Add better support for Django QuerySets.

Author: adamghill

django_unicorn/components/__init__.py

@@ -1,2 +1,3 @@
+from .types import *
 from .unicorn_view import *
 from .updaters import *

django_unicorn/components/types.py

@@ -0,0 +1,11 @@
+from typing import Generic, Iterator, TypeVar
+
+from django.db.models import Model, QuerySet
+
+
+M = TypeVar("M", bound=Model)
+
+
+class QueryType(Generic[M], QuerySet):
+    def __iter__(self) -> Iterator[M]:
+        ...

django_unicorn/static/js/component.js

@@ -224,8 +224,6 @@ export class Component {
             this.keyEls.push(element);
           }
 
-          console.log(element.actions);
-
           element.actions.forEach((action) => {
             if (this.actionEvents[action.eventType]) {
               this.actionEvents[action.eventType].push({ action, element });

django_unicorn/views/action_parsers/utils.py

@@ -1,5 +1,7 @@
 from typing import Any
 
+from django.db.models import QuerySet
+
 from django_unicorn.components import UnicornView
 from django_unicorn.decorators import timed
 
@@ -79,6 +81,15 @@ class TestView(UnicornView):
             # TODO: Check for iterable instad of list? `from collections.abc import Iterable`
             property_name_part = int(property_name_part)
 
+            if idx == len(property_name_parts) - 1:
+                component_or_field[property_name_part] = property_value
+                data_or_dict[property_name_part] = property_value
+            else:
+                component_or_field = component_or_field[property_name_part]
+                data_or_dict = data_or_dict[property_name_part]
+        elif isinstance(component_or_field, QuerySet):
+            property_name_part = int(property_name_part)
+
             if idx == len(property_name_parts) - 1:
                 component_or_field[property_name_part] = property_value
                 data_or_dict[property_name_part] = property_value

django_unicorn/views/utils.py

@@ -1,13 +1,30 @@
+import logging
 from dataclasses import is_dataclass
 from typing import Any, Union
 
-from django.db.models import Model
+from django.db.models import Model, QuerySet
 
-from django_unicorn.components import UnicornField, UnicornView
+from django_unicorn.components import QueryType, UnicornField, UnicornView
 from django_unicorn.decorators import timed
 from django_unicorn.utils import get_type_hints
 
 
+try:
+    from typing import get_args, get_origin
+except ImportError:
+    # Fallback to dunder methods for older versions of Python
+    def get_args(type_hint):
+        if hasattr(type_hint, "__args__"):
+            return type_hint.__args__
+
+    def get_origin(type_hint):
+        if hasattr(type_hint, "__origin__"):
+            return type_hint.__origin__
+
+
+logger = logging.getLogger(__name__)
+
+
 @timed
 def set_property_from_data(
     component_or_field: Union[UnicornView, UnicornField, Model], name: str, value: Any,
@@ -29,6 +46,8 @@ def set_property_from_data(
         # Re-get the field since it might have been set in `_is_component_field_model_or_unicorn_field`
         field = getattr(component_or_field, name)
 
+        type_hints = get_type_hints(component_or_field)
+
         if isinstance(value, dict):
             for key in value.keys():
                 key_value = value[key]
@@ -37,18 +56,20 @@ def set_property_from_data(
             set_property_from_data(field, field.name, value)
     else:
         type_hints = get_type_hints(component_or_field)
+        type_hint = type_hints.get(name)
 
-        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")
-
-            if is_dataclass(type_hints[name]):
-                value = type_hints[name](**value)
+        if _is_queryset(field, type_hint, value):
+            value = _create_queryset(field, type_hint, value)
+        elif type_hint:
+            if is_dataclass(type_hint):
+                value = type_hint(**value)
             else:
+                # 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")
                 try:
-                    value = type_hints[name](value)
+                    value = type_hint(value)
                 except TypeError:
                     # Ignore this exception because some type-hints can't be instantiated like this (e.g. `List[]`)
                     pass
@@ -107,3 +128,80 @@ def _is_component_field_model_or_unicorn_field(
         pass
 
