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Copy pathgoogler
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executable file
·3858 lines (3275 loc) · 133 KB
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#!/usr/bin/env python3
#
# Copyright © 2008 Henri Hakkinen
# Copyright © 2015-2021 Arun Prakash Jana <engineerarun@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import argparse
import atexit
import base64
import collections
import codecs
import functools
import gzip
import html.entities
import html.parser
import http.client
from http.client import HTTPSConnection
import locale
import logging
import os
import platform
import shutil
import signal
import socket
import ssl
import subprocess
from subprocess import Popen, PIPE, DEVNULL
import sys
import textwrap
import unicodedata
import urllib.parse
import uuid
import webbrowser
# Python optional dependency compatibility layer
try:
import readline
except ImportError:
pass
try:
import setproctitle
setproctitle.setproctitle('googler')
except (ImportError, Exception):
pass
from typing import (
Any,
Dict,
Generator,
Iterable,
Iterator,
List,
Match,
Optional,
Sequence,
Tuple,
Union,
cast,
)
# Basic setup
logging.basicConfig(format='[%(levelname)s] %(message)s')
logger = logging.getLogger()
def sigint_handler(signum, frame):
print('\nInterrupted.', file=sys.stderr)
sys.exit(1)
try:
signal.signal(signal.SIGINT, sigint_handler)
except ValueError:
# signal only works in main thread
pass
# Constants
_VERSION_ = '4.3.2'
_EPOCH_ = '20210115'
COLORMAP = {k: '\x1b[%sm' % v for k, v in {
'a': '30', 'b': '31', 'c': '32', 'd': '33',
'e': '34', 'f': '35', 'g': '36', 'h': '37',
'i': '90', 'j': '91', 'k': '92', 'l': '93',
'm': '94', 'n': '95', 'o': '96', 'p': '97',
'A': '30;1', 'B': '31;1', 'C': '32;1', 'D': '33;1',
'E': '34;1', 'F': '35;1', 'G': '36;1', 'H': '37;1',
'I': '90;1', 'J': '91;1', 'K': '92;1', 'L': '93;1',
'M': '94;1', 'N': '95;1', 'O': '96;1', 'P': '97;1',
'x': '0', 'X': '1', 'y': '7', 'Y': '7;1',
}.items()}
USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36'
text_browsers = ['elinks', 'links', 'lynx', 'w3m', 'www-browser']
# Self-upgrade parameters
#
# Downstream packagers are recommended to turn off the entire self-upgrade
# mechanism through
#
# make disable-self-upgrade
#
# before running `make install'.
ENABLE_SELF_UPGRADE_MECHANISM = True
API_REPO_BASE = 'https://api.github.com/repos/jarun/googler'
RAW_DOWNLOAD_REPO_BASE = 'https://raw.githubusercontent.com/jarun/googler'
debugger = False
# Monkeypatch textwrap for CJK wide characters.
def monkeypatch_textwrap_for_cjk():
try:
if textwrap.wrap.patched:
return
except AttributeError:
pass
psl_textwrap_wrap = textwrap.wrap
def textwrap_wrap(text, width=70, **kwargs):
if width <= 2:
width = 2
# We first add a U+0000 after each East Asian Fullwidth or East
# Asian Wide character, then fill to width - 1 (so that if a NUL
# character ends up on a new line, we still have one last column
# to spare for the preceding wide character). Finally we strip
# all the NUL characters.
#
# East Asian Width: https://www.unicode.org/reports/tr11/
return [
line.replace('\0', '')
for line in psl_textwrap_wrap(
''.join(
ch + '\0' if unicodedata.east_asian_width(ch) in ('F', 'W') else ch
for ch in unicodedata.normalize('NFC', text)
),
width=width - 1,
**kwargs
)
]
def textwrap_fill(text, width=70, **kwargs):
return '\n'.join(textwrap_wrap(text, width=width, **kwargs))
textwrap.wrap = textwrap_wrap
textwrap.fill = textwrap_fill
textwrap.wrap.patched = True
textwrap.fill.patched = True
monkeypatch_textwrap_for_cjk()
CoordinateType = Tuple[int, int]
class TrackedTextwrap:
"""
Implements a text wrapper that tracks the position of each source
character, and can correctly insert zero-width sequences at given
offsets of the source text.
