tag.
|
||
|
|
|
||
|
|
This is only called when the markup looks like <tag/>.
|
||
|
|
|
||
|
|
:param name: Name of the tag.
|
||
|
|
:param attrs: Dictionary of the tag's attributes.
|
||
|
|
"""
|
||
|
|
# is_startend() tells handle_starttag not to close the tag
|
||
|
|
# just because its name matches a known empty-element tag. We
|
||
|
|
# know that this is an empty-element tag and we want to call
|
||
|
|
# handle_endtag ourselves.
|
||
|
|
tag = self.handle_starttag(name, attrs, handle_empty_element=False)
|
||
|
|
self.handle_endtag(name)
|
||
|
|
|
||
|
|
def handle_starttag(self, name, attrs, handle_empty_element=True):
|
||
|
|
"""Handle an opening tag, e.g. '<tag>'
|
||
|
|
|
||
|
|
:param name: Name of the tag.
|
||
|
|
:param attrs: Dictionary of the tag's attributes.
|
||
|
|
:param handle_empty_element: True if this tag is known to be
|
||
|
|
an empty-element tag (i.e. there is not expected to be any
|
||
|
|
closing tag).
|
||
|
|
"""
|
||
|
|
# XXX namespace
|
||
|
|
attr_dict = {}
|
||
|
|
for key, value in attrs:
|
||
|
|
# Change None attribute values to the empty string
|
||
|
|
# for consistency with the other tree builders.
|
||
|
|
if value is None:
|
||
|
|
value = ''
|
||
|
|
attr_dict[key] = value
|
||
|
|
attrvalue = '""'
|
||
|
|
#print "START", name
|
||
|
|
sourceline, sourcepos = self.getpos()
|
||
|
|
tag = self.soup.handle_starttag(
|
||
|
|
name, None, None, attr_dict, sourceline=sourceline,
|
||
|
|
sourcepos=sourcepos
|
||
|
|
)
|
||
|
|
if tag and tag.is_empty_element and handle_empty_element:
|
||
|
|
# Unlike other parsers, html.parser doesn't send separate end tag
|
||
|
|
# events for empty-element tags. (It's handled in
|
||
|
|
# handle_startendtag, but only if the original markup looked like
|
||
|
|
# <tag/>.)
|
||
|
|
#
|
||
|
|
# So we need to call handle_endtag() ourselves. Since we
|
||
|
|
# know the start event is identical to the end event, we
|
||
|
|
# don't want handle_endtag() to cross off any previous end
|
||
|
|
# events for tags of this name.
|
||
|
|
self.handle_endtag(name, check_already_closed=False)
|
||
|
|
|
||
|
|
# But we might encounter an explicit closing tag for this tag
|
||
|
|
# later on. If so, we want to ignore it.
|
||
|
|
self.already_closed_empty_element.append(name)
|
||
|
|
|
||
|
|
def handle_endtag(self, name, check_already_closed=True):
|
||
|
|
"""Handle a closing tag, e.g. '</tag>'
|
||
|
|
|
||
|
|
:param name: A tag name.
|
||
|
|
:param check_already_closed: True if this tag is expected to
|
||
|
|
be the closing portion of an empty-element tag,
|
||
|
|
e.g. '<tag></tag>'.
|
||
|
|
"""
|
||
|
|
#print "END", name
|
||
|
|
if check_already_closed and name in self.already_closed_empty_element:
|
||
|
|
# This is a redundant end tag for an empty-element tag.
|
||
|
|
# We've already called handle_endtag() for it, so just
|
||
|
|
# check it off the list.
|
||
|
|
# print "ALREADY CLOSED", name
|
||
|
|
self.already_closed_empty_element.remove(name)
|
||
|
|
else:
|
||
|
|
self.soup.handle_endtag(name)
|
||
|
|
|
||
|
|
def handle_data(self, data):
|
||
|
|
"""Handle some textual data that shows up between tags."""
|
||
|
|
self.soup.handle_data(data)
|
||
|
|
|
||
|
|
def handle_charref(self, name):
|
||
|
|
"""Handle a numeric character reference by converting it to the
|
||
|
|
corresponding Unicode character and treating it as textual
|
||
|
|
data.
|
||
|
|
|
||
|
|
:param name: Character number, possibly in hexadecimal.
