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1# Copyright 2016 gRPC authors.
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15import http2_base_server
16import logging
17import messages_pb2
18
19# Set the number of padding bytes per data frame to be very large
20# relative to the number of data bytes for each data frame sent.
21_LARGE_PADDING_LENGTH = 255
22_SMALL_READ_CHUNK_SIZE = 5
23
24class TestDataFramePadding(object):
25  """
26    In response to an incoming request, this test sends headers, followed by
27    data, followed by a reset stream frame. Client asserts that the RPC failed.
28    Client needs to deliver the complete message to the application layer.
29  """
30  def __init__(self, use_padding=True):
31    self._base_server = http2_base_server.H2ProtocolBaseServer()
32    self._base_server._handlers['DataReceived'] = self.on_data_received
33    self._base_server._handlers['WindowUpdated'] = self.on_window_update
34    self._base_server._handlers['RequestReceived'] = self.on_request_received
35
36    # _total_updates maps stream ids to total flow control updates received
37    self._total_updates = {}
38    # zero window updates so far for connection window (stream id '0')
39    self._total_updates[0] = 0
40    self._read_chunk_size = _SMALL_READ_CHUNK_SIZE
41
42    if use_padding:
43      self._pad_length = _LARGE_PADDING_LENGTH
44    else:
45      self._pad_length = None
46
47  def get_base_server(self):
48    return self._base_server
49
50  def on_data_received(self, event):
51    logging.info('on data received. Stream id: %d. Data length: %d' % (event.stream_id, len(event.data)))
52    self._base_server.on_data_received_default(event)
53    if len(event.data) == 0:
54      return
55    sr = self._base_server.parse_received_data(event.stream_id)
56    stream_bytes = ''
57    # Check if full grpc msg has been read into the recv buffer yet
58    if sr:
59      response_data = self._base_server.default_response_data(sr.response_size)
60      logging.info('Stream id: %d. total resp size: %d' % (event.stream_id, len(response_data)))
61      # Begin sending the response. Add ``self._pad_length`` padding to each
62      # data frame and split the whole message into data frames each carrying
63      # only self._read_chunk_size of data.
64      # The purpose is to have the majority of the data frame response bytes
65      # be padding bytes, since ``self._pad_length`` >> ``self._read_chunk_size``.
66      self._base_server.setup_send(response_data , event.stream_id, pad_length=self._pad_length, read_chunk_size=self._read_chunk_size)
67
68  def on_request_received(self, event):
69    self._base_server.on_request_received_default(event)
70    logging.info('on request received. Stream id: %s.' % event.stream_id)
71    self._total_updates[event.stream_id] = 0
72
73  # Log debug info and try to resume sending on all currently active streams.
74  def on_window_update(self, event):
75    logging.info('on window update. Stream id: %s. Delta: %s' % (event.stream_id, event.delta))
76    self._total_updates[event.stream_id] += event.delta
77    total = self._total_updates[event.stream_id]
78    logging.info('... - total updates for stream %d : %d' % (event.stream_id, total))
79    self._base_server.on_window_update_default(event, pad_length=self._pad_length, read_chunk_size=self._read_chunk_size)
80