yt-dlp/yt_dlp/parsing.py
2023-03-18 18:38:46 +01:00

366 lines
12 KiB
Python

import collections
import contextlib
import itertools
import re
from html.parser import HTMLParser
from .compat import compat_HTMLParseError
from .utils import orderedSet
def iter_find(string, sub: str):
size = len(sub)
idx = -size
while True:
idx = string.find(sub, idx + size)
if idx == -1:
return
yield idx
class HTMLCommentRanges:
"""computes the offsets of HTML comments
comments start with '<!--' and end with the first '-->' encountered
note: markers within quotes are not ignored
"""
def __init__(self, html):
self._range_iter = self.ranges(html)
self._range = next(self._range_iter, None)
self._last_offset = 0
@staticmethod
def ranges(string, sopen='<!--', sclose='-->'):
assert not (sopen.startswith(sclose) or sclose.startswith(sopen))
open_iter = iter_find(string, sopen)
close_len = len(sclose)
close_iter = (idx + close_len for idx in iter_find(string, sclose))
next_open = next(open_iter, None)
next_close = next(close_iter, None)
while True:
if next_open is None:
return
while next_close is not None and next_open > next_close:
next_close = next(close_iter, None)
yield slice(next_open, next_close)
if next_close is None:
return
while next_open is not None and next_open < next_close:
next_open = next(open_iter, None)
def __contains__(self, offset):
assert isinstance(offset, int)
assert offset >= self._last_offset, 'offset must be in increasing order'
self._last_offset = offset
while self._range and self._range.stop is not None and offset >= self._range.stop:
self._range = next(self._range_iter, None)
return not (self._range is None or offset < self._range.start)
class HTMLTagParser(HTMLParser):
"""HTML parser which returns found elements as instances of 'Tag'
when STRICT=True can raise compat_HTMLParseError() on malformed HTML elements
usage:
parser = HTMLTagParser()
for tag_obj in parser.taglist(html):
tag_obj.text_and_html()
"""
STRICT = False
ANY_TAG_REGEX = re.compile(r'''<(?:"[^"]*"|'[^']*'|[^"'>])*?>''')
VOID_TAGS = {
'area', 'base', 'br', 'col', 'embed', 'hr', 'img', 'input',
'keygen', 'link', 'meta', 'param', 'source', 'track', 'wbr',
}
class Tag:
__slots__ = 'name', 'string', 'attrs', '_openrange', '_closerange'
def __init__(self, name, *, string='', attrs=()):
self.name = name
self.string = string
self.attrs = tuple(attrs)
self._openrange = None
self._closerange = None
def __str__(self):
return self.name
def __repr__(self):
return f'{self.__class__.__name__}({str(self)!r})'
def __eq__(self, other):
return self.name == other
def openrange(self, offset, startlen=0):
if isinstance(offset, slice):
self._openrange = offset
else:
self._openrange = slice(offset, offset + startlen)
def closerange(self, offset, stoplen=0):
if isinstance(offset, slice):
self._closerange = offset
else:
self._closerange = slice(offset, offset + stoplen)
def opentag(self):
return self.string[self._openrange] if self._openrange else ''
def html(self):
if not self._openrange:
return ''
if self._closerange:
return self.string[self._openrange.start:self._closerange.stop]
return self.string[self._openrange]
def text(self):
if self._openrange and self._closerange:
return self.string[self._openrange.stop:self._closerange.start]
return ''
def text_and_html(self):
return self.text(), self.html()
class AbortException(Exception):
pass
def __init__(self):
self.tagstack = collections.deque()
self._nestedtags = [[]]
super().__init__()
self._offset = self.offset
def predicate(self, tag, attrs):
""" return True for every encountered opening tag that should be processed """
return True
def callback(self, tag_obj):
""" this will be called when the requested tag is closed """
def reset(self):
super().reset()
self.tagstack.clear()
def taglist(self, data, reset=True, depth_first=False):
""" parse data and return found tag objects
@param data: html string
@param reset: reset state
@param depth_first: return order: as opened (False), as closed (True), nested (None)
@return: list of Tag objects
"""
def flatten(_list, first=True):
rlist = _list if first or not depth_first else itertools.chain(_list[1:], _list[:1])
for item in rlist:
if isinstance(item, list):
yield from flatten(item, first=False)
else:
yield item
if reset:
self.reset()
with contextlib.suppress(HTMLTagParser.AbortException):
self.feed(data)
if self.STRICT and self.tagstack:
orphans = ', '.join(map(repr, map(str, orderedSet(self.tagstack, lazy=True))))
raise compat_HTMLParseError(f'unclosed tag {orphans}')
taglist = self._nestedtags[0] if depth_first is None else list(flatten(self._nestedtags[0]))
self._nestedtags = [[]]
return taglist
def updatepos(self, i, j):
offset = self._offset = super().updatepos(i, j)
return offset
def handle_starttag(self, tag, attrs):
try:
# we use internal variable for performance reasons
tag_text = getattr(self, '_HTMLParser__starttag_text')
except AttributeError:
tag_text = HTMLTagParser.ANY_TAG_REGEX.match(self.rawdata[self._offset:]).group()
tag_obj = tag
tag_is_open = not (tag_text.endswith('/>') or tag in self.VOID_TAGS)
if self.predicate(tag, attrs):
tag_obj = self.Tag(tag, string=self.rawdata, attrs=attrs)