|
||
|
|
"""
|
||
|
|
# XXX workaround for a bug in HTMLParser. Remove this once
|
||
|
|
# it's fixed in all supported versions.
|
||
|
|
# http://bugs.python.org/issue13633
|
||
|
|
if name.startswith('x'):
|
||
|
|
real_name = int(name.lstrip('x'), 16)
|
||
|
|
elif name.startswith('X'):
|
||
|
|
real_name = int(name.lstrip('X'), 16)
|
||
|
|
else:
|
||
|
|
real_name = int(name)
|
||
|
|
|
||
|
|
data = None
|
||
|
|
if real_name < 256:
|
||
|
|
# HTML numeric entities are supposed to reference Unicode
|
||
|
|
# code points, but sometimes they reference code points in
|
||
|
|
# some other encoding (ahem, Windows-1252). E.g. “
|
||
|
|
# instead of É for LEFT DOUBLE QUOTATION MARK. This
|
||
|
|
# code tries to detect this situation and compensate.
|
||
|
|
for encoding in (self.soup.original_encoding, 'windows-1252'):
|
||
|
|
if not encoding:
|
||
|
|
continue
|
||
|
|
try:
|
||
|
|
data = bytearray([real_name]).decode(encoding)
|
||
|
|
except UnicodeDecodeError as e:
|
||
|
|
pass
|
||
|
|
if not data:
|
||
|
|
try:
|
||
|
|
data = chr(real_name)
|
||
|
|
except (ValueError, OverflowError) as e:
|
||
|
|
pass
|
||
|
|
data = data or "\N{REPLACEMENT CHARACTER}"
|
||
|
|
self.handle_data(data)
|
||
|
|
|
||
|
|
def handle_entityref(self, name):
|
||
|
|
"""Handle a named entity reference by converting it to the
|
||
|
|
corresponding Unicode character and treating it as textual
|
||
|
|
data.
|
||
|
|
|
||
|
|
:param name: Name of the entity reference.
|
||
|
|
"""
|
||
|
|
character = EntitySubstitution.HTML_ENTITY_TO_CHARACTER.get(name)
|
||
|
|
if character is not None:
|
||
|
|
data = character
|
||
|
|
else:
|
||
|
|
# If this were XML, it would be ambiguous whether "&foo"
|
||
|
|
# was an character entity reference with a missing
|
||
|
|
# semicolon or the literal string "&foo". Since this is
|
||
|
|
# HTML, we have a complete list of all character entity references,
|
||
|
|
# and this one wasn't found, so assume it's the literal string "&foo".
|
||
|
|
data = "&%s" % name
|
||
|
|
self.handle_data(data)
|
||
|
|
|
||
|
|
def handle_comment(self, data):
|
||
|
|
"""Handle an HTML comment.
|
||
|
|
|
||
|
|
:param data: The text of the comment.
|
||
|
|
"""
|
||
|
|
self.soup.endData()
|
||
|
|
self.soup.handle_data(data)
|
||
|
|
self.soup.endData(Comment)
|
||
|
|
|
||
|
|
def handle_decl(self, data):
|
||
|
|
"""Handle a DOCTYPE declaration.
|
||
|
|
|
||
|
|
:param data: The text of the declaration.
|
||
|
|
"""
|
||
|
|
self.soup.endData()
|
||
|
|
data = data[len("DOCTYPE "):]
|
||
|
|
self.soup.handle_data(data)
|
||
|
|
self.soup.endData(Doctype)
|
||
|
|
|
||
|
|
def unknown_decl(self, data):
|
||
|
|
"""Handle a declaration of unknown type -- probably a CDATA block.
|
||
|
|
|
||
|
|
:param data: The text of the declaration.
|
||
|
|
"""
|
||
|
|
if data.upper().startswith('CDATA['):
|
||
|
|
cls = CData
|
||
|
|
data = data[len('CDATA['):]
|
||
|
|
else:
|
||
|
|
cls = Declaration
|
||
|
|
self.soup.endData()
|
||
|
|
self.soup.handle_data(data)
|
||
|
|
self.soup.endData(cls)
|
||
|
|
|
||
|
|
def handle_pi(self, data):
|
||
|
|
"""Handle a processing instruction.
|
||
|
|
|
||
|
|
:param data: The text of the instruction.
|
||
|
|
"""
|
||
|
|
self.soup.endData()
|
||
|
|
self.soup.handle_data(data)
|
||
|
|
self.soup.endData(ProcessingInstruction)
|
||
|
|
|
||
|
|
|
||
|
|
class HTMLParserTreeBuilder(HTMLTreeBuilder):
|
||
|
|
"""A Beautiful soup `TreeBuilder` that uses the `HTMLParser` parser,
|
||
|
|
found in the Python standard library.
|
||
|
|
"""
|
||
|
|
is_xml = False
|
||
|
|
picklable = True
|
||
|
|
NAME = HTMLPARSER
|
||
|
|
features = [NAME, HTML, STRICT]
|
||
|
|
|
||
|
|
# The html.parser knows which line number and position in the
|
||
|
|
# original file is the source of an element.
|
||
|
|
TRACKS_LINE_NUMBERS = True
|
||
|
|
|
||
|
|
def __init__(self, parser_args=None, parser_kwargs=None, **kwargs):
|
||
|
|
"""Constructor.
