343 lines
12 KiB
Python
343 lines
12 KiB
Python
import asyncio
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import sys
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import warnings
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from contextlib import suppress
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from typing import Any, Optional
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from weakref import WeakKeyDictionary
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from ._wrapper import ffi, lib
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from .const import CurlECode, CurlMOpt
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from .curl import DEFAULT_CACERT, Curl, CurlError
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from .utils import CurlCffiWarning
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__all__ = ["AsyncCurl"]
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if sys.platform == "win32":
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# registry of asyncio loop : selector thread
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_selectors: WeakKeyDictionary = WeakKeyDictionary()
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PROACTOR_WARNING = """
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Proactor event loop does not implement add_reader family of methods required.
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Registering an additional selector thread for add_reader support.
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To avoid this warning use:
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asyncio.set_event_loop_policy(WindowsSelectorEventLoopPolicy())
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"""
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def get_selector(
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asyncio_loop: asyncio.AbstractEventLoop,
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) -> asyncio.AbstractEventLoop:
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"""Get selector-compatible loop
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Returns an object with ``add_reader`` family of methods,
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either the loop itself or a SelectorThread instance.
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Workaround Windows proactor removal of *reader methods.
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"""
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if asyncio_loop in _selectors:
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return _selectors[asyncio_loop]
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if not isinstance(
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asyncio_loop, getattr(asyncio, "ProactorEventLoop", type(None))
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):
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return asyncio_loop
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warnings.warn(PROACTOR_WARNING, CurlCffiWarning, stacklevel=2)
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from ._asyncio_selector import AddThreadSelectorEventLoop
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selector_loop = _selectors[asyncio_loop] = AddThreadSelectorEventLoop(
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asyncio_loop
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) # type: ignore
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# patch loop.close to also close the selector thread
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loop_close = asyncio_loop.close
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def _close_selector_and_loop():
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# restore original before calling selector.close,
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# which in turn calls eventloop.close!
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asyncio_loop.close = loop_close
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_selectors.pop(asyncio_loop, None)
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selector_loop.close()
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asyncio_loop.close = _close_selector_and_loop
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return selector_loop
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else:
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def get_selector(loop: asyncio.AbstractEventLoop) -> asyncio.AbstractEventLoop:
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return loop
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CURL_POLL_NONE = 0
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CURL_POLL_IN = 1
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CURL_POLL_OUT = 2
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CURL_POLL_INOUT = 3
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CURL_POLL_REMOVE = 4
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CURL_SOCKET_TIMEOUT = -1
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CURL_SOCKET_BAD = -1
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CURL_CSELECT_IN = 0x01
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CURL_CSELECT_OUT = 0x02
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CURL_CSELECT_ERR = 0x04
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CURLMSG_DONE = 1
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CURLPIPE_NOTHING = 0
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CURLPIPE_HTTP1 = 1 # deprecated
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CURLPIPE_MULTIPLEX = 2
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"""
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libcurl provides an event-based system for multiple handles with the following API:
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- curl_multi_socket_action, for detecting events
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- curl_multi_info_read, for reading the transfer status
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There are 2 callbacks:
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- socket_function, set by CURLMOPT_SOCKETFUNCTION, will be called for socket events.
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- timer_function, set by CURLMOPT_TIMERFUNCTION, will be called when timeouts happen.
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And it works like the following:
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Set up handles, callbacks first.
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When started, curl_multi_socket_action should be called to start everything.
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If there are data in/out, libcurl calls the socket_function callback, and it sets up
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`process_data` as asyncio loop reader/writer function. `process_data` will call
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curl_multi_info_read to determine whether a certain `await perform` has finished.
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When idle, libcurl will call the timer_function callback, which sets up a later call
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for socket_action to detect events.
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"""
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@ffi.def_extern()
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def timer_function(curlm, timeout_ms: int, clientp: Any) -> int:
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"""
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see: https://curl.se/libcurl/c/CURLMOPT_TIMERFUNCTION.html
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"""
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async_curl = ffi.from_handle(clientp)
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# Cancel the timer anyway, if it's -1, yes, libcurl says it should be cancelled.