tag_obj.openrange(self._offset, len(tag_text))
if tag_is_open:
nesting = [tag_obj]
self._nestedtags[-1].append(nesting)
self._nestedtags.append(nesting)
else:
self._nestedtags[-1].append(tag_obj)
self.callback(tag_obj)
if tag_is_open:
self.tagstack.appendleft(tag_obj)
handle_startendtag = handle_starttag
def handle_endtag(self, tag):
if '<' in tag:
if self.STRICT:
raise compat_HTMLParseError(f'malformed closing tag {tag!r}')
tag = tag[:tag.index('<')]
try:
idx = self.tagstack.index(tag)
if self.STRICT and idx:
open_tags = ''.join(f'</{tag}>' for tag in itertools.islice(self.tagstack, idx))
raise compat_HTMLParseError(
f'malnested closing tag {tag!r}, expected after {open_tags!r}')
tag_obj = self.tagstack[idx]
self.tagstack.remove(tag)
if isinstance(tag_obj, self.Tag):
close_idx = self.rawdata.find('>', self._offset) + 1
tag_obj.closerange(self._offset, close_idx - self._offset)
self._nestedtags.pop()
self.callback(tag_obj)
except ValueError as exc:
if isinstance(exc, compat_HTMLParseError):
raise
if self.STRICT:
raise compat_HTMLParseError(f'stray closing tag {tag!r}') from exc
class MatchingElementParser(HTMLTagParser):
""" optimized version of HTMLTagParser
"""
def __init__(self, matchfunc):
super().__init__()
self.matchfunc = matchfunc
self.found_none = True
def reset(self):
super().reset()
self.found_none = True
def callback(self, tag_obj):
raise self.AbortException()
def predicate(self, tag, attrs):
if self.found_none and self.matchfunc(tag, attrs):
self.found_none = False
return True
return False
@staticmethod
def class_value_regex(class_name):
return rf'[\w\s\-]*(?<![\w\-]){re.escape(class_name)}(?![\w\-])[\w\s\-]*'
@staticmethod
def matching_tag_regex(tag, attribute, value_regex, escape=True):
if isinstance(value_regex, re.Pattern):
value_regex = value_regex.pattern
elif escape:
value_regex = re.escape(value_regex)
return rf'''(?x)
<(?:{tag})
(?:\s(?:[^>"'\\]|"[^"\\]*"|'[^'\\]*')*)?
\s{re.escape(attribute)}\s*=\s*(?P<_q>['"])(?-x:{value_regex})(?P=_q)
'''
@classmethod
def iter_tags(cls, regex, html, *, matchfunc):
comments = HTMLCommentRanges(html)
parser = cls(matchfunc)
for match in re.finditer(regex, html):
if match.start() not in comments:
yield from parser.taglist(html[match.start():], reset=True)
@classmethod
def tags_by_name(cls, tag, html):
def matchfunc(tag_str, _attrs):
return tag_str == tag
tag_regex = rf'''<\s*{re.escape(tag)}(?:\s(?:[^>"'\\]|"[^"\\]*"|'[^'\\]*')*)?>'''
yield from cls.iter_tags(tag_regex, html, matchfunc=matchfunc)
@classmethod
def tags_by_attribute(cls, attribute, value, html, *, tag=r'[\w:.-]+', escape_value=True):
def matchfunc(_tag_str, attrs):
return any(attr == attribute and re.fullmatch(value, value_str)
for attr, value_str in attrs)
tag_regex = cls.matching_tag_regex(tag, attribute, value, escape_value)
yield from cls.iter_tags(tag_regex, html, matchfunc=matchfunc)
@classmethod
def extract_attributes(cls, html):
attr_dict = {}
def matchfunc(_tag, attrs):
attr_dict.update(attrs)
raise cls.AbortException()
with contextlib.suppress(cls.AbortException):
cls(matchfunc).feed(html)
return attr_dict
@classmethod
def get_elements_text_and_html_by_tag(cls, tag, html):
return [tag.text_and_html() for tag in cls.tags_by_name(tag, html)]
@classmethod
def get_element_text_and_html_by_tag(cls, tag, html):
tag = next(cls.tags_by_name(tag, html), None)
return tag and tag.text_and_html()
@classmethod
def get_elements_text_and_html_by_attribute(cls, *args, **kwargs):
return [tag.text_and_html() for tag in cls.tags_by_attribute(*args, **kwargs)]
@classmethod
def get_elements_by_attribute(cls, *args, **kwargs):
return [tag.text() for tag in cls.tags_by_attribute(*args, **kwargs)]
@classmethod
def get_elements_html_by_attribute(cls, *args, **kwargs):
return [tag.html() for tag in cls.tags_by_attribute(*args, **kwargs)]
@classmethod
def get_element_by_attribute(cls, *args, **kwargs):
tag = next(cls.tags_by_attribute(*args, **kwargs), None)
return tag and tag.text()
@classmethod
def get_element_html_by_attribute(cls, *args, **kwargs):
tag = next(cls.tags_by_attribute(*args, **kwargs), None)
return tag and tag.html()
@classmethod
def get_elements_by_class(cls, class_name, html):
value = cls.class_value_regex(class_name)
return [tag.text() for tag
in cls.tags_by_attribute('class', value, html, escape_value=False)]
@classmethod
def get_elements_html_by_class(cls, class_name, html):
value = cls.class_value_regex(class_name)
return [tag.html() for tag
in cls.tags_by_attribute('class', value, html, escape_value=False)]
@classmethod
def get_elements_text_and_html_by_class(cls, class_name, html):
value = cls.class_value_regex(class_name)
return [tag.text_and_html() for tag
in cls.tags_by_attribute('class', value, html, escape_value=False)]
@classmethod
def get_element_html_by_class(cls, class_name, html):
value = cls.class_value_regex(class_name)
tag = next(cls.tags_by_attribute('class', value, html, escape_value=False), None)
return tag and tag.html()
@classmethod
def get_element_by_class(cls, class_name, html):
value = cls.class_value_regex(class_name)
tag = next(cls.tags_by_attribute('class', value, html, escape_value=False), None)
return tag and tag.text()