<div class="screenshot">
<img src="/img/tutorial/request-form-models/image01.png">
</div>

## Forbid Extra Form Fields { #forbid-extra-form-fields }

In some special use cases (probably not very common), you might want to **restrict** the form fields to only those declared in the Pydantic model. And **forbid** any **extra** fields.

/// note

This is supported since FastAPI version `0.114.0`. 🤓

///

<div class="screenshot">
<img src="/img/tutorial/header-param-models/image01.png">
</div>

## Forbid Extra Headers { #forbid-extra-headers }

In some special use cases (probably not very common), you might want to **restrict** the headers that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

{* ../../docs_src/header_param_models/tutorial002_an_py310.py hl[10] *}

<div class="screenshot">
<img src="/img/tutorial/query-param-models/image01.png">
</div>

## Forbid Extra Query Parameters { #forbid-extra-query-parameters }

In some special use cases (probably not very common), you might want to **restrict** the query parameters that you want to receive.

You can use Pydantic's model configuration to `forbid` any `extra` fields:

{* ../../docs_src/query_param_models/tutorial002_an_py310.py hl[10] *}

But even if you **fill the data** and click "Execute", because the docs UI works with **JavaScript**, the cookies won't be sent, and you will see an **error** message as if you didn't write any values.

///

## Forbid Extra Cookies { #forbid-extra-cookies }

In some special use cases (probably not very common), you might want to **restrict** the cookies that you want to receive.

/// note | Заметка

Этот функционал доступен с версии `0.114.0`. 🤓

///

Вы можете сконфигурировать Pydantic-модель так, чтобы запретить (`forbid`) все дополнительные (`extra`) поля:

{* ../../docs_src/request_form_models/tutorial002_an_py39.py hl[12] *}

Если клиент попробует отправить дополнительные данные, то в ответ он получит **ошибку**.

У деяких особливих випадках (ймовірно, не дуже поширених) Ви можете захотіти **обмежити** query параметри, які дозволено отримувати.

Ви можете використати конфігурацію моделі Pydantic, щоб заборонити (`forbid`) будь-які зайві (`extra`) поля:

{* ../../docs_src/query_param_models/tutorial002_an_py310.py hl[10] *}

Якщо клієнт спробує надіслати **зайві** дані у **query параметрах**, він отримає **помилку**.

Вы можете сконфигурировать Pydantic-модель так, чтобы запретить (`forbid`) любые дополнительные (`extra`) поля:

{* ../../docs_src/cookie_param_models/tutorial002_an_py39.py hl[10] *}

Если клиент попробует отправить **дополнительные cookies**, то в ответ он получит **ошибку**.

     * Apply inbound settings and send an acknowledgement to the peer that provided them.
     *
     * We need to apply the settings and ack them atomically. This is because some HTTP/2
     * implementations (nghttp2) forbid peers from taking advantage of settings before they have
     * acknowledged! In particular, we shouldn't send frames that assume a new `initialWindowSize`
     * until we send the frame that acknowledges this new size.
     *

* [Forbid Extra Query Parameters](https://fastapi.tiangolo.com/tutorial/query-param-models/#forbid-extra-query-parameters)
* [Forbid Extra Headers](https://fastapi.tiangolo.com/tutorial/header-param-models/#forbid-extra-headers)
* [Forbid Extra Cookies](https://fastapi.tiangolo.com/tutorial/cookie-param-models/#forbid-extra-cookies)

### Features

      apply {
        // Create a private copy of the list.
        val protocolsCopy = protocols.toMutableList()

        // Validate that the list has everything we require and nothing we forbid.
        require(Protocol.H2_PRIOR_KNOWLEDGE in protocolsCopy || HTTP_1_1 in protocolsCopy) {
          "protocols must contain h2_prior_knowledge or http/1.1: $protocolsCopy"
        }