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http2_base_server.py
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http2_base_server.py
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# Copyright 2016, Google Inc.
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import logging
import messages_pb2
import struct
import h2
import h2.connection
import twisted
import twisted.internet
import twisted.internet.protocol
_READ_CHUNK_SIZE = 16384
_GRPC_HEADER_SIZE = 5
_MIN_SETTINGS_MAX_FRAME_SIZE = 16384
class H2ProtocolBaseServer(twisted.internet.protocol.Protocol):
def __init__(self):
self._conn = h2.connection.H2Connection(client_side=False)
self._recv_buffer = {}
self._handlers = {}
self._handlers['ConnectionMade'] = self.on_connection_made_default
self._handlers['DataReceived'] = self.on_data_received_default
self._handlers['WindowUpdated'] = self.on_window_update_default
self._handlers['RequestReceived'] = self.on_request_received_default
self._handlers['SendDone'] = self.on_send_done_default
self._handlers['ConnectionLost'] = self.on_connection_lost
self._handlers['PingAcknowledged'] = self.on_ping_acknowledged_default
self._stream_status = {}
self._send_remaining = {}
self._outstanding_pings = 0
def set_handlers(self, handlers):
self._handlers = handlers
def connectionMade(self):
self._handlers['ConnectionMade']()
def connectionLost(self, reason):
self._handlers['ConnectionLost'](reason)
def on_connection_made_default(self):
logging.info('Connection Made')
self._conn.initiate_connection()
self.transport.setTcpNoDelay(True)
self.transport.write(self._conn.data_to_send())
def on_connection_lost(self, reason):
logging.info('Disconnected %s' % reason)
def dataReceived(self, data):
try:
events = self._conn.receive_data(data)
except h2.exceptions.ProtocolError:
# this try/except block catches exceptions due to race between sending
# GOAWAY and processing a response in flight.
return
if self._conn.data_to_send:
self.transport.write(self._conn.data_to_send())
for event in events:
if isinstance(event, h2.events.RequestReceived) and self._handlers.has_key('RequestReceived'):
logging.info('RequestReceived Event for stream: %d' % event.stream_id)
self._handlers['RequestReceived'](event)
elif isinstance(event, h2.events.DataReceived) and self._handlers.has_key('DataReceived'):
logging.info('DataReceived Event for stream: %d' % event.stream_id)
self._handlers['DataReceived'](event)
elif isinstance(event, h2.events.WindowUpdated) and self._handlers.has_key('WindowUpdated'):
logging.info('WindowUpdated Event for stream: %d' % event.stream_id)
self._handlers['WindowUpdated'](event)
elif isinstance(event, h2.events.PingAcknowledged) and self._handlers.has_key('PingAcknowledged'):
logging.info('PingAcknowledged Event')
self._handlers['PingAcknowledged'](event)
self.transport.write(self._conn.data_to_send())
def on_ping_acknowledged_default(self, event):
logging.info('ping acknowledged')
self._outstanding_pings -= 1
def on_data_received_default(self, event):
self._conn.acknowledge_received_data(len(event.data), event.stream_id)
self._recv_buffer[event.stream_id] += event.data
def on_request_received_default(self, event):
self._recv_buffer[event.stream_id] = ''
self._stream_id = event.stream_id
self._stream_status[event.stream_id] = True
self._conn.send_headers(
stream_id=event.stream_id,
headers=[
(':status', '200'),
('content-type', 'application/grpc'),
('grpc-encoding', 'identity'),
('grpc-accept-encoding', 'identity,deflate,gzip'),
],
)
self.transport.write(self._conn.data_to_send())
def on_window_update_default(self, _, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
# try to resume sending on all active streams (update might be for connection)
for stream_id in self._send_remaining:
self.default_send(stream_id, pad_length=pad_length, read_chunk_size=read_chunk_size)
def send_reset_stream(self):
self._conn.reset_stream(self._stream_id)
self.transport.write(self._conn.data_to_send())
def setup_send(self, data_to_send, stream_id, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
logging.info('Setting up data to send for stream_id: %d' % stream_id)
self._send_remaining[stream_id] = len(data_to_send)
self._send_offset = 0
self._data_to_send = data_to_send
self.default_send(stream_id, pad_length=pad_length, read_chunk_size=read_chunk_size)
def default_send(self, stream_id, pad_length=None, read_chunk_size=_READ_CHUNK_SIZE):
if not self._send_remaining.has_key(stream_id):
# not setup to send data yet
return
while self._send_remaining[stream_id] > 0:
lfcw = self._conn.local_flow_control_window(stream_id)
padding_bytes = pad_length + 1 if pad_length is not None else 0
if lfcw - padding_bytes <= 0:
logging.info('Stream %d. lfcw: %d. padding bytes: %d. not enough quota yet' % (stream_id, lfcw, padding_bytes))
break
chunk_size = min(lfcw - padding_bytes, read_chunk_size)
bytes_to_send = min(chunk_size, self._send_remaining[stream_id])
logging.info('flow_control_window = %d. sending [%d:%d] stream_id %d. includes %d total padding bytes' %
(lfcw, self._send_offset, self._send_offset + bytes_to_send + padding_bytes,
stream_id, padding_bytes))
# The receiver might allow sending frames larger than the http2 minimum
# max frame size (16384), but this test should never send more than 16384
# for simplicity (which is always legal).
if bytes_to_send + padding_bytes > _MIN_SETTINGS_MAX_FRAME_SIZE:
raise ValueError("overload: sending %d" % (bytes_to_send + padding_bytes))
data = self._data_to_send[self._send_offset : self._send_offset + bytes_to_send]
try:
self._conn.send_data(stream_id, data, end_stream=False, pad_length=pad_length)
except h2.exceptions.ProtocolError:
logging.info('Stream %d is closed' % stream_id)
break
self._send_remaining[stream_id] -= bytes_to_send
self._send_offset += bytes_to_send
if self._send_remaining[stream_id] == 0:
self._handlers['SendDone'](stream_id)
def default_ping(self):
logging.info('sending ping')
self._outstanding_pings += 1
self._conn.ping(b'\x00'*8)
self.transport.write(self._conn.data_to_send())
def on_send_done_default(self, stream_id):
if self._stream_status[stream_id]:
self._stream_status[stream_id] = False
self.default_send_trailer(stream_id)
else:
logging.error('Stream %d is already closed' % stream_id)
def default_send_trailer(self, stream_id):
logging.info('Sending trailer for stream id %d' % stream_id)
self._conn.send_headers(stream_id,
headers=[ ('grpc-status', '0') ],
end_stream=True
)
self.transport.write(self._conn.data_to_send())
@staticmethod
def default_response_data(response_size):
sresp = messages_pb2.SimpleResponse()
sresp.payload.body = b'\x00'*response_size
serialized_resp_proto = sresp.SerializeToString()
response_data = b'\x00' + struct.pack('i', len(serialized_resp_proto))[::-1] + serialized_resp_proto
return response_data
def parse_received_data(self, stream_id):
""" returns a grpc framed string of bytes containing response proto of the size
asked in request """
recv_buffer = self._recv_buffer[stream_id]
grpc_msg_size = struct.unpack('i',recv_buffer[1:5][::-1])[0]
if len(recv_buffer) != _GRPC_HEADER_SIZE + grpc_msg_size:
return None
req_proto_str = recv_buffer[5:5+grpc_msg_size]
sr = messages_pb2.SimpleRequest()
sr.ParseFromString(req_proto_str)
logging.info('Parsed simple request for stream %d' % stream_id)
return sr