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# If not, to add a new timer, we need to cancel the old timer.
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if async_curl._timer:
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async_curl._timer.cancel() # If already called, cancel does nothing.
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async_curl._timer = None
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# libcurl says to install a timer which calls socket_action on fire.
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async_curl._timer = async_curl.loop.call_later(
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timeout_ms / 1000,
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async_curl.process_data,
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CURL_SOCKET_TIMEOUT, # -1
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CURL_POLL_NONE, # 0
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)
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return 0
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@ffi.def_extern()
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def socket_function(curl, sockfd: int, what: int, clientp: Any, data: Any) -> int:
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"""This callback is called when libcurl decides it's time to interact with certain
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sockets"""
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async_curl = ffi.from_handle(clientp)
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loop = async_curl.loop
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# Always remove and re-add fds
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if sockfd in async_curl._sockfds:
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loop.remove_reader(sockfd)
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loop.remove_writer(sockfd)
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# Need to read from the socket
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if what & CURL_POLL_IN:
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loop.add_reader(sockfd, async_curl.process_data, sockfd, CURL_CSELECT_IN)
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async_curl._sockfds.add(sockfd)
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# Need to write to the socket
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if what & CURL_POLL_OUT:
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loop.add_writer(sockfd, async_curl.process_data, sockfd, CURL_CSELECT_OUT)
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async_curl._sockfds.add(sockfd)
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# Need to remove the socket
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if what == CURL_POLL_REMOVE:
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async_curl._sockfds.remove(sockfd)
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return 0
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class AsyncCurl:
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"""Wrapper around curl_multi handle to provide asyncio support. It uses the libcurl
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socket_action APIs."""
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def __init__(self, cacert: str = "", loop=None):
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"""
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Parameters:
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cacert: CA cert path to use, by default, certs from ``certifi`` are used.
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loop: EventLoop to use.
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"""
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self._curlm = lib.curl_multi_init()
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self._cacert = cacert or DEFAULT_CACERT
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self._curl2future: dict[Curl, asyncio.Future] = {} # curl to future map
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self._curl2curl: dict[ffi.CData, Curl] = {} # c curl to Curl
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self._sockfds: set[int] = set() # sockfds
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self.loop = get_selector(
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loop if loop is not None else asyncio.get_running_loop()
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)
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self._timeout_checker = self.loop.create_task(self._force_timeout())
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self._timer: Optional[asyncio.TimerHandle] = None
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self._setup()
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def _setup(self):
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self.setopt(CurlMOpt.TIMERFUNCTION, lib.timer_function)
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self.setopt(CurlMOpt.SOCKETFUNCTION, lib.socket_function)
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self._self_handle = ffi.new_handle(self)
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self.setopt(CurlMOpt.SOCKETDATA, self._self_handle)
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self.setopt(CurlMOpt.TIMERDATA, self._self_handle)
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# self.setopt(CurlMOpt.PIPELINING, CURLPIPE_NOTHING)
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async def close(self):
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"""Close and cleanup running timers, readers, writers and handles."""
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# Close and wait for the force timeout checker to complete
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self._timeout_checker.cancel()
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with suppress(asyncio.CancelledError):
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await self._timeout_checker
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# Close all pending futures
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for curl, future in self._curl2future.items():
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lib.curl_multi_remove_handle(self._curlm, curl._curl)
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if not future.done() and not future.cancelled():
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future.set_result(None)
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# Cleanup curl_multi handle
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lib.curl_multi_cleanup(self._curlm)
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self._curlm = None
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# Remove add readers and writers
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for sockfd in self._sockfds:
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self.loop.remove_reader(sockfd)
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self.loop.remove_writer(sockfd)
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# Cancel all time functions
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if self._timer:
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self._timer.cancel()
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async def _force_timeout(self):
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"""This coroutine is used to safeguard from any missing signals from curl, and
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put everything back on track"""
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while True:
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if not self._curlm:
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break
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self.socket_action(CURL_SOCKET_TIMEOUT, CURL_POLL_NONE)
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await asyncio.sleep(0.1)
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def add_handle(self, curl: Curl):
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"""Add a curl handle to be managed by curl_multi. This is the equivalent of
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`perform` in the async world."""