|
||
|
|
|
||
|
|
:param parser_args: Positional arguments to pass into
|
||
|
|
the BeautifulSoupHTMLParser constructor, once it's
|
||
|
|
invoked.
|
||
|
|
:param parser_kwargs: Keyword arguments to pass into
|
||
|
|
the BeautifulSoupHTMLParser constructor, once it's
|
||
|
|
invoked.
|
||
|
|
:param kwargs: Keyword arguments for the superclass constructor.
|
||
|
|
"""
|
||
|
|
super(HTMLParserTreeBuilder, self).__init__(**kwargs)
|
||
|
|
parser_args = parser_args or []
|
||
|
|
parser_kwargs = parser_kwargs or {}
|
||
|
|
if CONSTRUCTOR_TAKES_STRICT and not CONSTRUCTOR_STRICT_IS_DEPRECATED:
|
||
|
|
parser_kwargs['strict'] = False
|
||
|
|
if CONSTRUCTOR_TAKES_CONVERT_CHARREFS:
|
||
|
|
parser_kwargs['convert_charrefs'] = False
|
||
|
|
self.parser_args = (parser_args, parser_kwargs)
|
||
|
|
|
||
|
|
def prepare_markup(self, markup, user_specified_encoding=None,
|
||
|
|
document_declared_encoding=None, exclude_encodings=None):
|
||
|
|
|
||
|
|
"""Run any preliminary steps necessary to make incoming markup
|
||
|
|
acceptable to the parser.
|
||
|
|
|
||
|
|
:param markup: Some markup -- probably a bytestring.
|
||
|
|
:param user_specified_encoding: The user asked to try this encoding.
|
||
|
|
:param document_declared_encoding: The markup itself claims to be
|
||
|
|
in this encoding.
|
||
|
|
:param exclude_encodings: The user asked _not_ to try any of
|
||
|
|
these encodings.
|
||
|
|
|
||
|
|
:yield: A series of 4-tuples:
|
||
|
|
(markup, encoding, declared encoding,
|
||
|
|
has undergone character replacement)
|
||
|
|
|
||
|
|
Each 4-tuple represents a strategy for converting the
|
||
|
|
document to Unicode and parsing it. Each strategy will be tried
|
||
|
|
in turn.
|
||
|
|
"""
|
||
|
|
if isinstance(markup, str):
|
||
|
|
# Parse Unicode as-is.
|
||
|
|
yield (markup, None, None, False)
|
||
|
|
return
|
||
|
|
|
||
|
|
# Ask UnicodeDammit to sniff the most likely encoding.
|
||
|
|
try_encodings = [user_specified_encoding, document_declared_encoding]
|
||
|
|
dammit = UnicodeDammit(markup, try_encodings, is_html=True,
|
||
|
|
exclude_encodings=exclude_encodings)
|
||
|
|
yield (dammit.markup, dammit.original_encoding,
|
||
|
|
dammit.declared_html_encoding,
|
||
|
|
dammit.contains_replacement_characters)
|
||
|
|
|
||
|
|
def feed(self, markup):
|
||
|
|
"""Run some incoming markup through some parsing process,
|
||
|
|
populating the `BeautifulSoup` object in self.soup.
|
||
|
|
"""
|
||
|
|
args, kwargs = self.parser_args
|
||
|
|
parser = BeautifulSoupHTMLParser(*args, **kwargs)
|
||
|
|
parser.soup = self.soup
|
||
|
|
try:
|
||
|
|
parser.feed(markup)
|
||
|
|
parser.close()
|
||
|
|
except HTMLParseError as e:
|
||
|
|
warnings.warn(RuntimeWarning(
|
||
|
|
"Python's built-in HTMLParser cannot parse the given document. This is not a bug in Beautiful Soup. The best solution is to install an external parser (lxml or html5lib), and use Beautiful Soup with that parser. See http://www.crummy.com/software/BeautifulSoup/bs4/doc/#installing-a-parser for help."))
|
||
|
|
raise e
|
||
|
|
parser.already_closed_empty_element = []
|
||
|
|
|
||
|
|
# Patch 3.2 versions of HTMLParser earlier than 3.2.3 to use some
|
||
|
|
# 3.2.3 code. This ensures they don't treat markup like <p></p> as a
|
||
|
|
# string.
|
||
|
|
#
|
||
|
|
# XXX This code can be removed once most Python 3 users are on 3.2.3.
|
||
|
|
if major == 3 and minor == 2 and not CONSTRUCTOR_TAKES_STRICT:
|
||
|
|
import re
|
||
|
|
attrfind_tolerant = re.compile(
|
||
|
|
r'\s*((?<=[\'"\s])[^\s/>][^\s/=>]*)(\s*=+\s*'
|
||
|
|
r'(\'[^\']*\'|"[^"]*"|(?![\'"])[^>\s]*))?')
