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contentdb/app/markdown/cleaner.py
2025-06-19 18:40:26 +01:00

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2.6 KiB
Python

# ContentDB
# Copyright (C) rubenwardy
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
from functools import partial
from bleach import Cleaner
from bleach.linkifier import LinkifyFilter, DEFAULT_CALLBACKS
# Based on
# https://github.com/Wenzil/mdx_bleach/blob/master/mdx_bleach/whitelist.py
#
# License: MIT
ALLOWED_TAGS = {
"h1", "h2", "h3", "h4", "h5", "h6", "hr",
"ul", "ol", "li",
"p",
"br",
"pre",
"code",
"blockquote",
"strong",
"em",
"a",
"img",
"table", "thead", "tbody", "tr", "th", "td",
"div", "span", "del", "s",
"details",
"summary",
"sup",
}
ALLOWED_CSS = [
"highlight", "codehilite",
"hll", "c", "err", "g", "k", "l", "n", "o", "x", "p", "ch", "cm", "cp", "cpf", "c1", "cs",
"gd", "ge", "gr", "gh", "gi", "go", "gp", "gs", "gu", "gt", "kc", "kd", "kn", "kp", "kr",
"kt", "ld", "m", "s", "na", "nb", "nc", "no", "nd", "ni", "ne", "nf", "nl", "nn", "nx",
"py", "nt", "nv", "ow", "w", "mb", "mf", "mh", "mi", "mo", "sa", "sb", "sc", "dl", "sd",
"s2", "se", "sh", "si", "sx", "sr", "s1", "ss", "bp", "fm", "vc", "vg", "vi", "vm", "il",
]
def allow_class(_tag, name, value):
return name == "class" and value in ALLOWED_CSS
def allow_a(_tag, name, value):
return name in ["href", "title", "data-username"] or (name == "class" and value == "header-anchor")
ALLOWED_ATTRIBUTES = {
"h1": ["id"],
"h2": ["id"],
"h3": ["id"],
"h4": ["id"],
"a": allow_a,
"img": ["src", "title", "alt"],
"code": allow_class,
"div": allow_class,
"span": allow_class,
"table": ["id"],
}
ALLOWED_PROTOCOLS = {"http", "https", "mailto"}
def linker_callback(attrs, new=False):
if new:
text = attrs.get("_text")
if not (text.startswith("http://") or text.startswith("https://")):
return None
return attrs
def clean_html(html: str):
cleaner = Cleaner(
tags=ALLOWED_TAGS,
attributes=ALLOWED_ATTRIBUTES,
protocols=ALLOWED_PROTOCOLS,
filters=[partial(LinkifyFilter,
callbacks=[linker_callback] + DEFAULT_CALLBACKS,
skip_tags={"pre", "code"})])
return cleaner.clean(html)