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"""
Encapsulation of html-related functionality.
BeautifulSoup should only get used here.
"""
import html
import logging
import re
from abc import ABC
from dataclasses import dataclass
from functools import cached_property
from bs4 import BeautifulSoup
from bs4 import NavigableString
from bs4 import Tag
@dataclass
class HTMLMatch(ABC):
node: "Node" = None
@dataclass
class HTMLExactTextMatch(HTMLMatch):
pass
@dataclass
class HTMLAttributeMatch(HTMLMatch):
attr: str = None
class Node:
soup = None
_page = None
def __init__(self, soup, page: "Page"):
self.soup = soup
self._page = page
@property
def root(self):
return self._page
@property
def text(self):
return self.soup.text
def find_all(self, item) -> list[HTMLMatch]:
return list(self._generate_find_all(item))
def _generate_find_all(self, item):
assert isinstance(item, str), "can only search for str at the moment"
# text
# - since text matches including whitespace, a regex is used
for soup_node in self.soup.find_all(
string=re.compile(r"^\s*%s\s*$" % html.escape(item))
):
# use parent node as found text is NaviableString and not Tag
node = self._page._get_node_for_soup(soup_node.parent)
yield HTMLExactTextMatch(node)
# attributes
for soup_node in self.soup.find_all():
for attr in soup_node.attrs:
if soup_node[attr] == item:
node = self._page._get_node_for_soup(soup_node)
yield HTMLAttributeMatch(node, attr)
# todo implement other find methods
def has_parent(self, node: "Node"):
for p in self.soup.parents:
if p == node.soup:
return True
return False
@cached_property
def parents(self):
return [self._page._get_node_for_soup(p) for p in self.soup.parents]
@property
def classes(self):
return self.soup.attrs.get("class", [])
@property
def id(self):
return self.soup.attrs.get("id", None)
@property
def tag_name(self):
return self.soup.name
def select(self, css_selector):
return [
self._page._get_node_for_soup(n) for n in self.soup.select(css_selector)
]
def __repr__(self):
if isinstance(self.soup, NavigableString):
return f"<{self.__class__.__name__} {self.soup.strip()[:10]=}>"
return (
f"<{self.__class__.__name__} {self.soup.name=}"
f" classes={self.soup.get('class', None)},"
f" text={''.join(self.soup.stripped_strings)[:10]}...>"
)
def __hash__(self):
return self.soup.__hash__()
# return super().__hash__()
def __eq__(self, other):
return isinstance(other, Node) and self.soup == other.soup
class Page(Node):
"""
One page, i.e. one HTML document.
"""
_node_registry = None
def __init__(self, html):
self.html = html
soup = BeautifulSoup(self.html, "lxml")
# register node for each soup
self._node_registry = {soup: self}
super().__init__(soup, self)
def _get_node_for_soup(self, soup) -> Node:
if soup not in self._node_registry:
self._node_registry[soup] = Node(soup, self)
return self._node_registry[soup]
def get_root_node(nodes: list[Node]) -> Node:
pages = [n._page for n in nodes]
assert len(set(pages)) == 1, "different pages found, cannot get a root"
root = _get_root_of_nodes(n.soup for n in nodes)
return pages[0]._get_node_for_soup(root)
def _get_root_of_nodes(soups):
soups = list(soups)
assert all(isinstance(n, Tag) for n in soups)
# root can be node itself, so it has to be added
parent_paths_of_nodes = [[node] + list(node.parents) for node in soups]
# paths are needed from top to bottom
parent_paths_rev = [list(reversed(pp)) for pp in parent_paths_of_nodes]
try:
ancestor = _get_root_of_paths(parent_paths_rev)
except RuntimeError as e:
raise RuntimeError(f"No common ancestor: {soups}") from e
return ancestor
def _get_root_of_paths(paths):
"""
Computes the first common ancestor for list of paths.
:param paths: list of list of nodes from top to bottom
:return: first common index or RuntimeError
"""
assert paths
assert all(p for p in paths)
# go through paths one by one, starting from bottom
for nodes in reversed(list(zip(*paths))):
if len(set(nodes)) == 1:
return nodes[0]
logging.info("failed to find ancestor for : %s", paths)
raise RuntimeError("No common ancestor")
def get_relative_depth(node: Node, root: Node):
node_parents = list(node.soup.parents)
# depth of root
i = node_parents.index(root.soup)
# depth of element
j = len(node_parents)
return j - i
def selector_matches_nodes(root: Node, selector: str, expected: list[Node]):
"""
Check whether the given selector matches the expected nodes.
"""
logging.info(
f"checking if selector matches nodes ({root=}, {selector=}, {expected=})"
)
# we care for equality here
# as selector should match the expected nodes in the exact given order
# we do this here, as wrapping Nodes can have side effects regarding equality
return root.soup.select(selector) == [n.soup for n in expected]
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