private int numOfFragments;
    /** The offset for fragment positioning. */
    private int fragmentOffset;
    /** Custom pre-tags for highlighting (null uses OpenSearch defaults). */
    private String[] preTags;
    /** Custom post-tags for highlighting (null uses OpenSearch defaults). */
    private String[] postTags;

    /**

        result = virtualHostHelper.processVirtualHost(s -> "processed_" + s, "default");
        assertEquals("processed_site1", result); // Still site1 due to header precedence

        // Test with custom header
        request.addHeader("Custom-Header", "custom.value");
        result = virtualHostHelper.processVirtualHost(s -> "processed_" + s, "default");
        assertEquals("processed_site1", result); // Still site1 due to header precedence
    }

        "uid": "${DS_PROMETHEUS}"
      },
      "description": "",
      "fieldConfig": {
        "defaults": {
          "color": {
            "mode": "palette-classic"
          },
          "custom": {
            "hideFrom": {
              "legend": false,
              "tooltip": false,
              "viz": false
            }
          },
          "mappings": [
            {

///

## Custom Headers { #custom-headers }

Keep in mind that custom proprietary headers can be added [using the `X-` prefix](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers).

def custom_openapi():
    if app.openapi_schema:
        return app.openapi_schema
    openapi_schema = get_openapi(
        title="Custom title",
        version="2.5.0",
        summary="This is a very custom OpenAPI schema",
        description="Here's a longer description of the custom **OpenAPI** schema",
        routes=app.routes,
    )
    openapi_schema["info"]["x-logo"] = {

@app.middleware("http")
async def custom_middleware(
    request: Request, call_next: Callable[[Request], Awaitable[Response]]
):
    response = await call_next(request)
    response.headers["custom"] = "foo"
    return response


@app.get("/user", dependencies=[Depends(set_up_request_state_dependency)])
def get_user():
    request_state = legacy_request_state_context_var.get()
    assert request_state

            Doc(
                """
                The default response class to be used.

                Read more in the
                [FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/#default-response-class).

                **Example**

                ```python
                from fastapi import FastAPI

///

## Returning a custom `Response` { #returning-a-custom-response }

The example above shows all the parts you need, but it's not very useful yet, as you could have just returned the `item` directly, and **FastAPI** would put it in a `JSONResponse` for you, converting it to a `dict`, etc. All that by default.

Now, let's see how you could use that to return a custom response.

            type[APIRoute],
            Doc(
                """
                Custom route (*path operation*) class to be used by this router.

                Read more about it in the
                [FastAPI docs for Custom Request and APIRoute class](https://fastapi.tiangolo.com/how-to/custom-request-and-route/#custom-apiroute-class-in-a-router).
                """
            ),
        ] = APIRoute,

### Custom Generate Unique ID Function { #custom-generate-unique-id-function }

FastAPI uses a **unique ID** for each *path operation*, which is used for the **operation ID** and also for the names of any needed custom models, for requests or responses.

You can customize that function. It takes an `APIRoute` and outputs a string.