|
||
|
|
HTMLParserTreeBuilder.attrfind_tolerant = attrfind_tolerant
|
||
|
|
|
||
|
|
locatestarttagend = re.compile(r"""
|
||
|
|
<[a-zA-Z][-.a-zA-Z0-9:_]* # tag name
|
||
|
|
(?:\s+ # whitespace before attribute name
|
||
|
|
(?:[a-zA-Z_][-.:a-zA-Z0-9_]* # attribute name
|
||
|
|
(?:\s*=\s* # value indicator
|
||
|
|
(?:'[^']*' # LITA-enclosed value
|
||
|
|
|\"[^\"]*\" # LIT-enclosed value
|
||
|
|
|[^'\">\s]+ # bare value
|
||
|
|
)
|
||
|
|
)?
|
||
|
|
)
|
||
|
|
)*
|
||
|
|
\s* # trailing whitespace
|
||
|
|
""", re.VERBOSE)
|
||
|
|
BeautifulSoupHTMLParser.locatestarttagend = locatestarttagend
|
||
|
|
|
||
|
|
from html.parser import tagfind, attrfind
|
||
|
|
|
||
|
|
def parse_starttag(self, i):
|
||
|
|
self.__starttag_text = None
|
||
|
|
endpos = self.check_for_whole_start_tag(i)
|
||
|
|
if endpos < 0:
|
||
|
|
return endpos
|
||
|
|
rawdata = self.rawdata
|
||
|
|
self.__starttag_text = rawdata[i:endpos]
|
||
|
|
|
||
|
|
# Now parse the data between i+1 and j into a tag and attrs
|
||
|
|
attrs = []
|
||
|
|
match = tagfind.match(rawdata, i+1)
|
||
|
|
assert match, 'unexpected call to parse_starttag()'
|
||
|
|
k = match.end()
|
||
|
|
self.lasttag = tag = rawdata[i+1:k].lower()
|
||
|
|
while k < endpos:
|
||
|
|
if self.strict:
|
||
|
|
m = attrfind.match(rawdata, k)
|
||
|
|
else:
|
||
|
|
m = attrfind_tolerant.match(rawdata, k)
|
||
|
|
if not m:
|
||
|
|
break
|
||
|
|
attrname, rest, attrvalue = m.group(1, 2, 3)
|
||
|
|
if not rest:
|
||
|
|
attrvalue = None
|
||
|
|
elif attrvalue[:1] == '\'' == attrvalue[-1:] or \
|
||
|
|
attrvalue[:1] == '"' == attrvalue[-1:]:
|
||
|
|
attrvalue = attrvalue[1:-1]
|
||
|
|
if attrvalue:
|
||
|
|
attrvalue = self.unescape(attrvalue)
|
||
|
|
attrs.append((attrname.lower(), attrvalue))
|
||
|
|
k = m.end()
|
||
|
|
|
||
|
|
end = rawdata[k:endpos].strip()
|
||
|
|
if end not in (">", "/>"):
|
||
|
|
lineno, offset = self.getpos()
|
||
|
|
if "\n" in self.__starttag_text:
|
||
|
|
lineno = lineno + self.__starttag_text.count("\n")
|
||
|
|
offset = len(self.__starttag_text) \
|
||
|
|
- self.__starttag_text.rfind("\n")
|
||
|
|
else:
|
||
|
|
offset = offset + len(self.__starttag_text)
|
||
|
|
if self.strict:
|
||
|
|
self.error("junk characters in start tag: %r"
|
||
|
|
% (rawdata[k:endpos][:20],))
|
||
|
|
self.handle_data(rawdata[i:endpos])
|
||
|
|
return endpos
|
||
|
|
if end.endswith('/>'):
|
||
|
|
# XHTML-style empty tag: <span attr="value" />
|
||
|
|
self.handle_startendtag(tag, attrs)
|
||
|
|
else:
|
||
|
|
self.handle_starttag(tag, attrs)
|
||
|
|
if tag in self.CDATA_CONTENT_ELEMENTS:
|
||
|
|
self.set_cdata_mode(tag)
|
||
|
|
return endpos
|
||
|
|
|
||
|
|
def set_cdata_mode(self, elem):
|
||
|
|
self.cdata_elem = elem.lower()
|
||
|
|
self.interesting = re.compile(r'</\s*%s\s*>' % self.cdata_elem, re.I)
|
||
|
|
|
||
|
|
BeautifulSoupHTMLParser.parse_starttag = parse_starttag
|
||
|
|
BeautifulSoupHTMLParser.set_cdata_mode = set_cdata_mode
|
||
|
|
|
||
|
|
CONSTRUCTOR_TAKES_STRICT = True
|