feat: delegate REST transcoding to google-api-core

Author: hebaalazzeh

packages/gapic-generator/api-common-protos

@@ -0,0 +1 @@
+Subproject commit 3332dec527759859840a3a2ff108c67a54708130

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/services/%service/_shared_macros.j2

@@ -198,22 +198,23 @@ def _get_http_options():
         service: The service.
         is_async (bool): Used to determine the code path i.e. whether for sync or async call.
         is_request_message_proto_plus_type (bool): Used to determine whether the request message is a proto-plus type. #}
-{% macro rest_call_method_common(body_spec, method_name, service, is_async=False, is_request_message_proto_plus_type=False) %}
+{% macro rest_call_method_common(body_spec, method_name, service, is_async=False, is_request_message_proto_plus_type=False, rest_numeric_enums=False) %}
 {% set service_name = service.name %}
 {% set await_prefix = "await " if is_async else "" %}
 {% set async_class_prefix = "Async" if is_async else "" %}
 
     http_options = _Base{{ service_name }}RestTransport._Base{{method_name}}._get_http_options()
-    {# TODO(https://github.com/googleapis/gapic-generator-python/issues/2274): Add debug log before intercepting a request #} 
     request, metadata = {{ await_prefix }}self._interceptor.pre_{{ method_name|snake_case }}(request, metadata)
-    transcoded_request = _Base{{ service_name }}RestTransport._Base{{method_name}}._get_transcoded_request(http_options, request)
-
-    {% if body_spec %}
-    body = _Base{{ service_name }}RestTransport._Base{{method_name}}._get_request_body_json(transcoded_request)
-    {% endif %}{# body_spec #}
-
-    # Jsonify the query params
-    query_params = _Base{{ service_name }}RestTransport._Base{{method_name}}._get_query_params_json(transcoded_request)
+    transcoded_request, body, query_params = rest_helpers.transcode(
+        http_options,
+        request,
+        required_fields_default_values=getattr(
+            _Base{{ service_name }}RestTransport._Base{{method_name}},
+            "__REQUIRED_FIELDS_DEFAULT_VALUES",
+            None,
+        ),
+        rest_numeric_enums={{ rest_numeric_enums }},
+    )
 
     if CLIENT_LOGGING_SUPPORTED and _LOGGER.isEnabledFor(logging.DEBUG):  # pragma: NO COVER
         request_url = "{host}{uri}".format(host=self._host, uri=transcoded_request['uri'])

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/_rest_mixins_base.py.j2

@@ -25,27 +25,7 @@
 
         {{ shared_macros.http_options_method(api.mixin_http_options["{}".format(name)])|indent(8)}}
 
-        @staticmethod
-        def _get_transcoded_request(http_options, request):
-            request_kwargs = json_format.MessageToDict(request)
-            transcoded_request = path_template.transcode(
-                http_options, **request_kwargs)
-            return transcoded_request
-
-        {% set body_spec = api.mixin_http_options["{}".format(name)][0].body %}
-        {%- if body_spec %}
-
-        @staticmethod
-        def _get_request_body_json(transcoded_request):
-            body = json.dumps(transcoded_request['body'])
-            return body
-
-        {%- endif %} {# body_spec #}
-
-        @staticmethod
-        def _get_query_params_json(transcoded_request):
-            query_params = json.loads(json.dumps(transcoded_request['query_params']))
-            return query_params
+        pass
 
     {% endfor %}
     {% endif %} {# rest in opts.transport #}

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest.py.j2

@@ -245,7 +245,7 @@ class {{service.name}}RestTransport(_Base{{ service.name }}RestTransport):
             {% endif %}
             """
 
-            {{ shared_macros.rest_call_method_common(body_spec, method.name, service, False, method.input.ident.is_proto_plus_type)|indent(8) }}
+            {{ shared_macros.rest_call_method_common(body_spec, method.name, service, False, method.input.ident.is_proto_plus_type, opts.rest_numeric_enums)|indent(8) }}
 