     return is_subclass_of_model or is_subclass_of_unicorn_field
+
+
+def _is_queryset(field, type_hint, value):
+    """
+    Determines whether a field is a `QuerySet` or not based on the current instance of the
+    component or the type hint.
+    """
+
+    return (
+        isinstance(field, QuerySet)
+        or (type_hint and get_origin(type_hint) is QueryType)
+    ) and isinstance(value, list)
+
+
+def _create_queryset(field, type_hint, value) -> QuerySet:
+    """
+    Create a queryset based on the `value`. If needed, the queryset will be created based on the `QueryType`.
+
+    For example, all of these ways fields are equivalent:
+
+    ```
+    class TestComponent(UnicornView):
+        queryset_with_empty_list: QueryType[SomeModel] = []
+        queryset_with_none: QueryType[SomeModel] = None
+        queryset_with_empty_queryset: QueryType[SomeModel] = SomeModel.objects.none()
+        queryset_with_no_typehint = SomeModel.objects.none()
+    ```
+
+    Params:
+        field: Field of the component.
+        type_hint: The optional type hint for the field.
+        value: JSON.
+    """
+
+    # Get original queryset, update it with dictionary data and then
+    # re-set the queryset; this is required because otherwise the
+    # property changes type from a queryset to the serialized queryset
+    # (which is an array of dictionaries)
+    queryset = field
+    model_type = None
+
+    if type_hint and not isinstance(queryset, QuerySet):
+        type_arguments = get_args(type_hint)
+
+        if type_arguments:
+            # First type argument should be the type of the model
+            queryset = type_arguments[0].objects.none()
+            model_type = type_arguments[0]
+
+    if not model_type and not isinstance(queryset, QuerySet):
+        raise Exception(f"Getting Django Model type failed for type: {type(queryset)}")
+
+    if not model_type:
+        # Assume that `queryset` is _actually_ a QuerySet so grab the
+        # `model` attribute in that case
+        model_type = queryset.model
+
+    for model_value in value:
+        model_found = False
+
+        # The following portion uses the internal `_result_cache` QuerySet API which
+        # is private and could potentially change in the future, but not sure how
+        # else to change internal models or append a new model to a QuerySet (probably
+        # because it isn't really allowed)
+        if queryset._result_cache is None:
+            # Explicitly set `_result_cache` to an empty list
+            queryset._result_cache = []
+
+        for (idx, model) in enumerate(queryset._result_cache):
+            if model.pk == model_value.get("pk"):
+                queryset._result_cache[idx] = model_type(**model_value)
+                model_found = True
+
+        if not model_found:
+            queryset._result_cache.append(model_type(**model_value))
+
+    return queryset

example/unicorn/components/models.py

@@ -1,28 +1,26 @@
-from typing import List
-
-from django_unicorn.components import UnicornView
+from django_unicorn.components import QueryType, UnicornView
 from example.coffee.models import Flavor
 
 
 class ModelsView(UnicornView):
-    # class attributes get stored on the class, so django-unicorn handles clearing
-    # this with `_resettable_attributes_cache` in components.py
     flavor: Flavor = Flavor()
-    flavors: List[Flavor] = []
+    flavors: QueryType[Flavor] = Flavor.objects.none()
 
     def mount(self):
-        self.flavors = list(Flavor.objects.all().order_by("-id")[:2])
+        self.refresh_flavors()
+
+    def refresh_flavors(self):
+        self.flavors = Flavor.objects.all().order_by("-id")[:2]
 
     def save_flavor(self):
         self.flavor.save()
         self.flavor = Flavor()
+        self.refresh_flavors()
 
-    def save(self, flavors_idx):
-        flavor_data = self.flavors[flavors_idx]
-        print("call save for idx", flavors_idx)
-        flavor = Flavor(**flavor_data)
-        flavor.save()
+    def save(self, flavor_idx: int):
+        flavor_data = self.flavors[flavor_idx]
+        flavor_data.save()
 
-    def save_specific(self, flavor: Flavor):
-        flavor.save()
-        print("call save on flavor", flavor)
+    def delete(self, flavor_to_delete: Flavor):
+        flavor_to_delete.delete()
+        self.refresh_flavors()

example/unicorn/templates/unicorn/models.html

@@ -5,8 +5,6 @@
         }
     </style>
 
-    <h3>Current flavors</h3>
-
     <div>
         <h3>Using unicorn:model with Django models</h3>
 
@@ -46,7 +44,7 @@ <h4>{{ flavor.pk }}</h4>
                 {{ flavor.decimal_value }}
                 <br />
 
