Sie können Header-Parameter genauso definieren, wie Sie `Query`-, `Path`- und `Cookie`-Parameter definieren.

## `Header` importieren { #import-header }

Importieren Sie zuerst `Header`:

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

## `Header`-Parameter deklarieren { #declare-header-parameters }

Deklarieren Sie dann die Header-Parameter mit derselben Struktur wie bei `Path`, `Query` und `Cookie`.

# Header 参数

定义 `Header` 参数的方式与定义 `Query`、`Path`、`Cookie` 参数相同。

## 导入 `Header`

首先，导入 `Header`：

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

## 声明 `Header` 参数

然后，使用和 `Path`、`Query`、`Cookie` 一样的结构定义 header 参数。

第一个值是默认值，还可以传递所有验证参数或注释参数：

{* ../../docs_src/header_params/tutorial001_an_py310.py hl[9] *}

/// note | 技术细节

`Header` 是 `Path`、`Query`、`Cookie` 的**兄弟类**，都继承自共用的 `Param` 类。

En esos casos, puedes usar el parámetro del decorador de path operation `response_model` en lugar del tipo de retorno.

Puedes usar el parámetro `response_model` en cualquiera de las *path operations*:

* `@app.get()`
* `@app.post()`
* `@app.put()`
* `@app.delete()`
* etc.

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

import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.function.Supplier;

import org.apache.maven.api.Language;
import org.apache.maven.api.ProducedArtifact;
import org.apache.maven.api.Project;

import os
import shutil

from fastapi.testclient import TestClient


def test_main():
    if os.path.isdir("./static"):  # pragma: nocover
        shutil.rmtree("./static")
    if os.path.isdir("./templates"):  # pragma: nocover
        shutil.rmtree("./templates")
    shutil.copytree("./docs_src/templates/templates/", "./templates")
    shutil.copytree("./docs_src/templates/static/", "./static")

from pathlib import Path

from fastapi.testclient import TestClient

from docs_src.custom_response import tutorial008_py39
from docs_src.custom_response.tutorial008_py39 import app

client = TestClient(app)


def test_get(tmp_path: Path):
    file_path: Path = tmp_path / "large-video-file.mp4"
    tutorial008_py39.some_file_path = str(file_path)
    test_content = b"Fake video bytes"
    file_path.write_bytes(test_content)

If you have quite some technical knowledge (coroutines, threads, blocking, etc.) and are curious about how FastAPI handles `async def` vs normal `def`, go ahead.

///

### Path operation functions { #path-operation-functions }

When you declare a *path operation function* with normal `def` instead of `async def`, it is run in an external threadpool that is then awaited, instead of being called directly (as it would block the server).

     *
     * @since 4.0.0
     */
    MavenExecutionRequest setTopDirectory(Path topDirectory);

    /**
     * Gets the directory of the topmost project being built, usually the current directory or the
     * directory pointed at by the {@code -f/--file} command line argument.
     *
     * @since 4.0.0
     */
    Path getTopDirectory();

    /**
     * Sets the root directory of the project.
     *

    public InvalidProjectModelException(String projectId, String message, File pomLocation) {
        super(projectId, message, pomLocation);
    }

    /**
     * @param projectId
     * @param pomLocation      absolute path of the pom file
     * @param message
     * @param validationResult
     * @deprecated use {@link File} constructor for pomLocation
     */
    @Deprecated
    public InvalidProjectModelException(

  <name>Model urls inheritance test child</name>
  <description>Flat directory structure case: module = ../child-artifact-id + child directory path == child-artifact-id</description>

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