/usr/lib/python3/dist-packages/protorpc/transport.py is in python3-protorpc-standalone 0.9.1-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 | #!/usr/bin/env python
#
# Copyright 2010 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""Transport library for ProtoRPC.
Contains underlying infrastructure used for communicating RPCs over low level
transports such as HTTP.
Includes HTTP transport built over urllib2.
"""
import httplib
import logging
import os
import socket
import sys
import urlparse
from . import messages
from . import protobuf
from . import remote
from . import util
__all__ = [
'RpcStateError',
'HttpTransport',
'LocalTransport',
'Rpc',
'Transport',
]
class RpcStateError(messages.Error):
"""Raised when trying to put RPC in to an invalid state."""
class Rpc(object):
"""Represents a client side RPC.
An RPC is created by the transport class and is used with a single RPC. While
an RPC is still in process, the response is set to None. When it is complete
the response will contain the response message.
"""
def __init__(self, request):
"""Constructor.
Args:
request: Request associated with this RPC.
"""
self.__request = request
self.__response = None
self.__state = remote.RpcState.RUNNING
self.__error_message = None
self.__error_name = None
@property
def request(self):
"""Request associated with RPC."""
return self.__request
@property
def response(self):
"""Response associated with RPC."""
self.wait()
self.__check_status()
return self.__response
@property
def state(self):
"""State associated with RPC."""
return self.__state
@property
def error_message(self):
"""Error, if any, associated with RPC."""
self.wait()
return self.__error_message
@property
def error_name(self):
"""Error name, if any, associated with RPC."""
self.wait()
return self.__error_name
def wait(self):
"""Wait for an RPC to finish."""
if self.__state == remote.RpcState.RUNNING:
self._wait_impl()
def _wait_impl(self):
"""Implementation for wait()."""
raise NotImplementedError()
def __check_status(self):
error_class = remote.RpcError.from_state(self.__state)
if error_class is not None:
if error_class is remote.ApplicationError:
raise error_class(self.__error_message, self.__error_name)
else:
raise error_class(self.__error_message)
def __set_state(self, state, error_message=None, error_name=None):
if self.__state != remote.RpcState.RUNNING:
raise RpcStateError(
'RPC must be in RUNNING state to change to %s' % state)
if state == remote.RpcState.RUNNING:
raise RpcStateError('RPC is already in RUNNING state')
self.__state = state
self.__error_message = error_message
self.__error_name = error_name
def set_response(self, response):
# TODO: Even more specific type checking.
if not isinstance(response, messages.Message):
raise TypeError('Expected Message type, received %r' % (response))
self.__response = response
self.__set_state(remote.RpcState.OK)
def set_status(self, status):
status.check_initialized()
self.__set_state(status.state, status.error_message, status.error_name)
class Transport(object):
"""Transport base class.
Provides basic support for implementing a ProtoRPC transport such as one
that can send and receive messages over HTTP.
Implementations override _start_rpc. This method receives a RemoteInfo
instance and a request Message. The transport is expected to set the rpc
response or raise an exception before termination.
"""
@util.positional(1)
def __init__(self, protocol=protobuf):
"""Constructor.
Args:
protocol: If string, will look up a protocol from the default Protocols
instance by name. Can also be an instance of remote.ProtocolConfig.
If neither, it must be an object that implements a protocol interface
by implementing encode_message, decode_message and set CONTENT_TYPE.
For example, the modules protobuf and protojson can be used directly.
"""
if isinstance(protocol, basestring):
protocols = remote.Protocols.get_default()
try:
protocol = protocols.lookup_by_name(protocol)
except KeyError:
protocol = protocols.lookup_by_content_type(protocol)
if isinstance(protocol, remote.ProtocolConfig):
self.__protocol = protocol.protocol
self.__protocol_config = protocol
else:
self.__protocol = protocol
self.__protocol_config = remote.ProtocolConfig(
protocol, 'default', default_content_type=protocol.CONTENT_TYPE)
@property
def protocol(self):
"""Protocol associated with this transport."""
return self.__protocol
@property
def protocol_config(self):
"""Protocol associated with this transport."""
return self.__protocol_config
def send_rpc(self, remote_info, request):
"""Initiate sending an RPC over the transport.
Args:
remote_info: RemoteInfo instance describing remote method.
request: Request message to send to service.
Returns:
An Rpc instance intialized with the request..
"""
request.check_initialized()
rpc = self._start_rpc(remote_info, request)
return rpc
def _start_rpc(self, remote_info, request):
"""Start a remote procedure call.
Args:
remote_info: RemoteInfo instance describing remote method.
request: Request message to send to service.
Returns:
An Rpc instance initialized with the request.
"""
raise NotImplementedError()
class HttpTransport(Transport):
"""Transport for communicating with HTTP servers."""
@util.positional(2)
def __init__(self,
service_url,
protocol=protobuf):
"""Constructor.