Wrapping result should be the same as that from PSL textwrap.wrap
with default settings except expand_tabs=False.
"""
def __init__(self, text: str, width: int):
self._original = text
# Do the job of replace_whitespace first so that we can easily
# match text to wrapped lines later. Note that this operation
# does not change text length or offsets.
whitespace = "\t\n\v\f\r "
whitespace_trans = str.maketrans(whitespace, " " * len(whitespace))
text = text.translate(whitespace_trans)
self._lines = textwrap.wrap(
text, width, expand_tabs=False, replace_whitespace=False
)
# self._coords track the (row, column) coordinate of each source
# character in the result text. It is indexed by offset in
# source text.
self._coords = [] # type: List[CoordinateType]
offset = 0
try:
if not self._lines:
# Source text only has whitespaces. We add an empty line
# in order to produce meaningful coordinates.
self._lines = [""]
for row, line in enumerate(self._lines):
assert text[offset : offset + len(line)] == line
col = 0
for _ in line:
self._coords.append((row, col))
offset += 1
col += 1
# All subsequent dropped whitespaces map to the last, imaginary column
# (the EOL character if you wish) of the current line.
while offset < len(text) and text[offset] == " ":
self._coords.append((row, col))
offset += 1
# One past the final character (think of it as EOF) should
# be treated as a valid offset.
self._coords.append((row, col))
except AssertionError:
raise RuntimeError(
"TrackedTextwrap: the impossible happened at offset {} of text {!r}".format(
offset, self._original
)
)
# seq should be a zero-width sequence, e.g., an ANSI escape sequence.
# May raise IndexError if offset is out of bounds.
def insert_zero_width_sequence(self, seq: str, offset: int) -> None:
row, col = self._coords[offset]
line = self._lines[row]
self._lines[row] = line[:col] + seq + line[col:]
# Shift coordinates of all characters after the given character
# on the same line.
shift = len(seq)
offset += 1
while offset < len(self._coords) and self._coords[offset][0] == row:
_, col = self._coords[offset]
self._coords[offset] = (row, col + shift)
offset += 1
@property
def original(self) -> str:
return self._original
@property
def lines(self) -> List[str]:
return self._lines
@property
def wrapped(self) -> str:
return "\n".join(self._lines)
# May raise IndexError if offset is out of bounds.
def get_coordinate(self, offset: int) -> CoordinateType:
return self._coords[offset]
### begin dim (DOM implementation with CSS support) ###
### https://github.com/zmwangx/dim/blob/master/dim.py ###
import html
import re
from collections import OrderedDict
from enum import Enum
from html.parser import HTMLParser
SelectorGroupLike = Union[str, "SelectorGroup", "Selector"]
class Node(object):
"""
Represents a DOM node.
Parts of JavaScript's DOM ``Node`` API and ``Element`` API are
mirrored here, with extensions. In particular, ``querySelector`` and
``querySelectorAll`` are mirrored.
Notable properties and methods: :meth:`attr()`, :attr:`classes`,
:attr:`html`, :attr:`text`, :meth:`ancestors()`,
:meth:`descendants()`, :meth:`select()`, :meth:`select_all()`,
:meth:`matched_by()`,
Attributes:
tag (:class:`Optional`\\[:class:`str`])
attrs (:class:`Dict`\\[:class:`str`, :class:`str`])
parent (:class:`Optional`\\[:class:`Node`])
children (:class:`List`\\[:class:`Node`])
"""
# Meant to be reimplemented by subclasses.
def __init__(self) -> None:
self.tag = None # type: Optional[str]
self.attrs = {} # type: Dict[str, str]
self.parent = None # type: Optional[Node]
self.children = [] # type: List[Node]
# Used in DOMBuilder.
self._partial = False
self._namespace = None # type: Optional[str]
# HTML representation of the node. Meant to be implemented by
# subclasses.
def __str__(self) -> str: # pragma: no cover
raise NotImplementedError
def select(self, selector: SelectorGroupLike) -> Optional["Node"]:
"""DOM ``querySelector`` clone. Returns one match (if any)."""
