# Request Body { #request-body }

When you need to send data from a client (let's say, a browser) to your API, you send it as a **request body**.

A **request** body is data sent by the client to your API. A **response** body is the data your API sends to the client.

<img src="/img/tutorial/body/image01.png">

そして、それらが使われる *パスオペレーション* のそれぞれのAPIドキュメントにも表示されます:

<img src="/img/tutorial/body/image02.png">

## エディターサポート

エディターによる型ヒントと補完が関数内で利用できます (Pydanticモデルではなく `dict` を受け取ると、同じサポートは受けられません):

<img src="/img/tutorial/body/image03.png">

型によるエラーチェックも可能です:

<img src="/img/tutorial/body/image04.png">

これは偶然ではなく、このデザインに基づいてフレームワークが作られています。

# Body - Fields { #body-fields }

The same way you can declare additional validation and metadata in *path operation function* parameters with `Query`, `Path` and `Body`, you can declare validation and metadata inside of Pydantic models using Pydantic's `Field`.

## Import `Field` { #import-field }

First, you have to import it:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

# Body - Updates { #body-updates }

## Update replacing with `PUT` { #update-replacing-with-put }

To update an item you can use the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/PUT" class="external-link" target="_blank">HTTP `PUT`</a> operation.

You can use the `jsonable_encoder` to convert the input data to data that can be stored as JSON (e.g. with a NoSQL database). For example, converting `datetime` to `str`.

# Body - Nested Models { #body-nested-models }

With **FastAPI**, you can define, validate, document, and use arbitrarily deeply nested models (thanks to Pydantic).

## List fields { #list-fields }

You can define an attribute to be a subtype. For example, a Python `list`:

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

This will make `tags` be a list, although it doesn't declare the type of the elements of the list.

# Body - Multiple Parameters { #body-multiple-parameters }

Now that we have seen how to use `Path` and `Query`, let's see more advanced uses of request body declarations.

## Mix `Path`, `Query` and body parameters { #mix-path-query-and-body-parameters }

First, of course, you can mix `Path`, `Query` and request body parameter declarations freely and **FastAPI** will know what to do.

        final EditBody body = new EditBody();
        body.id = entity.getId();
        body.dictId = dictId;
        body.token = entity.getToken();
        body.reading = entity.getReading();
        body.pos = entity.getPos();
        body.segmentation = entity.getSegmentation();
        return body;
    }

     * @param body create request payload
     * @return JSON response containing creation result and new entry ID
     */
    // POST /api/admin/dict/protwords/setting/{dictId}
    @Execute
    public JsonResponse<ApiResult> post$setting(final String dictId, final CreateBody body) {
        body.dictId = dictId;
        validateApi(body, messages -> {});
        body.crudMode = CrudMode.CREATE;

     * @param body the search body containing pagination and filter parameters
     * @return JSON response containing list of stopwords dictionary items
     */
    // GET /api/admin/dict/stopwords/settings/{dictId}
    @Execute
    public JsonResponse<ApiResult> get$settings(final String dictId, final SearchBody body) {
        body.dictId = dictId;
        validateApi(body, messages -> {});

     *
     * @param body the request body containing updated bad word information
     * @return JSON response with result status
     */
    @Execute
    public JsonResponse<ApiResult> put$setting(final EditBody body) {
        validateApi(body, messages -> {});
        body.crudMode = CrudMode.EDIT;
        final BadWord badWord = getBadWord(body).map(entity -> {
            try {