grpc/examples/python/route_guide/route_guide_server.py

# Copyright 2015, 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.

"""The Python implementation of the gRPC route guide server."""

from concurrent import futures
import time
import math

import grpc

import route_guide_pb2
import route_guide_resources

_ONE_DAY_IN_SECONDS = 60 * 60 * 24


def get_feature(feature_db, point):
  """Returns Feature at given location or None."""
  for feature in feature_db:
    if feature.location == point:
      return feature
  return None


def get_distance(start, end):
  """Distance between two points."""
  coord_factor = 10000000.0
  lat_1 = start.latitude / coord_factor
  lat_2 = end.latitude / coord_factor
  lon_1 = start.longitude / coord_factor
  lon_2 = end.longitude / coord_factor
  lat_rad_1 = math.radians(lat_1)
  lat_rad_2 = math.radians(lat_2)
  delta_lat_rad = math.radians(lat_2 - lat_1)
  delta_lon_rad = math.radians(lon_2 - lon_1)

  a = (pow(math.sin(delta_lat_rad / 2), 2) +
       (math.cos(lat_rad_1) * math.cos(lat_rad_2) *
        pow(math.sin(delta_lon_rad / 2), 2)))
  c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a))
  R = 6371000; # metres
  return R * c;

class RouteGuideServicer(route_guide_pb2.RouteGuideServicer):
  """Provides methods that implement functionality of route guide server."""

  def __init__(self):
    self.db = route_guide_resources.read_route_guide_database()

  def GetFeature(self, request, context):
    feature = get_feature(self.db, request)
    if feature is None:
      return route_guide_pb2.Feature(name="", location=request)
    else:
      return feature

  def ListFeatures(self, request, context):
    left = min(request.lo.longitude, request.hi.longitude)
    right = max(request.lo.longitude, request.hi.longitude)
    top = max(request.lo.latitude, request.hi.latitude)
    bottom = min(request.lo.latitude, request.hi.latitude)
    for feature in self.db:
      if (feature.location.longitude >= left and
          feature.location.longitude <= right and
          feature.location.latitude >= bottom and
          feature.location.latitude <= top):
        yield feature

  def RecordRoute(self, request_iterator, context):
    point_count = 0
    feature_count = 0
    distance = 0.0
    prev_point = None

    start_time = time.time()
    for point in request_iterator:
      point_count += 1
      if get_feature(self.db, point):
        feature_count += 1
      if prev_point:
        distance += get_distance(prev_point, point)
      prev_point = point

    elapsed_time = time.time() - start_time
    return route_guide_pb2.RouteSummary(point_count=point_count,
                                        feature_count=feature_count,
                                        distance=int(distance),
                                        elapsed_time=int(elapsed_time))

  def RouteChat(self, request_iterator, context):
    prev_notes = []
    for new_note in request_iterator:
      for prev_note in prev_notes:
        if prev_note.location == new_note.location:
          yield prev_note
      prev_notes.append(new_note)


def serve():
  server = grpc.server(futures.ThreadPoolExecutor(max_workers=10))
  route_guide_pb2.add_RouteGuideServicer_to_server(
      RouteGuideServicer(), server)
  server.add_insecure_port('[::]:50051')
  server.start()
  try:
    while True:
      time.sleep(_ONE_DAY_IN_SECONDS)
  except KeyboardInterrupt:
    server.stop(0)

if __name__ == '__main__':
  serve()