selector = self._normalize_selector(selector)
for node in self._select_all(selector):
return node
return None
def query_selector(self, selector: SelectorGroupLike) -> Optional["Node"]:
"""Alias of :meth:`select`."""
return self.select(selector)
def select_all(self, selector: SelectorGroupLike) -> List["Node"]:
"""DOM ``querySelectorAll`` clone. Returns all matches in a list."""
selector = self._normalize_selector(selector)
return list(self._select_all(selector))
def query_selector_all(self, selector: SelectorGroupLike) -> List["Node"]:
"""Alias of :meth:`select_all`."""
return self.select_all(selector)
def matched_by(
self, selector: SelectorGroupLike, root: Optional["Node"] = None
) -> bool:
"""
Checks whether this node is matched by `selector`.
See :meth:`SelectorGroup.matches()`.
"""
selector = self._normalize_selector(selector)
return selector.matches(self, root=root)
@staticmethod
def _normalize_selector(selector: SelectorGroupLike) -> "SelectorGroup":
if isinstance(selector, str):
return SelectorGroup.from_str(selector)
if isinstance(selector, SelectorGroup):
return selector
if isinstance(selector, Selector):
return SelectorGroup([selector])
raise ValueError("not a selector or group of selectors: %s" % repr(selector))
def _select_all(self, selector: "SelectorGroup") -> Generator["Node", None, None]:
for descendant in self.descendants():
if selector.matches(descendant, root=self):
yield descendant
def child_nodes(self) -> List["Node"]:
return self.children
def first_child(self) -> Optional["Node"]:
if self.children:
return self.children[0]
else:
return None
def first_element_child(self) -> Optional["Node"]:
for child in self.children:
if isinstance(child, ElementNode):
return child
return None
def last_child(self) -> Optional["Node"]:
if self.children:
return self.children[-1]
else:
return None
def last_element_child(self) -> Optional["Node"]:
for child in reversed(self.children):
if isinstance(child, ElementNode):
return child
return None
def next_sibling(self) -> Optional["Node"]:
""".. note:: Not O(1), use with caution."""
next_siblings = self.next_siblings()
if next_siblings:
return next_siblings[0]
else:
return None
def next_siblings(self) -> List["Node"]:
parent = self.parent
if not parent:
return []
try:
index = parent.children.index(self)
return parent.children[index + 1 :]
except ValueError: # pragma: no cover
raise ValueError("node is not found in children of its parent")
def next_element_sibling(self) -> Optional["ElementNode"]:
""".. note:: Not O(1), use with caution."""
for sibling in self.next_siblings():
if isinstance(sibling, ElementNode):
return sibling
return None
def previous_sibling(self) -> Optional["Node"]:
""".. note:: Not O(1), use with caution."""
previous_siblings = self.previous_siblings()
if previous_siblings:
return previous_siblings[0]
else:
return None
def previous_siblings(self) -> List["Node"]:
"""
Compared to the natural DOM order, the order of returned nodes
are reversed. That is, the adjacent sibling (if any) is the
first in the returned list.
"""
parent = self.parent
if not parent:
return []
try:
index = parent.children.index(self)
if index > 0:
return parent.children[index - 1 :: -1]
else:
return []
except ValueError: # pragma: no cover
raise ValueError("node is not found in children of its parent")
def previous_element_sibling(self) -> Optional["ElementNode"]:
""".. note:: Not O(1), use with caution."""
for sibling in self.previous_siblings():
if isinstance(sibling, ElementNode):
return sibling
return None
def ancestors(
self, *, root: Optional["Node"] = None
) -> Generator["Node", None, None]:
"""
Ancestors are generated in reverse order of depth, stopping at
`root`.
