DataclassJSONField implementation

django_jsonform/contrib/README.md

@@ -0,0 +1,3 @@
+# contrib
+
+Community contributed modules which extend the core `django-jsonform` project.

django_jsonform/contrib/dataclasses/README.md

@@ -0,0 +1,3 @@
+# `django_jsonform.contrib.dataclasses`
+
+**Status:** experimental

django_jsonform/contrib/dataclasses/forms/fields.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+import json
+from typing import Optional
+
+from django_jsonform.contrib.dataclasses.typedefs import SerializableValue
+from django_jsonform.forms.fields import JSONFormField
+
+
+class DataclassJSONFormField(JSONFormField):
+    def prepare_value(self, value: SerializableValue) -> Optional[str]:
+        if value is None:
+            return None
+        if isinstance(value, list):
+            return json.dumps(
+                [x if isinstance(x, dict) else x.to_dict(validate=False) for x in value]
+            )
+        return json.dumps(
+            value if isinstance(value, dict) else value.to_dict(validate=False)
+        )

django_jsonform/contrib/dataclasses/models/fields.py

@@ -0,0 +1,82 @@
+from __future__ import annotations
+
+import json
+from typing import TYPE_CHECKING, Any, List, Optional, Type
+
+from django_jsonform.contrib.dataclasses.forms.fields import DataclassJSONFormField
+from django_jsonform.contrib.dataclasses.typedefs import DataclassJsonSchema, SerializableValue
+from django_jsonform.contrib.dataclasses.utils import json_schema_array
+from django_jsonform.exceptions import JSONSchemaValidationError
+from django_jsonform.models.fields import JSONField
+
+if TYPE_CHECKING:
+    from django.db import models
+    from django.db.backends.base.base import BaseDatabaseWrapper
+    from django.db.models.expressions import Expression
+
+
+class DataclassJSONField(JSONField):
+    form_class = DataclassJSONFormField
+
+    def __init__(
+        self,
+        dataclass_cls: Type[DataclassJsonSchema],
+        *,
+        many: bool = False,
+        **kwargs: Any,
+    ) -> None:
+        self._dataclass_cls = dataclass_cls
+        self._many = many
+        self._json_schema = (
+            json_schema_array(dataclass_cls) if many else dataclass_cls.json_schema()
+        )
+
+        super().__init__(schema=self._json_schema, **kwargs)  # type: ignore
+
+    def from_db_value(
+        self,
+        value: Optional[str],
+        expression: Expression,
+        connection: BaseDatabaseWrapper,
+    ) -> SerializableValue:
+        if value is None:
+            return None
+        data = json.loads(value)
+        if isinstance(data, list):
+            return [self._dataclass_cls.from_dict(x, validate=False) for x in data]
+        return self._dataclass_cls.from_dict(data, validate=False)
+
+    def get_prep_value(self, value: SerializableValue) -> Optional[str]:
+        if value is None:
+            return None
+        if isinstance(value, list):
+            return json.dumps(
+                [x if isinstance(x, dict) else x.to_dict(validate=False) for x in value]
+            )
+        return json.dumps(
+            value if isinstance(value, dict) else value.to_dict(validate=False)
+        )
+
+    def validate(self, value: SerializableValue, model_instance: models.Model) -> None:
+        if value is None:
+            if not self.null:
+                raise JSONSchemaValidationError("Null value in non-nullable field.")  # type: ignore
+            return
+        values_to_validate = value if isinstance(value, list) else [value]
+        if len(values_to_validate) == 0:
+            if not self.blank:
+                raise JSONSchemaValidationError("Blank value in non-blank field.")  # type: ignore
+            return
+        errs: List[str] = []
+        for i, val in enumerate(values_to_validate):
+            try:
+                if isinstance(val, dict):
+                    self._dataclass_cls.from_dict(
+                        val, validate=True, validate_enums=True
+                    )
+                else:
+                    val.to_dict(validate=True, validate_enums=True)
+            except Exception as e:
+                errs.append(f"[{i}] {e}")
+        if errs:
+            raise JSONSchemaValidationError(errs)  # type: ignore

django_jsonform/contrib/dataclasses/typedefs.py

@@ -0,0 +1,14 @@
+from __future__ import annotations
+
+from typing import List, Optional, Union
+
+from dataclasses_jsonschema import JsonSchemaMixin
+from dataclasses_jsonschema.type_defs import JsonDict
+
+DataclassJsonSchema = JsonSchemaMixin
+"""TODO: Make this a Protocol or something. Not sure."""
+
+
+SerializableValue = Optional[
+    Union[DataclassJsonSchema, JsonDict, List[Union[DataclassJsonSchema, JsonDict]]]
+]

django_jsonform/contrib/dataclasses/utils.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+import dataclasses
+from typing import Type
+
+from dataclasses_jsonschema import JsonSchemaMixin
+from dataclasses_jsonschema.type_defs import JsonDict
+
+
+def json_schema_array(dataclass_cls: Type[JsonSchemaMixin]) -> JsonDict:
+    """Get JSON schema representing an array of `dataclass_cls`."""
+    WrapperDataClass = type("WrapperDataClass", (JsonSchemaMixin,), {})
+    WrapperDataClass.__annotations__["item"] = dataclass_cls
+    WrapperDataClass = dataclasses.dataclass(WrapperDataClass)
+
+    schema: JsonDict = WrapperDataClass.json_schema()  # type: ignore
+
+    schema["type"] = "array"
+    schema["description"] = f"An array of {dataclass_cls.__name__} objects."
+    del schema["required"]
+    schema["items"] = schema["properties"]["item"]
+    del schema["properties"]
+
+    return schema

django_jsonform/models/fields.py

@@ -24,6 +24,8 @@ class DjangoArrayField:
 
 
 class JSONField(DjangoJSONField):
+    form_class = JSONFormField
+
     def __init__(self, *args, **kwargs):
         self.schema = kwargs.pop('schema', {})
         self.pre_save_hook = kwargs.pop('pre_save_hook', None)
@@ -32,7 +34,7 @@ def __init__(self, *args, **kwargs):
 
     def formfield(self, **kwargs):
         return super().formfield(**{
-            'form_class': JSONFormField,
+            'form_class': self.form_class,
             'schema': self.schema,
             'model_name': self.model.__name__,
             'file_handler': self.file_handler,
@@ -49,6 +51,8 @@ def pre_save(self, model_instance, add):
 
 
 class ArrayField(DjangoArrayField):
+    form_class = ArrayFormField
+
     def __init__(self, *args, **kwargs):
         if hasattr(DjangoArrayField, 'mock_field'):
             raise ImproperlyConfigured('ArrayField requires psycopg2 to be installed.')
@@ -57,4 +61,4 @@ def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
 
     def formfield(self, **kwargs):
-        return super().formfield(**{'form_class': ArrayFormField, 'nested': self.nested, **kwargs})
+        return super().formfield(**{'form_class': self.form_class, 'nested': self.nested, **kwargs})