File size: 3,297 Bytes
8ba65bb | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 | """Conservative HTML sanitiser for captured source rich text.
Source product descriptions are rich text. They are reproduced structurally,
but only through an explicit tag/attribute allowlist, and every absolute
source-site link is rewritten to its local equivalent so the clone never sends
a visitor to the source origin.
"""
from __future__ import annotations
import re
from html.parser import HTMLParser
from urllib.parse import urlsplit
ALLOWED_TAGS = {
"p", "br", "strong", "b", "em", "i", "u", "ul", "ol", "li",
"h2", "h3", "h4", "span", "a", "table", "thead", "tbody", "tr", "th", "td",
}
VOID_TAGS = {"br"}
ALLOWED_ATTRS = {"a": {"href"}}
SOURCE_HOSTS = {"www.backcountry.com", "backcountry.com", "content.backcountry.com"}
def localize(href: str) -> str | None:
"""Keep same-site links as local paths; drop links that leave the clone."""
href = (href or "").strip()
if not href:
return None
if href.startswith("/"):
return href
parts = urlsplit(href)
if parts.scheme in ("http", "https") and parts.netloc in SOURCE_HOSTS:
return (parts.path or "/") + (f"?{parts.query}" if parts.query else "")
if href.startswith("#"):
return href
return None
class _Sanitizer(HTMLParser):
def __init__(self) -> None:
super().__init__(convert_charrefs=True)
self.parts: list[str] = []
self._open: list[str] = []
def handle_starttag(self, tag: str, attrs: list[tuple[str, str | None]]) -> None:
if tag not in ALLOWED_TAGS:
return
if tag == "a":
href = localize(dict(attrs).get("href") or "")
if not href:
# Unresolvable or external destination: keep the text, drop the link.
self._open.append("")
return
self.parts.append(f'<a href="{_escape(href)}">')
else:
self.parts.append(f"<{tag}>")
if tag not in VOID_TAGS:
self._open.append(tag)
def handle_endtag(self, tag: str) -> None:
if tag not in ALLOWED_TAGS or tag in VOID_TAGS:
return
while self._open:
open_tag = self._open.pop()
if open_tag:
self.parts.append(f"</{open_tag}>")
if open_tag == tag or open_tag == "":
break
def handle_data(self, data: str) -> None:
self.parts.append(_escape(data))
def close_all(self) -> str:
while self._open:
open_tag = self._open.pop()
if open_tag:
self.parts.append(f"</{open_tag}>")
return "".join(self.parts)
def _escape(text: str) -> str:
return (text.replace("&", "&").replace("<", "<")
.replace(">", ">").replace('"', """))
def clean_html(raw: str | None) -> str:
if not raw:
return ""
parser = _Sanitizer()
parser.feed(raw)
parser.close()
html = parser.close_all()
return re.sub(r"\s+", " ", html).strip()
def to_text(raw: str | None) -> str:
if not raw:
return ""
text = re.sub(r"<[^>]+>", " ", raw)
text = (text.replace("&", "&").replace("<", "<")
.replace(">", ">").replace(""", '"').replace(" ", " "))
return re.sub(r"\s+", " ", text).strip()
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