A :class:`RuntimeException` is raised if `root` is not in the
ancestral chain.
"""
if self is root:
return
ancestor = self.parent
while ancestor is not root:
if ancestor is None:
raise RuntimeError("provided root node not found in ancestral chain")
yield ancestor
ancestor = ancestor.parent
if root:
yield root
def descendants(self) -> Generator["Node", None, None]:
"""Descendants are generated in depth-first order."""
for child in self.children:
yield child
yield from child.descendants()
def attr(self, attr: str) -> Optional[str]:
"""Returns the attribute if it exists on the node, otherwise ``None``."""
return self.attrs.get(attr)
@property
def html(self) -> str:
"""
HTML representation of the node.
(For a :class:`TextNode`, :meth:`html` returns the escaped version of the
text.
"""
return str(self)
def outer_html(self) -> str:
"""Alias of :attr:`html`."""
return self.html
def inner_html(self) -> str:
"""HTML representation of the node's children."""
return "".join(child.html for child in self.children)
@property
def text(self) -> str: # pragma: no cover
"""This property is expected to be implemented by subclasses."""
raise NotImplementedError
def text_content(self) -> str:
"""Alias of :attr:`text`."""
return self.text
@property
def classes(self) -> List[str]:
return self.attrs.get("class", "").split()
def class_list(self) -> List[str]:
return self.classes
class ElementNode(Node):
"""
Represents an element node.
Note that tag and attribute names are case-insensitive; attribute
values are case-sensitive.
"""
def __init__(
self,
tag: str,
attrs: Iterable[Tuple[str, Optional[str]]],
*,
parent: Optional["Node"] = None,
children: Optional[Sequence["Node"]] = None
) -> None:
Node.__init__(self)
self.tag = tag.lower() # type: str
self.attrs = OrderedDict((attr.lower(), val or "") for attr, val in attrs)
self.parent = parent
self.children = list(children or [])
def __repr__(self) -> str:
s = "<" + self.tag
if self.attrs:
s += " attrs=%s" % repr(list(self.attrs.items()))
if self.children:
s += " children=%s" % repr(self.children)
s += ">"
return s
# https://ipython.readthedocs.io/en/stable/api/generated/IPython.lib.pretty.html
def _repr_pretty_(self, p: Any, cycle: bool) -> None: # pragma: no cover
if cycle:
raise RuntimeError("cycle detected in DOM tree")
p.text("<\x1b[1m%s\x1b[0m" % self.tag)
if self.attrs:
p.text(" attrs=%s" % repr(list(self.attrs.items())))
if self.children:
p.text(" children=[")
if len(self.children) == 1 and isinstance(self.first_child(), TextNode):
p.text("\x1b[4m%s\x1b[0m" % repr(self.first_child()))
else:
with p.indent(2):
for child in self.children:
p.break_()
if hasattr(child, "_repr_pretty_"):
child._repr_pretty_(p, False) # type: ignore
else:
p.text("\x1b[4m%s\x1b[0m" % repr(child))
p.text(",")
p.break_()
p.text("]")
p.text(">")
def __str__(self) -> str:
"""HTML representation of the node."""
s = "<" + self.tag
for attr, val in self.attrs.items():
s += ' %s="%s"' % (attr, html.escape(val))
if self.children:
s += ">"
s += "".join(str(child) for child in self.children)
s += "</%s>" % self.tag
else:
if _tag_is_void(self.tag):
s += "/>"
else:
s += "></%s>" % self.tag
return s
@property
def text(self) -> str:
"""The concatenation of all descendant text nodes."""
return "".join(child.text for child in self.children)
class TextNode(str, Node):
"""
Represents a text node.
Subclasses :class:`Node` and :class:`str`.
