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https://github.com/Garmelon/PFERD.git
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722970a255
Using the stdlib's http.cookie module, cookies are now stored as one "Set-Cookie" header per line. Previously, the aiohttp.CookieJar's save() and load() methods were used (which use pickling).
200 lines
8.0 KiB
Python
200 lines
8.0 KiB
Python
import asyncio
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import http.cookies
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import ssl
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from pathlib import Path, PurePath
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from typing import Any, Dict, List, Optional
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import aiohttp
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import certifi
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from aiohttp.client import ClientTimeout
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from ..auth import Authenticator
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from ..config import Config
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from ..logging import log
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from ..utils import fmt_real_path
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from ..version import NAME, VERSION
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from .crawler import Crawler, CrawlerSection
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class HttpCrawlerSection(CrawlerSection):
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def http_timeout(self) -> float:
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return self.s.getfloat("http_timeout", fallback=20)
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class HttpCrawler(Crawler):
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COOKIE_FILE = PurePath(".cookies")
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def __init__(
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self,
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name: str,
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section: HttpCrawlerSection,
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config: Config,
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shared_auth: Optional[Authenticator] = None,
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) -> None:
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super().__init__(name, section, config)
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self._authentication_id = 0
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self._authentication_lock = asyncio.Lock()
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self._request_count = 0
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self._http_timeout = section.http_timeout()
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self._cookie_jar_path = self._output_dir.resolve(self.COOKIE_FILE)
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self._shared_cookie_jar_paths: Optional[List[Path]] = None
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self._shared_auth = shared_auth
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self._output_dir.register_reserved(self.COOKIE_FILE)
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async def _current_auth_id(self) -> int:
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"""
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Returns the id for the current authentication, i.e. an identifier for the last
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successful call to [authenticate].
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This method must be called before any request that might authenticate is made, so the
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HttpCrawler can properly track when [authenticate] can return early and when actual
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authentication is necessary.
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"""
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# We acquire the lock here to ensure we wait for any concurrent authenticate to finish.
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# This should reduce the amount of requests we make: If an authentication is in progress
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# all future requests wait for authentication to complete.
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async with self._authentication_lock:
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self._request_count += 1
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return self._authentication_id
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async def authenticate(self, caller_auth_id: int) -> None:
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"""
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Starts the authentication process. The main work is offloaded to _authenticate, which
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you should overwrite in a subclass if needed. This method should *NOT* be overwritten.
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The [caller_auth_id] should be the result of a [_current_auth_id] call made *before*
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the request was made. This ensures that authentication is not performed needlessly.
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"""
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async with self._authentication_lock:
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log.explain_topic("Authenticating")
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# Another thread successfully called authenticate in-between
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# We do not want to perform auth again, so we return here. We can
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# assume the other thread suceeded as authenticate will throw an error
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# if it failed and aborts the crawl process.
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if caller_auth_id != self._authentication_id:
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log.explain(
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"Authentication skipped due to auth id mismatch."
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"A previous authentication beat us to the race."
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)
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return
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log.explain("Calling crawler-specific authenticate")
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await self._authenticate()
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self._authentication_id += 1
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# Saving the cookies after the first auth ensures we won't need to re-authenticate
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# on the next run, should this one be aborted or crash
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self._save_cookies()
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async def _authenticate(self) -> None:
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"""
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Performs authentication. This method must only return normally if authentication suceeded.
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In all other cases it must either retry internally or throw a terminal exception.
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"""
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raise RuntimeError("_authenticate() was called but crawler doesn't provide an implementation")
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def share_cookies(self, shared: Dict[Authenticator, List[Path]]) -> None:
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if not self._shared_auth:
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return
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if self._shared_auth in shared:
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self._shared_cookie_jar_paths = shared[self._shared_auth]
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else:
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self._shared_cookie_jar_paths = []
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shared[self._shared_auth] = self._shared_cookie_jar_paths
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self._shared_cookie_jar_paths.append(self._cookie_jar_path)
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def _load_cookies_from_file(self, path: Path) -> None:
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jar: Any = http.cookies.SimpleCookie()
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with open(path) as f:
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for i, line in enumerate(f):
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# Names of headers are case insensitive
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if line[:11].lower() == "set-cookie:":
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jar.load(line[11:])
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else:
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log.explain(f"Line {i} doesn't start with 'Set-Cookie:', ignoring it")
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self._cookie_jar.update_cookies(jar)
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def _save_cookies_to_file(self, path: Path) -> None:
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jar: Any = http.cookies.SimpleCookie()
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for morsel in self._cookie_jar:
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jar[morsel.key] = morsel
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with open(path, "w") as f:
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f.write(jar.output(sep="\n"))
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f.write("\n") # A trailing newline is just common courtesy
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def _load_cookies(self) -> None:
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log.explain_topic("Loading cookies")
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cookie_jar_path: Optional[Path] = None
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if self._shared_cookie_jar_paths is None:
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log.explain("Not sharing any cookies")
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cookie_jar_path = self._cookie_jar_path
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else:
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log.explain("Sharing cookies")
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max_mtime: Optional[float] = None
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for path in self._shared_cookie_jar_paths:
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if not path.is_file():
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log.explain(f"{fmt_real_path(path)} is not a file")
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continue
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mtime = path.stat().st_mtime
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if max_mtime is None or mtime > max_mtime:
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log.explain(f"{fmt_real_path(path)} has newest mtime so far")
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max_mtime = mtime
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cookie_jar_path = path
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else:
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log.explain(f"{fmt_real_path(path)} has older mtime")
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if cookie_jar_path is None:
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log.explain("Couldn't find a suitable cookie file")
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return
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log.explain(f"Loading cookies from {fmt_real_path(cookie_jar_path)}")
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try:
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self._load_cookies_from_file(cookie_jar_path)
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except Exception as e:
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log.explain("Failed to load cookies")
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log.explain(str(e))
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def _save_cookies(self) -> None:
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log.explain_topic("Saving cookies")
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try:
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log.explain(f"Saving cookies to {fmt_real_path(self._cookie_jar_path)}")
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self._save_cookies_to_file(self._cookie_jar_path)
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except Exception as e:
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log.warn(f"Failed to save cookies to {fmt_real_path(self._cookie_jar_path)}")
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log.warn(str(e))
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async def run(self) -> None:
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self._request_count = 0
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self._cookie_jar = aiohttp.CookieJar()
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self._load_cookies()
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async with aiohttp.ClientSession(
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headers={"User-Agent": f"{NAME}/{VERSION}"},
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cookie_jar=self._cookie_jar,
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connector=aiohttp.TCPConnector(ssl=ssl.create_default_context(cafile=certifi.where())),
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timeout=ClientTimeout(
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# 30 minutes. No download in the history of downloads was longer than 30 minutes.
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# This is enough to transfer a 600 MB file over a 3 Mib/s connection.
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# Allowing an arbitrary value could be annoying for overnight batch jobs
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total=15 * 60,
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connect=self._http_timeout,
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sock_connect=self._http_timeout,
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sock_read=self._http_timeout,
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)
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) as session:
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self.session = session
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try:
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await super().run()
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finally:
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del self.session
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log.explain_topic(f"Total amount of HTTP requests: {self._request_count}")
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# They are saved in authenticate, but a final save won't hurt
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self._save_cookies()
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