mirror of https://github.com/morpheus65535/bazarr
488 lines
18 KiB
Python
488 lines
18 KiB
Python
##############################################################################
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#
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# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
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# All Rights Reserved.
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#
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# This software is subject to the provisions of the Zope Public License,
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# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
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# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
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# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
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# FOR A PARTICULAR PURPOSE.
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#
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##############################################################################
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import socket
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import threading
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import time
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import traceback
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from waitress.buffers import OverflowableBuffer, ReadOnlyFileBasedBuffer
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from waitress.parser import HTTPRequestParser
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from waitress.task import ErrorTask, WSGITask
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from waitress.utilities import InternalServerError
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from . import wasyncore
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class ClientDisconnected(Exception):
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""" Raised when attempting to write to a closed socket."""
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class HTTPChannel(wasyncore.dispatcher):
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"""
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Setting self.requests = [somerequest] prevents more requests from being
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received until the out buffers have been flushed.
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Setting self.requests = [] allows more requests to be received.
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"""
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task_class = WSGITask
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error_task_class = ErrorTask
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parser_class = HTTPRequestParser
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# A request that has not been received yet completely is stored here
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request = None
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last_activity = 0 # Time of last activity
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will_close = False # set to True to close the socket.
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close_when_flushed = False # set to True to close the socket when flushed
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sent_continue = False # used as a latch after sending 100 continue
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total_outbufs_len = 0 # total bytes ready to send
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current_outbuf_count = 0 # total bytes written to current outbuf
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#
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# ASYNCHRONOUS METHODS (including __init__)
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#
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def __init__(self, server, sock, addr, adj, map=None):
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self.server = server
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self.adj = adj
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self.outbufs = [OverflowableBuffer(adj.outbuf_overflow)]
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self.creation_time = self.last_activity = time.time()
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self.sendbuf_len = sock.getsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF)
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# requests_lock used to push/pop requests and modify the request that is
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# currently being created
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self.requests_lock = threading.Lock()
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# outbuf_lock used to access any outbuf (expected to use an RLock)
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self.outbuf_lock = threading.Condition()
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wasyncore.dispatcher.__init__(self, sock, map=map)
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# Don't let wasyncore.dispatcher throttle self.addr on us.
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self.addr = addr
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self.requests = []
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def check_client_disconnected(self):
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"""
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This method is inserted into the environment of any created task so it
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may occasionally check if the client has disconnected and interrupt
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execution.
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"""
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return not self.connected
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def writable(self):
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# if there's data in the out buffer or we've been instructed to close
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# the channel (possibly by our server maintenance logic), run
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# handle_write
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return self.total_outbufs_len or self.will_close or self.close_when_flushed
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def handle_write(self):
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# Precondition: there's data in the out buffer to be sent, or
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# there's a pending will_close request
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if not self.connected:
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# we dont want to close the channel twice
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return
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# try to flush any pending output
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if not self.requests:
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# 1. There are no running tasks, so we don't need to try to lock
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# the outbuf before sending
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# 2. The data in the out buffer should be sent as soon as possible
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# because it's either data left over from task output
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# or a 100 Continue line sent within "received".
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flush = self._flush_some
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elif self.total_outbufs_len >= self.adj.send_bytes:
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# 1. There's a running task, so we need to try to lock
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# the outbuf before sending
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# 2. Only try to send if the data in the out buffer is larger
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# than self.adj_bytes to avoid TCP fragmentation
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flush = self._flush_some_if_lockable
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else:
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# 1. There's not enough data in the out buffer to bother to send
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# right now.
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flush = None
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if flush:
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try:
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flush()
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except OSError:
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if self.adj.log_socket_errors:
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self.logger.exception("Socket error")
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self.will_close = True
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except Exception: # pragma: nocover
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self.logger.exception("Unexpected exception when flushing")
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self.will_close = True
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if self.close_when_flushed and not self.total_outbufs_len:
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self.close_when_flushed = False
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self.will_close = True
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if self.will_close:
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self.handle_close()
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def readable(self):
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# We might want to read more requests. We can only do this if:
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# 1. We're not already about to close the connection.
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# 2. We're not waiting to flush remaining data before closing the
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# connection
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# 3. There are not too many tasks already queued
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# 4. There's no data in the output buffer that needs to be sent
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# before we potentially create a new task.
