ELI-397: Fixing nhs number missing from path error to be FHIR compliant (#284)

Author: shweta-nhs

src/eligibility_signposting_api/common/api_error_response.py

@@ -22,11 +22,13 @@ class FHIRIssueCode(str, Enum):
     FORBIDDEN = "forbidden"
     PROCESSING = "processing"
     VALUE = "value"
+    INVALID = "invalid"
 
 
 class FHIRSpineErrorCode(str, Enum):
     INVALID_NHS_NUMBER = "INVALID_NHS_NUMBER"
     INVALID_PARAMETER = "INVALID_PARAMETER"
+    BAD_REQUEST = "BAD_REQUEST"
     INTERNAL_SERVER_ERROR = "INTERNAL_SERVER_ERROR"
     REFERENCE_NOT_FOUND = "REFERENCE_NOT_FOUND"
 
@@ -145,3 +147,13 @@ def log_and_generate_response(
     fhir_error_code=FHIRSpineErrorCode.INVALID_NHS_NUMBER,
     fhir_display_message="The provided NHS number does not match the record.",
 )
+
+
+NHS_NUMBER_MISSING_ERROR = APIErrorResponse(
+    status_code=HTTPStatus.BAD_REQUEST,
+    fhir_issue_code=FHIRIssueCode.INVALID,
+    fhir_issue_severity=FHIRIssueSeverity.ERROR,
+    fhir_coding_system="https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
+    fhir_error_code=FHIRSpineErrorCode.BAD_REQUEST,
+    fhir_display_message="Bad Request",
+)

src/eligibility_signposting_api/common/request_validator.py

@@ -11,6 +11,7 @@
     INVALID_CONDITION_FORMAT_ERROR,
     INVALID_INCLUDE_ACTIONS_ERROR,
     NHS_NUMBER_MISMATCH_ERROR,
+    NHS_NUMBER_MISSING_ERROR,
 )
 from eligibility_signposting_api.config.contants import NHS_NUMBER_HEADER
 
@@ -59,6 +60,12 @@ def wrapper(event: LambdaEvent, context: LambdaContext) -> dict[str, Any] | None
             path_nhs_no = event.get("pathParameters", {}).get("id")
             header_nhs_no = event.get("headers", {}).get(NHS_NUMBER_HEADER)
 
+            if not path_nhs_no:
+                message = "Missing required NHS Number from path parameters"
+                return NHS_NUMBER_MISSING_ERROR.log_and_generate_response(
+                    log_message=message, diagnostics=message, location_param="id"
+                )
+
             if not validate_nhs_number(path_nhs_no, header_nhs_no):
                 message = f"NHS Number {path_nhs_no or ''} does not match the header NHS Number {header_nhs_no or ''}"
                 return NHS_NUMBER_MISMATCH_ERROR.log_and_generate_response(