microblog.pub/utils/webmentions.py

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2019-07-16 14:33:32 -05:00
import logging
from typing import Optional
from urllib.parse import urlparse
import requests
from bs4 import BeautifulSoup
from little_boxes.urlutils import is_url_valid
logger = logging.getLogger(__name__)
def _make_abs(url: Optional[str], parent: str) -> Optional[str]:
if url is None:
return None
if url.startswith("http"):
return url
return (
urlparse(parent)._replace(path=url, params="", query="", fragment="").geturl()
)
def _discover_webmention_endoint(url: str) -> Optional[str]:
try:
resp = requests.get(url, timeout=3)
except Exception:
return None
for k, v in resp.links.items():
if "webmention" in k:
return _make_abs(resp.links[k].get("url"), url)
soup = BeautifulSoup(resp.text, "html5lib")
wlinks = soup.find_all(["link", "a"], attrs={"rel": "webmention"})
for wlink in wlinks:
if "href" in wlink.attrs:
return _make_abs(wlink.attrs["href"], url)
return None
def discover_webmention_endoint(url: str) -> Optional[str]:
"""Discover the Webmention endpoint of a given URL, if any.
Passes all the tests at https://webmention.rocks!
"""
wurl = _discover_webmention_endoint(url)
if wurl is None:
return None
if not is_url_valid(wurl):
return None
return wurl