If for some reason you need to disable automatic conversion of underscores to hyphens, set the parameter `convert_underscores` of `Header` to `False`:

{* ../../docs_src/header_params/tutorial002_an_py310.py hl[10] *}

/// warning

Before setting `convert_underscores` to `False`, bear in mind that some HTTP proxies and servers disallow the usage of headers with underscores.

///

## Duplicate headers { #duplicate-headers }

            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## Disable Convert Underscores { #disable-convert-underscores }

The same way as with regular header parameters, when you have underscore characters in the parameter names, they are **automatically converted to hyphens**.

            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## 禁用下划线转换 { #disable-convert-underscores }

与常规的 header 参数相同，当参数名中包含下划线时，会**自动转换为连字符**。

例如，如果你的代码中有一个名为 `save_data` 的 header 参数，那么预期的 HTTP 头将是 `save-data`，并且在文档中也会以这种形式显示。

如果由于某些原因你需要禁用这种自动转换，你也可以在用于 header 参数的 Pydantic 模型中进行设置。

  static class EmptyTest {}

  static class EmptyTests {}

  static class EmptyTestSuite {}

  static class Foo {}

  @SuppressWarnings("IdentifierName") // We're testing that we ignore classes with underscores.
  static class Foo_Bar {}

  public static class PublicFoo {}

  static class FooTest {
    @SuppressWarnings("unused") // accessed reflectively
    public void testPublic() {}

            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## 밑줄 변환 비활성화하기 { #disable-convert-underscores }

일반적인 헤더 매개변수와 마찬가지로, 매개변수 이름에 밑줄 문자가 있으면 **자동으로 하이픈으로 변환**됩니다.

예를 들어, 코드에 `save_data` 헤더 매개변수가 있으면, 기대되는 HTTP 헤더는 `save-data`이고, 문서에서도 그렇게 표시됩니다.

어떤 이유로든 이 자동 변환을 비활성화해야 한다면, 헤더 매개변수용 Pydantic 모델에서도 비활성화할 수 있습니다.

            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

## 停用底線轉換 { #disable-convert-underscores }

與一般標頭參數相同，當參數名稱包含底線字元時，會自動轉換為連字號。

例如，若在程式碼中有標頭參數 `save_data`，實際期望的 HTTP 標頭為 `save-data`，在文件中也會如此顯示。

如果因某些原因需要停用這個自動轉換，你也可以在標頭參數的 Pydantic 模型上設定。

  static class EmptyTest {}

  static class EmptyTests {}

  static class EmptyTestSuite {}

  static class Foo {}

  @SuppressWarnings("IdentifierName") // We're testing that we ignore classes with underscores.
  static class Foo_Bar {}

  public static class PublicFoo {}

  static class FooTest {
    @SuppressWarnings("unused") // accessed reflectively
    public void testPublic() {}

    }

    @Test
    public void test_isFileSystemPath_gcs_various_bucket_names() {
        // GCS bucket names can contain lowercase letters, numbers, hyphens, underscores, and periods
        assertTrue(goAction.isFileSystemPath("gcs://my-bucket/file"));
        assertTrue(goAction.isFileSystemPath("gcs://my.bucket/file"));
        assertTrue(goAction.isFileSystemPath("gcs://my_bucket/file"));

     * <p>ASCII characters in the part are expected to be valid per RFC 1035, with underscore also
     * being allowed due to widespread practice.
     */

    String asciiChars = CharMatcher.ascii().retainFrom(part);

    if (!PART_CHAR_MATCHER.matchesAllOf(asciiChars)) {
      return false;
    }

    // No initial or final dashes or underscores.

    if (DASH_MATCHER.matches(part.charAt(0))

        value = "${123}";
        assertEquals("numeric", ResourceUtil.resolve(value));

        // Test with underscores in property names
        System.setProperty("test_var", "underscore");
        value = "${test_var}";
        assertEquals("underscore", ResourceUtil.resolve(value));

        // Clean up test properties
        System.clearProperty("var1");
        System.clearProperty("var2");