"""
def __new__(cls, text: str) -> "TextNode":
s = str.__new__(cls, text) # type: ignore
s.parent = None
return s # type: ignore
def __init__(self, text: str) -> None:
Node.__init__(self)
def __repr__(self) -> str:
return "<%s>" % str.__repr__(self)
# HTML-escaped form of the text node. use text() for unescaped
# version.
def __str__(self) -> str:
return html.escape(self)
def __eq__(self, other: object) -> bool:
"""
Two text nodes are equal if and only if they are the same node.
For string comparison, use :attr:`text`.
"""
return self is other
def __ne__(self, other: object) -> bool:
"""
Two text nodes are non-equal if they are not the same node.
For string comparison, use :attr:`text`.
"""
return self is not other
@property
def text(self) -> str:
return str.__str__(self)
class DOMBuilderException(Exception):
"""
Exception raised when :class:`DOMBuilder` detects a bad state.
Attributes:
pos (:class:`Tuple`\\[:class:`int`, :class:`int`]):
Line number and offset in HTML input.
why (:class:`str`):
Reason of the exception.
"""
def __init__(self, pos: Tuple[int, int], why: str) -> None:
self.pos = pos
self.why = why
def __str__(self) -> str: # pragma: no cover
return "DOM builder aborted at %d:%d: %s" % (self.pos[0], self.pos[1], self.why)
class DOMBuilder(HTMLParser):
"""
HTML parser / DOM builder.
Subclasses :class:`html.parser.HTMLParser`.
Consume HTML and builds a :class:`Node` tree. Once finished, use
:attr:`root` to access the root of the tree.
This parser cannot parse malformed HTML with tag mismatch.
"""
def __init__(self) -> None:
super().__init__(convert_charrefs=True)
# _stack is the stack for nodes. Each node is pushed to the
# stack when its start tag is processed, and remains on the
# stack until its parent node is completed (end tag processed),
# at which point the node is attached to the parent node as a
# child and popped from the stack.
self._stack = [] # type: List[Node]
# _namespace_stack is another stack tracking the parsing
# context, which is generally the default namespace (None) but
# changes when parsing foreign objects (e.g. 'svg' when parsing
# an <svg>). The top element is always the current parsing
# context, so popping works differently from _stack: an element
# is popped as soon as the corresponding end tag is processed.
self._namespace_stack = [None] # type: List[Optional[str]]
def handle_starttag(
self, tag: str, attrs: Sequence[Tuple[str, Optional[str]]]
) -> None:
node = ElementNode(tag, attrs)
node._partial = True
self._stack.append(node)
namespace = (
tag.lower()
if _tag_encloses_foreign_namespace(tag)
else self._namespace_stack[-1] # Inherit parent namespace
)
node._namespace = namespace
self._namespace_stack.append(namespace)
# For void elements (not in a foreign context), immediately
# invoke the end tag handler (see handle_startendtag()).
if not namespace and _tag_is_void(tag):
self.handle_endtag(tag)
def handle_endtag(self, tag: str) -> None:
tag = tag.lower()
children = []
while self._stack and not self._stack[-1]._partial:
children.append(self._stack.pop())
if not self._stack:
raise DOMBuilderException(self.getpos(), "extra end tag: %s" % repr(tag))
parent = self._stack[-1]
if parent.tag != tag:
raise DOMBuilderException(
self.getpos(),
"expecting end tag %s, got %s" % (repr(parent.tag), repr(tag)),
)
parent.children = list(reversed(children))
parent._partial = False
for child in children:
child.parent = parent
self._namespace_stack.pop()
