codekingpro/portable-devtools

1from __future__ import annotations2 3from collections.abc import Callable4from contextlib import suppress5import re6from urllib.parse import quote, unquote, urlparse, urlunparse  # noqa: F4017 8import mdurl9 10from .. import _punycode11 12RECODE_HOSTNAME_FOR = ("http:", "https:", "mailto:")13 14 15def normalizeLink(url: str) -> str:16    """Normalize destination URLs in links17 18    ::19 20        [label]:   destination   'title'21                ^^^^^^^^^^^22    """23    parsed = mdurl.parse(url, slashes_denote_host=True)24 25    # Encode hostnames in urls like:26    # `http://host/`, `https://host/`, `mailto:user@host`, `//host/`27    #28    # We don't encode unknown schemas, because it's likely that we encode29    # something we shouldn't (e.g. `skype:name` treated as `skype:host`)30    #31    if parsed.hostname and (32        not parsed.protocol or parsed.protocol in RECODE_HOSTNAME_FOR33    ):34        with suppress(Exception):35            parsed = parsed._replace(hostname=_punycode.to_ascii(parsed.hostname))36 37    return mdurl.encode(mdurl.format(parsed))38 39 40def normalizeLinkText(url: str) -> str:41    """Normalize autolink content42 43    ::44 45        <destination>46         ~~~~~~~~~~~47    """48    parsed = mdurl.parse(url, slashes_denote_host=True)49 50    # Encode hostnames in urls like:51    # `http://host/`, `https://host/`, `mailto:user@host`, `//host/`52    #53    # We don't encode unknown schemas, because it's likely that we encode54    # something we shouldn't (e.g. `skype:name` treated as `skype:host`)55    #56    if parsed.hostname and (57        not parsed.protocol or parsed.protocol in RECODE_HOSTNAME_FOR58    ):59        with suppress(Exception):60            parsed = parsed._replace(hostname=_punycode.to_unicode(parsed.hostname))61 62    # add '%' to exclude list because of https://github.com/markdown-it/markdown-it/issues/72063    return mdurl.decode(mdurl.format(parsed), mdurl.DECODE_DEFAULT_CHARS + "%")64 65 66BAD_PROTO_RE = re.compile(r"^(vbscript|javascript|file|data):")67GOOD_DATA_RE = re.compile(r"^data:image\/(gif|png|jpeg|webp);")68 69 70def validateLink(url: str, validator: Callable[[str], bool] | None = None) -> bool:71    """Validate URL link is allowed in output.72 73    This validator can prohibit more than really needed to prevent XSS.74    It's a tradeoff to keep code simple and to be secure by default.75 76    Note: url should be normalized at this point, and existing entities decoded.77    """78    if validator is not None:79        return validator(url)80    url = url.strip().lower()81    return bool(GOOD_DATA_RE.search(url)) if BAD_PROTO_RE.search(url) else True82