Use typehints to cast attributes to the correct type if possible.

Author: adamghill

django_unicorn/views.py

@@ -11,6 +11,7 @@
 
 import orjson
 from bs4 import BeautifulSoup
+from cachetools.lru import LRUCache
 
 from .call_method_parser import InvalidKwarg, parse_call_method_name, parse_kwarg
 from .components import UnicornField, UnicornView
@@ -26,7 +27,14 @@
 logger.setLevel(logging.DEBUG)
 
 
+type_hints_cache = LRUCache(maxsize=100)
+
+
 def handle_error(view_func):
+    """
+    Returns a JSON response with an error if necessary.
+    """
+
     def wrapped_view(*args, **kwargs):
         try:
             return view_func(*args, **kwargs)
@@ -38,6 +46,34 @@ def wrapped_view(*args, **kwargs):
     return wraps(view_func)(wrapped_view)
 
 
+def _get_type_hints(obj):
+    """
+    Get type hints from an object. These get cached in a local memory cache for quicker look-up later.
+
+    Returns:
+        An empty dictionary if no type hints can be retrieved.
+    """
+    try:
+        if obj in type_hints_cache:
+            return type_hints_cache[obj]
+    except TypeError:
+        # Ignore issues with checking for an object in the cache, e.g. when a Django model is missing a PK
+        pass
+
+    try:
+        type_hints = get_type_hints(obj)
+
+        # Cache the type hints just in case
+        type_hints_cache[obj] = type_hints
+
+        return type_hints
+    except TypeError:
+        #  Return an empty dictionary when there is a TypeError. From `get_type_hints`: "TypeError is
+        # raised if the argument is not of a type that can contain annotations, and an empty dictionary
+        # is returned if no annotations are present"
+        return {}
+
+
 @timed
 def _is_component_field_model_or_unicorn_field(
     component_or_field: Union[UnicornView, UnicornField, Model], name: str,
@@ -66,7 +102,7 @@ def _is_component_field_model_or_unicorn_field(
     component_type_hints = {}
 
     try:
-        component_type_hints = get_type_hints(component_or_field)
+        component_type_hints = _get_type_hints(component_or_field)
 
         if name in component_type_hints:
             is_subclass_of_model = issubclass(component_type_hints[name], Model)
@@ -81,7 +117,7 @@ def _is_component_field_model_or_unicorn_field(
                 if is_subclass_of_model or is_subclass_of_unicorn_field:
                     field = component_type_hints[name]()
                     setattr(component_or_field, name, field)
-    except TypeError as e:
+    except TypeError:
         pass
 
     return is_subclass_of_model or is_subclass_of_unicorn_field
@@ -115,6 +151,15 @@ def _set_property_from_data(
         else:
             _set_property_from_data(field, field.name, value)
     else:
+        type_hints = _get_type_hints(component_or_field)
+
+        if name in type_hints:
+            # Construct the specified type by passing the value in
+            # Usually the value will be a string (because it is coming from JSON)
+            # and basic types can be constructed by passing in a string,
+            # i.e. int("1") or float("1.1")
+            value = type_hints[name](value)
+
         if hasattr(component_or_field, "_set_property"):
             # Can assume that `component_or_field` is a component
             component_or_field._set_property(name, value)

tests/views/message/test_sync_input.py

@@ -1,30 +1,18 @@
-import time
-
 import orjson
-import shortuuid
 
-from django_unicorn.utils import generate_checksum
+from tests.views.message.utils import post_and_get_response
 
 
 def test_message_nested_sync_input(client):
     data = {"dictionary": {"name": "test"}}
-    message = {
-        "actionQueue": [
-            {
-                "payload": {"name": "dictionary.name", "value": "test1"},
-                "type": "syncInput",
-            }
-        ],
-        "data": data,
-        "checksum": generate_checksum(orjson.dumps(data)),
-        "id": shortuuid.uuid()[:8],
-        "epoch": time.time(),
-    }
-
-    response = client.post(
-        "/message/tests.views.fake_components.FakeComponent",
-        message,
-        content_type="application/json",
+    action_queue = [
+        {"payload": {"name": "dictionary.name", "value": "test1"}, "type": "syncInput",}
+    ]
+    response = post_and_get_response(
+        client,
+        url="/message/tests.views.fake_components.FakeComponent",
+        data=data,
+        action_queue=action_queue,
     )
 
     body = orjson.loads(response.content)

tests/views/message/test_type_hints.py

@@ -0,0 +1,74 @@
+from decimal import Decimal
+
+import orjson
+
+from django_unicorn.components import UnicornView
+from tests.views.message.utils import post_and_get_response
+
+
+class FakeObjectsComponent(UnicornView):
+    template_name = "templates/test_component.html"
+
+    decimal_example: Decimal = Decimal(1.1)
+    float_example: float = 1.2
+    int_example: int = 3
+
+    def assert_int(self):
+        assert self.int_example == 4
+
+    def assert_float(self):
+        assert self.float_example == 1.3
+
+    def assert_decimal(self):
+        assert self.decimal_example == Decimal(1.5)
+
+
+FAKE_OBJECTS_COMPONENT_URL = (
+    "/message/tests.views.message.test_type_hints.FakeObjectsComponent"
+)
+
+
+def test_message_int(client):
+    data = {"int_example": "4"}
+    action_queue = [{"payload": {"name": "assert_int"}, "type": "callMethod",}]
+    response = post_and_get_response(
+        client, url=FAKE_OBJECTS_COMPONENT_URL, data=data, action_queue=action_queue,
+    )
+
+    body = orjson.loads(response.content)
+
+    assert not body.get(
+        "error"
+    )  # UnicornViewError/AssertionError returns a a JsonResponse with "error" key
+    assert not body["errors"]
+
+
+def test_message_float(client):
+    data = {"float_example": "1.3"}
+    action_queue = [{"payload": {"name": "assert_float"}, "type": "callMethod",}]
+    response = post_and_get_response(
+        client, url=FAKE_OBJECTS_COMPONENT_URL, data=data, action_queue=action_queue,
+    )
+
+    body = orjson.loads(response.content)
+
+    assert not body.get(
+        "error"
+    )  # UnicornViewError/AssertionError returns a a JsonResponse with "error" key
+    assert not body["errors"]
+
+
+def test_message_decimal(client):
+    data = {"decimal_example": "1.5"}
+    action_queue = [{"payload": {"name": "assert_decimal"}, "type": "callMethod",}]
+    response = post_and_get_response(
+        client, url=FAKE_OBJECTS_COMPONENT_URL, data=data, action_queue=action_queue,
+    )
+
+    body = orjson.loads(response.content)
+
+    assert not body.get(
+        "error"
+    )  # UnicornViewError/AssertionError returns a a JsonResponse with "error" key
+    assert not body["errors"]
+

tests/views/message/utils.py

@@ -7,7 +7,6 @@
 
 
 def post_and_get_response(client, url="", data={}, action_queue=[]):
-    data = {}
     message = {
         "actionQueue": action_queue,
         "data": data,