|
| 1 | +import dataclasses |
| 2 | +import json |
| 3 | +import logging |
| 4 | +from copy import deepcopy |
| 5 | +from typing import Any, Dict, List, Mapping, Optional, Sequence, Tuple |
| 6 | + |
| 7 | +from pydantic import BaseModel |
| 8 | + |
| 9 | +from aws_lambda_powertools.event_handler import Response |
| 10 | +from aws_lambda_powertools.event_handler.api_gateway import Route |
| 11 | +from aws_lambda_powertools.event_handler.middlewares import BaseMiddlewareHandler, NextMiddleware |
| 12 | +from aws_lambda_powertools.event_handler.openapi.compat import ( |
| 13 | + ModelField, |
| 14 | + _model_dump, |
| 15 | + _normalize_errors, |
| 16 | + _regenerate_error_with_loc, |
| 17 | + get_missing_field_error, |
| 18 | +) |
| 19 | +from aws_lambda_powertools.event_handler.openapi.encoders import jsonable_encoder |
| 20 | +from aws_lambda_powertools.event_handler.openapi.exceptions import RequestValidationError |
| 21 | +from aws_lambda_powertools.event_handler.openapi.params import Param |
| 22 | +from aws_lambda_powertools.event_handler.openapi.types import IncEx |
| 23 | +from aws_lambda_powertools.event_handler.types import EventHandlerInstance |
| 24 | + |
| 25 | +logger = logging.getLogger(__name__) |
| 26 | + |
| 27 | + |
| 28 | +class OpenAPIValidationMiddleware(BaseMiddlewareHandler): |
| 29 | + """ |
| 30 | + OpenAPIValidationMiddleware is a middleware that validates the request against the OpenAPI schema defined by the |
| 31 | + Lambda handler. It also validates the response against the OpenAPI schema defined by the Lambda handler. It |
| 32 | + should not be used directly, but rather through the `enable_validation` parameter of the `ApiGatewayResolver`. |
| 33 | +
|
| 34 | + Examples |
| 35 | + -------- |
| 36 | +
|
| 37 | + ```python |
| 38 | + from typing import List |
| 39 | +
|
| 40 | + from pydantic import BaseModel |
| 41 | +
|
| 42 | + from aws_lambda_powertools.event_handler.api_gateway import ( |
| 43 | + APIGatewayRestResolver, |
| 44 | + ) |
| 45 | +
|
| 46 | + class Todo(BaseModel): |
| 47 | + name: str |
| 48 | +
|
| 49 | + app = APIGatewayRestResolver(enable_validation=True) |
| 50 | +
|
| 51 | + @app.get("/todos") |
| 52 | + def get_todos(): List[Todo]: |
| 53 | + return [Todo(name="hello world")] |
| 54 | + ``` |
| 55 | + """ |
| 56 | + |
| 57 | + def handler(self, app: EventHandlerInstance, next_middleware: NextMiddleware) -> Response: |
| 58 | + logger.debug("OpenAPIValidationMiddleware handler") |
| 59 | + |
| 60 | + route: Route = app.context["_route"] |
| 61 | + |
| 62 | + values: Dict[str, Any] = {} |
| 63 | + errors: List[Any] = [] |
| 64 | + |
| 65 | + try: |
| 66 | + # Process path values, which can be found on the route_args |
| 67 | + path_values, path_errors = _request_params_to_args( |
| 68 | + route.dependant.path_params, |
| 69 | + app.context["_route_args"], |
| 70 | + ) |
| 71 | + |
| 72 | + # Process query values |
| 73 | + query_values, query_errors = _request_params_to_args( |
| 74 | + route.dependant.query_params, |
| 75 | + app.current_event.query_string_parameters or {}, |
| 76 | + ) |
| 77 | + |
| 78 | + values.update(path_values) |
| 79 | + values.update(query_values) |
| 80 | + errors += path_errors + query_errors |
| 81 | + |
| 82 | + # Process the request body, if it exists |
