```Python hl_lines="1  11-21"
{!> ../../docs_src/security/tutorial007.py!}
```

////

这类似于：

```Python
if not (credentials.username == "stanleyjobson") or not (credentials.password == "swordfish"):
    # Return some error
    ...
```

但使用 `secrets.compare_digest()`，可以防御**时差攻击**，更加安全。

### 时差攻击

什么是**时差攻击**？

假设攻击者试图猜出用户名与密码。

他们发送用户名为 `johndoe`，密码为 `love123`  的请求。

然后，Python 代码执行如下操作：

```Python hl_lines="14"
{!../../docs_src/background_tasks/tutorial001.py!}
```

`.add_task()` 接收以下参数：

* 在后台运行的任务函数(`write_notification`)。
* 应按顺序传递给任务函数的任意参数序列(`email`)。
* 应传递给任务函数的任意关键字参数(`message="some notification"`)。

## 依赖注入

使用 `BackgroundTasks` 也适用于依赖注入系统，你可以在多个级别声明 `BackgroundTasks` 类型的参数：在 *路径操作函数* 里，在依赖中(可依赖)，在子依赖中，等等。

**FastAPI** 知道在每种情况下该做什么以及如何复用同一对象，因此所有后台任务被合并在一起并且随后在后台运行：

//// tab | Python 3.10+

    $env:PATH = [Environment]::GetEnvironmentVariable('PATH', 'Machine') + ';C:\tools\LLVM\bin'; \
    [Environment]::SetEnvironmentVariable('PATH', $env:PATH, 'Machine');

# Install MSYS2, and add some extra tools.
RUN (New-Object Net.WebClient).DownloadFile( \
         'https://repo.msys2.org/distrib/x86_64/msys2-base-x86_64-20240113.tar.xz', \
         'msys2.tar.xz'); \

	pconstants "istio.io/istio/cni/pkg/constants"
	"istio.io/istio/cni/pkg/pluginlistener"
	istiolog "istio.io/istio/pkg/log"
	"istio.io/istio/pkg/sleep"
)

// Just a composite of the CNI plugin add event struct + some extracted "args"
type CNIPluginAddEvent struct {
	Netns        string
	PodName      string
	PodNamespace string
	IPs          []IPConfig
}

// DEK is a data encryption key. It consists of a
// plaintext-ciphertext pair and the ID of the key
// used to generate the ciphertext.
//
// The plaintext can be used for cryptographic
// operations - like encrypting some data. The
// ciphertext is the encrypted version of the
// plaintext data and can be stored on untrusted
// storage.
type DEK struct {
	KeyID      string // Name of the master key

    // 256 characters long
    assertEquals(3500507768004279527L, fingerprint(Strings.repeat("test", 64).getBytes(UTF_8)));
  }

  public void testStringsConsistency() {
    for (String s : Arrays.asList("", "some", "test", "strings", "to", "try")) {
      assertEquals(HASH_FN.newHasher().putUnencodedChars(s).hash(), HASH_FN.hashUnencodedChars(s));
    }
  }

  public void testUtf8() {
    char[] charsA = new char[128];

    // The initial state corresponds to the ASCII string "somepseudorandomlygeneratedbytes",
    // big-endian encoded. There is nothing special about this value; the only requirement
    // was some asymmetry so that the initial v0 and v1 differ from v2 and v3.
    private long v0 = 0x736f6d6570736575L;
    private long v1 = 0x646f72616e646f6dL;
    private long v2 = 0x6c7967656e657261L;

import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;
import java.util.Map;

import org.apache.maven.api.model.Model;

/**
 * Handles serialization of a model into some kind of textual format like XML.
 *
 * @deprecated use {@link org.apache.maven.api.services.xml.ModelXmlFactory} instead
 */
@Deprecated(since = "4.0.0")
public interface ModelWriter {

    /**

import java.util.Optional;

import org.apache.maven.api.annotations.Experimental;
import org.apache.maven.api.annotations.Nonnull;

/**
 * The option of a command-line tool where to place the paths to some dependencies.
 * A {@code PathType} can identify the Java class-path, the Java module-path,
 * or another kind of path for another programming language for example.

```Python
    uvicorn.run(app, host="0.0.0.0", port=8000)
```

は実行されます。

---

そのモジュール (ファイル) をインポートした場合は、こうはなりません。

したがって、次のようなもう一つのファイル `importer.py` がある場合:

```Python
from myapp import app

# Some more code
```

`myapp.py` 内の自動変数には、値が `"__main __"` の変数 `__name__` はありません。

したがって、以下の行:

```Python
    uvicorn.run(app, host="0.0.0.0", port=8000)
```

は実行されません。

/// info | "情報"