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# Annotated Handlers

Type annotations to use with `__get_pydantic_core_schema__` and `__get_pydantic_json_schema__`.

## GetJsonSchemaHandler

Handler to call into the next JSON schema generation function.

### Attributes

#### mode

Json schema mode, can be `validation` or `serialization`.

**Type:** `JsonSchemaMode`

### Methods

#### resolve\_ref\_schema

```python
def resolve_ref_schema(maybe_ref_json_schema: JsonSchemaValue, /) -> JsonSchemaValue
```

Get the real schema for a `{"$ref": ...}` schema. If the schema given is not a `$ref` schema, it will be returned as is. This means you don't have to check before calling this function.

##### Returns

`JsonSchemaValue` -- A JsonSchemaValue that has no `$ref`.

##### Parameters

**`maybe_ref_json_schema`** : `JsonSchemaValue`

A JsonSchemaValue which may be a `$ref` schema.

##### Raises

- `LookupError` -- If the ref is not found.

## GetCoreSchemaHandler

Handler to call into the next CoreSchema schema generation function.

### Attributes

#### field\_name

Get the name of the closest field to this validator.

**Type:** [`str`](https://docs.python.org/3/builtins/stdtypes.html#str) | [`None`](https://docs.python.org/3/builtins/constants.html#None)

### Methods

#### generate\_schema

```python
def generate_schema(source_type: Any, /) -> core_schema.CoreSchema
```

Generate a schema unrelated to the current context. Use this function if e.g. you are handling schema generation for a sequence and want to generate a schema for its items. Otherwise, you may end up doing something like applying a `min_length` constraint that was intended for the sequence itself to its items!

##### Returns

`core_schema.CoreSchema` -- The `pydantic-core` CoreSchema generated.

##### Parameters

**`source_type`** : [`Any`](https://docs.python.org/3/library/typing.html#typing.Any)

The input type.

#### resolve\_ref\_schema

```python
def resolve_ref_schema(
    maybe_ref_schema: core_schema.CoreSchema,
    /,
) -> core_schema.CoreSchema
```

Get the real schema for a `definition-ref` schema. If the schema given is not a `definition-ref` schema, it will be returned as is. This means you don't have to check before calling this function.

##### Returns

`core_schema.CoreSchema` -- A concrete `CoreSchema`.

##### Parameters

**`maybe_ref_schema`** : `core_schema.CoreSchema`

A `CoreSchema`, `ref`-based or not.

##### Raises

- `LookupError` -- If the `ref` is not found.

## Related pages

- [API Documentation](./api-documentation-index.md)
- [Concepts](./concepts-index.md)
- [Dev Tools](./dev-tools-index.md)
- [Error Messages](./error-messages-index.md)
- [Examples](./examples-index.md)
- [Integrations](./integrations-index.md)
- [Internals](./internals-index.md)
- [Production Tools](./production-tools-index.md)
- [Pydantic](./pydantic-index.md)
- [Pydantic Core](./pydantic-core-index.md)

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