| 83 | + if route.dependant.body_params: |
| 84 | + (body_values, body_errors) = _request_body_to_args( |
| 85 | + required_params=route.dependant.body_params, |
| 86 | + received_body=self._get_body(app), |
| 87 | + ) |
| 88 | + values.update(body_values) |
| 89 | + errors.extend(body_errors) |
| 90 | + |
| 91 | + if errors: |
| 92 | + # Raise the validation errors |
| 93 | + raise RequestValidationError(_normalize_errors(errors)) |
| 94 | + else: |
| 95 | + # Re-write the route_args with the validated values, and call the next middleware |
| 96 | + app.context["_route_args"] = values |
| 97 | + response = next_middleware(app) |
| 98 | + |
| 99 | + # Process the response body if it exists |
| 100 | + raw_response = jsonable_encoder(response.body) |
| 101 | + |
| 102 | + # Validate and serialize the response |
| 103 | + return self._serialize_response(field=route.dependant.return_param, response_content=raw_response) |
| 104 | + except RequestValidationError as e: |
| 105 | + return Response( |
| 106 | + status_code=422, |
| 107 | + content_type="application/json", |
| 108 | + body=json.dumps({"detail": e.errors()}), |
| 109 | + ) |
| 110 | + |
| 111 | + def _serialize_response( |
| 112 | + self, |
| 113 | + *, |
| 114 | + field: Optional[ModelField] = None, |
| 115 | + response_content: Any, |
| 116 | + include: Optional[IncEx] = None, |
| 117 | + exclude: Optional[IncEx] = None, |
| 118 | + by_alias: bool = True, |
| 119 | + exclude_unset: bool = False, |
| 120 | + exclude_defaults: bool = False, |
| 121 | + exclude_none: bool = False, |
| 122 | + ) -> Any: |
| 123 | + """ |
| 124 | + Serialize the response content according to the field type. |
| 125 | + """ |
| 126 | + if field: |
| 127 | + errors: List[Dict[str, Any]] = [] |
| 128 | + # MAINTENANCE: remove this when we drop pydantic v1 |
| 129 | + if not hasattr(field, "serializable"): |
| 130 | + response_content = self._prepare_response_content( |
| 131 | + response_content, |
| 132 | + exclude_unset=exclude_unset, |
| 133 | + exclude_defaults=exclude_defaults, |
| 134 | + exclude_none=exclude_none, |
| 135 | + ) |
| 136 | + |
| 137 | + value = _validate_field(field=field, value=response_content, loc=("response",), existing_errors=errors) |
| 138 | + if errors: |
| 139 | + raise RequestValidationError(errors=_normalize_errors(errors), body=response_content) |
| 140 | + |
| 141 | + if hasattr(field, "serialize"): |
| 142 | + return field.serialize( |
| 143 | + value, |
| 144 | + include=include, |
| 145 | + exclude=exclude, |
| 146 | + by_alias=by_alias, |
| 147 | + exclude_unset=exclude_unset, |
| 148 | + exclude_defaults=exclude_defaults, |
| 149 | + exclude_none=exclude_none, |
| 150 | + ) |
| 151 | + |
| 152 | + return jsonable_encoder( |
| 153 | + value, |
| 154 | + include=include, |
| 155 | + exclude=exclude, |
| 156 | + by_alias=by_alias, |
| 157 | + exclude_unset=exclude_unset, |
| 158 | + exclude_defaults=exclude_defaults, |
| 159 | + exclude_none=exclude_none, |
| 160 | + ) |
| 161 | + else: |
| 162 | + # Just serialize the response content returned from the handler |
| 163 | + return jsonable_encoder(response_content) |
| 164 | + |
| 165 | + def _prepare_response_content( |
| 166 | + self, |
| 167 | + res: Any, |
| 168 | + *, |
| 169 | + exclude_unset: bool, |