# Make parser behavior for explicitly and implicitly void elements
# (e.g., <hr> vs <hr/>) consistent. The former triggers
# handle_starttag only, whereas the latter triggers
# handle_startendtag (which by default triggers both handle_starttag
# and handle_endtag). See https://bugs.python.org/issue25258.
#
# An exception is foreign elements, which aren't considered void
# elements but can be explicitly marked as self-closing according to
# the HTML spec (e.g. <path/> is valid but <path> is not).
# Therefore, both handle_starttag and handle_endtag must be called,
# and handle_endtag should not be triggered from within
# handle_starttag in that case.
#
# Note that for simplicity we do not check whether the foreign
# element in question is allowed to be self-closing by spec. (The
# SVG spec unfortunately doesn't provide a readily available list of
# such elements.)
#
# https://html.spec.whatwg.org/multipage/syntax.html#foreign-elements
def handle_startendtag(
self, tag: str, attrs: Sequence[Tuple[str, Optional[str]]]
) -> None:
if self._namespace_stack[-1] or _tag_encloses_foreign_namespace(tag):
self.handle_starttag(tag, attrs)
self.handle_endtag(tag)
else:
self.handle_starttag(tag, attrs)
def handle_data(self, text: str) -> None:
if not self._stack:
# Ignore text nodes before the first tag.
return
self._stack.append(TextNode(text))
@property
def root(self) -> "Node":
"""
Finishes processing and returns the root node.
Raises :class:`DOMBuilderException` if there is no root tag or
root tag is not closed yet.
"""
if not self._stack:
raise DOMBuilderException(self.getpos(), "no root tag")
if self._stack[0]._partial:
raise DOMBuilderException(self.getpos(), "root tag not closed yet")
return self._stack[0]
def parse_html(html: str, *, ParserClass: type = DOMBuilder) -> "Node":
"""
Parses HTML string, builds DOM, and returns root node.
The parser may raise :class:`DOMBuilderException`.
Args:
html: input HTML string
ParserClass: :class:`DOMBuilder` or a subclass
Returns:
Root note of the parsed tree. If the HTML string contains
multiple top-level elements, only the first is returned and the
rest are lost.
"""
builder = ParserClass() # type: DOMBuilder
builder.feed(html)
builder.close()
return builder.root
class SelectorParserException(Exception):
"""
Exception raised when the selector parser fails to parse an input.
Attributes:
s (:class:`str`):
The input string to be parsed.
cursor (:class:`int`):
Cursor position where the failure occurred.
why (:class:`str`):
Reason of the failure.
"""
def __init__(self, s: str, cursor: int, why: str) -> None:
self.s = s
self.cursor = cursor
self.why = why
def __str__(self) -> str: # pragma: no cover
return "selector parser aborted at character %d of %s: %s" % (
self.cursor,
repr(self.s),
self.why,
)
class SelectorGroup:
"""
Represents a group of CSS selectors.
A group of CSS selectors is simply a comma-separated list of
selectors. [#]_ See :class:`Selector` documentation for the scope of
support.
Typically, a :class:`SelectorGroup` is constructed from a string
(e.g., ``th.center, td.center``) using the factory function
:meth:`from_str`.
.. [#] https://www.w3.org/TR/selectors-3/#grouping
"""
def __init__(self, selectors: Iterable["Selector"]) -> None:
self._selectors = list(selectors)
def __repr__(self) -> str:
return "<SelectorGroup %s>" % repr(str(self))
def __str__(self) -> str:
return ", ".join(str(selector) for selector in self._selectors)
def __len__(self) -> int:
return len(self._selectors)
def __getitem__(self, index: int) -> "Selector":
return self._selectors[index]
def __iter__(self) -> Iterator["Selector"]:
return iter(self._selectors)
@classmethod
def from_str(cls, s: str) -> "SelectorGroup":
"""
Parses input string into a group of selectors.
:class:`SelectorParserException` is raised on invalid input. See
:class:`Selector` documentation for the scope of support.
Args:
s: input string
Returns:
Parsed group of selectors.
"""
i = 0
selectors = []
while i < len(s):
selector, i = Selector.from_str(s, i)
selectors.append(selector)
if not selectors:
raise SelectorParserException(s, i, "selector group is empty")
return cls(selectors)
def matches(self, node: "Node", root: Optional["Node"] = None) -> bool:
"""
Decides whether the group of selectors matches `node`.
The group of selectors matches `node` as long as one of the
selectors matches `node`.
If `root` is provided and child and/or descendant combinators
are involved, parent/ancestor lookup terminates at `root`.
"""
return any(selector.matches(node, root=root) for selector in self)
class Selector:
"""
Represents a CSS selector.
