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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,132 @@ | ||
| # Copyright 2021 Google LLC | ||
| # | ||
| # 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. | ||
|
|
||
| """Helpers for server-side streaming in REST.""" | ||
|
|
||
| from collections import deque | ||
| import string | ||
| from typing import Deque, Union | ||
|
|
||
| import proto | ||
| import requests | ||
| import google.protobuf.message | ||
| from google.protobuf.json_format import Parse | ||
|
|
||
|
|
||
| class ResponseIterator: | ||
| """Iterator over REST API responses. | ||
| Args: | ||
| response (requests.Response): An API response object. | ||
| response_message_cls (Union[proto.Message, google.protobuf.message.Message]): A response | ||
| class expected to be returned from an API. | ||
| Raises: | ||
| ValueError: If `response_message_cls` is not a subclass of `proto.Message` or `google.protobuf.message.Message`. | ||
| """ | ||
|
|
||
| def __init__( | ||
| self, | ||
| response: requests.Response, | ||
| response_message_cls: Union[proto.Message, google.protobuf.message.Message], | ||
| ): | ||
| self._response = response | ||
| self._response_message_cls = response_message_cls | ||
| # Inner iterator over HTTP response's content. | ||
| self._response_itr = self._response.iter_content(decode_unicode=True) | ||
| # Contains a list of JSON responses ready to be sent to user. | ||
| self._ready_objs: Deque[str] = deque() | ||
| # Current JSON response being built. | ||
| self._obj = "" | ||
| # Keeps track of the nesting level within a JSON object. | ||
| self._level = 0 | ||
| # Keeps track whether HTTP response is currently sending values | ||
| # inside of a string value. | ||
| self._in_string = False | ||
| # Whether an escape symbol "\" was encountered. | ||
| self._escape_next = False | ||
|
|
||
| def cancel(self): | ||
| """Cancel existing streaming operation.""" | ||
| self._response.close() | ||
|
|
||
| def _process_chunk(self, chunk: str): | ||
| if self._level == 0: | ||
| if chunk[0] != "[": | ||
| raise ValueError( | ||
| "Can only parse array of JSON objects, instead got %s" % chunk | ||
| ) | ||
| for char in chunk: | ||
| if char == "{": | ||
| if self._level == 1: | ||
| # Level 1 corresponds to the outermost JSON object | ||
| # (i.e. the one we care about). | ||
| self._obj = "" | ||
| if not self._in_string: | ||
| self._level += 1 | ||
| self._obj += char | ||
| elif char == "}": | ||
| self._obj += char | ||
| if not self._in_string: | ||
| self._level -= 1 | ||
| if not self._in_string and self._level == 1: | ||
| self._ready_objs.append(self._obj) | ||
| elif char == '"': | ||
| # Helps to deal with an escaped quotes inside of a string. | ||
| if not self._escape_next: | ||
| self._in_string = not self._in_string | ||
| self._obj += char | ||
| elif char in string.whitespace: | ||
| if self._in_string: | ||
| self._obj += char | ||
| elif char == "[": | ||
| if self._level == 0: | ||
| self._level += 1 | ||
| else: | ||
| self._obj += char | ||
| elif char == "]": | ||
| if self._level == 1: | ||
| self._level -= 1 | ||
| else: | ||
| self._obj += char | ||
| else: | ||
| self._obj += char | ||
| self._escape_next = not self._escape_next if char == "\\" else False | ||
|
|
||
| def __next__(self): | ||
| while not self._ready_objs: | ||
| try: | ||
| chunk = next(self._response_itr) | ||
| self._process_chunk(chunk) | ||
| except StopIteration as e: | ||
| if self._level > 0: | ||
| raise ValueError("Unfinished stream: %s" % self._obj) | ||
| raise e | ||
| return self._grab() | ||
|
|
||
| def _grab(self): | ||
| # Add extra quotes to make json.loads happy. | ||
| if issubclass(self._response_message_cls, proto.Message): | ||
| return self._response_message_cls.from_json( | ||
| self._ready_objs.popleft(), ignore_unknown_fields=True | ||
| ) | ||
| elif issubclass(self._response_message_cls, google.protobuf.message.Message): | ||
| return Parse(self._ready_objs.popleft(), self._response_message_cls()) | ||
| else: | ||
| raise ValueError( | ||
| "Response message class must be a subclass of proto.Message or google.protobuf.message.Message." | ||
| ) | ||
|
|
||
| def __iter__(self): | ||
