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# --------------------------------------------------------------------------
#
# Copyright (c) Microsoft Corporation. All rights reserved.
#
# The MIT License (MIT)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the ""Software""), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.
#
# --------------------------------------------------------------------------
import abc
from typing import Any, List, Union, Callable, AsyncIterator, Optional, Generic, TypeVar
from . import Request, Response, Pipeline, SansIOHTTPPolicy
AsyncHTTPResponseType = TypeVar("AsyncHTTPResponseType")
HTTPRequestType = TypeVar("HTTPRequestType")
try:
from contextlib import AbstractAsyncContextManager # type: ignore
except ImportError: # Python <= 3.7
class AbstractAsyncContextManager(object): # type: ignore
async def __aenter__(self):
"""Return `self` upon entering the runtime context."""
return self
@abc.abstractmethod
async def __aexit__(self, exc_type, exc_value, traceback):
"""Raise any exception triggered within the runtime context."""
return None
class AsyncHTTPPolicy(abc.ABC, Generic[HTTPRequestType, AsyncHTTPResponseType]):
"""An http policy ABC.
"""
def __init__(self) -> None:
# next will be set once in the pipeline
self.next = None # type: Optional[Union[AsyncHTTPPolicy[HTTPRequestType, AsyncHTTPResponseType], AsyncHTTPSender[HTTPRequestType, AsyncHTTPResponseType]]]
@abc.abstractmethod
async def send(self, request: Request, **kwargs: Any) -> Response[HTTPRequestType, AsyncHTTPResponseType]:
"""Mutate the request.
Context content is dependent of the HTTPSender.
"""
pass
class _SansIOAsyncHTTPPolicyRunner(AsyncHTTPPolicy[HTTPRequestType, AsyncHTTPResponseType]):
"""Async implementation of the SansIO policy.
"""
def __init__(self, policy: SansIOHTTPPolicy) -> None:
super(_SansIOAsyncHTTPPolicyRunner, self).__init__()
self._policy = policy
async def send(self, request: Request, **kwargs: Any) -> Response[HTTPRequestType, AsyncHTTPResponseType]:
self._policy.on_request(request, **kwargs)
try:
response = await self.next.send(request, **kwargs) # type: ignore
except Exception:
if not self._policy.on_exception(request, **kwargs):
raise
else:
self._policy.on_response(request, response, **kwargs)
return response
class AsyncHTTPSender(AbstractAsyncContextManager, abc.ABC, Generic[HTTPRequestType, AsyncHTTPResponseType]):
"""An http sender ABC.
"""
@abc.abstractmethod
async def send(self, request: Request[HTTPRequestType], **config: Any) -> Response[HTTPRequestType, AsyncHTTPResponseType]:
"""Send the request using this HTTP sender.
"""
pass
def build_context(self) -> Any:
"""Allow the sender to build a context that will be passed
across the pipeline with the request.
Return type has no constraints. Implementation is not
required and None by default.
"""
return None
def __enter__(self):
raise TypeError("Use async with instead")
def __exit__(self, exc_type, exc_val, exc_tb):
# __exit__ should exist in pair with __enter__ but never executed
pass # pragma: no cover
class AsyncPipeline(AbstractAsyncContextManager, Generic[HTTPRequestType, AsyncHTTPResponseType]):
"""A pipeline implementation.
This is implemented as a context manager, that will activate the context
of the HTTP sender.
"""
def __init__(self, policies: List[Union[AsyncHTTPPolicy, SansIOHTTPPolicy]] = None, sender: Optional[AsyncHTTPSender[HTTPRequestType, AsyncHTTPResponseType]] = None) -> None:
self._impl_policies = [] # type: List[AsyncHTTPPolicy[HTTPRequestType, AsyncHTTPResponseType]]
if sender:
self._sender = sender
else:
# Import default only if nothing is provided
from .aiohttp import AioHTTPSender
self._sender = AioHTTPSender()
for policy in (policies or []):
if isinstance(policy, SansIOHTTPPolicy):
self._impl_policies.append(_SansIOAsyncHTTPPolicyRunner(policy))
else:
self._impl_policies.append(policy)
for index in range(len(self._impl_policies)-1):
self._impl_policies[index].next = self._impl_policies[index+1]
if self._impl_policies:
self._impl_policies[-1].next = self._sender
def __enter__(self):
raise TypeError("Use 'async with' instead")
def __exit__(self, exc_type, exc_val, exc_tb):
# __exit__ should exist in pair with __enter__ but never executed
pass # pragma: no cover
async def __aenter__(self) -> 'AsyncPipeline':
await self._sender.__aenter__()
return self
async def __aexit__(self, *exc_details): # pylint: disable=arguments-differ
await self._sender.__aexit__(*exc_details)
async def run(self, request: Request, **kwargs: Any) -> Response[HTTPRequestType, AsyncHTTPResponseType]:
context = self._sender.build_context()
pipeline_request = Request(request, context)
first_node = self._impl_policies[0] if self._impl_policies else self._sender
return await first_node.send(pipeline_request, **kwargs) # type: ignore
__all__ = [
'AsyncHTTPPolicy',
'AsyncHTTPSender',
'AsyncPipeline',
]
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