# ボディ - フィールド

`Query`や`Path`、`Body`を使って *path operation関数* のパラメータに追加のバリデーションやメタデータを宣言するのと同じように、Pydanticの`Field`を使ってPydanticモデルの内部でバリデーションやメタデータを宣言することができます。

## `Field`のインポート

まず、以下のようにインポートします:

{* ../../docs_src/body_fields/tutorial001.py hl[4] *}

/// warning | 注意

`Field`は他の全てのもの（`Query`、`Path`、`Body`など）とは違い、`fastapi`からではなく、`pydantic`から直接インポートされていることに注意してください。

///

## モデルの属性の宣言

以下のように`Field`をモデルの属性として使用することができます:

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: int = Path(title="The ID of the item to get", ge=0, le=1000),
    q: str,
    size: float = Query(gt=0, lt=10.5),
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

		{
			path:   "/bucket/object///////",
			bucket: "bucket",
			object: "object///////",
		},
		// Test case 7 object has preceding separators.
		{
			path:   "/bucket////object////",
			bucket: "bucket",
			object: "///object////",
		},
		// Test case 8 url path is empty.
		{
			path:   "",
			bucket: "",
			object: "",
		},
	}

	// Validate all test cases.

     * @param path the {@link Path}, must not be {@code null}
     * @throws ProjectBuilderException if the project cannot be created
     * @throws IllegalArgumentException if an argument is {@code null} or invalid
     * @see #build(ProjectBuilderRequest)
     */
    @Nonnull
    default ProjectBuilderResult build(@Nonnull Session session, @Nonnull Path path) throws ProjectBuilderException {

///

## Declare atributos do modelo { #declare-model-attributes }

Você pode então utilizar `Field` com atributos do modelo:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}

`Field` funciona da mesma forma que `Query`, `Path` e `Body`, ele possui todos os mesmos parâmetros, etc.

/// note | Detalhes Técnicos

 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven.cling.invoker.mvnup.goals;

import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.Map;
import java.util.Optional;

import eu.maveniverse.domtrip.Document;
import eu.maveniverse.domtrip.Editor;

client = TestClient(app)


def test_custom_middleware_exception(tmp_path: Path):
    default_pydantic_max_size = 2**16
    path = tmp_path / "test.txt"
    path.write_bytes(b"x" * (default_pydantic_max_size + 1))

    with client:
        with open(path, "rb") as file:
            response = client.post("/middleware", files={"file": file})

	Path     string                        `yaml:"path" json:"path"`
	Creds    BatchJobReplicateCredentials  `yaml:"credentials" json:"credentials"`
}

// ValidPath returns true if path is valid
func (t BatchJobReplicateTarget) ValidPath() bool {
	return t.Path == "on" || t.Path == "off" || t.Path == "auto" || t.Path == ""
}

      this.domain = canonicalDomain
      this.hostOnly = hostOnly
    }

    fun path(path: String) =
      apply {
        require(path.startsWith("/")) { "path must start with '/'" }
        this.path = path
      }

    fun secure() =
      apply {
        this.secure = true
      }

    fun httpOnly() =
      apply {

/// tip | Dica

Note que neste caso, nós estamos declarando o parâmetro de path ao lado do parâmetro da requisição.

Assim, o parâmetro de path será extraído, validado, convertido para o tipo especificado e anotado com OpenAPI.

Do mesmo jeito, você pode declarar qualquer outro parâmetro normalmente, e além disso, obter o `Request` também.