# 응답을 직접 반환하기

**FastAPI**에서 *경로 작업(path operation)*을 생성할 때, 일반적으로 `dict`, `list`, Pydantic 모델, 데이터베이스 모델 등의 데이터를 반환할 수 있습니다.

기본적으로 **FastAPI**는 [JSON 호환 가능 인코더](../tutorial/encoder.md){.internal-link target=_blank}에 설명된 `jsonable_encoder`를 사용해 해당 반환 값을 자동으로 `JSON`으로 변환합니다.

그런 다음, JSON 호환 데이터(예: `dict`)를 `JSONResponse`에 넣어 사용자의 응답을 전송하는 방식으로 처리됩니다.

그러나 *경로 작업*에서 `JSONResponse`를 직접 반환할 수도 있습니다.

예를 들어, 사용자 정의 헤더나 쿠키를 반환해야 하는 경우에 유용할 수 있습니다.

```Python
q: Union[str, None] = Query(default=None, max_length=50)
```

Cela va valider les données, montrer une erreur claire si ces dernières ne sont pas valides, et documenter le paramètre dans le schéma `OpenAPI` de cette *path operation*.

## Rajouter plus de validation

Vous pouvez aussi rajouter un second paramètre `min_length` :

{* ../../docs_src/query_params_str_validations/tutorial003.py hl[9] *}

```JSON
{
    "detail": [
        {
            "loc": [
                "path",
                "item_id"
            ],
            "msg": "value is not a valid integer",
            "type": "type_error.integer"
        }
    ]
}
```

você receberá a versão em texto:

```
Validation errors:
Field: ('path', 'item_id'), Error: Input should be a valid integer, unable to parse string as an integer

// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package lex

import (
	"fmt"
	"os"
	"path/filepath"
	"slices"
	"strconv"
	"strings"
	"text/scanner"

	"cmd/asm/internal/flags"
	"cmd/internal/objabi"
	"cmd/internal/src"
)

// Input is the main input: a stack of readers and some macro definitions.

  <description>Most classical case: child in direct subdirectory with directory name == child artifactId</description>

  <!-- 5 inherited urls with ${project.artifactId} added to parent -->
  <url>http://www.apache.org/path/to/parent/child-artifact-id/</url>
  <scm>
    <connection>scm:my-scm:http://domain.org/base/child-artifact-id</connection>
    <developerConnection>scm:my-scm:https://domain.org/base/child-artifact-id/</developerConnection>

     * @param severity The severity level of the problem, may be {@code null} to default to
     *            {@link SettingsProblem.Severity#ERROR}.
     * @param source A hint about the source of the problem like a file path, may be {@code null}.
     * @param lineNumber The one-based index of the line containing the problem or {@code -1} if unknown.
     * @param columnNumber The one-based index of the column containing the problem or {@code -1} if unknown.

Si vas a la **UI de la documentación de la API** en `/docs` podrás ver la **documentación** de las cookies para tus *path operations*.

                            && ptv.getRawType() == List.class
                            && ptv.getActualTypeArguments()[0] == Path.class) {
                        result = res.getDispatchedPaths();
                    } else if (k == Dependency.class && v == Path.class) {
                        result = res.getDependencies();
                    }
                }
            } else {

     * creator of the problem, the general expectation is that the hint provides sufficient information to the user to
     * track the problem back to its origin. A concrete example for such a source hint can be the file path or URL from
     * which a POM was read.
     *
     * @return The hint about the source of the problem or an empty string if unknown, never {@code null}.
     */
    String getSource();

    /**

from starlette.datastructures import UploadFile as StarletteUploadFile


class UploadFile(StarletteUploadFile):
    """
    A file uploaded in a request.

    Define it as a *path operation function* (or dependency) parameter.

    If you are using a regular `def` function, you can use the `upload_file.file`
    attribute to access the raw standard Python file (blocking, not async), useful and