## Classe `APIRoute` personalizada em um router { #custom-apiroute-class-in-a-router }

Você também pode definir o parâmetro `route_class` de uma `APIRouter`:

{* ../../docs_src/custom_request_and_route/tutorial003_py310.py hl[26] *}

Nesse exemplo, as *operações de rota* sob o `router` irão usar a classe `TimedRoute` personalizada, e terão um cabeçalho extra `X-Response-Time` na resposta com o tempo que levou para gerar a resposta:

 */
object Punycode {
  val PREFIX_STRING = "xn--"
  val PREFIX = PREFIX_STRING.encodeUtf8()

  private const val BASE = 36
  private const val TMIN = 1
  private const val TMAX = 26
  private const val SKEW = 38
  private const val DAMP = 700
  private const val INITIAL_BIAS = 72
  private const val INITIAL_N = 0x80

  /**

        request.writeBytesWireFormat(buffer, 0);

        // Read desired access from buffer (offset 24-27 after 8 bytes reserved)
        int readAccess = (buffer[24] & 0xFF) | ((buffer[25] & 0xFF) << 8) | ((buffer[26] & 0xFF) << 16) | ((buffer[27] & 0xFF) << 24);
        assertEquals(access, readAccess);
    }

    @Test
    @DisplayName("Test file attributes setter")
    void testSetFileAttributes() {

        dstIndex += 8;
        writeInt8(0L, dst, dstIndex);
        dstIndex += 8;
        /* Samba 2.2.7 needs ATTR_NORMAL
         */
        writeInt2(0x80 | attributes, dst, dstIndex);
        dstIndex += 2;
        /* 6 zeros observed with NT */
        writeInt8(0L, dst, dstIndex);
        dstIndex += 6;

        /* Also observed 4 byte alignment but we stick
         * with the default for jCIFS which is 2 */

"13.7.5 UNIMPLEMENTED"
"13.7.6 UNIMPLEMENTED"
"13.7.7 UNIMPLEMENTED"
"13.7.8 UNIMPLEMENTED"
"13.7.9 UNIMPLEMENTED"
"2.1 OK"
"2.10 OK"
"2.11 OK"
"2.2 OK"
"2.3 OK"
"2.4 OK"
"2.5 OK"
"2.6 OK"
"2.7 OK"
"2.8 OK"
"2.9 OK"
"3.1 OK"
"3.2 NON-STRICT"
"3.3 NON-STRICT"
"3.4 NON-STRICT"
"3.5 OK"
"3.6 OK"
"3.7 OK"
"4.1.1 OK"
"4.1.2 OK"
"4.1.3 NON-STRICT"
"4.1.4 NON-STRICT"

    } catch (e: ClassCastException) {
      // On android 8.0, socket.connect throws a ClassCastException due to a bug
      // see https://issuetracker.google.com/issues/63649622
      if (Build.VERSION.SDK_INT == 26) {
        throw IOException("Exception in connect", e)
      } else {
        throw e
      }
    }
  }

  override fun newSSLContext(): SSLContext {
    StrictMode.noteSlowCall("newSSLContext")

Und dann ruft **FastAPI** diese Überschreibung anstelle der ursprünglichen Abhängigkeit auf.

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip | Tipp

Sie können eine Überschreibung für eine Abhängigkeit festlegen, die an einer beliebigen Stelle in Ihrer **FastAPI**-Anwendung verwendet wird.

E então o **FastAPI** chamará a sobreposição no lugar da dependência original.

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip | Dica

Você pode definir uma sobreposição de dependência para uma dependência que é utilizada em qualquer lugar da sua aplicação **FastAPI**.

对于这些用例，**FastAPI** 应用支持 `app.dependency_overrides` 属性，该属性就是**字典**。

要在测试时覆盖原有依赖项，这个字典的键应当是原依赖项（函数），值是覆盖依赖项（另一个函数）。

这样一来，**FastAPI** 就会调用覆盖依赖项，不再调用原依赖项。

{* ../../docs_src/dependency_testing/tutorial001_an_py310.py hl[26:27,30] *}

/// tip | 提示

**FastAPI** 应用中的任何位置都可以实现覆盖依赖项。

原依赖项可用于*路径操作函数*、*路径操作装饰器*（不需要返回值时）、`.include_router()` 调用等。

FastAPI 可以覆盖这些位置的依赖项。

///

然后，使用 `app.dependency_overrides` 把覆盖依赖项重置为空**字典**：

    </AssumedRoleUser>
    <Credentials>
      <AccessKeyId>Y4RJU1RNFGK48LGO9I2S</AccessKeyId>
      <SecretAccessKey>sYLRKS1Z7hSjluf6gEbb9066hnx315wHTiACPAjg</SecretAccessKey>
      <Expiration>2019-08-08T20:26:12Z</Expiration>