| 170 | + exclude_defaults: bool = False, |
| 171 | + exclude_none: bool = False, |
| 172 | + ) -> Any: |
| 173 | + """ |
| 174 | + Prepares the response content for serialization. |
| 175 | + """ |
| 176 | + if isinstance(res, BaseModel): |
| 177 | + return _model_dump( |
| 178 | + res, |
| 179 | + by_alias=True, |
| 180 | + exclude_unset=exclude_unset, |
| 181 | + exclude_defaults=exclude_defaults, |
| 182 | + exclude_none=exclude_none, |
| 183 | + ) |
| 184 | + elif isinstance(res, list): |
| 185 | + return [ |
| 186 | + self._prepare_response_content(item, exclude_unset=exclude_unset, exclude_defaults=exclude_defaults) |
| 187 | + for item in res |
| 188 | + ] |
| 189 | + elif isinstance(res, dict): |
| 190 | + return { |
| 191 | + k: self._prepare_response_content(v, exclude_unset=exclude_unset, exclude_defaults=exclude_defaults) |
| 192 | + for k, v in res.items() |
| 193 | + } |
| 194 | + elif dataclasses.is_dataclass(res): |
| 195 | + return dataclasses.asdict(res) |
| 196 | + return res |
| 197 | + |
| 198 | + def _get_body(self, app: EventHandlerInstance) -> Dict[str, Any]: |
| 199 | + """ |
| 200 | + Get the request body from the event, and parse it as JSON. |
| 201 | + """ |
| 202 | + |
| 203 | + content_type_value = app.current_event.get_header_value("content-type") |
| 204 | + if not content_type_value or content_type_value.startswith("application/json"): |
| 205 | + try: |
| 206 | + return app.current_event.json_body |
| 207 | + except json.JSONDecodeError as e: |
| 208 | + raise RequestValidationError( |
| 209 | + [ |
| 210 | + { |
| 211 | + "type": "json_invalid", |
| 212 | + "loc": ("body", e.pos), |
| 213 | + "msg": "JSON decode error", |
| 214 | + "input": {}, |
| 215 | + "ctx": {"error": e.msg}, |
| 216 | + }, |
| 217 | + ], |
| 218 | + body=e.doc, |
| 219 | + ) from e |
| 220 | + else: |
| 221 | + raise NotImplementedError("Only JSON body is supported") |
| 222 | + |
| 223 | + |
| 224 | +def _request_params_to_args( |
| 225 | + required_params: Sequence[ModelField], |
| 226 | + received_params: Mapping[str, Any], |
| 227 | +) -> Tuple[Dict[str, Any], List[Any]]: |
| 228 | + """ |
| 229 | + Convert the request params to a dictionary of values using validation, and returns a list of errors. |
| 230 | + """ |
| 231 | + values = {} |
| 232 | + errors = [] |
| 233 | + |
| 234 | + for field in required_params: |
| 235 | + value = received_params.get(field.alias) |
| 236 | + |
| 237 | + field_info = field.field_info |
| 238 | + if not isinstance(field_info, Param): |
| 239 | + raise AssertionError(f"Expected Param field_info, got {field_info}") |
| 240 | + |
| 241 | + loc = (field_info.in_.value, field.alias) |
| 242 | + |
| 243 | + # If we don't have a value, see if it's required or has a default |
| 244 | + if value is None: |
| 245 | + if field.required: |
| 246 | + errors.append(get_missing_field_error(loc=loc)) |
| 247 | + else: |
| 248 | + values[field.name] = deepcopy(field.default) |
| 249 | + continue |
| 250 | + |
| 251 | + # Finally, validate the value |
| 252 | + values[field.name] = _validate_field(field=field, value=value, loc=loc, existing_errors=errors) |
| 253 | + |
| 254 | + return values, errors |
| 255 | + |
| 256 | + |
| 257 | +def _request_body_to_args( |
| 258 | + required_params: List[ModelField], |