             {% if not method.void %}
             # Return the response

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest_asyncio.py.j2

@@ -203,7 +203,7 @@ class Async{{service.name}}RestTransport(_Base{{ service.name }}RestTransport):
             {% endif %}
             """
 
-            {{ shared_macros.rest_call_method_common(body_spec, method.name, service, True, method.input.ident.is_proto_plus_type)|indent(8) }}
+            {{ shared_macros.rest_call_method_common(body_spec, method.name, service, True, method.input.ident.is_proto_plus_type, opts.rest_numeric_enums)|indent(8) }}
 
             {% if not method.void %}
             # Return the response

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/rest_base.py.j2

@@ -120,51 +120,8 @@ class _Base{{ service.name }}RestTransport({{service.name}}Transport):
         def _get_unset_required_fields(cls, message_dict):
             return {k: v for k, v in cls.__REQUIRED_FIELDS_DEFAULT_VALUES.items() if k not in message_dict}
         {% endif %}{# required fields #}
-        
         {% set method_http_options = method.http_options %}
-        
         {{ shared_macros.http_options_method(method_http_options)|indent(8) }}
-        
-        @staticmethod
-        def _get_transcoded_request(http_options, request):
-            {% if method.input.ident.is_proto_plus_type %}
-            pb_request = {{method.input.ident}}.pb(request)
-            {% else %}
-            pb_request = request
-            {% endif %}
-            transcoded_request = path_template.transcode(http_options, pb_request)
-            return transcoded_request
-
-        {% set body_spec = method.http_options[0].body %}
-        {%- if body_spec %}
-
-        @staticmethod
-        def _get_request_body_json(transcoded_request):
-            # Jsonify the request body
-
-            body = json_format.MessageToJson(
-                transcoded_request['body'],
-                use_integers_for_enums={{ opts.rest_numeric_enums }}
-            )
-            return body
-
-        {%- endif %}{# body_spec #}
-
-        @staticmethod
-        def _get_query_params_json(transcoded_request):
-            query_params = json.loads(json_format.MessageToJson(
-                transcoded_request['query_params'],
-                use_integers_for_enums={{ opts.rest_numeric_enums }},
-            ))
-            {% if method.input.required_fields %}
-            query_params.update(_Base{{ service.name }}RestTransport._Base{{method.name}}._get_unset_required_fields(query_params))
-            {% endif %}{# required fields #}
-
-            {% if opts.rest_numeric_enums %}
-            query_params["$alt"] = "json;enum-encoding=int"
-            {% endif %}
-            return query_params
-
         {% endif %}{# method.http_options and not method.client_streaming #}
     {% endfor %}
 

packages/gapic-generator/generated_showcase/.coveragerc

@@ -0,0 +1,13 @@
+[run]
+branch = True
+
+[report]
+show_missing = True
+omit =
+    google/showcase/__init__.py
+    google/showcase/gapic_version.py
+exclude_lines =
+    # Re-enable the standard pragma
+    pragma: NO COVER
+    # Ignore debug-only repr
+    def __repr__

packages/gapic-generator/generated_showcase/.flake8

@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Copyright 2026 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.
+#
+[flake8]
+# TODO(https://github.com/googleapis/gapic-generator-python/issues/2333):
+# Resolve flake8 lint issues
+ignore = E203, E231, E266, E501, W503
+exclude =
+  # TODO(https://github.com/googleapis/gapic-generator-python/issues/2333):
+  # Ensure that generated code passes flake8 lint
+  **/gapic/**
+  **/services/**
+  **/types/**
+  # Exclude Protobuf gencode
+  *_pb2.py
+
+  # Standard linting exemptions.
+  **/.nox/**
+  __pycache__,
+  .git,
+  *.pyc,
+  conf.py

packages/gapic-generator/generated_showcase/LICENSE

@@ -0,0 +1,202 @@
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