fix(parser): accept SES events without common headers or invocation type

aws_lambda_powertools/utilities/data_classes/ses_event.py

@@ -20,35 +20,35 @@ def value(self) -> str:
 
 class SESMailCommonHeaders(DictWrapper):
     @property
-    def return_path(self) -> str:
+    def return_path(self) -> str | None:
         """The values in the Return-Path header of the email."""
-        return self["returnPath"]
+        return self.get("returnPath")
 
     @property
     def get_from(self) -> list[str]:
         """The values in the From header of the email."""
         # Note: this name conflicts with existing python builtins
-        return self["from"]
+        return self.get("from") or []
 
     @property
-    def date(self) -> str:
+    def date(self) -> str | None:
         """The date and time when Amazon SES received the message."""
-        return self["date"]
+        return self.get("date")
 
     @property
     def to(self) -> list[str]:
         """The values in the To header of the email."""
-        return self["to"]
+        return self.get("to") or []
 
     @property
-    def message_id(self) -> str:
+    def message_id(self) -> str | None:
         """The ID of the original message."""
-        return str(self["messageId"])
+        return self.get("messageId")
 
     @property
-    def subject(self) -> str:
+    def subject(self) -> str | None:
         """The value of the Subject header for the email."""
-        return str(self["subject"])
+        return self.get("subject")
 
     @property
     def cc(self) -> list[str]:
@@ -148,10 +148,10 @@ def function_arn(self) -> str:
         return self["functionArn"]
 
     @property
-    def invocation_type(self) -> str:
+    def invocation_type(self) -> str | None:
         """String that contains the invocation type of the Lambda function. Possible values are RequestResponse
         and Event. Present only for the Lambda action type."""
-        return self["invocationType"]
+        return self.get("invocationType")
 
 
 class SESReceipt(DictWrapper):

aws_lambda_powertools/utilities/parser/models/ses.py

@@ -11,7 +11,7 @@ class SesReceiptVerdict(BaseModel):
 
 class SesReceiptAction(BaseModel):
     type: Literal["Lambda"]  # noqa A003,VNE003
-    invocationType: Literal["Event"]
+    invocationType: Literal["Event", "RequestResponse"] | None = None
     functionArn: str
 
 
@@ -32,8 +32,9 @@ class SesMailHeaders(BaseModel):
 
 
 class SesMailCommonHeaders(BaseModel):
-    header_from: list[str] = Field(..., alias="from")
-    to: list[str]
+    # SES sends each common header only when the email has that header
+    header_from: list[str] | None = Field(None, alias="from")
+    to: list[str] | None = None
     cc: list[str] | None = None
     bcc: list[str] | None = None
     sender: list[str] | None = None
@@ -42,10 +43,10 @@ class SesMailCommonHeaders(BaseModel):
         validation_alias=AliasChoices("replyTo", "reply-to", "reply_to"),
         serialization_alias="replyTo",
     )
-    returnPath: str
-    messageId: str
-    date: str
-    subject: str
+    returnPath: str | None = None
+    messageId: str | None = None
+    date: str | None = None
+    subject: str | None = None
 
 
 class SesMail(BaseModel):

tests/unit/data_classes/required_dependencies/test_ses_event.py

@@ -55,3 +55,24 @@ def test_ses_trigger_event():
     assert parsed_event.record.raw_event == raw_event["Records"][0]
     assert parsed_event.mail.raw_event == raw_event["Records"][0]["ses"]["mail"]
     assert parsed_event.receipt.raw_event == raw_event["Records"][0]["ses"]["receipt"]
+
+
+def test_ses_trigger_event_without_common_headers_or_invocation_type():
+    # GIVEN an SES event for an email without any common headers and a Lambda action without an invocation type
+    raw_event = load_event("sesEvent.json")
+    raw_event["Records"][0]["ses"]["mail"]["commonHeaders"] = {}
+    del raw_event["Records"][0]["ses"]["receipt"]["action"]["invocationType"]
+
+    # WHEN reading the common headers and the action
+    parsed_event = SESEvent(raw_event)
+    common_headers = parsed_event.mail.common_headers
+    action = parsed_event.receipt.action
+
+    # THEN the missing headers are empty instead of raising KeyError
+    assert common_headers.return_path is None
+    assert common_headers.get_from == []
+    assert common_headers.date is None
+    assert common_headers.to == []
+    assert common_headers.message_id is None
+    assert common_headers.subject is None
+    assert action.invocation_type is None

tests/unit/parser/_pydantic/test_ses.py

@@ -1,3 +1,5 @@
+import pytest
+
 from aws_lambda_powertools.utilities.parser.models import SesModel, SesRecordModel
 from tests.functional.utils import load_event
 
@@ -117,3 +119,45 @@ def test_ses_trigger_event_with_optional_common_headers():
     assert common_headers.bcc == ["bcc@example.com"]
     assert common_headers.sender == ["sender@example.com"]
     assert common_headers.reply_to == ["reply@example.com"]
+
+
+@pytest.mark.parametrize("invocation_type", ["Event", "RequestResponse"])
+def test_ses_trigger_event_with_invocation_type(invocation_type):
+    # GIVEN an SES event from a Lambda action with either documented invocation type
+    raw_event = load_event("sesEvent.json")
+    raw_event["Records"][0]["ses"]["receipt"]["action"]["invocationType"] = invocation_type
+
+    # WHEN parsing the event
+    action = SesModel(**raw_event).Records[0].ses.receipt.action
+
+    # THEN the invocation type is kept
+    assert action.invocationType == invocation_type
+
+
+def test_ses_trigger_event_without_invocation_type():
+    # GIVEN an SES event whose Lambda action has no invocation type
+    raw_event = load_event("sesEvent.json")
+    del raw_event["Records"][0]["ses"]["receipt"]["action"]["invocationType"]
+
+    # WHEN parsing the event
+    action = SesModel(**raw_event).Records[0].ses.receipt.action
+
+    # THEN the invocation type is None
+    assert action.invocationType is None
+
+
+def test_ses_trigger_event_without_common_headers():
+    # GIVEN an SES event for an email without any common headers (SES only sends the ones the email has)
+    raw_event = load_event("sesEvent.json")
+    raw_event["Records"][0]["ses"]["mail"]["commonHeaders"] = {}
+
+    # WHEN parsing the event
+    common_headers = SesModel(**raw_event).Records[0].ses.mail.commonHeaders
+
+    # THEN every common header is None
+    assert common_headers.header_from is None
+    assert common_headers.to is None
+    assert common_headers.returnPath is None
+    assert common_headers.messageId is None
+    assert common_headers.date is None
+    assert common_headers.subject is None