Args:
service_url: URL where the service is located. All communication via
the transport will go to this URL.
protocol: The protocol implementation. Must implement encode_message and
decode_message. Can also be an instance of remote.ProtocolConfig.
"""
super(HttpTransport, self).__init__(protocol=protocol)
self.__service_url = service_url
def __get_rpc_status(self, response, content):
"""Get RPC status from HTTP response.
Args:
response: HTTPResponse object.
content: Content read from HTTP response.
Returns:
RpcStatus object parsed from response, else an RpcStatus with a generic
HTTP error.
"""
# Status above 400 may have RpcStatus content.
if response.status >= 400:
content_type = response.getheader('content-type')
if content_type == self.protocol_config.default_content_type:
try:
rpc_status = self.protocol.decode_message(remote.RpcStatus, content)
except Exception as decode_err:
logging.warning(
'An error occurred trying to parse status: %s\n%s',
str(decode_err), content)
else:
if rpc_status.is_initialized():
return rpc_status
else:
logging.warning(
'Body does not result in an initialized RpcStatus message:\n%s',
content)
# If no RpcStatus message present, attempt to forward any content. If empty
# use standard error message.
if not content.strip():
content = httplib.responses.get(response.status, 'Unknown Error')
return remote.RpcStatus(state=remote.RpcState.SERVER_ERROR,
error_message='HTTP Error %s: %s' % (
response.status, content or 'Unknown Error'))
def __set_response(self, remote_info, connection, rpc):
"""Set response on RPC.
Sets response or status from HTTP request. Implements the wait method of
Rpc instance.
Args:
remote_info: Remote info for invoked RPC.
connection: HTTPConnection that is making request.
rpc: Rpc instance.
"""
try:
response = connection.getresponse()
content = response.read()
if response.status == httplib.OK:
response = self.protocol.decode_message(remote_info.response_type,
content)
rpc.set_response(response)
else:
status = self.__get_rpc_status(response, content)
rpc.set_status(status)
finally:
connection.close()
def _start_rpc(self, remote_info, request):
"""Start a remote procedure call.
Args:
remote_info: A RemoteInfo instance for this RPC.
request: The request message for this RPC.
Returns:
An Rpc instance initialized with a Request.
"""
method_url = '%s.%s' % (self.__service_url, remote_info.method.func_name)
encoded_request = self.protocol.encode_message(request)
url = urlparse.urlparse(method_url)
if url.scheme == 'https':
connection_type = httplib.HTTPSConnection
else:
connection_type = httplib.HTTPConnection
connection = connection_type(url.hostname, url.port)
try:
self._send_http_request(connection, url.path, encoded_request)
rpc = Rpc(request)
except remote.RpcError:
# Pass through all ProtoRPC errors
connection.close()
raise
except socket.error as err:
connection.close()
raise remote.NetworkError('Socket error: %s %r' % (type(err).__name__,
err.args),
err)
except Exception as err:
connection.close()
raise remote.NetworkError('Error communicating with HTTP server',
err)
else:
wait_impl = lambda: self.__set_response(remote_info, connection, rpc)
rpc._wait_impl = wait_impl
return rpc
def _send_http_request(self, connection, http_path, encoded_request):
connection.request(
'POST',
http_path,
encoded_request,
headers={'Content-type': self.protocol_config.default_content_type,
'Content-length': len(encoded_request)})
class LocalTransport(Transport):
"""Local transport that sends messages directly to services.
Useful in tests or creating code that can work with either local or remote
services. Using LocalTransport is preferrable to simply instantiating a
single instance of a service and reusing it. The entire request process
involves instantiating a new instance of a service, initializing it with
request state and then invoking the remote method for every request.
"""
def __init__(self, service_factory):
"""Constructor.
Args:
service_factory: Service factory or class.
"""
super(LocalTransport, self).__init__()
self.__service_class = getattr(service_factory,
'service_class',
service_factory)
self.__service_factory = service_factory
@property
def service_class(self):
return self.__service_class
@property
def service_factory(self):
return self.__service_factory
def _start_rpc(self, remote_info, request):
"""Start a remote procedure call.
Args:
remote_info: RemoteInfo instance describing remote method.
request: Request message to send to service.
Returns:
An Rpc instance initialized with the request.
"""
rpc = Rpc(request)
def wait_impl():
instance = self.__service_factory()
try:
initalize_request_state = instance.initialize_request_state
except AttributeError:
pass
else:
host = unicode(os.uname()[1])
initalize_request_state(remote.RequestState(remote_host=host,
remote_address=u'127.0.0.1',
server_host=host,
server_port=-1))
try:
response = remote_info.method(instance, request)
assert isinstance(response, remote_info.response_type)
except remote.ApplicationError:
raise
except:
exc_type, exc_value, traceback = sys.exc_info()
message = 'Unexpected error %s: %s' % (exc_type.__name__, exc_value)
raise remote.ServerError(message)
rpc.set_response(response)
rpc._wait_impl = wait_impl
return rpc
|