Avec `Form`, vous pouvez déclarer les mêmes configurations que pour `Body` (ainsi que `Query`, `Path`, `Cookie`), y compris la validation, des exemples, un alias (p. ex. `user-name` au lieu de `username`), etc.

/// info

`Form` est une classe qui hérite directement de `Body`.

///

/// tip | Astuce

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

## Query Parameters with a Pydantic Model { #query-parameters-with-a-pydantic-model }

   *
   * <p>Note that the specified object may not be known by the compiler to be a {@link
   * java.io.Serializable} instance, and is thus declared an {@code Object}. For example, it might
   * be declared as a {@code List}.
   *
   * @return the re-serialized object
   * @throws RuntimeException if the specified object was not successfully serialized or
   *     deserialized
   */

## Import `Cookie` { #import-cookie }

First import `Cookie`:

{* ../../docs_src/cookie_params/tutorial001_an_py310.py hl[3] *}

## Declare `Cookie` parameters { #declare-cookie-parameters }

Then declare the cookie parameters using the same structure as with `Path` and `Query`.

You can define the default value as well as all the extra validation or annotation parameters:

Örneğin, **bir dict** veya bir veritabanı objesi döndürmek isteyip, ama **onu bir Pydantic model olarak declare etmek** isteyebilirsiniz. Böylece Pydantic model, döndürdüğünüz obje (ör. dict veya veritabanı objesi) için dokümantasyon, doğrulama vb. işlerin tamamını yapar.

Eğer dönüş tipi annotation’ını eklerseniz, araçlar ve editörler (doğru şekilde) fonksiyonunuzun, declare ettiğiniz tipten (ör. Pydantic model) farklı bir tip (ör. dict) döndürdüğünü söyleyip hata verir.

You can declare multiple path parameters and query parameters at the same time, **FastAPI** knows which is which.

And you don't have to declare them in any specific order.

They will be detected by name:

{* ../../docs_src/query_params/tutorial004_py310.py hl[6,8] *}

## Required query parameters { #required-query-parameters }

You can declare a `response_model`, using the default status code `200` (or a custom one if you need), and then declare additional information for that same response in `responses`, directly in the OpenAPI schema.

**FastAPI** will keep the additional information from `responses`, and combine it with the JSON Schema from your model.

When you create a **FastAPI** *path operation* you can normally return any data from it: a `dict`, a `list`, a Pydantic model, a database model, etc.

If you declare a [Response Model](../tutorial/response-model.md) FastAPI will use it to serialize the data to JSON, using Pydantic.

If you don't declare a response model, FastAPI will use the `jsonable_encoder` explained in [JSON Compatible Encoder](../tutorial/encoder.md) and put it in a `JSONResponse`.

This would allow you to **re-use the model** in **multiple places** and also to declare validations and metadata for all the parameters at once. 😎

/// note

This is supported since FastAPI version `0.115.0`. 🤓

///

## Header Parameters with a Pydantic Model { #header-parameters-with-a-pydantic-model }

# Streaming

## Stream JSON Lines

To stream JSON Lines, declare the return type and use `yield` to return the data.

```python
@app.get("/items/stream")
async def stream_items() -> AsyncIterable[Item]:
    for item in items:
        yield item
```

## Server-Sent Events (SSE)

To stream Server-Sent Events, use `response_class=EventSourceResponse` and `yield` items from the endpoint.