-                <button unicorn:click="save({{ forloop.counter0 }})">save(flavors_idx)</button>
+                <button unicorn:click="save({{ forloop.counter0 }})">save(flavor_idx)</button>
                 <button unicorn:click="delete({{ flavor.pk }})">delete(flavor.pk)</button>
             </div>
             {% endfor %}

tests/views/action_parsers/utils/__init__.py

@@ -1,25 +1,20 @@
 from datetime import datetime
 from typing import List
 
+import pytest
+
 from django_unicorn.components import UnicornView
 from django_unicorn.views.action_parsers.utils import set_property_value
-from django_unicorn.views.utils import set_property_from_data
+from example.coffee.models import Flavor
 
 
 class FakeComponent(UnicornView):
     string = "property_view"
     integer = 99
     datetime = datetime(2020, 1, 1)
     array: List[str] = []
-
-
-def test_set_property_from_data_str():
-    component = FakeComponent(component_name="test", component_id="12345678")
-    assert "property_view" == component.string
-
-    set_property_from_data(component, "string", "property_view_updated")
-
-    assert "property_view_updated" == component.string
+    model = Flavor(name="initial-flavor")
+    queryset = Flavor.objects.none()
 
 
 def test_set_property_value_str():
@@ -36,15 +31,6 @@ def test_set_property_value_str():
     assert "property_view_updated" == component.string
 
 
-def test_set_property_from_data_int():
-    component = FakeComponent(component_name="test", component_id="12345678")
-    assert 99 == component.integer
-
-    set_property_from_data(component, "integer", 100)
-
-    assert 100 == component.integer
-
-
 def test_set_property_value_int():
     component = FakeComponent(component_name="test", component_id="12345678")
     assert 99 == component.integer
@@ -54,33 +40,47 @@ def test_set_property_value_int():
     assert 100 == component.integer
 
 
-def test_set_property_from_data_datetime():
+def test_set_property_value_datetime():
     component = FakeComponent(component_name="test", component_id="12345678")
     assert datetime(2020, 1, 1) == component.datetime
 
-    set_property_from_data(component, "datetime", datetime(2020, 1, 2))
+    set_property_value(
+        component, "datetime", datetime(2020, 1, 2), {"datetime": datetime(2020, 1, 2)}
+    )
 
     assert datetime(2020, 1, 2) == component.datetime
 
 
-def test_set_property_from_data_list():
-    """
-    Prevent attempting to instantiate `List[]` type-hint doesn't throw TypeError
-    """
+def test_set_property_value_model():
     component = FakeComponent(component_name="test", component_id="12345678")
-    assert component.array == []
+    assert "initial-flavor" == component.model.name
 
-    set_property_from_data(component, "array", ["string"])
+    set_property_value(
+        component,
+        "model",
+        Flavor(name="test-flavor"),
+        {"model": {"name": "test-flavor"}},
+    )
 
-    assert ["string"] == component.array
+    assert "test-flavor" == component.model.name
 
 
-def test_set_property_value_datetime():
+@pytest.mark.django_db
+def test_set_property_value_queryset():
     component = FakeComponent(component_name="test", component_id="12345678")
-    assert datetime(2020, 1, 1) == component.datetime
+    assert len(component.queryset) == 0
+
+    flavor_one = Flavor(name="test-flavor-one")
+    flavor_one.save()
+    flavor_two = Flavor(name="test-flavor-two")
+    flavor_two.save()
+    queryset = Flavor.objects.all()[:2]
 
     set_property_value(
-        component, "datetime", datetime(2020, 1, 2), {"datetime": datetime(2020, 1, 2)}
+        component,
+        "queryset",
+        queryset,
+        {"queryset": [{"name": "test-flavor-one"}, {"name": "test-flavor-two"}]},
     )
 
-    assert datetime(2020, 1, 2) == component.datetime
+    assert len(queryset) == 2

tests/views/test_unicorn_builtins.py renamed to tests/views/action_parsers/utils/test_set_property_value.py

@@ -12,7 +12,7 @@
 def test_message_db_input_update(client):
     flavor = Flavor(id=1, name="Enzymatic-Flowery")
     flavor.save()
-    data = {"flavors": [{"pk": flavor.pk, "title": flavor.name}]}
+    data = {"flavors": [{"pk": flavor.pk, "name": flavor.name}]}
 
     message = {
         "actionQueue": [