},
			shouldFail: false,
		},
		// Fail if header key is not in canonicalized form
		{
			header: http.Header{
				"x-amz-meta-appid": []string{"amz-meta"},
			},
			metadata: map[string]string{
				"x-amz-meta-appid": "amz-meta",
			},
			shouldFail: false,
		},
		// Support multiple values
		{
			header: http.Header{
				"x-amz-meta-key": []string{"amz-meta1", "amz-meta2"},
			},

                                "in": "header",
                                "required": True,
                                "schema": {"type": "string", "title": "Host"},
                            },
                            {
                                "name": "save_data",
                                "in": "header",
                                "required": True,

	// Retrieve the scheme from X-Forwarded-Proto.
	if proto := r.Header.Get(xForwardedProto); proto != "" {
		scheme = strings.ToLower(proto)
	} else if proto = r.Header.Get(xForwardedScheme); proto != "" {
		scheme = strings.ToLower(proto)
	} else if proto := r.Header.Get(forwarded); proto != "" {
		// match should contain at least two elements if the protocol was
		// specified in the Forwarded header. The first element will always be

		return code
	}
	return -1
}

func fwdHeadersToS3(h http.Header, w http.ResponseWriter) {
	const trim = "x-amz-fwd-header-"
	for k, v := range h {
		if stringsHasPrefixFold(k, trim) {
			w.Header()[k[len(trim):]] = v
		}
	}
}

func fwdStatusToAPIError(resp *http.Response) *APIError {
	if status := resp.Header.Get(xhttp.AmzFwdStatus); status != "" && StatusCode(status) > -1 {
		apiErr := &APIError{

		}
	}
}

var fromContentMD5Tests = []struct {
	Header     http.Header
	ETag       ETag
	ShouldFail bool
}{
	{Header: http.Header{}, ETag: nil}, // 0
	{Header: http.Header{"Content-Md5": []string{"1B2M2Y8AsgTpgAmY7PhCfg=="}}, ETag: must("d41d8cd98f00b204e9800998ecf8427e")},                             // 1

from fastapi import FastAPI, Header
from pydantic import BaseModel

app = FastAPI()


class CommonHeaders(BaseModel):
    class Config:
        extra = "forbid"

    host: str
    save_data: bool
    if_modified_since: str | None = None
    traceparent: str | None = None
    x_tag: list[str] = []


@app.get("/items/")
async def read_items(headers: Annotated[CommonHeaders, Header()]):

    val derReader = DerReader(buffer)

    derReader.read("test") { header ->
      assertThat(header.tag).isEqualTo(2L)
      assertThat(header.tagClass).isEqualTo(DerHeader.TAG_CLASS_CONTEXT_SPECIFIC)
      assertThat(header.length).isEqualTo(7L)

      derReader.read("test") { header ->
        assertThat(header.tag).isEqualTo(3L)
        assertThat(header.tagClass).isEqualTo(DerHeader.TAG_CLASS_APPLICATION)

		clientIP = ipv6fix(clientIP)
		if req.Header.Get(xRealIP) == "" {
			req.Header.Set(xRealIP, clientIP)
		}
	}

	xfProto := req.Header.Get(xForwardedProto)
	if xfProto == "" {
		if req.TLS != nil {
			req.Header.Set(xForwardedProto, "https")
		} else {
			req.Header.Set(xForwardedProto, "http")
		}
	}

	if xfPort := req.Header.Get(xForwardedPort); xfPort == "" {

async def read_main(item_id: str, x_token: str = Header()):
    if x_token != fake_secret_token:
        raise HTTPException(status_code=400, detail="Invalid X-Token header")
    if item_id not in fake_db:
        raise HTTPException(status_code=404, detail="Item not found")
    return fake_db[item_id]


@app.post("/items/", response_model=Item)
async def create_item(item: Item, x_token: str = Header()):
    if x_token != fake_secret_token:

	// Reference:
	//	http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html#tag_20_92_13_06
	FormatUSTAR

	// FormatPAX represents the PAX header format defined in POSIX.1-2001.
	//
	// PAX extends USTAR by writing a special file with Typeflag TypeXHeader
	// preceding the original header. This file contains a set of key-value
	// records, which are used to overcome USTAR's shortcomings, in addition to