fix(event_handler): validate POST bodies on BedrockAgentResolver (#3903)

Author: rubenfonseca

aws_lambda_powertools/utilities/data_classes/bedrock_agent_event.py

@@ -1,3 +1,4 @@
+from functools import cached_property
 from typing import Any, Dict, List, Optional
 
 from aws_lambda_powertools.utilities.data_classes.common import BaseProxyEvent, DictWrapper
@@ -112,3 +113,16 @@ def query_string_parameters(self) -> Optional[Dict[str, str]]:
     @property
     def resolved_headers_field(self) -> Optional[Dict[str, Any]]:
         return {}
+
+    @cached_property
+    def json_body(self) -> Any:
+        # In Bedrock Agent events, body parameters are encoded differently
+        # @see https://docs.aws.amazon.com/bedrock/latest/userguide/agents-lambda.html#agents-lambda-input
+        if not self.request_body:
+            return None
+
+        json_body = self.request_body.content.get("application/json")
+        if not json_body:
+            return None
+
+        return {x.name: x.value for x in json_body.properties}

tests/functional/event_handler/test_bedrock_agent.py

@@ -2,7 +2,9 @@
 from typing import Any, Dict
 
 from aws_lambda_powertools.event_handler import BedrockAgentResolver, Response, content_types
+from aws_lambda_powertools.event_handler.openapi.params import Body
 from aws_lambda_powertools.event_handler.openapi.pydantic_loader import PYDANTIC_V2
+from aws_lambda_powertools.shared.types import Annotated
 from aws_lambda_powertools.utilities.data_classes import BedrockAgentEvent
 from tests.functional.utils import load_event
 
@@ -157,3 +159,28 @@ def claims():
 
     body = result["response"]["responseBody"]["text/plain"]["body"]
     assert body == "Something went wrong"
+
+
+def test_bedrock_agent_with_post():
+    # GIVEN a Bedrock Agent resolver with a POST method
+    app = BedrockAgentResolver()
+
+    @app.post("/send-reminders", description="Sends reminders")
+    def send_reminders(
+        _claim_id: Annotated[int, Body(description="Claim ID", alias="claimId")],
+        _pending_documents: Annotated[str, Body(description="Social number and VAT", alias="pendingDocuments")],
+    ) -> Annotated[bool, Body(description="returns true if I like the email")]:
+        return True
+
+    # WHEN calling the event handler
+    result = app(load_event("bedrockAgentPostEvent.json"), {})
+
+    # THEN process the event correctly
+    assert result["messageVersion"] == "1.0"
+    assert result["response"]["apiPath"] == "/send-reminders"
+    assert result["response"]["httpMethod"] == "POST"
+    assert result["response"]["httpStatusCode"] == 200
+
+    # THEN return the correct result
+    body = result["response"]["responseBody"]["application/json"]["body"]
+    assert json.loads(body) is True