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curl._ensure_cacert()
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errcode = lib.curl_multi_add_handle(self._curlm, curl._curl)
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self._check_error(errcode)
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future = self.loop.create_future()
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self._curl2future[curl] = future
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self._curl2curl[curl._curl] = curl
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return future
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def socket_action(self, sockfd: int, ev_bitmask: int) -> int:
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"""wrapper for curl_multi_socket_action,
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returns the number of running curl handles."""
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running_handle = ffi.new("int *")
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errcode = lib.curl_multi_socket_action(
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self._curlm, sockfd, ev_bitmask, running_handle
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)
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self._check_error(errcode)
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return running_handle[0]
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def process_data(self, sockfd: int, ev_bitmask: int):
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"""Call curl_multi_info_read to read data for given socket."""
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if not self._curlm:
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warnings.warn(
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"Curlm already closed! quitting from process_data",
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CurlCffiWarning,
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stacklevel=2,
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)
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return
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self.socket_action(sockfd, ev_bitmask)
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msg_in_queue = ffi.new("int *")
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while True:
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try:
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curl_msg = lib.curl_multi_info_read(self._curlm, msg_in_queue)
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# NULL is returned as a signal that no more to be get at this point
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if curl_msg == ffi.NULL:
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break
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if curl_msg.msg == CURLMSG_DONE:
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curl = self._curl2curl[curl_msg.easy_handle]
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retcode = curl_msg.data.result
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if retcode == 0:
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self.set_result(curl)
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else:
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self.set_exception(curl, curl._get_error(retcode, "perform"))
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else:
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print("NOT DONE") # Will not reach, for nothing else being defined.
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except Exception:
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warnings.warn(
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"Unexpected curl multi state in process_data, "
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"please open an issue on GitHub\n",
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CurlCffiWarning,
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stacklevel=2,
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)
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def _pop_future(self, curl: Curl):
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errcode = lib.curl_multi_remove_handle(self._curlm, curl._curl)
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self._check_error(errcode)
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self._curl2curl.pop(curl._curl, None)
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return self._curl2future.pop(curl, None)
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def remove_handle(self, curl: Curl):
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"""Cancel a future for given curl handle."""
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future = self._pop_future(curl)
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if future and not future.done() and not future.cancelled():
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future.cancel()
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def set_result(self, curl: Curl):
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"""Mark a future as done for given curl handle."""
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future = self._pop_future(curl)
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if future and not future.done() and not future.cancelled():
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future.set_result(None)
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def set_exception(self, curl: Curl, exception):
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"""Raise exception of a future for given curl handle."""
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future = self._pop_future(curl)
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if future and not future.done() and not future.cancelled():
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future.set_exception(exception)
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def _check_error(self, errcode: int, *args: Any):
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if errcode == CurlECode.OK:
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return
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errmsg = lib.curl_multi_strerror(errcode)
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action = " ".join([str(a) for a in args])
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raise CurlError(
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f"Failed in {action}, multi: ({errcode}) {errmsg}. "
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"See https://curl.se/libcurl/c/libcurl-errors.html first for more "
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"details. Please open an issue on GitHub to help debug this error.",
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)
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def setopt(self, option, value):
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"""Wrapper around curl_multi_setopt."""
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if option in (
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CurlMOpt.PIPELINING,
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CurlMOpt.MAXCONNECTS,
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CurlMOpt.MAX_HOST_CONNECTIONS,
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CurlMOpt.MAX_PIPELINE_LENGTH,
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CurlMOpt.MAX_TOTAL_CONNECTIONS,
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CurlMOpt.MAX_CONCURRENT_STREAMS,
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):
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c_value = ffi.new("long*", value)
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else:
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c_value = value
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return lib.curl_multi_setopt(self._curlm, option, c_value)
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