import jwt
from fastapi import Depends, FastAPI, HTTPException, Security, status
from fastapi.security import (
    OAuth2PasswordBearer,
    OAuth2PasswordRequestForm,
    SecurityScopes,
)
from jwt.exceptions import InvalidTokenError
from pwdlib import PasswordHash
from pydantic import BaseModel, ValidationError

# to get a string like this run:
# openssl rand -hex 32

    // Escapers operate on characters: no characters, no escaping.
    Assert.assertEquals("", escaper.escape(""));
    // Assert that escapers throw null pointer exceptions.
    try {
      escaper.escape((String) null);
      Assert.fail("exception not thrown when escaping a null string");
    } catch (NullPointerException e) {
      // pass
    }
  }

  /**

Creamos una `HTTPException` que podemos reutilizar (`raise`) más tarde en varios puntos.

En esta excepción, incluimos los scopes requeridos (si los hay) como un string separado por espacios (usando `scope_str`). Ponemos ese string que contiene los scopes en el header `WWW-Authenticate` (esto es parte de la especificación).

     * so we only verify its acceptance here.
     */
    @Test
    void testConstructor() {
        // The constructor should not throw any exceptions with valid inputs.
        new DosFileFilter("*.*", SmbFile.ATTR_ARCHIVE);
        new DosFileFilter("?", SmbFile.ATTR_DIRECTORY);
        new DosFileFilter("file.txt", SmbFile.ATTR_READONLY | SmbFile.ATTR_HIDDEN);
    }

      // actual response status.
      code == 100 -> true

      // Handle Processing (102) & Early Hints (103) and any new codes without failing
      // 100 and 101 are the exceptions with different meanings
      // But Early Hints not currently exposed
      code in (102 until 200) -> true

      else -> false
    }

### Hintergrundtasks und Abhängigkeiten mit `yield`, Technische Details { #background-tasks-and-dependencies-with-yield-technical-details }

import jwt
from fastapi import Depends, FastAPI, HTTPException, Security, status
from fastapi.security import (
    OAuth2PasswordBearer,
    OAuth2PasswordRequestForm,
    SecurityScopes,
)
from jwt.exceptions import InvalidTokenError
from pwdlib import PasswordHash
from pydantic import BaseModel, ValidationError

# to get a string like this run:
# openssl rand -hex 32

        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join();
        }

        // Then - no exceptions should have been thrown
        assertTrue(true); // If we reach here, no exceptions occurred
    }

    /**
     * Test consistency across multiple calls
     */
    @Test
    @DisplayName("Test consistency across multiple calls")

            // Wait for completion
            for (Thread t : threads) {
                t.join();
            }

            // Verify thread safety - no unexpected exceptions
            assertEquals(0, exceptionCount.get(), "Should not have unexpected exceptions");

            // At least some threads should complete successfully
            assertTrue(successfulThreads.get() > 0, "At least some threads should complete successfully");

一般情况下可能不会需要在代码中直接使用响应头。

但对于某些高级应用场景，还是需要添加自定义响应头：

{* ../../docs_src/handling_errors/tutorial002.py hl[14] *}

## 安装自定义异常处理器

添加自定义处理器，要使用 [Starlette 的异常工具](https://www.starlette.dev/exceptions/)。

假设要触发的自定义异常叫作 `UnicornException`。

且需要 FastAPI 实现全局处理该异常。

此时，可以用 `@app.exception_handler()` 添加自定义异常控制器：

{* ../../docs_src/handling_errors/tutorial003.py hl[5:7,13:18,24] *}