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return not (
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self.will_close
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or self.close_when_flushed
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or len(self.requests) > self.adj.channel_request_lookahead
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or self.total_outbufs_len
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)
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def handle_read(self):
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try:
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data = self.recv(self.adj.recv_bytes)
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except OSError:
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if self.adj.log_socket_errors:
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self.logger.exception("Socket error")
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self.handle_close()
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return
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if data:
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self.last_activity = time.time()
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self.received(data)
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else:
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# Client disconnected.
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self.connected = False
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def send_continue(self):
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"""
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Send a 100-Continue header to the client. This is either called from
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receive (if no requests are running and the client expects it) or at
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the end of service (if no more requests are queued and a request has
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been read partially that expects it).
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"""
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self.request.expect_continue = False
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outbuf_payload = b"HTTP/1.1 100 Continue\r\n\r\n"
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num_bytes = len(outbuf_payload)
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with self.outbuf_lock:
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self.outbufs[-1].append(outbuf_payload)
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self.current_outbuf_count += num_bytes
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self.total_outbufs_len += num_bytes
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self.sent_continue = True
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self._flush_some()
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self.request.completed = False
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def received(self, data):
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"""
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Receives input asynchronously and assigns one or more requests to the
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channel.
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"""
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if not data:
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return False
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with self.requests_lock:
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while data:
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if self.request is None:
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self.request = self.parser_class(self.adj)
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n = self.request.received(data)
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# if there are requests queued, we can not send the continue
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# header yet since the responses need to be kept in order
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if (
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self.request.expect_continue
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and self.request.headers_finished
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and not self.requests
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and not self.sent_continue
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):
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self.send_continue()
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if self.request.completed:
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# The request (with the body) is ready to use.
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self.sent_continue = False
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if not self.request.empty:
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self.requests.append(self.request)
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if len(self.requests) == 1:
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# self.requests was empty before so the main thread
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# is in charge of starting the task. Otherwise,
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# service() will add a new task after each request
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# has been processed
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self.server.add_task(self)
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self.request = None
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if n >= len(data):
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break
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data = data[n:]
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return True
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def _flush_some_if_lockable(self):
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# Since our task may be appending to the outbuf, we try to acquire
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# the lock, but we don't block if we can't.
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if self.outbuf_lock.acquire(False):
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try:
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self._flush_some()
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if self.total_outbufs_len < self.adj.outbuf_high_watermark:
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self.outbuf_lock.notify()
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finally:
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self.outbuf_lock.release()
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def _flush_some(self):
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# Send as much data as possible to our client
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sent = 0
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dobreak = False
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while True:
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outbuf = self.outbufs[0]
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# use outbuf.__len__ rather than len(outbuf) FBO of not getting
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# OverflowError on 32-bit Python
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outbuflen = outbuf.__len__()
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while outbuflen > 0:
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chunk = outbuf.get(self.sendbuf_len)
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num_sent = self.send(chunk)
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if num_sent:
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outbuf.skip(num_sent, True)
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outbuflen -= num_sent
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sent += num_sent
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self.total_outbufs_len -= num_sent
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else:
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# failed to write anything, break out entirely
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dobreak = True
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break
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else:
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# self.outbufs[-1] must always be a writable outbuf
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if len(self.outbufs) > 1:
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toclose = self.outbufs.pop(0)
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try:
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toclose.close()
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except Exception:
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self.logger.exception("Unexpected error when closing an outbuf")
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else:
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# caught up, done flushing for now
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dobreak = True
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if dobreak:
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break
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if sent:
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self.last_activity = time.time()
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return True
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return False
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def handle_close(self):
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with self.outbuf_lock:
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for outbuf in self.outbufs:
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try:
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outbuf.close()
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except Exception:
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self.logger.exception(
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"Unknown exception while trying to close outbuf"
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)
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self.total_outbufs_len = 0
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self.connected = False
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self.outbuf_lock.notify()
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wasyncore.dispatcher.close(self)
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def add_channel(self, map=None):
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"""See wasyncore.dispatcher
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This hook keeps track of opened channels.
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"""
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wasyncore.dispatcher.add_channel(self, map)
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self.server.active_channels[self._fileno] = self
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def del_channel(self, map=None):
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"""See wasyncore.dispatcher
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This hook keeps track of closed channels.
