validate case #2714

data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py

@@ -63,8 +63,7 @@ def create_case(self, maybe_case: dict, num_cases: int = 1):
         if num_cases <= 0:
             return "Must create a positive number of cases", 400
         try:
-            case = Case.from_dict(maybe_case)
-            self.check_case_preconditions(case)
+            case = self.create_case_if_valid(maybe_case)
             for i in range(num_cases):
                 self.store.insert_case(case)
             return "", 201
@@ -75,6 +74,25 @@ def create_case(self, maybe_case: dict, num_cases: int = 1):
             # PreconditionError means it's a case, but not one we can use
             return pe.args[0], 422
 
+    def validate_case_dictionary(self, maybe_case: dict):
+        """Check whether a case _could_ be valid, without storing it if it is."""
+        try:
+            case = self.create_case_if_valid(maybe_case)
+            return "", 204
+        except ValueError as ve:
+            # ValueError means we can't even turn this into a case
+            return ve.args[0], 400
+        except PreconditionError as pe:
+            # PreconditionError means it's a case, but not one we can use
+            return pe.args[0], 422
+
+    def create_case_if_valid(self, maybe_case: dict):
+        """Attempts to create a case from an input dictionary and validate it against
+        the application rules. Raises ValueError or PreconditionError on invalid input."""
+        case = Case.from_dict(maybe_case)
+        self.check_case_preconditions(case)
+        return case
+
     def check_case_preconditions(self, case: Case):
         if case.confirmation_date < self.outbreak_date:
             raise PreconditionError("Confirmation date is before outbreak began")

data-serving/reusable-data-service/reusable_data_service/main.py

@@ -25,10 +25,14 @@ def list_cases():
         filter = request.args.get("q", type=str)
         return case_controller.list_cases(page=page, limit=limit, filter=filter)
     else:
+        potential_case = request.get_json()
+        validate_only = request.args.get("validate_only", type=bool)
+        if validate_only:
+            return case_controller.validate_case_dictionary(potential_case)
         count = request.args.get("num_cases", type=int)
         if count is None:
             count = 1
-        return case_controller.create_case(request.get_json(), num_cases=count)
+        return case_controller.create_case(potential_case, num_cases=count)
 
 def set_up_controllers():
     global case_controller

data-serving/reusable-data-service/tests/test_case_controller.py

@@ -140,3 +140,16 @@ def test_create_valid_case_with_positive_count_adds_to_collection(case_controlle
     )
     assert status == 201
     assert case_controller.store.count_cases() == 7
+
+
+def test_validate_case_with_invalid_case_is_400_error(case_controller):
+    (response, status) = case_controller.validate_case_dictionary({})
+    assert status == 400
+
+
+def test_validate_case_with_valid_case_returns_204_and_does_not_add_case(case_controller):
+    (response, status) = case_controller.validate_case_dictionary(
+        {"confirmation_date": date(2021, 6, 3)}
+    )
+    assert status == 204
+    assert case_controller.store.count_cases() == 0

data-serving/reusable-data-service/tests/test_case_end_to_end.py

@@ -174,3 +174,12 @@ def test_post_multiple_case_list_cases_round_trip(client_with_patched_mongo):
     assert get_response.status_code == 200
     assert len(get_response.json["cases"]) == 3
     assert get_response.json["cases"][0]["confirmation_date"] == "2022-01-23"
+
+def test_post_case_validate_only(client_with_patched_mongo):
+    post_response = client_with_patched_mongo.post("/api/cases?validate_only=true", json = {
+        "confirmation_date": "2022-01-23T13:45:01.234Z"
+    })
+    assert post_response.status_code == 204
+    get_response = client_with_patched_mongo.get("/api/cases")
+    assert get_response.status_code == 200
+    assert len(get_response.json["cases"]) == 0