| 259 | + received_body: Optional[Dict[str, Any]], |
| 260 | +) -> Tuple[Dict[str, Any], List[Dict[str, Any]]]: |
| 261 | + """ |
| 262 | + Convert the request body to a dictionary of values using validation, and returns a list of errors. |
| 263 | + """ |
| 264 | + values: Dict[str, Any] = {} |
| 265 | + errors: List[Dict[str, Any]] = [] |
| 266 | + |
| 267 | + received_body, field_alias_omitted = _get_embed_body( |
| 268 | + field=required_params[0], |
| 269 | + required_params=required_params, |
| 270 | + received_body=received_body, |
| 271 | + ) |
| 272 | + |
| 273 | + for field in required_params: |
| 274 | + # This sets the location to: |
| 275 | + # { "user": { object } } if field.alias == user |
| 276 | + # { { object } if field_alias is omitted |
| 277 | + loc: Tuple[str, ...] = ("body", field.alias) |
| 278 | + if field_alias_omitted: |
| 279 | + loc = ("body",) |
| 280 | + |
| 281 | + value: Optional[Any] = None |
| 282 | + |
| 283 | + # Now that we know what to look for, try to get the value from the received body |
| 284 | + if received_body is not None: |
| 285 | + try: |
| 286 | + value = received_body.get(field.alias) |
| 287 | + except AttributeError: |
| 288 | + errors.append(get_missing_field_error(loc)) |
| 289 | + continue |
| 290 | + |
| 291 | + # Determine if the field is required |
| 292 | + if value is None: |
| 293 | + if field.required: |
| 294 | + errors.append(get_missing_field_error(loc)) |
| 295 | + else: |
| 296 | + values[field.name] = deepcopy(field.default) |
| 297 | + continue |
| 298 | + |
| 299 | + # MAINTENANCE: Handle byte and file fields |
| 300 | + |
| 301 | + # Finally, validate the value |
| 302 | + values[field.name] = _validate_field(field=field, value=value, loc=loc, existing_errors=errors) |
| 303 | + |
| 304 | + return values, errors |
| 305 | + |
| 306 | + |
| 307 | +def _validate_field( |
| 308 | + *, |
| 309 | + field: ModelField, |
| 310 | + value: Any, |
| 311 | + loc: Tuple[str, ...], |
| 312 | + existing_errors: List[Dict[str, Any]], |
| 313 | +): |
| 314 | + """ |
| 315 | + Validate a field, and append any errors to the existing_errors list. |
| 316 | + """ |
| 317 | + validated_value, errors = field.validate(value, value, loc=loc) |
| 318 | + |
| 319 | + if isinstance(errors, list): |
| 320 | + processed_errors = _regenerate_error_with_loc(errors=errors, loc_prefix=()) |
| 321 | + existing_errors.extend(processed_errors) |
| 322 | + elif errors: |
| 323 | + existing_errors.append(errors) |
| 324 | + |
| 325 | + return validated_value |
| 326 | + |
| 327 | + |
| 328 | +def _get_embed_body( |
| 329 | + *, |
| 330 | + field: ModelField, |
| 331 | + required_params: List[ModelField], |
| 332 | + received_body: Optional[Dict[str, Any]], |
| 333 | +) -> Tuple[Optional[Dict[str, Any]], bool]: |
| 334 | + field_info = field.field_info |
| 335 | + embed = getattr(field_info, "embed", None) |
| 336 | + |
| 337 | + # If the field is an embed, and the field alias is omitted, we need to wrap the received body in the field alias. |
| 338 | + field_alias_omitted = len(required_params) == 1 and not embed |
| 339 | + if field_alias_omitted: |
| 340 | + received_body = {field.alias: received_body} |
| 341 | + |
| 342 | + return received_body, field_alias_omitted |
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