| return self |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,132 @@ | ||
| # Copyright 2021 Google LLC | ||
| # | ||
| # 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. | ||
|
|
||
| """Helpers for server-side streaming in REST.""" | ||
|
|
||
| from collections import deque | ||
| import string | ||
| from typing import Deque, Union | ||
|
|
||
| import proto | ||
| import requests | ||
| import google.protobuf.message | ||
| from google.protobuf.json_format import Parse | ||
|
|
||
|
|
||
| class ResponseIterator: | ||
| """Iterator over REST API responses. | ||
| Args: | ||
| response (requests.Response): An API response object. | ||
| response_message_cls (Union[proto.Message, google.protobuf.message.Message]): A response | ||
| class expected to be returned from an API. | ||
| Raises: | ||
| ValueError: If `response_message_cls` is not a subclass of `proto.Message` or `google.protobuf.message.Message`. | ||
| """ | ||
|
|
||
| def __init__( | ||
| self, | ||
| response: requests.Response, | ||
| response_message_cls: Union[proto.Message, google.protobuf.message.Message], | ||
| ): | ||
| self._response = response | ||
| self._response_message_cls = response_message_cls | ||
| # Inner iterator over HTTP response's content. | ||
| self._response_itr = self._response.iter_content(decode_unicode=True) | ||
| # Contains a list of JSON responses ready to be sent to user. | ||
| self._ready_objs: Deque[str] = deque() | ||
| # Current JSON response being built. | ||
| self._obj = "" | ||
| # Keeps track of the nesting level within a JSON object. | ||
| self._level = 0 | ||
| # Keeps track whether HTTP response is currently sending values | ||
| # inside of a string value. | ||
| self._in_string = False | ||
| # Whether an escape symbol "\" was encountered. | ||
| self._escape_next = False | ||
|
|
||
| def cancel(self): | ||
| """Cancel existing streaming operation.""" | ||
| self._response.close() | ||
|
|
||
| def _process_chunk(self, chunk: str): | ||
| if self._level == 0: | ||
| if chunk[0] != "[": | ||
| raise ValueError( | ||
| "Can only parse array of JSON objects, instead got %s" % chunk | ||
| ) | ||
| for char in chunk: | ||
| if char == "{": | ||
| if self._level == 1: | ||
| # Level 1 corresponds to the outermost JSON object | ||
| # (i.e. the one we care about). | ||
| self._obj = "" | ||
| if not self._in_string: | ||
| self._level += 1 | ||
| self._obj += char | ||
| elif char == "}": | ||
| self._obj += char | ||
| if not self._in_string: | ||
| self._level -= 1 | ||
| if not self._in_string and self._level == 1: | ||
| self._ready_objs.append(self._obj) | ||
| elif char == '"': | ||
| # Helps to deal with an escaped quotes inside of a string. | ||
| if not self._escape_next: | ||
| self._in_string = not self._in_string | ||
| self._obj += char | ||
| elif char in string.whitespace: | ||
| if self._in_string: | ||
| self._obj += char | ||
| elif char == "[": | ||
| if self._level == 0: | ||
| self._level += 1 | ||
| else: | ||
| self._obj += char | ||
| elif char == "]": | ||
| if self._level == 1: | ||
| self._level -= 1 | ||
| else: | ||
| self._obj += char | ||
| else: | ||
| self._obj += char | ||
| self._escape_next = not self._escape_next if char == "\\" else False | ||
|
|
||
| def __next__(self): | ||
| while not self._ready_objs: | ||
| try: | ||
| chunk = next(self._response_itr) | ||
| self._process_chunk(chunk) | ||
| except StopIteration as e: | ||
| if self._level > 0: | ||
| raise ValueError("Unfinished stream: %s" % self._obj) | ||
| raise e | ||
| return self._grab() | ||
|
|
||
| def _grab(self): | ||
| # Add extra quotes to make json.loads happy. | ||
| if issubclass(self._response_message_cls, proto.Message): | ||
| return self._response_message_cls.from_json( | ||
| self._ready_objs.popleft(), ignore_unknown_fields=True | ||
| ) | ||
| elif issubclass(self._response_message_cls, google.protobuf.message.Message): | ||
| return Parse(self._ready_objs.popleft(), self._response_message_cls()) | ||
| else: | ||
| raise ValueError( | ||
| "Response message class must be a subclass of proto.Message or google.protobuf.message.Message." | ||
| ) | ||
|
|
||
| def __iter__(self): | ||
| return self |