From 1c5eb4df93d78e791082d9282330ebf0faacd222 Mon Sep 17 00:00:00 2001 From: Ken Bandes Date: Mon, 20 Sep 2021 14:40:51 -0400 Subject: [PATCH] feat: Add helper function to format query_params for rest transport. (#275) Co-authored-by: Kenneth Bandes --- google/api_core/rest_helpers.py | 94 +++++++++++++++++++++++++++++++++ tests/unit/test_rest_helpers.py | 77 +++++++++++++++++++++++++++ 2 files changed, 171 insertions(+) create mode 100644 google/api_core/rest_helpers.py create mode 100644 tests/unit/test_rest_helpers.py diff --git a/google/api_core/rest_helpers.py b/google/api_core/rest_helpers.py new file mode 100644 index 00000000..23fb614f --- /dev/null +++ b/google/api_core/rest_helpers.py @@ -0,0 +1,94 @@ +# 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 rest transports.""" + +import functools +import operator + + +def flatten_query_params(obj): + """Flatten a nested dict into a list of (name,value) tuples. + + The result is suitable for setting query params on an http request. + + .. code-block:: python + + >>> obj = {'a': + ... {'b': + ... {'c': ['x', 'y', 'z']} }, + ... 'd': 'uvw', } + >>> flatten_query_params(obj) + [('a.b.c', 'x'), ('a.b.c', 'y'), ('a.b.c', 'z'), ('d', 'uvw')] + + Note that, as described in + https://github.com/googleapis/googleapis/blob/48d9fb8c8e287c472af500221c6450ecd45d7d39/google/api/http.proto#L117, + repeated fields (i.e. list-valued fields) may only contain primitive types (not lists or dicts). + This is enforced in this function. + + Args: + obj: a nested dictionary (from json), or None + + Returns: a list of tuples, with each tuple having a (possibly) multi-part name + and a scalar value. + + Raises: + TypeError if obj is not a dict or None + ValueError if obj contains a list of non-primitive values. + """ + + if obj is not None and not isinstance(obj, dict): + raise TypeError("flatten_query_params must be called with dict object") + + return _flatten(obj, key_path=[]) + + +def _flatten(obj, key_path): + if obj is None: + return [] + if isinstance(obj, dict): + return _flatten_dict(obj, key_path=key_path) + if isinstance(obj, list): + return _flatten_list(obj, key_path=key_path) + return _flatten_value(obj, key_path=key_path) + + +def _is_primitive_value(obj): + if obj is None: + return False + + if isinstance(obj, (list, dict)): + raise ValueError("query params may not contain repeated dicts or lists") + + return True + + +def _flatten_value(obj, key_path): + return [(".".join(key_path), obj)] + + +def _flatten_dict(obj, key_path): + items = (_flatten(value, key_path=key_path + [key]) for key, value in obj.items()) + return functools.reduce(operator.concat, items, []) + + +def _flatten_list(elems, key_path): + # Only lists of scalar values are supported. + # The name (key_path) is repeated for each value. + items = ( + _flatten_value(elem, key_path=key_path) + for elem in elems + if _is_primitive_value(elem) + ) + return functools.reduce(operator.concat, items, []) diff --git a/tests/unit/test_rest_helpers.py b/tests/unit/test_rest_helpers.py new file mode 100644 index 00000000..5932fa55 --- /dev/null +++ b/tests/unit/test_rest_helpers.py @@ -0,0 +1,77 @@ +# 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. + +import pytest + +from google.api_core import rest_helpers + + +def test_flatten_simple_value(): + with pytest.raises(TypeError): + rest_helpers.flatten_query_params("abc") + + +def test_flatten_list(): + with pytest.raises(TypeError): + rest_helpers.flatten_query_params(["abc", "def"]) + + +def test_flatten_none(): + assert rest_helpers.flatten_query_params(None) == [] + + +def test_flatten_empty_dict(): + assert rest_helpers.flatten_query_params({}) == [] + + +def test_flatten_simple_dict(): + assert rest_helpers.flatten_query_params({"a": "abc", "b": "def"}) == [ + ("a", "abc"), + ("b", "def"), + ] + + +def test_flatten_repeated_field(): + assert rest_helpers.flatten_query_params({"a": ["x", "y", "z", None]}) == [ + ("a", "x"), + ("a", "y"), + ("a", "z"), + ] + + +def test_flatten_nested_dict(): + obj = {"a": {"b": {"c": ["x", "y", "z"]}}, "d": {"e": "uvw"}} + expected_result = [("a.b.c", "x"), ("a.b.c", "y"), ("a.b.c", "z"), ("d.e", "uvw")] + + assert rest_helpers.flatten_query_params(obj) == expected_result + + +def test_flatten_repeated_dict(): + obj = { + "a": {"b": {"c": [{"v": 1}, {"v": 2}]}}, + "d": "uvw", + } + + with pytest.raises(ValueError): + rest_helpers.flatten_query_params(obj) + + +def test_flatten_repeated_list(): + obj = { + "a": {"b": {"c": [["e", "f"], ["g", "h"]]}}, + "d": "uvw", + } + + with pytest.raises(ValueError): + rest_helpers.flatten_query_params(obj)