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"""
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fd = self._fileno # next line sets this to None
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wasyncore.dispatcher.del_channel(self, map)
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ac = self.server.active_channels
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if fd in ac:
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del ac[fd]
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#
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# SYNCHRONOUS METHODS
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#
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def write_soon(self, data):
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if not self.connected:
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# if the socket is closed then interrupt the task so that it
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# can cleanup possibly before the app_iter is exhausted
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raise ClientDisconnected
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if data:
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# the async mainloop might be popping data off outbuf; we can
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# block here waiting for it because we're in a task thread
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with self.outbuf_lock:
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self._flush_outbufs_below_high_watermark()
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if not self.connected:
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raise ClientDisconnected
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num_bytes = len(data)
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if data.__class__ is ReadOnlyFileBasedBuffer:
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# they used wsgi.file_wrapper
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self.outbufs.append(data)
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nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)
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self.outbufs.append(nextbuf)
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self.current_outbuf_count = 0
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else:
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if self.current_outbuf_count >= self.adj.outbuf_high_watermark:
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# rotate to a new buffer if the current buffer has hit
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# the watermark to avoid it growing unbounded
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nextbuf = OverflowableBuffer(self.adj.outbuf_overflow)
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self.outbufs.append(nextbuf)
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self.current_outbuf_count = 0
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self.outbufs[-1].append(data)
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self.current_outbuf_count += num_bytes
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self.total_outbufs_len += num_bytes
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if self.total_outbufs_len >= self.adj.send_bytes:
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self.server.pull_trigger()
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return num_bytes
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return 0
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def _flush_outbufs_below_high_watermark(self):
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# check first to avoid locking if possible
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if self.total_outbufs_len > self.adj.outbuf_high_watermark:
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with self.outbuf_lock:
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while (
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self.connected
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and self.total_outbufs_len > self.adj.outbuf_high_watermark
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):
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self.server.pull_trigger()
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self.outbuf_lock.wait()
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def service(self):
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"""Execute one request. If there are more, we add another task to the
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server at the end."""
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request = self.requests[0]
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if request.error:
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task = self.error_task_class(self, request)
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else:
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task = self.task_class(self, request)
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try:
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if self.connected:
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task.service()
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else:
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task.close_on_finish = True
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except ClientDisconnected:
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self.logger.info("Client disconnected while serving %s" % task.request.path)
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task.close_on_finish = True
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except Exception:
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self.logger.exception("Exception while serving %s" % task.request.path)
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if not task.wrote_header:
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if self.adj.expose_tracebacks:
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body = traceback.format_exc()
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else:
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body = "The server encountered an unexpected internal server error"
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req_version = request.version
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req_headers = request.headers
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err_request = self.parser_class(self.adj)
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err_request.error = InternalServerError(body)
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# copy some original request attributes to fulfill
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# HTTP 1.1 requirements
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err_request.version = req_version
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try:
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err_request.headers["CONNECTION"] = req_headers["CONNECTION"]
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except KeyError:
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pass
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task = self.error_task_class(self, err_request)
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try:
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task.service() # must not fail
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except ClientDisconnected:
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task.close_on_finish = True
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else:
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task.close_on_finish = True
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if task.close_on_finish:
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with self.requests_lock:
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self.close_when_flushed = True
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for request in self.requests:
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request.close()
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self.requests = []
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else:
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# before processing a new request, ensure there is not too
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# much data in the outbufs waiting to be flushed
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# NB: currently readable() returns False while we are
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# flushing data so we know no new requests will come in
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# that we need to account for, otherwise it'd be better
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# to do this check at the start of the request instead of
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# at the end to account for consecutive service() calls
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if len(self.requests) > 1:
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self._flush_outbufs_below_high_watermark()
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# this is a little hacky but basically it's forcing the
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# next request to create a new outbuf to avoid sharing
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# outbufs across requests which can cause outbufs to
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# not be deallocated regularly when a connection is open
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# for a long time
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if self.current_outbuf_count > 0:
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self.current_outbuf_count = self.adj.outbuf_high_watermark
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request.close()
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# Add new task to process the next request
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with self.requests_lock:
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self.requests.pop(0)
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if self.connected and self.requests:
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self.server.add_task(self)
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elif (
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self.connected
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and self.request is not None
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and self.request.expect_continue
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and self.request.headers_finished
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and not self.sent_continue
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):
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# A request waits for a signal to continue, but we could
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# not send it until now because requests were being
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# processed and the output needs to be kept in order
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self.send_continue()
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if self.connected:
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self.server.pull_trigger()
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self.last_activity = time.time()
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def cancel(self):
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""" Cancels all pending / active requests """
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self.will_close = True
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self.connected = False
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self.last_activity = time.time()
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self.requests = []
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