這個命令會建立或修改一些[環境變數](environment-variables.md){.internal-link target=_blank}，這些環境變數將在接下來的指令中可用。

其中之一是 `PATH` 變數。

/// tip

你可以在 [環境變數](environment-variables.md#path-environment-variable){.internal-link target=_blank} 部分了解更多關於 `PATH` 環境變數的內容。

///

啟用虛擬環境會將其路徑 `.venv/bin`（在 Linux 和 macOS 上）或 `.venv\Scripts`（在 Windows 上）加入到 `PATH` 環境變數中。

假設在啟用環境之前，`PATH` 變數看起來像這樣：

//// tab | Linux, macOS

```plaintext

这个命令会创建或修改一些[环境变量](environment-variables.md){.internal-link target=_blank}，这些环境变量将在接下来的命令中可用。

其中之一是 `PATH` 变量。

/// tip

你可以在 [环境变量](environment-variables.md#path-environment-variable){.internal-link target=_blank} 部分了解更多关于 `PATH` 环境变量的内容。

///

激活虚拟环境会将其路径 `.venv/bin`（在 Linux 和 macOS 上）或 `.venv\Scripts`（在 Windows 上）添加到 `PATH` 环境变量中。

假设在激活环境之前，`PATH` 变量看起来像这样：

//// tab | Linux, macOS

```plaintext

* o dependable
* o dependant

* limitado por I/O
* limitado por CPU
* concorrência
* paralelismo
* multiprocessamento

* a env var
* a variável de ambiente
* o `PATH`
* a variável `PATH`

* a autenticação
* o provedor de autenticação
* a autorização
* o formulário de autorização
* o provedor de autorização
* o usuário se autentica
* o sistema autentica o usuário

    assertThat(request.requestLine).isEqualTo(
      "GET /a/deep/path?key=foo%20bar HTTP/1.1",
    )
    val requestUrl = request.url
    assertThat(requestUrl.scheme).isEqualTo("http")
    assertThat(requestUrl.host).isEqualTo(server.hostName)
    assertThat(requestUrl.port).isEqualTo(server.port)
    assertThat(requestUrl.encodedPath).isEqualTo("/a/deep/path")
    assertThat(requestUrl.queryParameter("key")).isEqualTo("foo bar")
  }

{* ../../docs_src/bigger_applications/app_an_py39/routers/users.py hl[1,3] title["app/routers/users.py"] *}

### *Operações de Rota* com `APIRouter` { #path-operations-with-apirouter }

E então você o utiliza para declarar suas *operações de rota*.

Utilize-o da mesma maneira que utilizaria a classe  `FastAPI`:

<div class="termy">

```console
$ <font color="#4E9A06">fastapi</font> dev <u style="text-decoration-style:single">main.py</u>
<font color="#3465A4">INFO    </font> Using path <font color="#3465A4">main.py</font>
<font color="#3465A4">INFO    </font> Resolved absolute path <font color="#75507B">/home/user/code/awesomeapp/</font><font color="#AD7FA8">main.py</font>

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package main

import (
	"context"
	"crypto/md5"
	"flag"
	"fmt"
	"io"
	"log"
	"net/url"
	"os"
	"path"
	"strconv"
	"strings"
	"time"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
)

var (
	endpoint, accessKey, secretKey string
	minModTimeStr                  string

def create_invoice(invoice: Invoice, callback_url: Union[HttpUrl, None] = None):
    """
    Create an invoice.

    This will (let's imagine) let the API user (some external developer) create an
    invoice.

    And this path operation will:

    * Send the invoice to the client.
    * Collect the money from the client.
    * Send a notification back to the API user (the external developer), as a callback.

{* ../../docs_src/schema_extra_example/tutorial002_py310.py hl[2,8:11] *}

## `examples` im JSON-Schema – OpenAPI { #examples-in-json-schema-openapi }

Bei Verwendung von:

* `Path()`
* `Query()`
* `Header()`
* `Cookie()`
* `Body()`
* `Form()`
* `File()`

}

func (a badDisk) AppendFile(ctx context.Context, volume string, path string, buf []byte) error {
	return errFaultyDisk
}

func (a badDisk) ReadFileStream(ctx context.Context, volume, path string, offset, length int64) (io.ReadCloser, error) {
	return nil, errFaultyDisk
}

func (a badDisk) CreateFile(ctx context.Context, origvolume, volume, path string, size int64, reader io.Reader) error {
	return errFaultyDisk
}