pferd/PFERD/ffm.py

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# Fakultät für Mathematik (FfM)
import aiohttp
import asyncio
import bs4
import logging
import pathlib
import re
from .organizer import Organizer
from . import utils
__all__ = [
"FfM",
]
logger = logging.getLogger(__name__)
class FfM:
BASE_URL = "http://www.math.kit.edu/"
LINK_RE = re.compile(r"^https?://www.math.kit.edu/.*/(.*\.pdf)$")
RETRY_ATTEMPTS = 5
RETRY_DELAY = 1 # seconds
def __init__(self, base_path):
self.base_path = base_path
self._session = aiohttp.ClientSession()
async def synchronize(self, urlpart, to_dir, transform=lambda x: x):
logging.info(f"Synchronizing {urlpart} to {to_dir} using the FfM synchronizer.")
sync_path = pathlib.Path(self.base_path, to_dir)
orga = Organizer(self.base_path, sync_path)
orga.clean_temp_dir()
await self._crawl(orga, urlpart, transform)
orga.clean_sync_dir()
orga.clean_temp_dir()
async def close(self):
await self._session.close()
async def _crawl(self, orga, urlpart, transform):
url = self.BASE_URL + urlpart
async with self._session.get(url) as resp:
text = await resp.text()
soup = bs4.BeautifulSoup(text, "html.parser")
for found in soup.find_all("a", href=self.LINK_RE):
url = found["href"]
filename = re.match(self.LINK_RE, url).group(1)
logger.debug(f"Found file {filename} at {url}")
old_path = pathlib.PurePath(filename)
new_path = transform(old_path)
if new_path is None:
continue
logger.debug(f"Transformed from {old_path} to {new_path}")
temp_path = orga.temp_file()
await self._download(url, temp_path)
orga.add_file(temp_path, new_path)
async def _download(self, url, to_path):
for t in range(self.RETRY_ATTEMPTS):
try:
async with self._session.get(url) as resp:
await utils.stream_to_path(resp, to_path)
except aiohttp.client_exceptions.ServerDisconnectedError:
logger.debug(f"Try {t+1} out of {self.RETRY_ATTEMPTS} failed, retrying in {self.RETRY_DELAY} s")
await asyncio.sleep(self.RETRY_DELAY)
else:
return
else:
logger.error(f"Could not download {url}")
raise utils.OutOfTriesException(f"Try {self.RETRY_ATTEMPTS} out of {self.RETRY_ATTEMPTS} failed.")