Recall that a CSS selector is a chain of one or more *sequences of
simple selectors* separated by *combinators*. [#selectors-3]_ This
concept is represented as a cons list of sequences of simple
selectors (in right to left order). This class in fact holds a
single sequence, with an optional combinator and reference to the
previous sequence.
For instance, ``main#main p.important.definition >
a.term[id][href]`` would be parsed into (schematically) the
following structure::
">" tag='a' classes=('term') attrs=([id], [href]) ~>
" " tag='p' classes=('important', 'definition') ~>
tag='main' id='main'
Each line is held in a separate instance of :class:`Selector`,
linked together by the :attr:`previous` attribute.
Supported grammar (from selectors level 3 [#selectors-3]_):
- Type selectors;
- Universal selectors;
- Class selectors;
- ID selectors;
- Attribute selectors;
- Combinators.
Unsupported grammar:
- Pseudo-classes;
- Pseudo-elements;
- Namespace prefixes (``ns|``, ``*|``, ``|``) in any part of any
selector.
Rationale:
- Pseudo-classes have too many variants, a few of which even
complete with an admittedly not-so-complex minilanguage. These add
up to a lot of code.
- Pseudo-elements are useless outside rendering contexts, hence out of
scope.
- Namespace support is too niche to be worth the parsing headache.
*Using namespace prefixes may confuse the parser!*
Note that the parser only loosely follows the spec and priotizes
ease of parsing (which includes readability and *writability* of
regexes), so some invalid selectors may be accepted (in fact, false
positives abound, but accepting valid inputs is a much more
important goal than rejecting invalid inputs for this library), and
some valid selectors may be rejected (but as long as you stick to
the scope outlined above and common sense you should be fine; the
false negatives shouldn't be used by actual human beings anyway).
In particular, whitespace character is simplified to ``\\s`` (ASCII
mode) despite CSS spec not counting U+000B (VT) as whitespace,
identifiers are simplified to ``[\\w-]+`` (ASCII mode), and strings
(attribute selector values can be either identifiers or strings)
allow escaped quotes (i.e., ``\\'`` inside single-quoted strings and
``\\"`` inside double-quoted strings) but everything else is
interpreted literally. The exact specs for CSS identifiers and
strings can be found at [#]_.
Certain selectors and combinators may be implemented in the parser
but not implemented in matching and/or selection APIs.
.. [#selectors-3] https://www.w3.org/TR/selectors-3/
.. [#] https://www.w3.org/TR/CSS21/syndata.html
Attributes:
tag (:class:`Optional`\\[:class:`str`]):
Type selector.
classes (:class:`List`\\[:class:`str`]):
Class selectors.
id (:class:`Optional`\\[:class:`str`]):
ID selector.
attrs (:class:`List`\\[:class:`AttributeSelector`]):
Attribute selectors.
combinator (:class:`Optional`\\[:class:`Combinator`]):
Combinator with the previous sequence of simple selectors in
chain.
previous (:class:`Optional`\\[:class:`Selector`]):
Reference to the previous sequence of simple selectors in
chain.
"""
def __init__(
self,
*,
tag: Optional[str] = None,
classes: Optional[Sequence[str]] = None,
id: Optional[str] = None,
attrs: Optional[Sequence["AttributeSelector"]] = None,
combinator: Optional["Combinator"] = None,
previous: Optional["Selector"] = None
) -> None:
self.tag = tag.lower() if tag else None
self.classes = list(classes or [])
self.id = id
self.attrs = list(attrs or [])
self.combinator = combinator
self.previous = previous
def __repr__(self) -> str:
return "<Selector %s>" % repr(str(self))
def __str__(self) -> str:
sequences = []
delimiters = []
seq = self
while True:
sequences.append(seq._sequence_str_())
if seq.previous:
if seq.combinator == Combinator.DESCENDANT:
delimiters.append(" ")
elif seq.combinator == Combinator.CHILD:
delimiters.append(" > ")