linkding/bookmarks/services/website_loader.py
2023-05-30 22:04:54 +02:00

104 lines
3.5 KiB
Python

import logging
from dataclasses import dataclass
from functools import lru_cache
import requests
from bs4 import BeautifulSoup
from charset_normalizer import from_bytes
from django.utils import timezone
logger = logging.getLogger(__name__)
@dataclass
class WebsiteMetadata:
url: str
title: str
description: str
def to_dict(self):
return {
'url': self.url,
'title': self.title,
'description': self.description,
}
# Caching metadata avoids scraping again when saving bookmarks, in case the
# metadata was already scraped to show preview values in the bookmark form
@lru_cache(maxsize=10)
def load_website_metadata(url: str):
title = None
description = None
try:
start = timezone.now()
page_text = load_page(url)
end = timezone.now()
logger.debug(f'Load duration: {end - start}')
start = timezone.now()
soup = BeautifulSoup(page_text, 'html.parser')
title = soup.title.string.strip() if soup.title is not None else None
description_tag = soup.find('meta', attrs={'name': 'description'})
description = description = description_tag['content'].strip() if description_tag and description_tag[
'content'] else None
end = timezone.now()
logger.debug(f'Parsing duration: {end - start}')
finally:
return WebsiteMetadata(url=url, title=title, description=description)
CHUNK_SIZE = 50 * 1024
MAX_CONTENT_LIMIT = 5000 * 1024
def load_page(url: str):
headers = fake_request_headers()
size = 0
content = None
iteration = 0
# Use with to ensure request gets closed even if it's only read partially
with requests.get(url, timeout=10, headers=headers, stream=True) as r:
for chunk in r.iter_content(chunk_size=CHUNK_SIZE):
size += len(chunk)
iteration = iteration + 1
if content is None:
content = chunk
else:
content = content + chunk
logger.debug(f'Loaded chunk (iteration={iteration}, total={size / 1024})')
# Stop reading if we have parsed end of head tag
end_of_head = '</head>'.encode('utf-8')
if end_of_head in content:
logger.debug(f'Found closing head tag after {size} bytes')
content = content.split(end_of_head)[0] + end_of_head
break
# Stop reading if we exceed limit
if size > MAX_CONTENT_LIMIT:
logger.debug(f'Cancel reading document after {size} bytes')
break
if hasattr(r, '_content_consumed'):
logger.debug(f'Request consumed: {r._content_consumed}')
# Use charset_normalizer to determine encoding that best matches the response content
# Several sites seem to specify the response encoding incorrectly, so we ignore it and use custom logic instead
# This is different from Response.text which does respect the encoding specified in the response first,
# before trying to determine one
results = from_bytes(content or '')
return str(results.best())
DEFAULT_USER_AGENT = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.0.0 Safari/537.36'
def fake_request_headers():
return {
"Accept": "text/html,application/xhtml+xml,application/xml",
"Accept-Encoding": "gzip, deflate",
"Dnt": "1",
"Upgrade-Insecure-Requests": "1",
"User-Agent": DEFAULT_USER_AGENT,
}