contentdb/app/markdown.py
rubenwardy 609354cd35 Hypertext: Fix various issues
* Change link color
* Return absolute URLs
* Provide link to tables (with anchor)
* Provide link to image when include_images=false
* Escape backward slashes
* Make package info more compact
2024-04-05 18:17:07 +01:00

208 lines
5.3 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
import bleach
from bleach import Cleaner
from bleach.linkifier import LinkifyFilter
from bs4 import BeautifulSoup
from markdown import Markdown
from flask import url_for
from jinja2.utils import markupsafe
from markdown.extensions import Extension
from markdown.inlinepatterns import SimpleTagInlineProcessor
from markdown.inlinepatterns import Pattern
from markdown.extensions.codehilite import CodeHiliteExtension
from xml.etree import ElementTree
# 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",
}
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
ALLOWED_ATTRIBUTES = {
"h1": ["id"],
"h2": ["id"],
"h3": ["id"],
"h4": ["id"],
"a": ["href", "title", "data-username"],
"img": ["src", "title", "alt"],
"code": allow_class,
"div": allow_class,
"span": allow_class,
"table": ["id"],
}
ALLOWED_PROTOCOLS = {"http", "https", "mailto"}
md = None
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 render_markdown(source):
html = md.convert(source)
cleaner = Cleaner(
tags=ALLOWED_TAGS,
attributes=ALLOWED_ATTRIBUTES,
protocols=ALLOWED_PROTOCOLS,
filters=[partial(LinkifyFilter,
callbacks=[linker_callback] + bleach.linkifier.DEFAULT_CALLBACKS,
skip_tags={"pre", "code"})])
return cleaner.clean(html)
class DelInsExtension(Extension):
def extendMarkdown(self, md):
del_proc = SimpleTagInlineProcessor(r"(\~\~)(.+?)(\~\~)", "del")
md.inlinePatterns.register(del_proc, "del", 200)
ins_proc = SimpleTagInlineProcessor(r"(\+\+)(.+?)(\+\+)", "ins")
md.inlinePatterns.register(ins_proc, "ins", 200)
RE_PARTS = dict(
USER=r"[A-Za-z0-9._-]*\b",
REPO=r"[A-Za-z0-9_]+\b"
)
class MentionPattern(Pattern):
ANCESTOR_EXCLUDES = ("a",)
def __init__(self, config, md):
MENTION_RE = r"(@({USER})(?:\/({REPO}))?)".format(**RE_PARTS)
super(MentionPattern, self).__init__(MENTION_RE, md)
self.config = config
def handleMatch(self, m):
from app.models import User
label = m.group(2)
user = m.group(3)
package_name = m.group(4)
if package_name:
el = ElementTree.Element("a")
el.text = label
el.set("href", url_for("packages.view", author=user, name=package_name))
return el
else:
if User.query.filter_by(username=user).count() == 0:
return None
el = ElementTree.Element("a")
el.text = label
el.set("href", url_for("users.profile", username=user))
el.set("data-username", user)
return el
class MentionExtension(Extension):
def __init__(self, *args, **kwargs):
super(MentionExtension, self).__init__(*args, **kwargs)
def extendMarkdown(self, md):
md.ESCAPED_CHARS.append("@")
md.inlinePatterns.register(MentionPattern(self.getConfigs(), md), "mention", 20)
MARKDOWN_EXTENSIONS = ["fenced_code", "tables", CodeHiliteExtension(guess_lang=False), "toc", DelInsExtension(), MentionExtension()]
MARKDOWN_EXTENSION_CONFIG = {
"fenced_code": {},
"tables": {}
}
def init_markdown(app):
global md
md = Markdown(extensions=MARKDOWN_EXTENSIONS,
extension_configs=MARKDOWN_EXTENSION_CONFIG,
output_format="html")
@app.template_filter()
def markdown(source):
return markupsafe.Markup(render_markdown(source))
def get_headings(html: str):
soup = BeautifulSoup(html, "html.parser")
headings = soup.find_all(["h1", "h2", "h3"])
root = []
stack = []
for heading in headings:
this = {"link": heading.get("id") or "", "text": heading.text, "children": []}
this_level = int(heading.name[1:]) - 1
while this_level <= len(stack):
stack.pop()
if len(stack) > 0:
stack[-1]["children"].append(this)
else:
root.append(this)
stack.append(this)
return root
def get_user_mentions(html: str) -> set:
soup = BeautifulSoup(html, "html.parser")
links = soup.select("a[data-username]")
return set([x.get("data-username") for x in links])