Enhance pydantic model schema generation

- For pydantic based models, enhance the open api schema generation by differntiating between "validation" and "serialization" models.
- The default mode used by the pydantic TypeAdapter when generating JSON schemas is a "validation" schema.
- Add an additional option to the `model_schema` called `schema_mode` that will execute the TypeAdapter schema generation in the selected mode.
- When generating Open API paths for response models, change the schema_mode to "serialization" instead of "validation". This allows us to use models that have custom fields (e.g. computed fields or custom serialization logic) to be correctly converted to an Open API schema.

Author: bselman1

src/quart_schema/conversion.py

@@ -2,7 +2,7 @@
 
 from dataclasses import fields, is_dataclass
 from inspect import isclass
-from typing import Any, Dict, List, Optional, Type, TypeVar, Union
+from typing import Any, Dict, List, Literal, Optional, Type, TypeVar, Union
 
 import humps
 from quart import current_app
@@ -73,6 +73,8 @@ class MsgSpecValidationError(Exception):  # type: ignore
 
 T = TypeVar("T", bound=Model)
 
+JsonSchemaMode = Literal['validation', 'serialization']
+
 
 def convert_response_return_value(
     result: ResponseReturnValue | HTTPException,
@@ -184,9 +186,9 @@ def model_load(
         raise exception_class(error)
 
 
-def model_schema(model_class: Type[Model], *, preference: Optional[str] = None) -> dict:
+def model_schema(model_class: Type[Model], *, preference: Optional[str] = None, schema_mode: JsonSchemaMode = "validation") -> dict:
     if _use_pydantic(model_class, preference):
-        return TypeAdapter(model_class).json_schema(ref_template=PYDANTIC_REF_TEMPLATE)
+        return TypeAdapter(model_class).json_schema(ref_template=PYDANTIC_REF_TEMPLATE, mode=schema_mode)
     elif _use_msgspec(model_class, preference):
         _, schema = schema_components([model_class], ref_template=MSGSPEC_REF_TEMPLATE)
         return list(schema.values())[0]

src/quart_schema/extension.py

@@ -488,7 +488,9 @@ def _build_path(func: Callable, rule: Rule, app: Quart) -> Tuple[dict, dict]:
     for status_code in response_models.keys():
         model_class, headers_model_class = response_models[status_code]
         schema = model_schema(
-            model_class, preference=app.config["QUART_SCHEMA_CONVERSION_PREFERENCE"]
+            model_class,
+            preference=app.config["QUART_SCHEMA_CONVERSION_PREFERENCE"],
+            schema_mode="serialization",
         )
         definitions, schema = _split_convert_definitions(
             schema, app.config["QUART_SCHEMA_CONVERT_CASING"]